Form manual for chemical history protocols

Preliminary note

The explanatory texts on this page are linked to the form for recording history protocols of chemical reactions and may therefore read alike in places. They were generated with the help of AI and subsequently edited. Despite this review, errors and misleading formulations must be expected.

The structure of molecules determines whether reactants can react with one another. The phases of the substances determine whether and how quickly the reactants find each other. In the history protocol, great care should be taken in recording phases. Perhaps the linked model of the ideal substance that the author has developed can help to form a picture of how substances are transported in the reaction mixture, and strengthen the courage to use affine substances as catalysts.

This form is a further development of the doctoral thesis from 1994. In the form, the recording of separation methods has been developed further systematically, although the form is unfortunately not always one-to-one, as the separation method recrystallisation shows, which can also be described as a method with four separate separation steps (dissolving, filtering, precipitating, filtering). First ideas have also been developed on how the parallelism of work in the laboratory can be represented and recorded in a reasonably simple way.

You will find at the following Error information page link Notes on where and how to report errors.

Ideas, suggestions and criticism are welcome – via the form for new enquiries.

Table of contents (All entries of this page — tap to open)

1 Session and server

1.1 Initials and person responsible

The two fields at the head of the form say who is working here. The initials are the short form — at most five characters, and they mark every line of the log below. The full name is what makes that mark resolvable a year later, when nobody in the room remembers who “MK” was.

Nothing can be entered before both fields are filled. The list of blocks lies under a veil until then, and the veil stops the keyboard as well as the mouse. That is deliberately in the way: an entry that nobody answers for looks like a record but is not one, and once it is in the archive it cannot be told apart from a record that somebody stands behind.

The picker beside the two fields offers pairs this browser has seen before and takes one over in a single step — both fields at once, never the initials alone with somebody else’s name left standing next to them. That list lives in this browser and nowhere else; it goes to no server, and “Forget this pair” removes an entry from it for good.

The button Manage editors under the fields opens two lists. The first holds the pairs this browser keeps, each with its own “Forget this pair” button. From the second person on, the second lists the earlier editors in this form with the moment each of them took over. That list belongs to the record, not to the browser: it travels in the data ZIP and can be read there. “Reset list” starts it afresh after a question: only the pair standing in the fields is kept. The removed list is written into the log as a line of its own (field operator-history-reset) — in full, not cut at 200 characters, and with the initials of whoever reset it. The record therefore still says who worked on it.

The same holds for the log, a hidden field that nobody types into. Every manual entry and every button press is written into it as one line — moment, initials, field, value. A line whose field begins with click: is a button press, not an entry.

What the log does not do: it records what the form saw, not what anyone meant. A correction two seconds later is a second line, not a replacement of the first. Values are cut at 200 characters and the log at 5000 lines, so a long free text stands in it shortened — the record itself is where it is read in full. Fields the form computes (a Kelvin value, a molar amount) are not logged: nobody entered them. And a password is never written down, whatever it is named — the log travels in the data ZIP, and a secret with a timestamp beside it would be a leak with a date on it.

1.2 Experiment name

The experiment name says what this record is. It is a required entry and heads the suggested name of every file the form saves on the local machine (<date code>_<experiment name>). On the server it is one of the six recognition fields.

Scheme: a name composed of several parts is easier to find again later than a free title. A proven pattern is a letter for the kind of work, a hyphen, and then the target substance or substances:

A — analysis
S — synthesis
M — preparing a mixture or solution
P — preparation, preliminary work such as drying
E — extraction

Examples:

A-ZnCuNaClKaolinit — analysis of a mixture of zinc, copper, sodium chloride and kaolinite on the semi-micro scale
S-Acetylsalicylsaeure — synthesis of acetylsalicylic acid from salicylic acid
E-Coffein — extraction of caffeine from tea
M-NaOH01molar — preparing a sodium hydroxide solution of 0.1 mol/l

What the parts look like in detail depends on the setting — a research laboratory needs other distinctions than a school practical. Prefer names that give meaning: names that describe the experiment instead of merely filing it. PraktikumVersuch2Tag2 says when the experiment came up in the course, but not what was done.

Umlauts, spaces and special characters become underscores in the file name. Avoiding them (ae instead of ä) gives file names that look exactly like the experiment name.

1.3 Version

The version tells several runs or revisions of the same experiment apart. It is a required entry. On the server, experiment name and version together with the other recognition fields form the address of the record — a new version therefore creates a new record instead of overwriting the old one.

Scheme: three notations have proven themselves:

Version number — 1, 2, 2.1: for planned repetitions and revisions.
Version letter — a, b, c: for parallel runs of the same day, such as two groups on the same experiment.
Date code — YYYYMMDDhhmm, for example 202609191430 for 19 September 2026, 14:30: for a chronological series.

The date code runs in descending order — year, month, day, hour, minute, each with a leading zero. Only in this order does a file list sort the versions into their time sequence by itself, and a date can be found again without conversion. 19.09.2026, by contrast, puts the nineteenth of every month side by side.

1.4 Server recognition data

These six fields are the address of a record on the server. City, organisation, name, experiment, version and password are hashed together; the result is the only name under which an uploaded record can be found again. Whoever can reproduce all six can fetch the record — whoever cannot, cannot. Experiment and version stand above the fold, because they also name the record on the local machine.

The entries are optional. Nothing in this form needs a server. Purely local work means filling in only what belongs on the protocol itself.

Where which data is kept:

In the browser (localStorage, this browser on this machine): the whole form content, the attachments, the own partial forms and the material stock. Nothing of it leaves the machine until a button is pressed.
In files on the local machine: whatever is saved by hand — data ZIP, file ZIP, teilformulare.json.
On the server, and only after “save to server”: the two archives, plus one bookkeeping row per archive. That row holds the hash of the six fields, a separate hash of the three author fields, the experiment and version in the clear, the storage path — and a journal of accesses with IP addresses.

What the server never sees in the clear: city, organisation, name and password. They only ever enter a hash.

How to judge the security: there is no login. The protection is that the address is hard to guess — security through obscurity, nothing more. It keeps a passer-by out; it does not keep out anyone who knows or can guess the six entries. The purpose of the store is scientific: to compare yields against changed reaction conditions across many runs. The many fields exist so that records stay distinguishable, not so that anybody is identified.

Therefore: no confidential data belongs here — no unpublished results that must be kept back, no third-party data, no personal data, no password used elsewhere. Every entry can be overwritten by anyone who can form the same address. Only correct data belongs in the store; otherwise the record is to be marked as deletable.

1.5 No contribution to the research; delete from the server

This box answers one single question: is the uploaded record to go into the research on reaction conditions?

Ticked means: no contribution. At upload the server notes the moment the deadline runs out, and a scheduled job then deletes the archives and the bookkeeping row. For that record the store is no more than a halfway house for handing it on — to your own supervisor, say. Unticked means: the record stays and may be evaluated. The mark is set at upload time and applies to that upload.

Why two times are named. The deadline deletes nothing by itself; it only marks. The deletion happens at the next run of the job reactionlog:purge-expired-records, and that one is scheduled daily. Between the deadline and the deletion there is therefore up to one more day. The second, longer number is the reliable one: before it the record is certainly still there, after it certainly gone.

What the collection is for. The question is: which reaction condition changes the yield — and by how much? Not which synthesis works, but what it is down to when the same procedure ends twice in two different ways.

Why student syntheses serve that question. A research preparation is a poor data point for it: there every condition is deliberately held constant, and the number of repetitions stays small. The teaching lab is the opposite case. The same procedure is carried out by many hands, and the conditions scatter unintentionally — room temperature and humidity, stirring time, degree of drying and drying agent, exclusion of light, inert gas, age and purity of the substances used, the experience of the person at the bench. Precisely this involuntary scatter is the raw material of a statistical evaluation: without variation in the cause no effect can be measured.

What the numbers buy. A course with a few dozen participants delivers more repetitions of the same procedure per term than a single working group gathers in years. Across several terms and several institutions this grows into a sample in which an effect of a few percentage points can be separated from the noise — and in which absent effects become visible too. That a condition a procedure expressly insists on changes nothing about the yield is a result nobody else publishes.

What is evaluated. Yield, purity and characteristic values against the recorded conditions — amount, temperature, pressure, humidity, mixing, darkness, inert gas, drying. For that it counts not only that something is entered but how completely: a condition left blank is not a measurement but a gap, and gaps are the commonest reason for a protocol to drop out of an evaluation.

Why a wrong figure is expensive. A sample tolerates scatter, but not invented values: a single grossly wrong record shifts a mean further than ten right ones hold it. Since there is no login, nobody can come back and tidy up. A trial run, a set of figures not yet checked, or an upload made to test the mechanism therefore belongs ticked — it then goes by itself.

What the box does not do:

It deletes nothing in the browser and nothing on the local machine. The protocol stays where it is.
It is no protection. Within the deadline the record can be fetched and overwritten by anyone who can form its address.
It does not make the record anonymous. Whoever writes a name into the protocol uploads it along with the rest.

Re-uploading decides afresh. Uploading the same record again writes the mark anew: an upload without the tick removes the deadline of the previous one, an upload with it starts the deadline over.

Deletion is final — there is no wastebasket.

On this installation the deadline is 24 h; because the purge job runs once a day, a marked record is gone after 48 h at the latest. The purge job reactionlog:purge-expired-records demonstrably runs here — its last run was on 2026-10-12 04:00.

1.6 Manage locally

Here the protocol is written to files on this machine or read back from them. Reading in replaces the form on the screen.

Save data ZIP: the whole form content (state.json) and the protocol as text. It holds the head entries — only pass it on where they belong.
Save file ZIP: the uploaded files, one folder per subform and field. It is read in after the data ZIP, because only the data ZIP creates the fields.
Save server ZIP: both archives in one file (data.zip, files.zip), the way “Save to server” sends them to the server. “Load server ZIP” reads the data first, then the files.

1.7 Store on the server

Save to server files the data archive and the file archive under the address formed from the six server recognition data. Load from server fetches both back with the same six entries. Check combination only asks whether the address is already taken and changes nothing.

An older state under the same address is set aside as a backup copy. With the deletion mark the record is removed after 24 hours. Without a server, the same content can be saved as “Save server ZIP” under “Manage locally”.

1.8 Quality criteria

The quality criteria decide which entries of a subform count as must or should; the plugin delivers them.

Load local quality criteria file (JSON) replaces them only in this browser tab and only until the tab is closed. Save local quality criteria file (JSON) writes the criteria in force, with the form version, to a file; adapted and uploaded by the operator, it applies to everyone.

1.9 Templates for subforms

A template is a filled subform under a name of its own. It is saved at the block through the gear and kept in this browser.

Here whole collections are moved: Export writes the templates of one subform, or all of them, to a file; Import adds to the collection from such a file, replacing templates of the same name; Delete thins it out. Reload appears where the page brings a collection of its own, and reads it in again.

1.10 Protocols in this browser

The browser keeps several protocols side by side. The one on the screen is saved continuously.

Load over loads another protocol into this form; the one standing here stays saved. Delete removes a protocol from the browser; if it is still open in another tab, it writes itself back on its next save. “Delete all stored data” under “Discard” removes all of them at once.

1.11 Discard

Three deletions that reach differently far. None can be undone; whatever should remain is to be saved as a file first. Records on the server are not touched.

Delete the form: empties the protocol on the screen together with its head entries. Other protocols, templates and materials stay.
Delete all stored data: removes all protocols, all templates for subforms, the material stock and the stored editors from this browser. A warning comes first; afterwards the page reloads and sets up its delivered templates and materials again.
Delete settings and cookies: resets the bright/dark display, the remembered start view of the subforms and the state of the menu, and deletes the cookies of the page that a script can read. The display is in fact not kept in a cookie but in the storage of the browser; it is reset here all the same. A warning comes first; afterwards the page reloads.

↑ To the table of contents

2 Separation

2.1 Short notation and overview of the separation methods

The short notation is a learning aid still under development that attempts to categorise separation methods systematically. The example ◇/K(c),μ/~#T\⊕ reads as follows: the crystalline phase (◇/…) remains behind as the stationary phase once the concentration equilibrium (K(c)) and the filtration (μ) have been applied — shown by …/K(c),μ/… —, while the mobile phase carried out of the separation system is liquid (…/~#…). The temperature was varied (…#T\…), and auxiliary substances (…\⊕) were used.

Structure: stat./principle/mob.#parameters\process-params — the stationary main phase on the left, the mobile one on the right, the separation principle in between; the decisive separation quantity is named in the descriptions; after # follow the measurable driving quantities, after \ the process parameters (mode of operation, auxiliary substances). The target fraction is marked underlined in the symbol, according to whether the mobile phase or the stationary phase contains the target substance. For the mobile phase an intermediate phase may be listed in brackets, as for example in distillation. Several short notations joined by → describe a combined method made of separation steps that run one after another (e. g. dissolving → filtration → crystallising out = recrystallisation); the combined short symbol names the phases involved with +. Alternative, equivalent notations of the same method (e. g. one-stage vs. two-stage, batch vs. continuous), or one notation per target fraction (e. g. target filtrate vs. target filter residue), are separated by ||; a horizontal double arrow ⇄ after \ marks counter-current/continuous operation (a process parameter, not a driving quantity).

Phase symbols (stationary / mobile)

◇ — crystal: solid, regularly ordered phase.
↓ — solid: solid matter or bulk material.
∴ — colloidal: very finely divided suspended phase.
~ — liquid: liquid phase.
🜄 — water: aqueous phase.
⇅ — critical: supercritical fluid.
↑ — gaseous: gas or vapour phase.
↯ — plasma.
? — undefined/special: no material phase laid down.

Separation principle symbols

ρ — density: separation in a gravity or centrifugal field.
aρ — density in an acceleration field: sink-float in a heavy medium (gravity or centrifugal acceleration).
Φ — magnetism.
C — electrostatic attraction.
U — electric field (charge migration).
μ — size/geometry: sieve or pore action.
K(p) — partial-pressure equilibrium (evaporating/condensing).
K(c) — distribution equilibrium (shaking out/dissolving).
K(a) — adsorption equilibrium (surface binding).
|○ — selection by floating up.
ν — sound/ultrasound: acoustic forces (e. g. standing ultrasonic waves).
λ — light: optical/photonic forces.
? — special method.

Driving quantities after #

p — pressure difference greater than zero.
T — temperature difference greater than zero.
U — voltage relevant.
I — current relevant.
v — (wind or flow) velocity.
∅ — diameter or pore size.
B — magnetic flux density.
g — gravity/centrifugal force.
– — no additional driving quantity.

Process parameters after \ (mode of operation/apparatus, not driving quantities)

⇄ — counter-current/continuous operation (continuous; horizontal double arrow).
⊕ — auxiliary substances markedly affect the effectiveness.
⦀ — separation layer (membrane/filter/sieve): a process component, not an auxiliary substance.

Other signs

|| — “or”: separates two different definitions from one another.
→ — arrow: points to a cascade of separation operations.

Auxiliary substance (definition)

An auxiliary substance is a substance added to the mixture that enables or improves the separation and is in contact or mixed with the product (solvent, precipitant or entrainer, eluent, carrier gas, complexing agent). Apparatus-side separation layers (⦀: membrane, filter, sieve) and other process components are not auxiliary substances. They should or must behave indifferently towards the target fraction and usually stand out only through their special geometric properties (pore size). Where chemical properties matter, as for example in membranes with ion-specific channels, the membranes are to be classified as an auxiliary substance as well.

Overview list of the separation methods (ordered by short symbol; analogous methods combined):

◇/K(p)/↑#p, T — Freeze drying (lyophilisation) — Frozen solvent sublimes in vacuum; the method is very gentle on biomolecules. The stationary phase is crystalline (◇), the mobile phase is gaseous (↑). The separation principle is the partial-pressure equilibrium (K(p)) with the separation quantity equilibrium constant K. The target product usually collects in the stationary phase. The temperature difference is ΔT [2-4], the pressure difference Δp [4-5]; counter-current operation is not possible. The process duration lies in the range of days. No auxiliary substance is required in either phase. The influence of the chemical environment is very low. Special feature: The dried material stays in the product vessel; the water vapour deposits on the condenser (ice trap).
◇/K(p)/◇(↑)#p, T || ◇/K(p)/↑#T → ↑/K(p)/◇#T — Sublimation — A substance passes directly from solid to gaseous and resublimes for purification. Alternative (two-stage, ||): evaporation and subsequent deposition at a lower temperature — ◇/K(p)/↑#T → ↑/K(p)/◇#T. The stationary phase is crystalline (◇), the mobile phase is gaseous (↑). The separation principle is the partial-pressure equilibrium (K(p)) with the separation quantity equilibrium constant K. The target product usually collects in the mobile phase. The temperature difference is ΔT [2-4], the pressure difference Δp [1-4]; counter-current operation is not possible. The process duration lies in the hour range. No auxiliary substance is required in either phase; the relevant driving quantities are pressure and temperature. The influence of the chemical environment is low. Special feature: The pure sublimate is collected on a cooled surface/on the cold finger.
◇/K(c)/◇(~)#T\⊕ || ◇/K(c)/~#T\⊕ → ~/K(c)/◇#T\⊕ → ◇/μ/~#p, ∅ — Crystallisation/recrystallisation — Purification proceeds via temperature- and solvent-dependent solubility; Repetition increases the purity. Alternative (three-stage, ||): dissolving, crystallising out and subsequent filtration — ◇/K(c)/~#T\⊕ → ~/K(c)/◇#T\⊕ → ◇/μ/~#p, ∅ (after crystallising out, the crystals are filtered off from the mother liquor). The stationary phase is crystalline (◇), the mobile phase is liquid (~). The separation principle is the distribution equilibrium (K(c)) with the separation quantity distribution coefficient K. The target product usually collects in the stationary phase. The temperature difference is ΔT [2-4], the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the hour range. An auxiliary substance is required in the mobile phase; the choice of solvent markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The crystals are filtered off, the mother liquor discarded; The purity rises over several stages.
◇/K(c)/~#T — Melt crystallisation (analogous: zone melting) — This short notation covers melt crystallisation and zone melting: the substance crystallises out of its own melt; in zone melting a travelling melt zone pushes impurities to the end of the rod (ultrapurification of semiconductors). The stationary phase is crystalline (◇), the mobile phase is liquid (~). The separation principle is the distribution equilibrium (K(c)) with the separation quantity distribution coefficient K. The target product usually collects in the stationary phase. The temperature difference is ΔT [2-5], the pressure difference Δp 0; counter-current operation is possible depending on the variant. The process duration lies in the range of hours to days. No auxiliary substance is required in either phase. The influence of the chemical environment is low to medium. Special feature: The pure crystal remains behind, the residual melt (impurities) is drawn off or migrates to the end.
↓/ρ/↓#v || ?/ρ/↓#v || ↓,↓/ρ/↓#v — Classification (analogous: air classification, centrifugal classification) — Disperse particles separate by settling velocity in a rising air stream or a centrifugal field. The stationary phase is the coarse fraction left behind (↓) or undefined (?), the mobile phase is the fine fraction carried out in the air stream (↓). The separation principle is density (ρ) with the separation quantities density ρ and particle/pore size d. The target product can usually be in either phase (both highlighted). The temperature difference is ΔT 0, the pressure difference Δp [0-1]; counter-current operation is possible. The process duration lies in the range of seconds to minutes. An auxiliary substance is required in the mobile phase; the relevant driving quantity is wind speed. The influence of the chemical environment is none. Special feature: Fine material is carried out in the air stream, coarse material falls out — both fractions are caught.
↓/aρ/~#\⊕ — Density separation (sink-float) (analogous: heavy-media separation) — In a heavy medium of defined density the light material floats and the heavy material sinks. The “stationary phase” here is the solid (↓), the mobile phase is liquid (~) because of the final decanting. The separation principle is density in an acceleration field (aρ) — gravity or centrifugal acceleration — with the separation quantity density ρ. The target product is usually in the stationary phase (light material as well as heavy material). The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the minute range. An auxiliary substance may be required in the mobile phase; the density of the heavy medium markedly affects the separation (⊕). The influence of the chemical environment is low. Special feature: Floating material is skimmed off, sinking material discharged at the bottom.
↓/Φ/↓#B || ↓/Φ/↓#B\⇄ — Magnetic separation — Ferromagnetic and paramagnetic components are separated off in a magnetic field. Alternative (continuous, ||): as a continuous drum/belt separation in counter-current — ↓/Φ/↓#B\⇄. The stationary phase is solid (↓), the mobile phase is solid (↓). The separation principle is magnetism (Φ) with the separation quantity magnetic susceptibility χ. The target product usually collects in the stationary phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the second range. No auxiliary substance is required in either phase; the relevant driving quantity is magnetic flux density. The influence of the chemical environment is none. Special feature: The magnetic fraction is held on the magnetic belt/drum and released once it leaves the field.
↓/Φ/↓#B || ↓/Φ/↓#B\⇄ — Eddy-current separation — Electrically conductive parts (e.g. non-ferrous metals) are repelled by induced eddy currents in an alternating field. Alternative (continuous, ||): as a continuous belt separation in counter-current — ↓/Φ/↓#B\⇄. The stationary phase is solid (↓), the mobile phase is solid (↓). The separation principle is magnetism/induction (Φ) with the separation quantity electrical conductivity σel. The target product usually collects in the stationary phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the second range. No auxiliary substance is required in either phase; the relevant driving quantity is magnetic flux density. The influence of the chemical environment is none. Special feature: Conductive parts are flung over the belt edge and caught separately.
↓/C/↑#U — Electrostatic precipitation — Aerosol particles are charged and deposited in a high-voltage field (electrostatic precipitator). The stationary phase is solid (↓), the mobile phase is gaseous (↑). The separation principle is electrostatic attraction (C) with the separation quantity charge q. The target product usually collects in the stationary phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the second range. An auxiliary substance is required in the stationary phase; the relevant driving quantity is voltage. The influence of the chemical environment is low. Special feature: The dust is knocked off the collecting electrode into a bunker.
↓/U/~#U, I\⊕ — Electrodeposition (electroplating) — Metals are deposited electrolytically on an electrode. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is an electric field (U) with the separation quantity redox potential E°. The target product usually collects in the stationary phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the range of minutes to hours. An auxiliary substance is required in both phases; the relevant driving quantities are voltage and current, and the choice of electrolyte markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The metal adheres as a layer on the cathode and is stripped/drawn off.
↓/U/~#U — Electrodialysis (analogous: capacitive deionisation, CDI) — Ions migrate in an electric field through ion-exchange membranes, or are removed electrosorptively (CDI). The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is an electric field (U) with the separation quantity charge q. The target product usually collects in the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is possible. The process duration lies in the range of minutes to hours. An auxiliary substance is required in the stationary phase; the relevant driving quantity is voltage. The influence of the chemical environment is medium. Special feature: The desalinated diluate is drawn off as the product stream, the concentrate led separately.
↓/U/~#U\⊕ — Electromembrane extraction — Ions migrate through an impregnated liquid membrane, driven by an electric field. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is an electric field (U) with the separation quantity charge q. The target product usually collects in the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the minute range. An auxiliary substance is required in both phases; the relevant driving quantity is voltage, and the choice of liquid membrane markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The target ions are enriched in the acceptor solution and removed.
↓/U/~#U — Electroosmosis — Pore liquid is transported through a porous medium in an electric field. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is an electric field (U) with the separation quantity zeta potential ζ — the electrokinetic potential at the shear plane of the electrochemical double layer between pore wall and liquid; it determines how strongly the liquid is carried along in the field. The target product usually collects in the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the hour range. No auxiliary substance is required in either phase; the relevant driving quantity is voltage. The influence of the chemical environment is medium. Special feature: The transported liquid is collected/pumped off on the cathode side.
↓/U/~#p\⊕ — Ion-exchange chromatography (analogous: ion exchange / chelating IE) — This short notation covers the chromatographic and the preparative variant: charged substances bind reversibly to a charged resin and are eluted by a salt/pH gradient or exchanged stoichiometrically. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is charge in a field (U) with the separation quantity charge q. The target product usually collects in the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp [1-3]. The process duration lies in the range of minutes to hours. An auxiliary substance is required in both phases; the choice of resin/eluent markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The bound ions are eluted by a salt/pH gradient and collected as fractions.
↓/U/~#p, U\⊕ — Capillary electrochromatography (CEC) — A hybrid of electrophoresis and chromatography with electroosmotic flow. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is an electric field (U) with the separation quantities charge q and distribution coefficient K. The target product usually collects in the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp [1-2]; counter-current operation is not possible. The process duration lies in the minute range. An auxiliary substance is required in both phases; the relevant driving quantities are pressure and voltage, and the choice of phases markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The analyte is eluted electroosmotically and detected/fractionated at the capillary end.
↓/μ/~#–\⦀ — Dialysis — Small dissolved molecules equalise diffusively across a semipermeable membrane. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is size/geometry (μ) with the separation quantity concentration c. The target product usually collects in the stationary phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is possible. The process duration lies in the hour range. The separation layer (semipermeable membrane) is a process component and not an auxiliary substance; in the dialysate (mobile phase) an auxiliary substance (buffer solution) is needed. The influence of the chemical environment is low. Special feature: The purified retentate remains in the dialysis tubing; Small molecules pass into the dialysate.
↓/μ/~#p, ∅\⦀ || ↓/μ/~#p, ∅\⦀ — Filtration (analogous: pressure/vacuum/membrane filtration) — A suspension is pressed or sucked through a porous medium; the solid remains behind as filter cake. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is size/geometry (μ) with the separation quantity particle/pore size d. The target product can usually be in either phase (both highlighted). The temperature difference is ΔT 0, the pressure difference Δp [1-3]; counter-current operation is not possible. The process duration lies in the minute range. No auxiliary substance is required in either phase; the separation layer (filter) is a process component and not an auxiliary substance; the relevant driving quantities are pressure and pore size. The influence of the chemical environment is low. The first short notation aims at the filter residue (stationary), the second at the filtrate (mobile). Special feature: The solid remains as filter cake, the filtrate in the collecting vessel — depending on the aim, both are usable.
↓/μ/~#p, ∅ — Size-exclusion chromatography (SEC/GPC) — Molecules separate by hydrodynamic volume or molar mass in a porous gel. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is size/geometry (μ) with the separation quantity molar mass M. The target product usually collects in the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp [1-3]; counter-current operation is not possible. The process duration lies in the range of minutes to hours. An auxiliary substance is required in both phases; the relevant driving quantities are pressure and pore size. The influence of the chemical environment is low. Special feature: The fractions are collected by elution volume; Large molecules elute first.
↓/μ/~#p, ∅\⦀ — Microfiltration — A membrane retains particles and microorganisms (0.1–10 µm), usually in crossflow. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is size/geometry (μ) with the separation quantity particle/pore size d. The target product usually collects in the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp [1-3]; counter-current operation is possible. The process duration lies in the minute range. No auxiliary substance is required in either phase; the separation layer (membrane) is a process component and not an auxiliary substance; the relevant driving quantities are pressure and pore size. The influence of the chemical environment is low. Special feature: The permeate (clear filtrate) is drawn off, the retentate recirculated in crossflow.
↓/μ/↑#p, ∅\⊕ — Molecular sieves (analogous: zeolite adsorption) — Substances are incorporated size- and shape-selectively into defined pore lattices (drying, gas purification). The stationary phase is solid (↓), the mobile phase is gaseous (↑). The separation principle is size/geometry (μ) with the separation quantity particle/pore size d. The target product usually collects in the mobile phase. The temperature difference is ΔT [0-1], the pressure difference Δp [1-3]; counter-current operation is possible. The process duration lies in the minute range. An auxiliary substance is required in the stationary phase; the relevant driving quantities are pressure and pore size, and the choice of sieve type markedly affects the separation (⊕). The influence of the chemical environment is medium. Special feature: The dried/cleaned product gas is drawn off; the sieve unloaded by regeneration.
↓/μ/~#p, ∅\⦀ — Nanofiltration — A membrane separates small organic molecules and polyvalent ions. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is size/geometry (μ) with the separation quantities particle/pore size d and charge q. The target product usually collects in the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp [3-4]; counter-current operation is possible. The process duration lies in the minute range. No auxiliary substance is required in either phase; the separation layer (membrane) is a process component and not an auxiliary substance; the relevant driving quantities are pressure and pore size. The influence of the chemical environment is medium. Special feature: The permeate is the product; polyvalent ions remain behind in the retentate.
↓/μ/↓#∅\⦀ || ↓/μ/↓#∅\⦀ — Sieving — Bulk material is classified mechanically by grain size on sieves of defined mesh width. The stationary phase is solid (↓), the mobile phase is solid (↓). The separation principle is size/geometry (μ) with the separation quantity particle/pore size d. The target product can usually be in either phase (both highlighted). The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the minute range. No auxiliary substance is required in either phase; the separation layer (sieve) is a process component and not an auxiliary substance; the relevant driving quantity is mesh/grain size. The influence of the chemical environment is none. The first short notation aims at the oversize (sieve residue, stationary), the second at the undersize (sieve throughput, mobile). Special feature: Oversize and undersize are collected separately (sieve residue/sieve throughput).
↓/μ/~#p, ∅\⦀ — Ultrafiltration — A membrane retains macromolecules by a molar-mass cut-off. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is size/geometry (μ) with the separation quantity molar mass M. The target product usually collects in the stationary phase. The temperature difference is ΔT 0, the pressure difference Δp [2-3]; counter-current operation is possible. The process duration lies in the minute range. No auxiliary substance is required in either phase; the separation layer (membrane) is a process component and not an auxiliary substance; the relevant driving quantities are pressure and pore size. The influence of the chemical environment is low. Special feature: The concentrated retentate is the product; the permeate is discarded.
↓/μ/🜄#p\⦀ — Reverse osmosis (analogous: forward osmosis) — Solvent permeates against the osmotic pressure (RO), or driven by a draw solution (FO). The stationary phase is solid (↓), the mobile phase is water (🜄). The separation principle is size/geometry (μ) with the separation quantity concentration c. The target product usually collects in the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp [4-5]; counter-current operation is possible. The process duration lies in the minute range. No auxiliary substance is required in either phase; the separation layer (membrane) is a process component and not an auxiliary substance; the relevant driving quantity is pressure. The influence of the chemical environment is medium. Special feature: The permeate (pure water) is drawn off, the concentrate discarded as waste water.
↓/K(p)/↑#T\⦀ — Membrane distillation — Vapour is transported through a hydrophobic membrane, driven by a temperature difference. The stationary phase is solid (↓), the mobile phase is gaseous (↑). The separation principle is the partial-pressure equilibrium (K(p)) with the separation quantity equilibrium constant K. The target product usually collects in the mobile phase. The temperature difference is ΔT [2-3], the pressure difference Δp [0-1]; counter-current operation is possible. The process duration lies in the hour range. No auxiliary substance is required in either phase; the separation layer (membrane) is a process component and not an auxiliary substance; the relevant driving quantity is temperature. The influence of the chemical environment is low. Special feature: The distillate condenses on the cold permeate side and is collected.
↓/K(p)/↑#p, T\⦀ — Pervaporation — One component evaporates selectively through a dense membrane; it separates azeotropes. The stationary phase is solid (↓), the mobile phase is gaseous (↑). The separation principle is the partial-pressure equilibrium (K(p)) with the separation quantity equilibrium constant K. The target product usually collects in the mobile phase. The temperature difference is ΔT [1-2], the pressure difference Δp [2-4]; counter-current operation is not possible. The process duration lies in the hour range. No auxiliary substance is required in either phase; the separation layer (membrane) is a process component and not an auxiliary substance; the relevant driving quantities are pressure and temperature. The influence of the chemical environment is high. Special feature: The permeate vapour is drawn off and condensed out.
↓/K(c)/~#T\⊕, ∅\⦀ — Clathrate/inclusion formation — Guest molecules are enclosed shape-selectively in a host lattice (urea adduct, gas hydrates). General note: With water (gas hydrates) the formation is strongly pressure- and temperature-sensitive, with other substances often highly substance-specific. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is the distribution equilibrium (K(c)) with the separation quantity geometric fit. The target product usually collects in the stationary phase. The temperature difference is ΔT [1-3], the pressure difference Δp [0-3]; counter-current operation is not possible. The process duration lies in the hour range. An auxiliary substance is required in the mobile phase; the choice of host substance markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The inclusion adduct is filtered off as a crystal and thermally broken up again.
↓/K(c)/~#\⊕ — Solid-liquid extraction (analogous: maceration, percolation) — Soluble components are dissolved out of a solid. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is the distribution equilibrium (K(c)) with the separation quantity distribution coefficient K. The target product usually collects in the mobile phase. The temperature difference is ΔT [0-2], the pressure difference Δp 0; counter-current operation is possible. The process duration lies in the hour range. An auxiliary substance is required in the mobile phase; the choice of solvent markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The extract (miscella) is drawn off; the raffinate (solid) discarded.
↓/K(c)/~#\⊕ — Paper/thin-layer chromatography (analogous: TLC) — A planar partition chromatography with capillary eluent flow. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is the distribution equilibrium (K(c)) with the separation quantity distribution coefficient K. The target product usually collects in the stationary phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the range of minutes to hours. An auxiliary substance is required in both phases; the choice of eluent markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The substance spots are located on the plate, scraped off and eluted.
↓/K(c)/~#T\⊕ — Soxhlet extraction (analogous: ultrasonic/microwave extraction) — This short notation covers the thermally and physically intensified solid-liquid extractions: cyclic hot extraction with refluxing solvent, or intensification by cavitation or dielectric heating. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is the distribution equilibrium (K(c)) with the separation quantity distribution coefficient K. The target product usually collects in the mobile phase. The temperature difference is ΔT [1-3], the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the range of minutes to hours. An auxiliary substance is required in the mobile phase; the choice of solvent markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The extract collects in the round-bottom flask; the solvent is returned by distillation.
↓/K(c)/⇅#p, T\⊕ — Supercritical fluid extraction (SFE) — The extraction is carried out with supercritical CO₂; the selectivity can be steered via pressure/temperature. The stationary phase is solid (↓), the mobile phase is supercritical (⇅). The separation principle is the distribution equilibrium (K(c)) with the separation quantity distribution coefficient K. The target product usually collects in the mobile phase. The temperature difference is ΔT [1-2], the pressure difference Δp [4-5]; counter-current operation is not possible. The process duration lies in the range of minutes to hours. An auxiliary substance is required in the mobile phase; the choice of CO₂/modifier markedly affects the separation (⊕). The influence of the chemical environment is medium. Special feature: After the pressure is lowered, the extract drops out of the CO₂ and is separated off.
↓/K(a)/~#\⊕ — Adsorption (activated carbon/silica gel/Al₂O₃) — Substances attach to the surface of a solid adsorbent. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is the adsorption equilibrium (K(a)) with the separation quantity adsorption coefficient K. The target product usually collects in the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp [0-1]; counter-current operation is possible. The process duration lies in the minute range. An auxiliary substance is required in the stationary phase; the choice of adsorbent markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The cleaned stream is the product; the loaded adsorbent is regenerated or exchanged.
↓/K(a)/~#p\⊕ — Affinity chromatography — A biospecific interaction binds the target substance to an immobilised ligand. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is the adsorption equilibrium (K(a)) with the separation quantity affinity. The target product usually collects in the stationary phase. The temperature difference is ΔT 0, the pressure difference Δp [1-2]; counter-current operation is not possible. The process duration lies in the hour range. An auxiliary substance is required in both phases; the choice of ligand markedly affects the separation (⊕). The influence of the chemical environment is very high. Special feature: The bound target substance is eluted selectively (competitor/pH change) and collected as eluate.
↓/K(a)/~#\⊕ — Biological separation — A biomass binds or accumulates the target substance (bioadsorption, biosorption). The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is the adsorption equilibrium (K(a)) with the separation quantity affinity. The target product usually collects in the stationary phase. The temperature difference is ΔT [0-1], the pressure difference Δp 0; counter-current operation is possible. The process duration lies in the range of hours to days. An auxiliary substance is required in the stationary phase; the choice of biomass markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The target substance accumulates in the biomass; it is recovered by harvesting the biomass, with desorption where applicable.
↓/K(a)/~#p\⊕ — Chiral chromatography — Enantiomers are separated on a chiral stationary phase. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is the adsorption equilibrium (K(a)) with the separation quantity affinity. The target product usually collects in the mobile phase. The temperature difference is ΔT [0-1], the pressure difference Δp [2-4]; counter-current operation is not possible. The process duration lies in the range of minutes to hours. An auxiliary substance is required in both phases; the choice of chiral phase markedly affects the separation (⊕). The influence of the chemical environment is very high. Special feature: The enantiomers elute as separate peaks and are collected as fractions.
↓/K(a)/~#p\⊕ — Solid-phase extraction (SPE) (analogous: membrane adsorption, dispersive SPE, QuEChERS) — This short notation covers the adsorptive enrichment/clean-up methods with the target substance in the stationary phase: enrichment on a sorbent or a functionalised membrane with subsequent elution. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is the adsorption equilibrium (K(a)) with the separation quantity adsorption coefficient K. The target product usually collects in the stationary phase. The temperature difference is ΔT 0, the pressure difference Δp [1-2]; counter-current operation is not possible. The process duration lies in the minute range. An auxiliary substance is required in both phases; the choice of sorbent/eluent markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The analyte is fixed on the sorbent, the matrix washed away and then eluted with little solvent.
↓/K(a)/~#p\⊕ — Column/flash chromatography (analogous: HPLC/UHPLC, HIC, simulated moving bed (SMB)) — This short notation covers the preparative and analytical liquid chromatographies with the target substance in the mobile phase: from the silica gel column through high-pressure liquid chromatography and hydrophobic interaction to continuous SMB. The stationary phase is solid (↓), the mobile phase is liquid (~). The separation principle is the adsorption equilibrium (K(a)) with the separation quantity adsorption coefficient K. The target product usually collects in the mobile phase. The temperature difference is ΔT [0-1], the pressure difference Δp [1-5] (Flash niedrig, UHPLC hoch); counter-current operation is possible depending on the variant (SMB). The process duration lies in the range of minutes to hours. An auxiliary substance is required in both phases; the choice of stationary/mobile phase markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The fractions are collected at the column outlet by retention time (fraction collector).
↓/K(a)/↑#p, T\⊕ — Swing adsorption (analogous: PSA, VSA, TSA) — A cyclic adsorption and desorption via pressure (PSA), vacuum (VSA) or temperature swing (TSA); e.g. O₂/N₂ generation. The stationary phase is solid (↓), the mobile phase is gaseous (↑). The separation principle is the adsorption equilibrium (K(a)) with the separation quantity adsorption coefficient K. The target product usually collects in the mobile phase. The temperature difference is ΔT [0-3], the pressure difference Δp [2-5]; counter-current operation is possible. The process duration lies in the minute range. An auxiliary substance is required in the stationary phase; the relevant driving quantities are pressure and temperature, and the choice of adsorbent markedly affects the separation (⊕). The influence of the chemical environment is medium. Special feature: The product gas is drawn off in the adsorption phase; the desorbate flushed out in the opposite cycle.
∴/U/🜄#U — Electrocoagulation — Metal hydroxides generated in situ from sacrificial electrodes destabilise colloids. The stationary phase is colloidal (∴), the mobile phase is water (🜄). The separation principle is an electric field (U) with the separation quantity zeta potential ζ. The target product usually collects in the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the minute range. An auxiliary substance is required in the stationary phase; the relevant driving quantity is voltage. The influence of the chemical environment is high. Special feature: The clarified water is drawn off; the floc sludge skimmed off or settled.
∴/K(c)/~#\⊕ — Precipitation (analogous: salting out) — A reagent or a high salt concentration forms a sparingly soluble phase. The stationary phase is colloidal (∴), the mobile phase is liquid (~). The separation principle is the distribution equilibrium (K(c)) with the separation quantity distribution coefficient K. The target product usually collects in the stationary phase. The temperature difference is ΔT [0-1], the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the minute range. An auxiliary substance is required in the mobile phase; the choice of precipitant/salt markedly affects the separation (⊕). The influence of the chemical environment is very high. Special feature: The precipitate is filtered off or centrifuged; the filtrate is discarded.
∴/K(c)/🜄#\⊕ — Coagulation/flocculation — Colloidal particles are destabilised and aggregated into settleable flocs. The stationary phase is colloidal (∴), the mobile phase is water (🜄). The separation principle is the distribution equilibrium (K(c)) with the separation quantity zeta potential ζ. The target product usually collects in the stationary phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the minute range. An auxiliary substance is required in the mobile phase; the choice of flocculant markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The flocs sediment or float; the clear water is decanted.
~/ρ/~#p — Field-flow fractionation (FFF) — In a laminar carrier stream a cross field separates by size and molar mass. The stationary phase is liquid (~), the mobile phase is liquid (~). The separation principle is density in a field (ρ) with the separation quantities particle/pore size d and molar mass M. The target product usually collects in the mobile phase. The temperature difference is ΔT [0-5], the pressure difference Δp [1-2]; counter-current operation is not possible. The process duration lies in the range of minutes to hours. An auxiliary substance is required in the mobile phase. The influence of the chemical environment is low. Special feature: The fractions are collected by elution time (size-dependent migration).
~/U/~#U\⊕ — Electrophoresis (analogous: capillary electrophoresis) — Charged particles migrate in an electric field and separate by charge and size. The stationary phase is liquid (~), the mobile phase is liquid (~). The separation principle is an electric field (U) with the separation quantities charge q and molar mass M. The target product usually collects in the stationary phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the range of minutes to hours. An auxiliary substance is required in the stationary phase; the relevant driving quantity is voltage, and the choice of buffer/gel markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The bands are located in the gel and cut out, or detected at the capillary end.
~/U/~#U\⊕ — Isoelectric focusing (IEF) — Amphoteric substances separate in a pH gradient at their respective isoelectric point. The stationary phase is liquid (~), the mobile phase is liquid (~). The separation principle is an electric field (U) with the separation quantity isoelectric point pI. The target product usually collects in the stationary phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the hour range. An auxiliary substance is required in the stationary phase; the relevant driving quantity is voltage, and the choice of ampholytes markedly affects the separation (⊕). The influence of the chemical environment is very high. Special feature: The bands focused at the pI are extracted from the gel strip.
~/U/~#U\⊕ — Isotachophoresis — Substances separate in sharp zones between a fast leading and a slow terminating electrolyte. The stationary phase is liquid (~), the mobile phase is liquid (~). The separation principle is an electric field (U) with the separation quantity charge q. The target product usually collects in the stationary phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the minute range. An auxiliary substance is required in the stationary phase; the relevant driving quantity is voltage, and the choice of leading/terminating electrolyte markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The zones migrate at the same speed; the fraction cut is made at the sharp zone boundaries.
~/K(p)/↑#T || ↓/K(p)/↑#T || ~/K(p)/~(↑)#T || ↓/K(p)/~(↑)#T — Evaporation/vaporisation (analogous: spray drying) — This short notation covers concentrating/drying by solvent evaporation with the target substance in the stationary phase: evaporating a solution or spraying it into a hot gas stream. The stationary phase is liquid (~), the mobile phase is gaseous (↑). The separation principle is the partial-pressure equilibrium (K(p)) with the separation quantity equilibrium constant K. The target product usually collects in the stationary phase. The temperature difference is ΔT [2-5], the pressure difference Δp [0-3]; counter-current operation is possible depending on the variant (spray drying). The process duration lies in the range of seconds to hours. An auxiliary substance is required in the mobile phase depending on the variant (carrier gas). The influence of the chemical environment is low to medium. Special feature: Concentrate or powder remains behind as the product; the vapours are discarded or condensed out.
~/K(p)/~(↑)#T — Simple distillation (analogous: stripping, condensation) — This short notation covers the single-stage phase transitions liquid↔gaseous with the target substance in the gas phase: simple evaporation+condensation, driving out with stripping gas, and the liquefaction of vapours. The stationary phase is liquid (~), the mobile phase is gaseous (↑). The separation principle is the partial-pressure equilibrium (K(p)) with the separation quantity equilibrium constant K. The target product usually collects in the mobile phase. The temperature difference is ΔT [1-5], the pressure difference Δp [0-2]; counter-current operation is possible depending on the variant (stripping). The process duration lies in the range of minutes to hours. An auxiliary substance is required in the mobile phase depending on the variant (stripping gas). The influence of the chemical environment is low to medium. Special feature: The vapour is condensed in the condenser and collected in the receiver.
~/K(p)/↑#p, T || ~/K(p)/↑#p, T — Cryogenic gas separation — At low temperatures the mixture is liquefied and rectified (e.g. air separation into O₂/N₂/Ar). The stationary phase is liquid (~), the mobile phase is gaseous (↑). The separation principle is the partial-pressure equilibrium (K(p)) with the separation quantity equilibrium constant K. The target product can usually be in either phase (both highlighted). The temperature difference is ΔT [4-5], the pressure difference Δp [2-4]; counter-current operation is possible. The process duration lies in the minute range. No auxiliary substance is required in either phase; the relevant driving quantities are pressure and temperature. The influence of the chemical environment is low. The first short notation aims at the liquid product (stationary), the second at the gaseous product (mobile). Special feature: The product gases are drawn off at different column heights/temperatures.
~/20*K(p)/~(↑)#T\⊕ — Rectification (analogous: fractional/azeotropic/extractive distillation) — A multistage counter-current distillation in columns; with an entrainer/solvent as azeotropic or extractive distillation. The stationary phase is liquid (~), the mobile phase is gaseous (↑). The separation principle is the partial-pressure equilibrium (K(p)) with the separation quantity equilibrium constant K. The target product usually collects in the mobile phase (top product). The temperature difference is ΔT [3-5], the pressure difference Δp 0; counter-current operation is possible. The process duration lies in the hour range. An auxiliary substance is required in the stationary phase; the relevant driving quantity is temperature, and an entrainer markedly affects the separation (⊕). The influence of the chemical environment is medium. Special feature: The top product is obtained at the condenser, the bottom product at the reboiler — both are usable.
~/K(p)/~(↑)#p, T || ↓/K(p)/↓(↑)#p, T — Vacuum distillation (analogous: short-path/molecular distillation) — This short notation covers the pressure-reduced distillations: distillation at reduced pressure, or in high vacuum with short vapour paths for thermolabile substances. The stationary phase is liquid (~), the mobile phase is gaseous (↑). The separation principle is the partial-pressure equilibrium (K(p)) with the separation quantity equilibrium constant K. The target product usually collects in the mobile phase. The temperature difference is ΔT [2-4], the pressure difference Δp [3-5]; counter-current operation is possible depending on the variant. The process duration lies in the range of minutes to hours. No auxiliary substance is required in either phase; the relevant driving quantities are pressure and temperature. The influence of the chemical environment is low. Special feature: The distillate is collected under vacuum at the condenser — gentle on high boilers.
~/K(p)/~(🜄)#T\⊕ || 🜄/K(p)/~(🜄)#T\⊕ || ~/K(p)/↓(🜄)#T\⊕ — Steam/carrier-vapour distillation — Substances of low volatility that are immiscible with water (e.g. essential oils) are carried along in the steam. The stationary phase is liquid (~), the mobile phase is gaseous (↑). The separation principle is the partial-pressure equilibrium (K(p)) with the separation quantity equilibrium constant K. The target product usually collects in the mobile phase. The temperature difference is ΔT [2-3], the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the hour range. An auxiliary substance is required in the mobile phase; the relevant driving quantity is temperature, and the carrier vapour markedly affects the separation (⊕). The influence of the chemical environment is low. The stationary phase is usually water (second short notation with 🜄). Special feature: The oil/water distillate condenses; the target oil is phase-separated in the separator.
~/K(c)/🜄#\⊕ || 🜄/K(c)/~#\⊕ — Liquid-liquid extraction (analogous: reactive extraction, ATPS) — A substance distributes between two immiscible liquids. One of the two liquids is usually aqueous and denser than the organic phase; which is why it is the mobile phase in the separating funnel. The stationary phase is liquid (~), the mobile phase is liquid (~). The separation principle is the distribution equilibrium (K(c)) with the separation quantity distribution coefficient K. The target product usually collects in the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is possible. The process duration lies in the minute range. An auxiliary substance is required in the mobile phase; the choice of extractant markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The extract phase is separated off; the target substance recovered by back-extraction or evaporation.
~/K(c)/↑#p, T\⊕ — Gas chromatography (GC) — Volatile analytes distribute between carrier gas and column film at elevated temperature. The stationary phase is liquid (~), the mobile phase is gaseous (↑). The separation principle is the distribution equilibrium (K(c)) with the separation quantity distribution coefficient K. The target product usually collects in the mobile phase. The temperature difference is ΔT [2-4], the pressure difference Δp [2-3]; counter-current operation is not possible. The process duration lies in the minute range. An auxiliary substance is required in both phases; the relevant driving quantities are pressure and temperature, and the choice of stationary phase/carrier gas markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The analytes are detected/fractionated separated in time at the column outlet.
~/K(c)/↑#\⊕ — Gas scrubbing/absorption (analogous: physical/chemical absorption) — Gas components are taken up into a wash liquid, physically or chemically. The stationary phase is liquid (~), the mobile phase is gaseous (↑). The separation principle is the distribution equilibrium (K(c)) with the separation quantity distribution coefficient K. The target product usually collects in the stationary phase. The temperature difference is ΔT [0-2], the pressure difference Δp [0-1]; counter-current operation is possible. The process duration lies in the range of seconds to minutes. An auxiliary substance is required in the stationary phase; the choice of wash liquid markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The loaded wash liquid is drawn off; the target substance recovered by desorption/stripping.
🜄/K(c)/~#\⊕ — Counter-current extraction/chromatography (Craig/CCC/CPC) — A multistage liquid-liquid distribution in counter-current, discrete (Craig) or continuous (CCC/CPC) without a solid support. The stationary phase is water (🜄), the mobile phase is liquid (~). The separation principle is the distribution equilibrium (K(c)) with the separation quantity distribution coefficient K. The target product usually collects in the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp [0-3]; counter-current operation is possible. The process duration lies in the hour range. An auxiliary substance is required in both phases; the choice of solvent system markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The fractions are collected at the outlet of the apparatus; the stationary phase is liquid.
🜄↓/|○/↓(↑)#U, I — Electroflotation — Particles float up on electrolytically generated, very fine gas bubbles. The stationary phase is the aqueous solid suspension (🜄↓), the mobile phase is the solid floating up on gas bubbles (↓(↑)). The separation principle is flotation. The target product usually collects as foam and is skimmed off as the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the minute range. An auxiliary substance is required in the stationary phase; the relevant driving quantity is voltage. The influence of the chemical environment is medium. Special feature: The float (solid) is skimmed off; the clear water drawn off below as the product.
🜄↓/|○/↓(↑)#\⊕ — Flotation (analogous: foam fractionation) — This short notation covers the foam- and bubble-borne enrichments: hydrophobic particles attach to rising gas bubbles (flotation), or surface-active substances accumulate in the foam (foam fractionation). The stationary phase is the aqueous solid suspension (🜄↓), the mobile phase is the solid floating up on gas bubbles (↓(↑)). The separation principle is flotation (|○) with the separation quantity surface tension σ. The target product usually collects in the foam and is skimmed off the stationary phase as the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is possible depending on the variant. The process duration lies in the minute range. An auxiliary substance is required in the stationary phase; the choice of collector/frother or surfactants markedly affects the separation (⊕). The influence of the chemical environment is high. Special feature: The valuable material is skimmed off with the foam (foam product).
↑/μ/↑#p\⦀ — Gas permeation (analogous: membrane gas separation) — A gas mixture separates through the different permeability of a membrane. Both phases are gaseous: the stationary phase is the gaseous retentate on the high-pressure side (↑), the mobile phase is the gaseous permeate on the low-pressure side (↑). The membrane itself is not a phase of its own but acts as a filter — it realises the separation principle size/geometry (μ) with the separation quantity permeability P. The target product usually collects in the mobile phase (permeate). The temperature difference is ΔT 0, the pressure difference Δp [3-4]; counter-current operation is possible (retentate and permeate led in counter-current). The process duration lies in the minute range. No auxiliary substance is required in either phase; the separation layer (membrane) is a process component and not an auxiliary substance. The relevant driving quantity is pressure. The influence of the chemical environment is low. Special feature: The permeate stream is drawn off on the low-pressure side.
?/ρ/~#p, v || ?/ρ/↓#p, v — Hydrocyclone — A continuous centrifugal separation in a conical flow vortex without moving parts. The stationary phase is undefined (?), the mobile phase is liquid (~) or solid (↓). The separation principle is density in a centrifugal field (ρ) with the separation quantities density ρ and particle/pore size d. The target product can usually be in either phase (both highlighted). The temperature difference is ΔT 0, the pressure difference Δp [1-2]; counter-current operation is not possible. The process duration lies in the second range. No auxiliary substance is required in either phase; the relevant driving quantity is pressure. The influence of the chemical environment is none. Special feature: Coarse material leaves through the underflow (apex), fine material/clear liquid through the overflow (vortex finder).
?/ρ/~#– || ↓,~/ρ/~#– — Sedimentation (analogous: decanting) — Denser constituents settle in the gravity field; the supernatant liquid is poured off. The stationary phase is undefined (?), the mobile phase is liquid (~). The separation principle is density in a gravity field (ρ) with the separation quantity density ρ. The target product can usually be in either phase (both highlighted). The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the hour range. No auxiliary substance is required in either phase. The influence of the chemical environment is low. Special feature: The clear upper phase is poured off, the sediment remains at the bottom.
?/ρ/~#g || ↓,~/ρ/↓#g — Centrifugation — Centrifugal force accelerates the settling and separates by differences in density and size. The stationary phase is undefined (?), the mobile phase is liquid (~). The separation principle is density in a centrifugal field (ρ) with the separation quantity density ρ. The target product can usually be in either phase (both highlighted). The temperature difference is ΔT [0-1], the pressure difference Δp 0; counter-current operation is not possible. The process duration lies in the minute range. No auxiliary substance is required in either phase; the relevant driving quantity is gravity or centrifugal force. The influence of the chemical environment is low. Special feature: The pellet lies at the bottom, the supernatant is decanted/pipetted off.
?/μ/↑#T — Gas diffusion (analogous: thermal diffusion) — Gases separate by molar mass through different diffusion rates, or in a temperature gradient (isotope separation). The stationary phase is undefined (?), the mobile phase is gaseous (↑). The separation principle is size/geometry (μ) with the separation quantity molar mass M. The target product can usually be in either phase (both highlighted). The temperature difference is ΔT [0-5], the pressure difference Δp [0-2]; counter-current operation is possible. The process duration lies in the range of hours to days. No auxiliary substance is required in either phase; the relevant driving quantity is temperature. The influence of the chemical environment is low. Special feature: The light and the heavy fraction are drawn off at different ends of the cascade.
?/ν/~#– — Acoustophoresis (analogous: ultrasonic separation) — In a microchannel a standing ultrasonic wave bundles particles at pressure nodes or antinodes by the acoustic radiation force; separation is by particle size and acoustic contrast (density/compressibility). No material stationary phase is defined (?), the mobile phase is liquid (~). The separation principle is sound/ultrasound (ν) with the separation quantity particle size d (the acoustic contrast factor acts in addition). The target product usually collects in the mobile phase. The temperature difference is ΔT 0, the pressure difference Δp 0; counter-current operation is possible depending on the design. The process duration lies in the range of seconds to minutes. No auxiliary substance is required in either phase; the relevant driving quantity is the ultrasonic field (frequency/power). The influence of the chemical environment is low. Special feature: The particles bundled at the pressure nodes are drawn off as an enriched side stream.
↓/μ/~#p, ∅ → ↓/K(p)/~(↑)#T — Rotary evaporation (combination; analogous: rotary evaporating, rotary-evaporator work-up) — In this example rotary evaporation combines two separation processes. First dissolving and filtration: the substance is dissolved and separated from insoluble matter by filtration under (reduced?) pressure (↓/μ/~#p, ∅). Second the evaporation: the solvent is evaporated off (on the rotary evaporator), so that the substance remains as a solid (↓/K(p)/~(↑)#T). The target product is the recovered solid in the stationary phase, while the liquid phase is led off via the gas phase and collected again as a liquid. The temperature difference lies at ΔT [1-4], the pressure difference at Δp [0-3]; Solvents markedly affect the separation. The duration lies in the range of minutes to hours, the chemical influence is medium. Special feature: Insoluble matter is filtered off; the solvent is drawn off on the rotary evaporator, the solid remains behind in the flask.
↓/K(c)/~#\⊕ → ↓/μ/~#p, ∅ — Reprecipitation (combination; analogous: purification precipitation, reprecipitating) — This combination joins two separation processes. First the precipitation: a reagent or salting out precipitates the target substance as a sparingly soluble phase (↓/K(c)/~#\⊕). Second the filtration: the precipitate is filtered off and washed (↓/μ/~#p, ∅). The target product is the purified solid (filter cake) in the stationary phase. The temperature difference lies at ΔT [0-1], the pressure difference at Δp [1-3]; the precipitant markedly affects the separation. The duration lies in the minute range, the chemical influence is high. Special feature: The precipitate is precipitated, separated as filter cake and washed; the filtrate is discarded.
↓/K(c)/~#p,∅\⦀ → ◇/K(c),μ/~#T,∅\⊕,⦀ — Recrystallisation (combination; analogous: recrystallising) — Recrystallisation combines two separation processes. First the dissolving: the substance is dissolved (usually hot), insoluble foreign matter is separated off by filtration (↓/K(c)/~#p,∅\⦀). Second the crystallising out: on cooling, the least soluble substances crystallise out first and are then filtered or decanted off (◇/K(c),μ/~#T,∅\⊕,⦀); this can be triggered by cooling, by evaporating the solvent, or by adding a foreign substance (antisolvent). The target product is the purified crystal in the stationary phase. The temperature difference lies at ΔT [2-4], the pressure difference at Δp [0-3]; Auxiliary substances (solvent, antisolvent where applicable) markedly affect the separation. The duration lies in the hour range, the chemical influence is high. Special feature: Hot filtration removes insoluble matter; the pure crystal is harvested on cooling, the mother liquor discarded.
↓/K(a)/~#p\⊕ → ↓/K(p)/~(↑)#T — Solid-phase work-up (combination; analogous: SPE clean-up, eluting and evaporating) — This combination joins two separation processes. First the solid-phase extraction: the target substance is enriched on a sorbent, the matrix washed away and the substance eluted with little solvent (↓/K(a)/~#p\⊕). Second the evaporation: the eluate is concentrated to dryness (↓/K(p)/~(↑)#T). The target product is the dried residue in the stationary phase. The temperature difference lies at ΔT [2-5], the pressure difference at Δp [1-5]; the choice of sorbent and eluent markedly affects the separation. The duration lies in the range of minutes to hours, the chemical influence is high. Special feature: The target substance is sorbed and eluted; the eluate is then evaporated to dryness.
🜄/K(c)/~#\⊕ → ~/K(p)/~(↑)#T — Shaking out and evaporating (combination; analogous: extractive work-up, shaking out) — This combination joins two separation processes. First the liquid-liquid extraction: the target substance is transferred into an immiscible solvent phase by shaking out (🜄/K(c)/~#\⊕). Second the evaporation: the solvent is evaporated off, so that the target substance remains as a concentrate/residue (~/K(p)/~(↑)#T). The target product is the concentrated residue (liquid phase) in the stationary phase. The temperature difference lies at ΔT [2-5], the pressure difference at Δp [0-3]; the extractant markedly affects the separation. The duration lies in the range of minutes to hours, the chemical influence is high. Special feature: The target substance is transferred into the extract phase; after the solvent has been evaporated off, the residue remains behind.

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2.2 Target fraction

2.2.1 Target fraction of the separation

This block holds the target fraction the separation is to obtain — for example the stationary or the mobile phase.

A separation always serves the recovery or enrichment of one particular component. Without a named target fraction it stays open which of the resulting fractions is the one looked for, and the success of the separation cannot be judged.

2.2.2 Name of the stationary fraction

This field gives the stationary fraction a name. The name fields serve to create a reference for further processing: under this name the subform “Section start” takes up the fraction together with mass and volume of the output, and the fraction-name field in the subform “Characterisation” offers it as a suggestion.

When the separation step is created, the name is assigned automatically: the prefix “S-” for the stationary fraction, the base fragment “T-” and the running number of the subform in the history protocol — for instance “S-T-3”. The name may be overwritten and is at most 20 characters long.

A name should occur only once in the protocol; if two separation steps carry the same name, the section start refers to the first.

2.2.3 Name of the mobile fraction

This field gives the mobile fraction a name. The name fields serve to create a reference for further processing: under this name the subform “Section start” takes up the fraction together with mass and volume of the output, and the fraction-name field in the subform “Characterisation” offers it as a suggestion.

When the separation step is created, the name is assigned automatically: the prefix “M-” for the mobile fraction, the base fragment “T-” and the running number of the subform in the history protocol — for instance “M-T-3”. The name may be overwritten and is at most 20 characters long.

A name should occur only once in the protocol; if two separation steps carry the same name, the section start refers to the first.

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2.3 Separation principle (Separation type)

Here stands the physical separation principle, that is, the force or property by which separation occurs. The list offers: density or Brownian motion in the gravitational field (sedimentation/centrifugation), magnetism (magnetic separation), electrostatic attraction (electrostatic separation), electric field (electrophoresis), size or geometric form (filtration/sieving), partial-pressure equilibrium (distillation/rectification), distribution equilibrium (liquid-liquid extraction/shaking out, chromatography), surface adsorption equilibrium (chromatography), selection by observation (manual sorting/picking), selection by floating (flotation), sound/ultrasound (acoustophoresis), light (photonic/optical separation) and special methods (special procedure).

The principle determines which material property brings about the separation. Substances can only be separated if they differ sufficiently in the chosen property.

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2.4 Phase in the system

2.4.1 Stationary phase

This block holds the stationary phase — the fixed part of the separation system.

The stationary phase is one of the two answers the target fraction of the separation can take; what is entered here describes the phase that stays behind in the separation system.

2.4.2 State of matter of the stationary phase (Stat: Phase)

Here stands the state of matter of the stationary phase — for example solid, or liquid on a support. This phase remains behind in the separation process or, in a continuous process, is transported away in counter-current.

The state determines the interaction with the substances to be separated: a solid adsorbs differently than a liquid film or a gas phase.

2.4.3 Viscosity of the stationary phase (Visc.)

Here stands the viscosity of the retained, stationary phase — roughly and qualitatively, and only if that phase is liquid or gel-like.

The viscosity governs how quickly and easily substances enter the stationary phase and leave it again, and with that the sharpness of the separation.

2.4.4 Stationary secondary phase (Stat: 2nd phase)

Here a secondary phase of the stationary fraction can be specified.

This is useful because a separated mixture can consist of more than one phase. For systematics, a main phase and a secondary phase are distinguished; further phases are not listed, even if — for example across different crystals — additional phases could exist.

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2.5 Phase in the discharge

2.5.1 Mobile phase

This block holds the mobile phase — the moving part of the separation system, which carries the substances past the stationary phase.

The mobile phase is the other answer the target fraction of the separation can take; what is entered here describes the medium that moves.

2.5.2 State of matter of the mobile phase (Mob: Phase)

Here stands the state of matter of the mobile phase — for example liquid or gaseous. This phase moves through the separation system and carries the substances away as discharge.

The state determines the kind of substance transport: a liquid mobile phase carries substances differently than a carrier gas.

2.5.3 Viscosity of the mobile phase (Visc.)

Here stands the viscosity of the mobile phase — roughly and qualitatively.

The viscosity governs the flow rate and the pressure required, and with that the duration and the sharpness of the separation.

2.5.4 Mobile secondary phase (Mob: 2nd phase)

Here a secondary phase of the mobile fraction can be specified.

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2.6 Output

2.6.1 Output of the separation

This block holds the output of the separation: mass and volume of the recovered stationary and mobile phase.

The figures say how much of each phase is available for further use. After a purification step the target fraction counts as carried over in full.

Several fractions: the outputs of individual fractions — for example the fractions of a chromatography — cannot yet be recorded separately here. Enter the total amount up to the last fraction, then add one substance input/output per fraction that describes this fraction with its amount.

2.6.2 Mass of the stationary phase (m(stat) [g])

Here stands the mass of the recovered stationary phase, in grams. If a different unit is given, a conversion into grams is attempted.

What does not belong here: a phase measured by volume. For that the volume field stands beside it, and for an amount without a figure the vague amount below.

2.6.3 Volume of the stationary phase (V(stat) [ml])

Here stands the volume of the recovered stationary phase, in millilitres. Liquid and gel-like phases are usually measured rather than weighed. If a different unit is given, a conversion into millilitres is attempted.

What does not belong here: a weighed portion. For that the mass field stands beside it, and for an amount without a figure the vague amount below.

2.6.4 Vague amount of the stationary phase

This radio list is for the case in which the procedure names no exact number for the stationary fraction — “a beaker full”, “a knife tip”, “as needed”. One of the listed terms is chosen instead of inventing a figure.

Each term carries a stored average amount and a tolerance. The protocol therefore states an order of magnitude and, in the same breath, that it is one — mass and volume stay empty, and that is the point.

What does not belong here: a weighed or measured quantity. Where a number exists, it goes into the mass or volume field beside this list; a term chosen in addition would claim two different statements about one fraction.

2.6.5 Mass of the mobile phase (m(mob) [g])

Here stands the mass of the recovered mobile phase, in grams. If a different unit is given, a conversion into grams is attempted.

What does not belong here: a phase measured by volume. For that the volume field stands beside it, and for an amount without a figure the vague amount below.

2.6.6 Volume of the mobile phase (V(mob) [ml])

Here stands the volume of the recovered mobile phase, in millilitres. The mobile phase — eluate, solvent — is usually measured rather than weighed. If a different unit is given, a conversion into millilitres is attempted.

What does not belong here: a weighed portion. For that the mass field stands beside it, and for an amount without a figure the vague amount below.

2.6.7 Vague amount of the mobile phase

This radio list is for the case in which the procedure names no exact number for the mobile fraction — “a beaker full”, “a few millilitres”, “as needed”. One of the listed terms is chosen instead of inventing a figure.

What does not belong here: a measured eluate volume. Where a number exists, it goes into the mass or volume field beside this list; a term chosen in addition would claim two different statements about one fraction.

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2.7 Quick help: name of the method

2.7.1 Quick help: name of the method

This block names the separation step twice: with its identifier in the experiment (“T-3”), to which an auxiliary substance refers, and with one customary name of the method — the word under which a later reader looks for it.

The entries are radio buttons because a step carries exactly one such name. Where two terms both seem to fit, they usually describe two steps, and the second one belongs in a block of its own.

The pictogram shows both in its headline: the English name of the method, behind it the identifier in brackets and — separated by a hyphen — the two fraction names of the target fraction, stationary before mobile and joined by a slash, each cut to its first seven characters; an empty name shows as “-”: “Distillation (T-3) - S-T-3/M-T-3”. The choice steers no other field; what the method did is said by the phases, the principle and the parameters in the other accordions.

2.7.2 Identifier of the separation step

The identifier names this separation step within the experiment — short enough to fit into the pictogram next to the name of the method: “Distillation (T-3)”.

It is the address by which an auxiliary substance refers to the step: in the substance input/output subform, accordion “Auxiliary substance”, the field “Separation name” takes the identifier of the separation step the substance serves.

When the subform is inserted, the field is prefilled with T- and a number: one plus the number of subforms already in the record. The third block of an experiment is therefore first called “T-3”. The number is not updated when other blocks are moved or deleted — a name that changed with every rearrangement would be no name.

The suggestion may be overwritten, for instance with an abbreviation from the lab notebook; at most 20 characters are allowed. A template does not take the identifier along: it belongs to the single step, not to its pattern. The history protocol names the identifier in the first sentence of the separation step.

2.7.3 Unknown

Unknown is the starting position of the quick help and stays selected until another term is chosen.

It is not a statement, and it is therefore the only entry that does not appear in the history protocol. A separation step whose name nobody has settled on should say nothing about its name — not “unknown”, which would read like a finding.

The reset button of the subform returns to this entry, so a wrong choice can be taken back — a radio group cannot otherwise be unselected.

2.7.4 Adsorption

Adsorption holds a substance at the surface of a solid — activated charcoal, silica gel, an ion exchanger — while the rest of the mixture flows past.

Choose this term when the surface itself is the separating agent and the step ends with the loading. If the loaded phase is then washed with a mobile phase so that the substances run apart along the bed, the step is a chromatography.

2.7.5 Chromatography

Chromatography separates substances by their different dwell time between a stationary phase and a mobile phase flowing through it — column, thin layer, gas or liquid chromatography.

The term is right whenever the mixture travels a path and separates along it. What distinguishes it from a single adsorption step is the movement: not “held or not held”, but “held longer or shorter”.

2.7.6 Decanting

Decanting pours the supernatant liquid off a settled sediment — without a filter, by tilting the vessel steadily.

In most cases the term names only the procedure itself, not the wait for the solid to settle: settling is sedimentation, pouring off is decanting. Whoever records both is recording, properly and correctly, two separation steps. Where the sedimentation step is missing, knowledgeable chemists usually assume it implicitly.

2.7.7 Distillation

Distillation separates via the vapour phase: the more volatile part evaporates, condenses elsewhere and is collected separately.

What carries the separation is the difference in boiling points, not the temperature alone. If the residue is the target and the vapour is discarded, the step is rather an evaporation.

2.7.8 Dialysis

Dialysis lets small particles migrate through a semipermeable membrane into an outer medium while large molecules stay behind — the driving force is the difference in concentration.

The term fits when the gradient alone drives the migration. With an electric field added it becomes electrodialysis; if excess pressure forces the solvent through, reverse osmosis.

2.7.9 Evaporating

Evaporating vaporises the solvent and discards it; the target is the residue that stays behind.

The term states which part counts. If the vapour is collected because it is the valuable product, the step belongs to distillation.

2.7.10 Electrodialysis

Electrodialysis pulls ions through ion-selective membranes because an electric field drives them — used for desalination, for instance.

It differs from dialysis in its driving force, and from electrophoresis in that the membrane makes the selection rather than the migration speed.

2.7.11 Electrophoresis

In electrophoresis charged particles migrate through a carrier material at different speeds in an electric field and thereby separate by charge and size.

The term covers gel and capillary electrophoresis. If a membrane and not the migration distance does the separating, it is electrodialysis.

2.7.12 Extraction (shake-out)

In shake-out extraction a substance distributes between two immiscible liquids; once the phases are separated it sits mostly in one of them. One of the two solvents is usually an aqueous phase.

The term means liquid-liquid extraction in the separating funnel. If a solid is exhaustively extracted with circulating solvent, it is a Soxhlet extraction.

2.7.13 Extraction (Soxhlet)

In an extraction a (porous) or comminuted solid is usually extracted with a solvent. Where one liquid is extracted with another, it is usually called shaking out. One speaks of a Soxhlet extraction when the solvent is cyclically evaporated and condensed above the sample, then runs through the sample to extract it and finally returns to the flask to be evaporated again.

The recycling is the hallmark — the same small portion of solvent works for many hours. A single pour-over is not a Soxhlet extraction.

2.7.14 Filtration

Filtration retains solid at a filter medium while the liquid passes through — driven by gravity, vacuum or excess pressure.

The term fits the ordinary paper or frit filter. Where the cut-off lies in the micrometre range and a membrane does the work, microfiltration is the entry.

2.7.15 Precipitation

In precipitation a dissolved substance is converted into a poorly soluble form by a reagent, a solvent or a change of pH and drops out as a solid.

Precipitation creates the phase that is to be separated in the first place; it is therefore almost always followed by a second step — filtration, centrifugation or decanting.

2.7.16 Freeze drying

Freeze drying removes water from the frozen sample by subliming the ice directly under vacuum; the sample stays cold throughout. By reducing the available activation energy the cold prevents unwanted side reactions during the drying process.

It is the entry where warmth would damage the product. Without freezing and vacuum the step is an evaporation, not freeze drying.

2.7.17 Cold precipitation

In cold precipitation a substance drops out of a solvent as a solid because it dissolves less well at 0 °C — in an ice bath or a refrigerator — than at room temperature. Unlike precipitation, no reagent is added; the cold alone lowers the solubility.

Choose this term when cooling creates the solid. As with precipitation, a second step almost always follows — filtration, centrifugation or decanting. If crystals are grown on purpose from a solution saturated while hot, the step is a crystallisation or recrystallisation.

The temperature actually reached and the waiting time belong in the temperature and duration fields of the separation step.

2.7.18 Crystallisation

In crystallisation a dissolved substance forms a crystal lattice out of the supersaturated solution and thereby separates from everything that stays dissolved.

The term means winning crystals for the first time. If already crystalline material is dissolved and crystallised again in order to purify it, that is recrystallisation.

2.7.19 Microfiltration

Microfiltration separates at a membrane with pores in the micrometre range — fine enough for cells, turbidity and larger particles, permeable for dissolved molecules.

The term says something about the cut-off, not about the apparatus. It belongs to the membrane; the paper filter stays a filtration.

2.7.20 Sedimentation

In sedimentation heavier particles sink in the gravitational field until a clear upper phase stands above the sediment.

Sedimentation is the settling itself, and it takes time. If a centrifuge replaces the waiting, it is centrifugation; pouring off afterwards is decanting.

2.7.21 Sublimation

In sublimation a solid passes directly into the gas phase and settles on a cold surface as a solid again — without ever being liquid.

It separates sublimable from non-sublimable parts and often yields very pure material. Applied to the water of a frozen sample, the same process is called freeze drying.

2.7.22 Reverse osmosis

Reverse osmosis forces the solvent through a dense membrane at a pressure above the osmotic pressure; the dissolved substances stay behind.

The hallmark is the pressure against the natural gradient. Without it the solvent migrates the other way — that is dialysis.

2.7.23 Recrystallisation

Recrystallisation purifies material that is already crystalline: it is dissolved hot, the solution is cooled, and the substance crystallises out purer than before.

One pass is rarely enough. If the procedure is repeated until the melting point stops moving, every repetition belongs in the record as a stage of its own.

2.7.24 Centrifugation

Centrifugation accelerates the settling in the centrifugal field; it separates in minutes what gravity would need hours for, and packs the sediment more tightly.

The speed or the acceleration belongs in the parameters — without it the step is not repeatable, since “centrifuged off” covers 500 as well as 15,000 revolutions.

2.7.25 Other (…)

Other is the entry for a separation process that none of the listed terms describes correctly.

The choice is optional. It only helps to avoid misunderstandings and to phrase the history protocol more concisely.

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2.8 System aspects

2.8.1 Procedural aspects of the separation

This block holds the procedural aspects of the separation: moisture content, counter-current operation and the need for auxiliary substances.

These aspects determine the practical execution of the separation — they are the boundary conditions that decide separation sharpness and effort.

2.8.2 Air humidity in the laboratory = moisture in the separation system? (%)

Here stands the air humidity of the laboratory that is in contact with the separation system where no protective-gas atmosphere is present. The humidity of the laboratory air can therefore influence the moisture in the separation system and with it the efficiency of the separation.

Water alters the interaction between the substances and the stationary phase, and with it the migration speeds and the separation sharpness; it may also react with the preparation itself.

2.8.3 Counter-current operation (⇅)

Here stands whether the separation runs in counter-current — stationary and mobile phase, or two material streams, led in opposite directions. The material stream coming from the reactor then counts nominally as the stationary one.

Counter-current operation can improve the efficiency of the separation considerably or simplify the procedure: for larger quantities it is superior to a batch process, which is limited to a maximum amount. It brings its own process-engineering preconditions with it.

2.8.4 Auxiliary substance required (⊕!)

Here stands whether the separation needs an auxiliary substance — a precipitant, a complexing agent, a solubiliser, a foaming agent, an antifoam, a flocculating agent, a degumming agent, …

An auxiliary substance can enable or markedly improve a separation, and at the same time has to be removed again as an impurity. The note therefore also keeps the necessary post-purification in view.

2.8.5 Separation layer [membrane/filter/sieve] (⦀)

Here stands whether the separation uses a separation layer — a membrane, a filter or a sieve through which the mixture is led.

The separation layer is a process component and not an auxiliary substance: it is not mixed into the product and does not have to be removed as an impurity afterwards. It is typical of filtration, membrane and sieving methods. The material of the separation layer should react with the substances neither directly nor catalytically (surface catalyst).

What does not belong here: solvents, precipitants and eluents. Those are auxiliary substances and are recorded in the field beside it.

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2.9 Time required for separation

2.9.1 Time span of the separation

This block holds the time span over which the separation runs: start, end and the span calculated from them or entered by hand. Where the time unit is missing from the span, the minute (min) is assumed as the unit.

Many separation methods need a minimum duration to reach a sufficient resolution; without the time span it stays open whether the separation ran to completion.

Too short a separation time leaves the resolution incomplete, too long a one costs effort and can endanger sensitive substances.

2.9.2 Duration (qualitative)

Here stands the duration as a customary name instead of a pair of timestamps — “a few minutes”, “overnight”, “several days”. It stands BESIDE the measured time span, not instead of it: whoever has both enters both.

Every term carries its substitute value in seconds with it. The values are mean values of customary wordings, not limits — “overnight” is read as 18 h, not as the exact length of the night.

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2.10 Pressure and temperature

2.10.1 Temperature and pressure

This block holds the temperature and pressure conditions of the separation.

Both quantities move the solubilities, distribution equilibria and volatilities on which many separation processes rest; without them the separation procedure is not reproducible.

2.10.2 Value at the inlet / difference (Main)

Here stands the main value of the parameter — the separation temperature, the separation pressure.

It is the value inside the separation system. It may hold for the whole system including the output, or only within the system while a different value prevails at the output. It is often that very difference which makes the separation possible.

2.10.3 Value at the discharge (Add)

Here stands the value at the output — the parameter at the outlet of the separation system.

Matching the value inside the system, the same value prevails everywhere. Differing from it, there is a gradient between separation system and output, and that difference is what realises the separation.

2.10.4 Temperature (T)

Here stands the temperature at which the separation takes place. The second field of the row, where given, holds the differing temperature at the output of the separated fraction.

The temperature shifts the solubilities, vapour pressures and distribution coefficients that underlie distillation, extraction and many other separation processes.

2.10.5 Pressure (p)

Here stands the pressure at which the separation takes place. The second field of the row, where given, holds the differing pressure at the output of the separated fraction.

The pressure shifts boiling points and gas solubilities; a vacuum distillation, for instance, spares thermally sensitive substances.

2.10.6 Temperature (Qual. T., qualitative)

Every term carries its conventional value in kelvin with it — in the parenthesis of the label and as a machine value in the markup. A temperature that was never measured is therefore still a supported statement and not a guess.

2.10.7 Pressure (Qual. p, qualitative)

The terms are ordered by value and state it in scientific notation in pascal (1·10⁻¹ up to 1·10⁹ Pa). Across ten powers of ten one shared unit reads better than a change between kPa, MPa and GPa.

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2.11 Stirring parameters

2.11.1 Stirring

This block holds the stirring — how strongly the separation system is moved, and with which tool.

Mechanical mixing helps decide whether phases meet or part: stirring too weakly leaves layers standing, stirring too strongly tears open a boundary that has just formed. That is why stirring stands beside the intensive measured parameters and not inside them.

2.11.2 Stirring stage in the main part (Main)

This column carries the stirring stage in the first or main part of the separation: the choice on the fixed scale and, beside it, a measured value with a unit, for example 120 rpm.

The stage is coarse and therefore comparable everywhere; the number beside it is exact and holds for this device only. Together they say more than either alone.

2.11.3 Stirring stage in the second part (Add)

This column carries the stirring stage in the second or additional part of the separation — the same scale and the same measured value as on the left, but for the other section.

Where the stirring differs over a period, only the pair of both stages describes the process; with steady stirring this column stays empty.

2.11.4 Stirring intensity (↺)

Here stands the stirring intensity with which the phase is moved during the separation. Beside each of the two levels a measured value with a unit may stand, for example 120 rpm.

The fixed scale runs from -- rigid and - calm through undefined to + gentle, ++ strong, * turbulent and ** chaotic stirring/kneading. The mechanical mixing substantially influences reaction and separation behaviour.

2.11.5 Stirrer type (⚙️)

Here stands which stirring tool was used: a magnetic stirrer, a KPG stirrer (KPG = core-drawn precision glass apparatus; a driven glass shaft with a rigid blade) or a mixing nozzle.

The three differ not merely in strength but in the kind of motion they produce. A magnetic stir bar drives the liquid near the bottom of the vessel and stalls in viscous or heavily loaded mixtures; a KPG stirrer reaches the whole volume and tolerates suspensions; a mixing nozzle mixes by a jet instead of a rotating part and can introduce a gas or a second liquid while it does so. In a separation the tool decides whether the two phases actually meet: an extraction stirred only near the bottom leaves the upper phase almost untouched.

✋ Manual mixing means that the mixing was done by hand, without a stirring drive. This can be swirling an Erlenmeyer flask, stirring with a glass rod or a spatula, grinding in a mortar or working with a manual hand mixer. The specification beside it names which of these was used.

What does not belong here: how strongly it was stirred. That is what the intensity scale and the specification beside it are for.

2.11.6 Stirrer specification (📝)

This free-text field holds the exact stirring tool of the separation: model, speed and the geometry of the stirring element — for example “Rühry Cool Dauerwelle, 2000 rpm, induction rod”.

The field is free text on purpose. Listing every device on earth would be endless and out of date within a year, while the one thing that makes a run repeatable — this device, at this speed, with this stirring element — fits into a single line.

It is worth noting the speed even when the number looks unremarkable. The scale above says “strongly stirred”, but the same wording covers 200 and 900 rpm, and between the two lies the difference between a suspension and a splashed flask.

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2.12 Intensive measured parameters

2.12.1 Intensive

This block holds further, freely definable parameters of the separation.

Every separation process can have control variables of its own — flow rate, layer thickness, field strength. They have no field of their own and are named here.

2.12.2 Value inside the separation system (Main)

Here stands the main value of a freely chosen additional separation parameter — its value inside the separation system.

That value either holds for the whole system including the output, or it differs from the value at the output and thereby brings about the separation.

2.12.3 Value at the output (Add)

Here stands the value at the output of the freely chosen separation parameter.

A deviation from the value inside the separation system is the gradient that drives the separation; agreement means a parameter constant across the system.

2.12.4 Extensive quantity 1 (Ext. 1)

The first row of the “Extensive” block records a freely nameable extensive quantity of the separation — one that grows with the size of the batch: number of theoretical plates, column length, membrane area, filled bed volume.

The name field carries the designation, the middle field the value with its unit, the right one a base value it is to be read against. Both value fields are independent — nothing is calculated from them.

Extensive quantities are worth recording because they scale. A number of plates or a column length explains why the same procedure separates in one lab and does not in another.

2.12.5 Extensive quantity 2 (Ext. 2)

The second row of the “Extensive” block holds a further extensive quantity, most often a retention: the distance a substance has travelled, read against the distance of the front or of a reference.

Value and base are noted separately and on purpose. The quotient of the two would be quickly formed, but only the two raw numbers say on which plate, in which chamber and against which front the value was read.

Whoever wants the relative value calculated will find the component porthd-retentionvalue in the characterisation form; this row deliberately stays plain.

2.12.6 Freely definable parameter 1 (? - unknown)

The first two fields hold a freely nameable separation parameter together with its own designation; the third, where filled, holds the differing parameter at the output. It can be the electrical voltage, the magnetic field strength or the unfortunately non-standardised stirring intensity.

As with temperature and pressure, the value may hold inside the separation system or differ from the value at the output — such a difference can carry the separation. Several special quantities are often of interest at the same time; that is what the second and third free parameter are for.

2.12.7 Freely definable parameter 2 (? - unknown)

The first two fields hold a second freely nameable separation parameter together with its own designation; the third, where filled, holds the differing parameter at the output.

As with temperature and pressure, the value may hold inside the separation system or differ from the value at the output — such a difference can carry the separation. Complex separations can involve a multitude of control variables, and this field keeps room for the last of them.

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2.13 General system conditions

2.13.1 Framework conditions of the separation

This block holds the special framework conditions under which the separation ran: darkness, shielding, dryness with the drying agent used, and separation from the working atmosphere.

A substance can survive the reaction and then perish during the workup. A column open to the air, a fraction standing in the light, a solvent that has drawn moisture — the loss then falls on the separation, not on the synthesis. What is recorded here is which disturbing influences were deliberately excluded.

2.13.2 Inert gas atmosphere (▣)

Here stands that the separation takes place under a protective gas atmosphere. The condition applies to the separation system itself as well as to the output.

The substances to be separated may be air- or oxygen-sensitive and must not oxidise during the separation.

2.13.3 Separation in the dark (☀)

Here stands that the separation takes place with the exclusion of light. The condition applies to the separation system itself as well as to the output, that is, the fractions obtained.

Light-sensitive substances would decompose under the influence of light during the separation.

2.13.4 No electrosmog (¬↯)

Here stands that the separation takes place free of electromagnetic interference fields. The condition applies to the separation system itself as well as to the output. Bear in mind that a magnetic stirrer carries a magnetic field into the system which is considerably stronger than the magnetic field of the earth and therefore counts as mild electrosmog as well.

Where the separation principle rests on electrical or magnetic forces, external fields disturb it. Electromagnetic fields can moreover influence the reaction or the formation of crystals.

2.13.5 Dryness (☂)

Here stands that the separation takes place with the exclusion of moisture. The condition applies to the separation system itself as well as to the output; the degree of dryness and the drying agents used belong in the field beside it. Otherwise an interaction with the air humidity of the laboratory sets in.

Moisture alters the interaction with the stationary phase and damages hydrolysis-sensitive substances.

2.13.6 Drying agent (Tm)

Here stands which drying agent was used, if the work was done under dry conditions according to the checkbox. From that the degree of dryness approximately reached can be estimated. The condition applies to the separation system itself as well as to the output.

The agents differ markedly in strength and mechanism: sodium and lithium as well as P₂O₅ act chemically (very strong); molecular sieves, calcium sulfate and silica gel act by adsorption (ultra-dry to moderate); calcium oxide chemically and adsorptively. “?” stands for an unknown agent, “other” for one not listed.

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2.14 Auxiliary substances in the separation

2.14.1 For the stationary phase

2.14.1.1 Chemical aspects of the stationary phase

This block holds the chemical aspects of the stationary phase:

Moisture: dry, damp, wet or lab air — the water content governs adsorption and the activity of the stationary medium.
Acid-base behaviour (Brønsted): protonic (H), weakly protonic (h), amphoteric (A), aprotic (N), ionic (I), proton acceptor (oh) up to strong acceptor (OH) — it determines proton exchange and selectivity.
Substance category (multiple selection): metal, magnetic, hard/soft acid or base, ionic, polar, Lewis acid/base, aromatic, aliphatic, inert.

The chemical nature of the stationary phase decides which substances are retained, and how strongly.

2.14.1.2 Moisture (stationary phase)

Here stands the moisture of the stationary phase — the water or solvent content of the separating medium.

Dry: activated, anhydrous medium — maximum adsorption power.
Damp / wet: partly or heavily loaded with water — deactivated, weaker binding.
Lab air: in equilibrium with room humidity — a reproducible standard state.

The moisture shifts the adsorption strength and the selectivity of the medium.

2.14.1.3 Acid-base behaviour (stationary phase)

This field records the Brønsted acid-base behaviour of the stationary phase — its ability to donate or accept protons.

Protonic (H) / weakly protonic (h): proton donor of differing strength.
Amphoteric (A): can both donate and accept protons.
Aprotic (N): no proton exchange.
Ionic (I): built from ions.
Proton acceptor (oh) / strong acceptor (OH): basic, takes up protons.

The acid-base behaviour governs the interaction with and retention of protic substances.

2.14.1.4 Substance category (stationary phase)

This field assigns the stationary phase to one or more substance categories (multiple selection).

Metal / magnetic: metallic or magnetisable media.
Hard/soft acid or base, Lewis acid/base: two different acid-base concepts — the Lewis concept stresses the electron-pair acceptor/donor properties (rather with organic molecules), while the HSAB concept looks more at the charge/radius ratio and the polarisability (rather with inorganic, salt-like substances).
Ionic / polar: charged or polar interactions.
Aromatic / aliphatic: π-system or chain structure.
Inert: largely unreactive chemically.

The category describes which interaction types the medium separates by.

2.14.2 For the discharge phase

2.14.2.1 Chemical aspects of the mobile phase

This block holds the chemical aspects of the mobile phase:

Moisture: dry, damp, wet or lab air — the water content governs the eluting strength and the activity of the mobile medium.
Acid-base behaviour (Brønsted): protonic (H), weakly protonic (h), amphoteric (A), aprotic (N), ionic (I), proton acceptor (oh) up to strong acceptor (OH) — it determines proton exchange and selectivity.
Substance category (multiple selection): metal, magnetic, hard/soft acid or base, ionic, polar, Lewis acid/base, aromatic, aliphatic, inert.

The chemical nature of the mobile phase controls the migration speed of the substances and with it the separation sharpness.

2.14.2.2 Moisture (mobile phase)

Here stands the moisture of the mobile phase — the water or solvent content of the transport medium.

Dry: anhydrous eluent — strong, undiluted action.
Damp / wet: partly or heavily water-bearing — changes the eluting strength.
Lab air: in equilibrium with room humidity — a reproducible standard state.

The moisture shifts the eluting strength and with it the migration of the substances.

2.14.2.3 Acid-base behaviour (mobile phase)

This field records the Brønsted acid-base behaviour of the mobile phase — its ability to donate or accept protons.

Protonic (H) / weakly protonic (h): proton donor of differing strength.
Amphoteric (A): can both donate and accept protons.
Aprotic (N): no proton exchange.
Ionic (I): built from ions.
Proton acceptor (oh) / strong acceptor (OH): basic, takes up protons.

The acid-base behaviour governs the interaction with and migration speed of protic substances.

2.14.2.4 Substance category (mobile phase)

This field assigns the mobile phase to one or more substance categories (multiple selection).

Metal / magnetic: metallic or magnetisable media.
Hard/soft acid or base, Lewis acid/base: two different acid-base concepts — the Lewis concept stresses the electron-pair acceptor/donor properties (rather with organic molecules), while the HSAB concept looks more at the charge/radius ratio and the polarisability (rather with inorganic, salt-like substances).
Ionic / polar: charged or polar interactions.
Aromatic / aliphatic: π-system or chain structure.
Inert: largely unreactive chemically.

The category describes which interaction types the transport medium separates by.

2.14.3 Second stationary phase

2.14.3.1 Chemical aspects of the second stationary phase

This block describes the chemical aspects of the second stationary phase (moisture, acid-base behaviour, substance category). It refers to the phase chosen under “2nd phase” — that phase is held in place by the separation method as well.

Moisture: dry, damp, wet or lab air.
Acid-base behaviour (Brønsted): protonic (H) through strong proton acceptor (OH).
Substance category (multiple selection): metal, magnetic, hard/soft acid or base, ionic, polar, Lewis acid/base, aromatic, aliphatic, inert.

The block stays locked while no second phase is selected, so that no chemistry is recorded for a phase that does not exist.

2.14.3.2 Moisture (second stationary phase)

This field records the moisture of the second stationary phase — its water or solvent content.

Dry: anhydrous, at full activity.
Damp / wet: partly or heavily loaded with water — deactivated.
Lab air: in equilibrium with room humidity, a reproducible standard state.

The value is recorded separately from the main phase, because both phases can carry different moisture.

2.14.3.3 Acid-base behaviour (second stationary phase)

This field records the Brønsted acid-base behaviour of the second stationary phase — its ability to donate or accept protons.

Protonic (H) / weakly protonic (h): proton donor of differing strength.
Amphoteric (A): can both donate and accept protons.
Aprotic (N): no proton exchange.
Ionic (I): built from ions.
Proton acceptor (oh) / strong acceptor (OH): basic, takes up protons.

Together with the main phase the entry shows whether the two phases differ in their proton exchange.

2.14.3.4 Substance category (second stationary phase)

This field assigns the second stationary phase to one or more substance categories (multiple selection).

Metal / magnetic: metallic or magnetisable media.
Hard/soft acid or base, Lewis acid/base: two different acid-base concepts — the Lewis concept stresses the electron-pair acceptor/donor properties (rather with organic molecules), while the HSAB concept looks more at the charge/radius ratio and the polarisability (rather with inorganic, salt-like substances).
Ionic / polar: charged or polar interactions.
Aromatic / aliphatic: π-system or chain structure.
Inert: largely unreactive chemically.

The categories appear in the pictogram to the right of the phase glyphs, opposite those of the main phase.

2.14.4 Second mobile phase

2.14.4.1 Chemical aspects of the second mobile phase

This block describes the chemical aspects of the second mobile phase (moisture, acid-base behaviour, substance category). It refers to the phase chosen under “2nd phase” — that phase is moved by the separation method as well.

Moisture: dry, damp, wet or lab air.
Acid-base behaviour (Brønsted): protonic (H) through strong proton acceptor (OH).
Substance category (multiple selection): metal, magnetic, hard/soft acid or base, ionic, polar, Lewis acid/base, aromatic, aliphatic, inert.

The block stays locked while no second phase is selected, so that no chemistry is recorded for a phase that does not exist.

2.14.4.2 Moisture (second mobile phase)

This field records the moisture of the second mobile phase — its water or solvent content.

Dry: anhydrous, at full activity.
Damp / wet: partly or heavily loaded with water — deactivated.
Lab air: in equilibrium with room humidity, a reproducible standard state.

The value is recorded separately from the main phase, because both phases can carry different moisture.

2.14.4.3 Acid-base behaviour (second mobile phase)

This field records the Brønsted acid-base behaviour of the second mobile phase — its ability to donate or accept protons.

Protonic (H) / weakly protonic (h): proton donor of differing strength.
Amphoteric (A): can both donate and accept protons.
Aprotic (N): no proton exchange.
Ionic (I): built from ions.
Proton acceptor (oh) / strong acceptor (OH): basic, takes up protons.

Together with the main phase the entry shows whether the two phases differ in their proton exchange.

2.14.4.4 Substance category (second mobile phase)

This field assigns the second mobile phase to one or more substance categories (multiple selection).

Metal / magnetic: metallic or magnetisable media.
Hard/soft acid or base, Lewis acid/base: two different acid-base concepts — the Lewis concept stresses the electron-pair acceptor/donor properties (rather with organic molecules), while the HSAB concept looks more at the charge/radius ratio and the polarisability (rather with inorganic, salt-like substances).
Ionic / polar: charged or polar interactions.
Aromatic / aliphatic: π-system or chain structure.
Inert: largely unreactive chemically.

The categories appear in the pictogram to the right of the phase glyphs, opposite those of the main phase.

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2.15 Multistage separation

2.15.1 Special features

This accordion holds what is special about the separation: whether it ran in several stages, which stage this block describes, and to which larger process the step belongs. Countercurrent operation and other peculiarities of the setup also belong here.

A multi-stage separation is not a repeated attempt but one attempt in parts — a column run twice, an extraction against three fresh portions of solvent. Only the stage number says which part of the yield the figures below refer to.

2.15.2 Multistage separation (⇶)

This mark states that the separation did not run in a single pass: a column run twice, an extraction against three fresh portions of solvent, a recrystallisation repeated until the melting point stopped moving. The use of a Vigreux column in a distillation can also be regarded as a multi-stage separation.

It changes how everything below is to be read. Without the mark a second stage looks like a repetition of the experiment with deviating values; with it, it is the continuation of the first, and a yield falling from stage to stage is the expected course rather than a contradiction.

What does not belong here: how many stages there were. That is carried by the stage number and the method name beside it.

2.15.3 Stage number (#)

Here stands the number of the stage that this block describes — 1 for the first pass, 2 for the second, and so on. Counting starts at 1 and runs without gaps.

The number is the reference of every quantity in the block. A yield of 60 % means one thing after the first stage and something quite different after the third; without it the values of several stages cannot be told apart, and an overall yield calculated from them is wrong by whole factors.

What does not belong here: a zero. An empty field is not stage 0 but “unstated”, and for a separation that ran in one pass it stays empty.

2.15.4 Part of process name (✎)

This field names the larger process of which this separation step is a part — “workup of batch 14”, “purification cascade A”, “counter-current series 3”.

It is needed because the stages of a multi-stage separation are scattered over several blocks. The stage number says which one it is, the phases and parameters say what happened — only this name binds the stages back together.

Deliberately free text: what a process is called is a matter of the lab and of the person keeping the record, and a closed list would force a step into a drawer it does not fit.

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2.16 Remarks on the whole separation (Notes & files)

This accordion at the end of the block holds a free text and files for the whole separation step — not for a single field, but for everything the block records.

A form only ever captures what is expected, or what its author considered most important. The remark is the place for what went unconsidered, or for the unexpected: which fraction was cloudy, why a column was run a second time, which observation belongs to no single field. It stays attached to its step instead of drifting into a separate note that nobody finds again.

Files are possible here, but not recommended. The form is not a file store: attachments are kept only in this browser's storage and travel only in the file ZIP. Spectra, photos and recordings are better managed in a real electronic lab notebook. The field exists so that a recording can be captured with its step when there is no other place for it.

If something important has been forgotten, please create a ticket so that it can be improved in future versions. The place for that is the Error page.

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3 Characterisation

3.1 Overview of the characterisation

This sub-form describes how a substance or a fraction was characterised. By default the immediately preceding fraction is meant, otherwise the fraction named in the nickname.

It records all methods by which the fraction was characterised and enables the associated storage of documents.

The methods range from the in-vivo test through the substance description to molecular and atomistic investigation methods. The i-links of the individual fields jump to the matching detailed explanation on this info page, provided they have been enabled by checkbox in the settings.

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3.2 Fraction

3.2.1 Fraction name

Here stands the name of the characterised fraction. By default the field is empty and then refers to the immediately preceding fraction; the autocomplete offers every fraction name assigned in the separation sub-forms, and a free name may be entered instead.

The name is what ties this characterisation to one particular fraction; without it, the measurement stands beside the separation without belonging to any part of it.

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3.3 Substance properties

3.3.1 Substance description

This accordion holds what the substance looks like: state of matter, measured purity and the observed colour. The manufacturer’s specification is accepted as a measured purity too, as long as the vessel and its contents appear outwardly trustworthy.

These are the properties a reader can check without an instrument — the first comparison against what was expected, and the plain description that every later measurement is attached to.

3.3.2 Theoretical / calculated data (Calc)

Here stands that the substance is characterised by theoretical or computed data — from quantum-chemical calculations or from tabulated values.

Computed data can serve as a reference standard: measured properties can be checked against calculated expected values. The entry here, however, says only something general. It may be that at least one characterisation was not made by comparison with values from the literature but rested on values obtained by calculation. The entry may equally say only that certain deeper theoretical calculations (quantum-mechanical calculations, reactivity simulations, force-field calculations, …) were carried out for the substance and documented.

3.3.3 State of matter of the substance (Phase)

Here stands the state of matter — solid, liquid, gaseous, dissolved — of the characterised substance or fraction under the storage conditions. Where the fraction is a mixture, the value may also be ?.

The state of matter determines handling, storage and further processing and gives a first indication of the identity of the substance.

3.3.4 Measured purity (Pur)

Here the purity of the substance is stated. Either taken from the manufacturer’s data sheet (from technical grade to analytical grade) or verified by documented measurements of one’s own (mass spectrometry, TLC, titrations, …).

Impurities disturb subsequent reactions, falsify measurements and reduce the yield of further steps. The classification decides whether the product is suitable for the intended purpose or has to be purified further.

3.3.5 Colour

The observed colour of a substance is a very conspicuous and a very poor description criterion, because even traces of foreign matter can change the colour. The only comparable criteria that are poorer still are a marked taste or a penetrating smell — aspects this form deliberately does without, with a view to potential dangers to health. (Note: if the laboratory smells, the ventilation in the laboratory is broken, and with it your safety is at risk.)

Colour is the first and cheapest observation: it distinguishes substances, indicates oxidation or decomposition, and a deviation from the expected colour is often the earliest sign that something went wrong. The field fixes an impression that is otherwise only remembered.

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3.4 Spectroscopy

3.4.1 Infrared spectroscopy (IR)

Infrared spectroscopy examines the vibrations of molecular bonds and makes functional groups visible.

It shows the presence of characteristic groups — carbonyl, hydroxyl, amines — and thereby supports the presumed structure. A characteristic band pattern confirms the identity of the substance and can reveal impurities or incomplete conversions.

3.4.2 Microwave spectroscopy (MW)

Microwave spectroscopy is correlated with the rotational states of molecules in the gas phase.

It yields very precise information on molecular geometry and moments of inertia and thereby makes bond lengths and angles of smaller molecules accessible.

3.4.3 UV/Vis spectroscopy

UV/Vis spectroscopy measures the absorption of ultraviolet and visible light by electronic transitions.

It captures conjugated systems, colour and concentrations; over the Beer-Lambert law it also yields quantitative concentration measurements. What it makes accessible is the electronic structure and the content of a substance, and with them its identity and purity.

3.4.4 X-ray spectroscopy (Xray)

X-ray spectroscopy uses X-radiation to reach the elemental composition and the bonding states.

It yields element-specific information and can show the presence of particular elements and their oxidation states.

3.4.5 Mössbauer spectroscopy (Möß)

Mössbauer spectroscopy examines the resonance absorption of gamma radiation by atomic nuclei, above all of iron.

It resolves very fine differences of the nuclear environment and reaches the oxidation state, the spin state and the coordination environment of iron-bearing and similar compounds.

3.4.6 Mass spectrometry (MS)

Mass spectrometry determines the mass of molecules and of their fragments after ionisation.

It gives the isotope distribution of the molar masses (when unfragmented) directly, and the fragmentation pattern permits conclusions about the structure. Its sensitivity also makes traces of impurities visible.

3.4.7 Atomic emission / atomic absorption spectroscopy (AES)

Atomic emission and atomic absorption spectroscopy determine elements by the light their atoms emit or absorb.

They capture metals and other elements quantitatively, down to low concentrations, and so give the element content of the substance.

3.4.8 Optical polarisation (Pol)

The optical polarisation measurement records how far a substance turns the plane of vibration of polarised light.

It shows optical activity and chirality and distinguishes mirror-image isomers. For a chiral active substance it is the measurement that establishes the stereochemical purity.

3.4.9 Crystal structure analysis (Xtal)

The crystal structure analysis — usually by X-ray diffraction — determines the spatial arrangement of the atoms in the solid.

It yields bond lengths, angles and the three-dimensional arrangement directly, and with them the complete molecular and crystal structure.

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3.5 Measured properties

3.5.1 Thermodynamics

3.5.1.1 Thermodynamic constants

This block holds thermodynamic constants of the substance, such as melting temperature and boiling temperature.

These characteristic quantities help with the test of identity and purity: a sharp melting point speaks for a pure substance, and the measured values can be compared with the literature data. They also make the behaviour of a substance under temperature changes predictable.

3.5.1.2 Melting point

Here stands the melting point of the characterised substance — the temperature at which the solid turns liquid.

A sharp melting point speaks for purity, a broad melting range points to impurities or to a mixture. The measured value can be compared with literature data in order to check the identity — a classical, simple means of identification. The melting temperature is less sensitive to pressure than the boiling temperature.

3.5.1.3 Boiling point

Here stands the boiling point of the substance — the temperature at which it passes into the gaseous state. It carries meaning only together with the pressure at which it was measured.

The boiling point identifies liquids and decides whether a distillation can separate two components at all.

3.5.1.4 Decomposition point

Here stands the decomposition point — the temperature at which the substance changes chemically instead of merely melting or boiling.

It marks the upper limit of any reversible thermal treatment: above it the substance does not remain the one that was weighed in, and drying, distilling or melting above this temperature would destroy the original substance.

3.5.1.5 Parameter 1

Here stands a freely nameable measured value among the thermodynamic constants — number, unit and, beside them, the name of the quantity.

No further list for intensive thermodynamic measured values is defined here. Thermal conductivity, heat capacity and other similar values can be entered here with a name, a value plus a unit. In case of doubt, or where a misunderstanding is possible, please give further details in the free text.

3.5.1.6 Parameter 2

Here stands a second freely nameable measured value among the thermodynamic constants — number, unit and, beside them, the name of the quantity.

3.5.2 Physics

3.5.2.1 Physical properties

This block holds the physical properties of the substance: density, refractive index, solubility, conductivity.

These properties describe the substance measurably and can be held against literature values — which makes them the working instrument of identity and quality control.

3.5.2.2 Refractive index

Here stands the refractive index of the substance, usually measured on a liquid with a refractometer. The refractive index is a unitless number. If a unit is entered, an error message is shown.

It can be determined quickly and on a small sample and reacts sensitively to water content and residual solvent, so it checks identity and purity without consuming material.

3.5.2.3 Density

Here stands the density of the substance — mass per volume, with the unit beside the value. Please state the units. No conversion to kg/l takes place.

The density converts a measured volume into a mass and back, which every calculation of amounts relies on. Like the other constants it depends on temperature and purity.

3.5.2.4 Viscosity

Here stands the viscosity — how strongly the substance resists flowing.

It decides how a liquid can be handled at all: pipetting, filtering, stirring and pumping depend on it, and it changes strongly with temperature.

3.5.2.5 Resistance

Here stands the electrical resistance of the substance or of its solution — or its reciprocal, the conductivity.

It shows whether free ions are present: it distinguishes a salt solution from a molecular one, detects residual electrolyte after a wash, and serves as a purity criterion for water.

3.5.2.6 Parameter 4

Here stands a freely nameable measured value among the physical properties — number, unit and, beside them, the name of the quantity.

No further list for intensive physical measured values is defined here. Surface tension, fractal dimension and other similar values can be entered here with a name, a value plus a unit. In case of doubt, or where a misunderstanding is possible, please give further details in the free text.

3.5.2.7 Parameter 5

Here stands a second freely nameable measured value among the physical properties — number, unit and, beside them, the name of the quantity.

3.5.2.8 Parameter 6

Here stands a third freely nameable measured value among the physical properties — number, unit and, beside them, the name of the quantity.

3.5.2.9 Parameter 7

Here stands a fourth freely nameable measured value among the physical properties — number, unit and, beside them, the name of the quantity.

3.5.3 Chemistry

3.5.3.1 Chemical properties

This block holds the chemical properties of the substance: reactivity, acid-base behaviour, redox behaviour, stability.

They determine how the substance reacts in further reactions and under which conditions it stays stable — and with that, its suitability for the planned application.

3.5.3.2 Empirical molecular formula

Here stands the empirical molecular formula of the substance, optionally with the mass fraction of each element in percent. Beside the formula the field carries the element fractions, the tolerance of the percentage sum (2 percentage points by default) and a multiplier for scaling the indices.

The elemental composition is an instrument-independent identity feature and allows a plausibility check of the assumed structure.

3.5.4 Solubility

3.5.4.1 Solubility (good / moderate / poor)

This sub-block holds the solubility behaviour of the substance in common solvents, graded as highly, moderately and poorly soluble.

The solubility pattern characterises the substance, guides the choice of solvent for work-up and crystallisation, and gives indications of polarity and purity.

3.5.4.2 Highly soluble in

Here stand the solvents in which the substance is highly soluble — several may be marked.

What dissolves well is suitable as a reaction medium and for washing a residue — and is precisely unsuitable for triggering a precipitation.

3.5.4.3 Moderately soluble in

Here stand the solvents in which the substance is moderately soluble — several may be marked.

Moderate solubility is exactly what a recrystallisation needs: dissolving when hot, crystallising when cold. The middle class is therefore the most valuable one for purification.

3.5.4.4 Poorly soluble in

Here stand the solvents in which the substance is poorly soluble — several may be marked.

Poor solubility is a tool, not a defect: such solvents precipitate the substance, wash it with little loss and separate it from better-dissolving impurities.

3.5.5 Theoretical values

3.5.5.1 Theoretical properties

This accordion marks data that were calculated or derived theoretically rather than measured.

A calculated value carries a different uncertainty from a measured one: it is only as good as the model behind it and must never be read as evidence. The accordion keeps calculation and measurement apart in the record.

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3.6 Effects

3.6.1 Biological tests

3.6.1.1 Biological tests

This accordion holds the living systems on which the substance was tested: humans, animals, plants or cell cultures.

A biological effect is, for many substances, the reason they are made at all — and the system tested decides what a result may be transferred to. Note that the chemistry of a body changes gradually over a lifetime.

3.6.1.2 Human tests

Here stands a biological test relating to humans — on tolerability or on efficacy.

It applies where the substance is meant to develop a physiological effect or where its safety has to be shown. Such tests are subject to strict ethical and legal requirements.

3.6.1.3 Animal tests

Here stands a biological test on animal organisms.

It applies where the biological effect or the toxicity is investigated in a living system. Animal experiments are strictly regulated by law and have to be ethically justified.

3.6.1.4 Plant & insect tests

Here stands a biological test on plants and insects.

It applies where a fertilising, protective or inhibiting effect on plants, or a repellent or lethal effect on insects, is investigated.

3.6.1.5 Microbial tests

Here stands a biological test at the cellular level — cell cultures — or at the microbiological level: bacterial and fungal cultures.

Such tests investigate the effect on single cells without claiming a whole organism, and so allow early and targeted statements about a cellular, fungicidal or antibacterial effect.

3.6.2 Microscopy

3.6.2.1 Microscopy

This accordion holds which microscopy was used: light, electron or emission microscopy.

The method decides what can be seen at all — a crystal habit needs a different resolution from a surface structure.

3.6.2.2 Emission microscopy

Here stands a surface analysis by emission microscopy.

It makes surface condition, adsorption potentials and other local properties visible by means of emitted radiation, and so documents the microstructure of the surface.

3.6.2.3 Classical microscopy

Here stands a surface analysis by classical light microscopy.

It is the simple way to crystal form, grain size and homogeneity and gives first indications of purity and crystallinity.

3.6.2.4 Electron / atomic force microscopy

Here stands a surface analysis by electron or atomic force microscopy.

It resolves down to the nanometre range and reaches surface structures a light microscope cannot show. Recent studies find that many catalysed surface reactions run preferentially at step edges and corners; the shape of a substance can matter as much for the efficiency of a reaction as its molecular structure.

3.6.3 Description of the shape

3.6.3.1 Description of the shape under the microscope

Sixteen short catalogues for what the eyepiece shows: shape, arrangement, surface, behaviour in polarised light.

They describe the finding, while the three ticks above name the method. Every list carries a „?“ for ‚not looked at‘ and a „…“ for a case that belongs in the notes rather than in a term. None of these entries is drawn in the pictogram — they live in the record and in the protocol.

3.6.3.2 Shape of the crystals

The outline of the single crystal as it appears under the microscope.

The shape follows the lattice and the speed of growth: needles and fibres point to fast growth out of a thin solution, plates and prisms to slow growth.

3.6.3.3 Arrangement of the crystals

How the single crystals lie towards one another.

An arrangement is a finding of its own: rosettes and stars arise around a nucleus, parallel bundles along a surface — the arrangement tells where the growth started.

3.6.3.4 Size of the crystals

A rough size class of the single crystal, not a measurement.

Whoever has measured the edge length writes the number into the notes; here stands only the impression at the eyepiece, which every later reader can compare.

3.6.3.5 Branching of the crystals

Whether a crystal branches out while it grows.

Treelike (dendritic) growth is the sign of a strongly supersaturated solution or of quick cooling — the crystal had no time to grow evenly.

3.6.3.6 Surface of the crystals

What the face of the crystal looks like.

Striations and a granular face carry information about the growth steps; a smooth face speaks for undisturbed growth.

3.6.3.7 Tips and ends of the crystals

How a crystal ends at its tip.

Rounded ends point to a beginning dissolution, sharp tips to growth that was still going on when the sample was taken.

3.6.3.8 Birefringence

How strongly the crystal splits the light between crossed polarisers.

Only an optically isotropic body (cubic lattice, glass, liquid) stays dark. Any birefringence is therefore already a statement about the lattice.

3.6.3.9 Twinning

Whether two or more crystals have grown together in a lawful position.

Twins are not an impurity: they follow the symmetry of the lattice. Lamellar twins in particular often appear only under polarised light.

3.6.3.10 Inclusions in the crystals

What the crystal has enclosed while growing.

An inclusion is trapped mother liquor, dust or gas. It lowers the purity without showing up in an elemental analysis — and it explains a melting point that is too low.

3.6.3.11 Cracks in the crystals

Whether the crystal is cracked or shattered.

Cracks arise on drying, on grinding and on quick cooling. They decide whether the sample can still be judged under polarised light at all.

3.6.3.12 Contour of the crystals

How regular the outline of the crystal is.

A regular contour speaks for an undisturbed lattice; an irregular one for growth against an obstacle, for attrition or for a beginning dissolution.

3.6.3.13 Aggregate of the crystals

Whether single crystals lie there or a grown-together body.

The distinction decides what can be measured at all: a single crystal can be indexed, a large aggregate only weighed and described.

3.6.3.14 Transparency of the crystals

How much light the crystal lets through.

A substance that is transparent as a single crystal may look white as a powder — the transparency belongs to the single crystal, the colour to the sample.

3.6.3.15 Behaviour in polarised light

What happens when the sample is turned between crossed polarisers.

No change at all means an isotropic body. A change in brightness and interference colours prove an ordered, anisotropic lattice.

3.6.3.16 Colour change on rotation

Whether the colour changes while the sample is turned (pleochroism).

The effect needs a coloured, anisotropic crystal: the lattice swallows light of different directions differently. It is a property of the substance, not of the lighting.

3.6.3.17 Extinction between crossed polarisers

At which angle the crystal goes dark while it is turned.

Straight extinction (parallel to an edge) and oblique extinction distinguish crystal systems — it is the cheapest hint at the symmetry that a light microscope gives.

3.6.4 Chromatography

3.6.4.1 Chromatography note

This block holds the characterisation by chromatography — a separation technique that serves identification and purity testing at once. An Rf or Rt value is always to be entered in the subform.

Chromatography characterises a substance by its Rf or Rt value and at the same time makes impurities visible as additional signals. What is recorded here are the separation conditions and the characteristic values that make a substance comparable and recognisable.

3.6.4.2 Rf value (TLC/paper)

Here stands the Rf value of thin-layer or paper chromatography — the ratio of the migration distance of the substance to that of the eluent, a value between 0 and 1. Entered separately are the migration distance of the front (base value) and the distance of the substance (component value); the Rf value is the ratio of the two.

Under defined conditions the Rf value is characteristic of a substance. It is the comparison value by which a substance is recognised and told apart from its impurities.

3.6.4.3 Rt value (LC/GC)

Here stands the Rt value — the retention time of liquid or gas chromatography, the time a substance needs to reach the detector. Entered separately are the running time of the eluent through the column (base value) and the running time of the substance (component value); the retention value is the ratio of the two.

Under defined conditions the Rt value is characteristic of a substance; the number of signals beside it also allows the purity to be judged.

3.6.4.4 Type of chromatography (type)

Here stands the purpose of the chromatographic technique. Thin-layer chromatography mostly represents an analytical chromatography, while column and liquid chromatography mostly stand for preparative applications. With gas chromatography one tends to pursue analytical goals.

Different techniques suit different classes of substance and questions. Without the technique the characteristic values Rf and Rt cannot be classified.

3.6.4.5 Mobile phase (fluid, eluent, solvent)

Here stands the mobile phase, the eluent of the chromatography.

Its composition determines the migration speed and with it the separation of the substances. Without it an Rf or Rt value is not reproducible.

3.6.4.6 Stationary phase (fill, packing material, filler)

Here stands the stationary phase, the packing of the chromatographic separation path.

It retains the substances to differing degrees and thereby produces the separation effect. Without it the characteristic values are not reproducible.

3.6.4.7 Driving pressure (p)

Here stands the driving pressure with which the mobile phase is conveyed through the separation path.

In high-performance liquid chromatography it determines the flow rate and with it the separation performance and duration, and so influences the retention time.

3.6.4.8 Additional separating force (F+)

Here stands an additional separating force acting beyond the ordinary flow — an electric field in electrophoresis, for instance.

Such a force allows the separation by further properties, charge above all, and so adds a second separation principle to the first.

3.6.4.9 Detection method (det)

Here stands the detection method by which the separated substances are detected at the end of the separation path — UV absorption, refractive index, mass spectrometry.

The detection determines which substances become visible at all and how sensitively they can be detected; it is how the separation results were recorded.

3.6.4.10 Two-dimensional chromatography (2D)

Here stands that the separation was carried out two-dimensionally — one after the other in two different directions, or with two different systems.

The second dimension raises the separation performance considerably and resolves mixtures that would overlap in one dimension.

3.6.4.11 Conditions during the chromatography (Cond)

This sub-block holds the conditions kept during the chromatographic separation: closed off from the atmosphere, exclusion of light, freedom from electrosmog, dryness and the drying agent used.

A chromatogram runs for minutes to hours, and in thin-layer chromatography large surfaces can lie open. A plate developed in daylight, a column drawing air humidity, a sample oxidising on silica — the spot then shifts or disappears, and the substance appears to carry the cause of the wrong measurement, although the sensitive framework conditions were not kept reproducibly. With the framework conditions of a chromatography the greatest care should be taken.

A condition left unticked here is reported in the protocol as left to chance. That is the honest statement, not a blank.

3.6.4.12 Inert gas atmosphere (▣)

The ticked checkbox represents the framework condition that the chromatography ran in a closed space under an oxygen-free inert-gas atmosphere, for example under N₂ or Ar gas, whereby the gas need not necessarily be dry.

Air- or oxygen-sensitive substances must not oxidise during the separation; the inert atmosphere keeps oxygen and atmospheric moisture out for the length of the analysis.

3.6.4.13 Exclusion of light (☀)

The ticked checkbox represents the framework condition that the chromatography ran with the exclusion of light.

Light-sensitive substances could decompose during the separation or enter reversible reactions that falsify the result; the darkness rules out a photochemical influence on the results.

3.6.4.14 Protection against electrosmog (¬↯)

The ticked checkbox represents the framework condition that the chromatography ran free of electromagnetic interference fields. Bear in mind that a magnetic stirrer carries a magnetic field into the system which is considerably stronger than the magnetic field of the earth and therefore counts as mild electrosmog as well.

Where field-assisted separation or detection methods are used, external fields disturb them. Electromagnetic fields can moreover influence the reaction or the formation of crystals.

3.6.4.15 Dryness (☂)

The ticked checkbox represents the framework condition that the chromatography ran with the exclusion of moisture. Otherwise an interaction sets in with the air humidity of the laboratory, or with the moisture in an undried inert gas (Ar, N₂, …).

Moisture alters the stationary phase and damages hydrolysis-sensitive substances.

3.6.4.16 Drying agent (Tm)

3.6.5 Electrochemistry

3.6.5.1 Electrochemistry

This accordion holds which electrochemical method was used: potentiometry, coulometry, amperometry or a special procedure.

These methods measure what a spectrum cannot show: the willingness of the substance to give up or take on electrons, and how much of it is present. They document the redox behaviour beside the structure.

3.6.5.2 Potentiometry

Potentiometry measures the electrical voltage — the potential — of a solution without appreciable current flow.

It helps determine ion concentrations and pH values and so opens up redox equilibria; what it captures quantitatively is the electrochemical behaviour of the substance.

3.6.5.3 Coulometry

Coulometry determines an amount of substance from the electric charge needed for its complete conversion.

In the ideal case, and where no side reaction runs, it yields an absolute and very precise quantity determination resting directly on Faraday's law.

3.6.5.4 Amperometry

Amperometry measures the electric current that flows through an electrochemical reaction at a fixed voltage.

The measured current is proportional to the concentration of an electroactive substance, which makes concentrations accessible through the current flow and allows sensitive determinations.

3.6.5.5 Additional electrochemical methods (? - unknown)

Here stand further, special electrochemical methods — voltammetry, impedance spectroscopy and the like.

They answer particular electrochemical questions the standard methods do not cover, and keep the record open for a specialised analysis.

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3.7 Magnetic resonance measurements (NMR/ESR)

3.7.1 NMR / ESR spin coupling

This accordion holds the matrix of nucleus × coupling partner: each ticked cell is one recorded spectrum.

A coupling reveals neighbourhood — which nuclei sit next to each other — and so turns a list of signals into a structural skeleton. The matrix distinguishes fourteen measurements that would otherwise all be called “NMR”.

3.7.2 ¹H NMR spectroscopy (H-1)

Proton NMR spectroscopy (¹H) examines the nuclear spin of the hydrogen nuclei and so reaches the bonding environment of the nucleus. With special measurement settings, the resonance couplings with other spins may possibly have been measured in parallel as well.

It makes the number, kind and neighbourhood of the hydrogen atoms visible and thereby opens up the carbon skeleton. Chemical shift, splitting and integration together confirm the structure and reveal impurities.

3.7.3 ¹³C NMR spectroscopy (C-13)

Carbon NMR spectroscopy (¹³C) examines the nuclear spin of the carbon nuclei and so reaches the bonding environment of the nucleus. With special measurement settings, the resonance couplings with other spins may possibly have been measured in parallel as well.

It depicts the carbon skeleton directly and lets the number of chemically different carbon atoms be read off; it complements the ¹H spectrum.

3.7.4 Heteronuclear NMR spectroscopy (Hetero)

Heteronuclear NMR spectroscopy examines the nuclear spin of magnetically active nuclei other than hydrogen and carbon — nitrogen, phosphorus, fluorine — and so reaches the bonding environment of the nucleus. With special measurement settings, the resonance couplings with other spins may possibly have been measured in parallel as well.

It applies where such heteroatoms play a key role in the structure and are to be detected specifically.

3.7.5 Electron spin resonance (ESR/EPR)

Electron spin resonance — ESR, also EPR — examines unpaired electrons in a substance. With special measurement settings, the resonance couplings with other spins may possibly have been measured in parallel as well.

It makes the environment of unpaired electrons visible and so gives access to radicals, paramagnetic centres such as transition-metal ions, and oxidation states.

3.7.6 H1-NMR (H-1–∅)

Here stands that a H1-NMR spectrum was taken — a spectrum of the ¹H nucleus without evaluating a coupling.

This spectrum carries the base information: which nuclei of this kind are present at all, and what surroundings they sit in.

3.7.7 H1-H1-NMR (H-1–H)

Here stands that a H1-H1-NMR spectrum was taken — a spectrum of the ¹H nucleus, evaluated for the coupling with ¹H. The dependencies may have been found by 2D-NMR or by higher-dimensional NMR techniques.

Only the coupling reveals neighbourhood: it shows which nuclei sit next to each other in the molecule and turns a list of signals into a structural skeleton. The matrix distinguishes fourteen measurements that would otherwise all be called “NMR”.

3.7.8 H1-C13-NMR (H-1–C)

Here stands that a H1-C13-NMR spectrum was taken — a spectrum of the ¹H nucleus, evaluated for the coupling with ¹³C. The dependencies may have been found by 2D-NMR or by higher-dimensional NMR techniques.

3.7.9 H1-Hetero-NMR (H-1–X)

Here stands that a H1-Hetero-NMR spectrum was taken — a spectrum of the ¹H nucleus, evaluated for the coupling with a hetero nucleus. The dependencies may have been found by 2D-NMR or by higher-dimensional NMR techniques.

3.7.10 H1-e⁻-ESR (H-1–e⁻)

Here stands that a H1-e⁻-ESR spectrum was taken — a spectrum of the ¹H nucleus, evaluated for the coupling with the unpaired electron. The dependencies may have been found by 2D-NMR or by higher-dimensional NMR techniques.

3.7.11 C13-NMR (C-13–∅)

Here stands that a C13-NMR spectrum was taken — a spectrum of the ¹³C nucleus without evaluating a coupling. The dependencies may have been found by 2D-NMR or by higher-dimensional NMR techniques.

This spectrum carries the base information: which nuclei of this kind are present at all, and what surroundings they sit in.

3.7.12 C13-C13-NMR (C-13–C)

Here stands that a C13-C13-NMR spectrum was taken — a spectrum of the ¹³C nucleus, evaluated for the coupling with ¹³C. The dependencies may have been found by 2D-NMR or by higher-dimensional NMR techniques.

3.7.13 C13-Hetero-NMR (C-13–X)

Here stands that a C13-Hetero-NMR spectrum was taken — a spectrum of the ¹³C nucleus, evaluated for the coupling with a hetero nucleus. The dependencies may have been found by 2D-NMR or by higher-dimensional NMR techniques.

3.7.14 C13-e⁻-ESR (C-13–e⁻)

Here stands that a C13-e⁻-ESR spectrum was taken — a spectrum of the ¹³C nucleus, evaluated for the coupling with the unpaired electron. The dependencies may have been found by 2D-NMR or by higher-dimensional NMR techniques.

3.7.15 Hetero-NMR (Hetero–∅)

Here stands that a Hetero-NMR spectrum was taken — a spectrum of the hetero nucleus without evaluating a coupling. The dependencies may have been found by 2D-NMR or by higher-dimensional NMR techniques.

This spectrum carries the base information: which nuclei of this kind are present at all, and what surroundings they sit in.

3.7.16 Hetero-Hetero-NMR (Hetero–X)

Here stands that a Hetero-Hetero-NMR spectrum was taken — a spectrum of the hetero nucleus, evaluated for the coupling with a hetero nucleus. The dependencies may have been found by 2D-NMR or by higher-dimensional NMR techniques.

3.7.17 Hetero-e⁻-ESR (Hetero–e⁻)

Here stands that a Hetero-e⁻-ESR spectrum was taken — a spectrum of the hetero nucleus, evaluated for the coupling with the unpaired electron. The dependencies may have been found by 2D-NMR or by higher-dimensional NMR techniques.

3.7.18 ESR - electron spin resonance (electron–∅)

Here stands that a ESR spectrum was taken — a spectrum of the e⁻ nucleus without evaluating a coupling.

This spectrum carries the base information: which nuclei of this kind are present at all, and what surroundings they sit in.

3.7.19 ESR with e⁻-e⁻ coupling (electron–e⁻)

Here stands that a ESR with e⁻-e⁻ coupling spectrum was taken — a spectrum of the e⁻ nucleus, evaluated for the coupling with the unpaired electron. The dependencies may have been found by 2D-NMR or by higher-dimensional NMR techniques.

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3.8 Long-term storage

3.8.1 Storage conditions

This accordion holds how the substance is kept after the work: in the dark, dry, closed off from the atmosphere, free of electrosmog, and over which drying agent.

Many preparations change more in storage than during the synthesis — light, moisture and oxygen work slowly but without pause. What is recorded here makes a later deviation attributable.

3.8.2 Inert gas atmosphere (▣)

The ticked checkbox represents the framework condition that the substance is stored under a protective gas atmosphere, for example under N₂ or Ar gas, whereby the gas need not necessarily be dry.

Air- or oxygen-sensitive substances would otherwise oxidise or react with components of the air, and the product would lose its stability over time.

3.8.3 Exclusion of light (☀)

The ticked checkbox represents the framework condition that the substance is stored with the exclusion of light.

Light-sensitive substances decompose or change their properties under light; the darkness prevents photochemical degradation during storage.

3.8.4 Protection against electrosmog (¬↯)

The ticked checkbox represents the framework condition that the substance is stored free of electromagnetic interference fields. Bear in mind that even a magnetic stirrer standing nearby carries in a magnetic field which is considerably stronger than the magnetic field of the earth and therefore counts as mild electrosmog as well.

It applies where the substance has magnetic or field-sensitive properties that are to be preserved. Electromagnetic fields can moreover influence the reaction or the formation of crystals.

3.8.5 Dryness (☂)

The ticked checkbox represents the framework condition that the substance is stored with the exclusion of moisture. Otherwise an interaction with the air humidity of the laboratory sets in.

Hygroscopic or hydrolysis-sensitive substances would otherwise take up water or be decomposed, and both shelf life and purity would suffer.

3.8.6 Drying agent (Tm)

Here stands which drying agent the substance is kept over, if it is stored dry according to the checkbox. From that the degree of dryness the storage approximately reaches can be estimated.

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4 Observation

4.1 Overview of the observation

This sub-form is devoted to the observation of the reaction space or of the space in which the separation takes place in a separation procedure. Observations are always tied to points in time and always describe only a short period. Which space is meant always follows implicitly from the preceding description in the course protocol.

Observations capture how a system behaves (colour, turbidity, gas evolution, second phase appearing) and are the empirical basis for interpreting a preparation. The i-links of the individual fields jump to the matching detailed explanation in this overview page.

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4.2 Time

4.2.1 Point in time of the observation

This block holds the point in time at which an observation was made on the reaction system. Because the period of an observation is always relatively short, the end point of the observation is not recorded here.

Reactions are dynamic processes: colour, temperature, gas evolution and turbidity change over the course. Only the link between an observation and a point in time makes the sequence reconstructible and the relation between two observations visible.

4.2.2 Timestamp (Time)

This block of output field, input field and buttons records the timestamp of the observation. Timestamp means the number of seconds that have elapsed since 1 January 1970 (Unix time). The entered point in time is mentioned in the protocol and is also shown in the SVG at the top left without the year. A time span is deliberately not recorded, because an observation always takes place within a relatively short time span.

Many phenomena occur during a reaction or during a separation procedure only at particular times, and their temporal position permits conclusions about reaction rate and mechanism. A later repetition can check specifically whether the same processes occur at the same times.

On operating it: the upper field shows the currently stored point in time to the minute. The field below it allows the manual entry of a point in time, which is transferred into the upper field after confirmation, whereas faulty entries instead lead to error notices. With the “Now” button the current point in time can be entered, while with the “Delete” button an entry can be deleted. Through the select box “Earlier value” a date value already entered in the present block can be restored.

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4.3 Phase in the system

4.3.1 Observed phase

This block describes the observed phase or the observed phases in the reaction system; besides the state of matter, the viscosity is to be estimated as well. An interpretative assessment of the moisture, of the acid-base properties and of further chemical properties is omitted, because it contradicts observing.

The state of the reaction mixture can change during the conversion: a solid melts, a solution separates, a melt solidifies. The description fixes the physical state at the time of the observation and so makes the change over time readable.

4.3.2 State of matter of the phase (Phase)

Here the state of matter can be specified, for example solid, liquid, gaseous, dissolved, aqueous solution and so on.

The state of matter determines reactivity, mixing and phase boundaries. A phase change during the reaction is often the visible sign of a substance conversion, and comparing the observed state with the expected one is how an unexpected transition becomes visible.

4.3.3 Viscosity of the phase (Visc.)

Here stands the viscosity — the thickness or flowability of the observed phase.

A change in viscosity points to polymerisation, gel formation, a change in concentration or a temperature influence. Thickening and thinning are often the first perceptible signs of a material change, and so an indirect reading of the reaction progress.

4.3.4 Observed secondary phase (2nd phase)

Here the state of matter of the secondary phase can be specified, provided a second phase is present in the observed reaction or separation space.

This is useful because the observed system can consist of more than one phase. For systematics, a main phase and a secondary phase are distinguished; further phases are not listed, even if — for example across different crystals — additional phases could exist.

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4.4 Pressure and temperature

4.4.1 Temperature and pressure

This block holds the temperature and pressure conditions under which the observation was made.

Both quantities control reaction rate, position of equilibrium and state of matter. Even small deviations can change the outcome of a reaction, which is why the remaining observations can only be read against them.

4.4.2 Mean value or lower limit (Main)

Here stands the main value of the parameter — the governing temperature or pressure at the time of observation. Where an upper value is given as well, this entry is the lower bound of the measured range.

It is the reference point the reaction is oriented by and against which a planned target value is compared.

4.4.3 Upper limit (Add)

Here stands the additional value beside the main value — an upper limit, a final value, the other end of a range.

Many conditions are sensibly described not as a single point but as a range: a temperature interval within which a process is observed. The additional value carries the fluctuation a single main value could not show.

4.4.4 Temperature (T)

Here stands the temperature of the reaction system at the time of observation.

The temperature influences the reaction rate exponentially, shifts equilibria and decides whether side or decomposition reactions occur. Only with it can it be judged whether the reaction ran inside the intended window.

4.4.5 Pressure (p)

Here stands the pressure under which the observation was made.

Where gases are involved the pressure shifts gas equilibria, influences boiling points and solubilities, and in closed apparatus it is safety-relevant. It carries both the reading of gas-involving processes and the assessment of an overpressure risk.

4.4.6 Qualitative temperature statement (Qual. T.)

Every term carries its conventional value in kelvin with it — in the parenthesis of the label and as a machine value in the markup. In this way even a temperature that was not measured exactly is given an approximate statement.

4.4.7 Qualitative pressure statement (Qual. p)

Here a customary name represents the approximate, unmeasured pressure statement. Terms such as “water-jet pump”, “standard pressure”, “high vacuum” can be used as a synonym for approximate pressure values or orders of magnitude of pressure. If nothing is selected, the entry stays empty and standard pressure (1013 hPa) is assumed.

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4.5 Stirring parameters

4.5.1 Stirring

This block holds the stirring — how strongly the observed phase is moved, and with which tool.

In an observation the movement is part of the picture: a stirring bar throws a funnel, a nozzle a trail of bubbles. Without that note the look of the phase cannot be told apart from the phenomenon that was to be observed.

4.5.2 Lower or middle stirring stage (Main)

This column carries the lower or middle stirring stage: the choice on the fixed scale and, beside it, a measured value with a unit, for example 120 rpm.

The stage is coarse and therefore comparable everywhere; the number beside it is exact and holds for this device only. Together they say more than either alone.

4.5.3 Upper stirring stage (Add)

This column carries the upper stirring stage — the same scale and the same measured value as on the left, but for the other end of a span.

Where the stirring differs over a period, only the pair of both stages describes the process; with steady stirring this column stays empty.

4.5.4 Stirring intensity (↺)

Here stands the stirring intensity with which the phase is moved during the observation. Beside each of the two levels a measured value with a unit may stand, for example 120 rpm.

4.5.5 Stirrer type (⚙️)

Here stands which stirring tool was used: a magnetic stirrer, a KPG stirrer (KPG = core-drawn precision glass apparatus; a driven glass shaft with a rigid blade) or a mixing nozzle.

The three differ not merely in strength but in the kind of motion they produce. A magnetic stir bar drives the liquid near the bottom of the vessel and stalls in viscous or heavily loaded mixtures; a KPG stirrer reaches the whole volume and tolerates suspensions; a mixing nozzle mixes by a jet instead of a rotating part and can introduce a gas or a second liquid while it does so. For an observation the tool is itself part of the picture: a stir bar throws a vortex, a nozzle a train of bubbles, and without the note the appearance cannot be told apart from the phenomenon that was to be observed.

What does not belong here: how strongly it was stirred. That is what the intensity scale and the specification beside it are for.

4.5.6 Stirrer specification (📝)

This free-text field holds the exact stirring tool during the observation: model, speed and the geometry of the stirring element — for example “Rühry Cool Dauerwelle, 2000 rpm, induction rod”.

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4.6 Intensive measured parameters

4.6.1 Intensive

This block holds further, freely definable parameters observed beyond temperature and pressure.

Every reaction can have measured quantities of its own — conductivity, refractive index, density, irradiance. They have no field of their own and are named here.

4.6.2 Mean value or lower limit (Main)

Here stands the main value of a freely chosen additional parameter — the mean value or the lower limit of a quantity that fits none of the standard fields.

It is what makes an unconventional measured quantity quantitatively recordable at all.

4.6.3 Upper limit (Add)

Here stands the additional value of the freely chosen parameter — the upper limit of a range, or a comparison value.

Individual measured quantities, too, are often described more sensibly as a span than as a single value; the additional value carries that span.

4.6.4 Freely definable parameter 1 (? - unknown)

Here stands a second freely nameable parameter of the observation.

Several unusual quantities are often of interest at the same time and are to be documented side by side; that is what the second and third free parameter are for.

4.6.5 Freely definable parameter 2 (? - unknown)

Here stands a third freely nameable parameter of the observation.

Complex experiments can show a multitude of observable quantities; this field keeps room for the last of them.

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4.7 Observations and effects

4.7.1 Activities

The alphabetical keyword list of everything that was observed to change during the reaction. Every keyword stands for one statement. If no keyword really fits, that can be defined in the free text.

Several words may mean the same thing — they are synonyms and deliver one and the same value. Words in a dashed frame are mirrors: they set the term they stand for, and compound terms set several at once.

If an important keyword is missing, please leave a ticket in English on the Error page.

4.7.2 Keywords of the effects

4.7.2.1 Cooling

The mixture becomes colder although it is not cooled from outside — the reaction takes up heat. Typical when dissolving certain salts and in many decompositions.

Misting of the outer vessel wall can sometimes be observed on stronger cooling.

4.7.2.2 Alkalisation

The pH value grows during the observation. A change from pH 2 to pH 5 is an alkalisation as well, although the solution is still acidic (pH < 7). Alkalisation is the counterpart of acidification.

If a solution feels soapy on accidental contact (an accident?), this can be a hint at a more strongly alkaline solution. Such touch tests are not advisable for reasons of health and safety, though. Using an indicator paper is always the better way.

4.7.2.3 Tarnishing

A solid surface loses its shine or covers itself with a layer. Unlike a colour change this concerns only the interface, not the whole material.

As with aluminium the tarnish layer can protect the metal, or it can keep eating in as rust does with iron. That depends on the material and on the kind of tarnish layer.

4.7.2.4 Acidification

The pH value falls during the observation. A change from pH 13 to pH 10 is an acidification as well, although the solution is still alkaline (pH > 7). Acidification is the counterpart of alkalisation.

The numeric value itself belongs in the parameter block; here only the observation of the shift is recorded.

4.7.2.5 Clarification

A cloudy solution becomes transparent again. That may mean the suspended matter dissolves or that it settles — clarity alone does not say which of the two paths it was.

It is therefore worth ticking dissolution or sedimentation alongside.

4.7.2.6 Dissolution

Existing solid disappears into the liquid phase. The counterpart of precipitation and frequently the first step of a reaction.

If a residue remains, the dissolution is incomplete; that belongs in the remark, not in a tick of its own.

4.7.2.7 Floating

Particles of solid or droplets rise and collect at the surface. Adhering gas bubbles can carry light particles upwards — the process that flotation exploits technically.

If the floating layer forms a firm cover, the compound term crust formation fits better; it sets floating and precipitation at once.

4.7.2.8 Surging

The batch rises in the vessel, driven by the gas being formed. The compound term sets gas evolution and volume increase, because both apply at once.

If the risen batch persists as foam, foam formation is meant in addition.

4.7.2.9 Pressure drop

In a closed system the pressure falls — gas is consumed, condensed or dissolved.

A vacuum can suck liquid back out of a receiver; that is the most frequent way a batch becomes contaminated unnoticed.

4.7.2.10 Pressure rise

In a closed system the pressure rises — through gas formation, through evaporation or through warming.

Rising pressure in an apparatus not built for it is a safety event; the relief measure belongs in the remark.

4.7.2.11 Decolouration

The colour disappears entirely or becomes distinctly paler. Listed separately as a special case of colour change, because the disappearance of a colour is often the end point of a conversion.

Whoever follows a titration records here the point at which the colour does not return.

4.7.2.12 Demixing

A uniform liquid, a diffuse emulsion or a cloudy suspension becomes two separate layers. After the demixing the phase boundaries are usually clearly visible, and the division into two lends itself to a photograph.

The density of the substances decides which one lies on top and which one below.

4.7.2.13 Heating

The reaction mixture becomes distinctly hot — the heat comes from the reaction itself, not from an external source. This is the strong grade; a merely noticeable warming is a term of its own.

Without a thermometer the entry is an estimate. Whoever wants to follow the course also records the temperature in the parameter block.

4.7.2.14 Solidification

The liquid phase becomes solid. The term covers both: solidification on cooling and curing, where a reaction permanently removes mobility.

Whoever wants to tell them apart records the temperature alongside: solidification at falling temperature, whereas (reactive) curing mostly takes place at constant or rising temperature.

4.7.2.15 Warming

The weak grade of heat evolution: the vessel feels warmer without becoming hot. Keeping it apart from heating is worthwhile because the two grades point to different orders of magnitude of the reaction heat.

The distinction is deliberately coarse — it replaces no calorimetry but records what was perceptible without an instrument. Whoever wants to know it exactly measures the rise in temperature with a thermometer.

4.7.2.16 Colour change

The colour of the mixture changes. Which colours were involved belongs in the remark — the tick only records that a change took place at all.

A colour change of an indicator is at the same time a statement about acidity; then acidification or alkalisation fits as well.

4.7.2.17 Flame formation

An open flame stands above the batch. The observation is at the same time a safety event and belongs in the remark with the time of day.

If a black residue remains, charring fits in addition; for both together there is the compound term burning.

4.7.2.18 Gas evolution

Gas is formed out of the mixture, recognisable from rising bubbles or from the pressure in a closed vessel.

Whether the gas comes from the reaction or is merely evaporated solvent is decided by the temperature — if the bubbles only rise on heating, the compound term boiling is meant.

4.7.2.19 Noise

The reaction is audible — from the hiss of escaping gas to the crackling of crystallising salts.

A single loud bang with a pressure wave is no longer an ordinary noise but a deflagration. Observing a deflagration is at the same time a safety event and belongs in the remark together with the time of day.

4.7.2.20 Curdling

The liquid curdles: flakes appear and at the same time a clear phase separates. Both belong together, which is why the compound term sets both ticks.

Pure clumping without a separated phase is not curdling — then lumping alone suffices.

4.7.2.21 Change of odour

The smell changes noticeably. This perception is the least reliable in the record — it depends on the person and tires within minutes.

Deliberate wafting remains the only permissible way to smell; the kind of odour belongs in the remark. Noticing a strong change of odour is at the same time a safety event and belongs in the remark together with the time of day, because a stench can point to dangerous gases.

4.7.2.22 Glowing

Solid shines because it is hot — from dark red glow to flying sparks. An indication of temperatures far above what a thermometer in the batch still captures.

Glowing without a flame is possible; only when a flame stands does flame formation come in addition.

4.7.2.23 Lumping

Fine particles aggregate into lumps or flakes. Unlike in crystallisation no shaped form arises.

Together with a demixing this yields the compound term curdling.

4.7.2.24 Colloid formation

Finely dispersed particles arise in the mixture which neither dissolve nor settle: they stay suspended. The border with turbidity is a fluid one — a colloid may look clear to the eye and still be one.

The simplest proof is the Tyndall effect: a beam of light sent sideways through the vessel is scattered by the particles and becomes visible as a luminous path. In a true solution the beam stays invisible.

The second mark is filtration: a suspension clears up behind the filter, a colloid does not — the turbidity is kept after filtering, because the particles pass through the pores of the paper.

4.7.2.25 Condensation

Vapour becomes liquid again on a colder surface — the classic fogging of the vessel wall or condenser.

Condensate says nothing about its origin: it may come from the batch or from the laboratory air when the vessel cools. The accompanying observation (evaporation or cooling) decides that.

4.7.2.26 Crystallisation

Recognisably shaped crystals appear — faces, edges, often colour as well. That distinguishes crystallisation from a shapeless precipitate.

The distinction matters for the later characterisation: only shaped crystals are of use for a structure determination.

4.7.2.27 Crust formation

A firm cover stands at the surface. Crust formation is a compound term: it describes two processes at once — a solid appears, and this solid floats.

The tick therefore sets both single terms. In the record they appear separately, because they can be refuted separately: a crust may also consist of dried-up batch without a reaction having formed a solid.

4.7.2.28 Change of conductivity

The electrical conductivity of the solution changes — a measure of how many mobile ions are present.

The observation needs an instrument; without one it stays a guess and then belongs in the remark rather than in the tick.

4.7.2.29 Light emission

The mixture emits light of its own without becoming glowing hot. Technical terms for this excitation of light are chemiluminescence, phosphorescence and also fluorescence.

If the light comes from the heat, glowing is the right term; the two separate cold and hot light.

4.7.2.30 Precipitation

A solid forms in the solution. Whether it settles, floats or stays suspended is a second observation and is ticked separately.

A mere turbidity without recognisable particles stays turbidity — the difference is whether the solid can be seen as such.

4.7.2.31 Fall in surface tension

The surface becomes softer: drops run out, the liquid wets the glass, the meniscus flattens. An indication of a surface-active substance in the batch.

Without an instrument this is an observation of behaviour, not a number — the measured value belongs in the measured properties.

4.7.2.32 Rise in surface tension

The surface becomes firmer: the liquid beads off, contracts into drops, the meniscus curves more strongly.

Typical when a surface-active substance has been consumed or has precipitated — then a look at precipitation is worthwhile.

4.7.2.33 Smoke formation

Visible plumes stand above the batch. Smoke contains solid or liquid suspended particles and is therefore visible — a clear gas would not be.

The observation says nothing about toxicity; it is nevertheless the occasion to check the fume hood.

4.7.2.34 Change of acidity

The pH value shifts without the direction being recorded. The term remains for cases in which only the turn of an indicator was visible.

If the direction is known, acidification or alkalisation are the more precise ticks.

4.7.2.35 Foam formation

The gas bubbles persist and build a layer of foam. That presupposes a surface-active substance — pure solvents do not foam.

Foam is also a practical risk: it can carry the batch over the rim of the vessel.

4.7.2.36 Melting

A solid becomes liquid. What is observed is the transition itself, not the numeric melting point — that belongs in the measured properties.

If a substance deliquesces in moist air without becoming warm, that is not melting but dissolution in the absorbed water.

4.7.2.37 Sedimentation

Solid collects at the bottom of the vessel. What is observed is the movement, not the formation — the solid may have precipitated before or been present from the start.

Together with floating, sedimentation says something about the density of the solid relative to the liquid.

4.7.2.38 Boiling

The liquid boils: vapour bubbles form inside and rise. That is evaporation and gas evolution in one, which is why the tick sets both.

Rising bubbles alone are not yet boiling — they may also come from a reaction. Only the connection with the temperature makes it boiling.

4.7.2.39 Sublimation

A solid passes into the gas phase without becoming liquid first; often together with its counterpart, the deposition of fresh crystals at a colder spot.

The term also covers this deposition — both directions are the same phenomenon and in the flask can be seen only together anyway.

4.7.2.40 Turbidity

The solution loses its transparency without individual particles being recognisable. The cause is finest suspended solid particles or droplets.

If the solid becomes visible or settles, precipitation and sedimentation are the more precise terms to add.

4.7.2.41 Burning

The material burns and leaves a carbonaceous residue. The compound term sets flame formation and charring, because in the record both traces count separately.

A soot-free flame without residue is not burning in this sense — then flame formation alone suffices.

4.7.2.42 Evaporation

Liquid passes into the gas phase — recognisable from the falling level, from vapour above the batch or from condensate higher up.

If bubbles rise out of the liquid, the compound term boiling applies in addition; it sets evaporation and gas evolution at once.

4.7.2.43 Thickening

The liquid flows more heavily than before — recognisable at the stirrer, in the pouring behaviour or from the movement of bubbles.

If it becomes so viscous that it no longer flows, solidification is reached; the boundary is gradual and belongs in the remark.

4.7.2.44 Thinning

The liquid flows more easily than before. Usually heat is behind it, sometimes the breakdown of long molecules.

If a solid becomes liquid in the first place, melting is the more precise term.

4.7.2.45 Charring

Organic material decomposes into a black, carbonaceous residue. A clear sign that the temperature was too high or that a strongly dehydrating substance is at work.

If a flame stands at the same time, the compound term burning fits.

4.7.2.46 Mixing

Previously separate phases become a single uniform one. The counterpart of demixing and often the effect of an added mediator.

Mere stirring without lasting uniformity is not mixing — the state has to hold after the stirrer is switched off.

4.7.2.47 Deflagration

The conversion runs abruptly and releases its energy within fractions of a second. The tick is a safety note, not a mere point in the course.

Time of day, batch size and the state of the apparatus belong in the remark without fail — without them the incident cannot be evaluated.

4.7.2.48 Volume decrease

The batch takes up less space. On mixing two liquids this is a known effect: the sum of the single volumes is larger than the mixture.

If liquid disappears in the process, evaporation or dissolution are the more precise terms.

4.7.2.49 Volume increase

The batch takes up more space than before — through gas formation, through swelling of a solid or through thermal expansion.

In a closed vessel the same cause shows up as a pressure rise; which of the two ticks fits depends solely on the design.

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4.8 System conditions

4.8.1 General conditions of the observation

This block holds the special framework conditions under which the observation was made: darkness, shielding, dryness, inert gas atmosphere.

Certain reactions are sensitive to light, moisture, air or electromagnetic influences. What is recorded here is which disturbing influences were deliberately excluded — the point on which the repeatability of a sensitive synthesis rests.

4.8.2 Inert gas atmosphere (▣)

The ticked checkbox represents the framework condition that the observation was made under a protective gas atmosphere, for example under N₂ or Ar gas, whereby the gas need not necessarily be dry.

Many substances are air- or oxygen-sensitive and would oxidise or ignite in air; excluding oxygen and atmospheric moisture is what makes the reaction possible at all.

4.8.3 Exclusion of light (☀)

The ticked checkbox represents the framework condition that the observation was made with the exclusion of light.

Light-sensitive substances would decompose under light or enter undesired photochemical reactions; the darkness keeps the batch stable.

4.8.4 Protection against electrosmog (¬↯)

The ticked checkbox represents the framework condition that the observation was made free of electromagnetic interference fields. Bear in mind that a magnetic stirrer carries a magnetic field into the system which is considerably stronger than the magnetic field of the earth and therefore counts as mild electrosmog as well.

Where sensitive measurements are taken — conductivity, weak signals — fields falsify them. Electromagnetic fields can moreover influence the reaction or the formation of crystals.

4.8.5 Dryness (☂)

The ticked checkbox represents the framework condition that the observation was made with the exclusion of moisture. Otherwise an interaction with the air humidity of the laboratory sets in.

Many reagents are hydrolysis-sensitive and react undesirably with water or atmospheric moisture; for a water-sensitive synthesis the exclusion is indispensable.

4.8.6 Drying agent (Tm)

Here stands which drying agent was used, if the work was done under dry conditions according to the checkbox. From that the degree of dryness approximately reached can be estimated.

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4.9 Chemical phase assessment

4.9.1 Interpretive chemical characterisation

This block holds the interpretive chemical characterisation of the observed phases, kept apart by main phase and, where present, by a second, secondary phase.

Moisture content, acid-base behaviour and substance category determine the reaction behaviour and so complete the assessment of the observations during the characterisation or during the change of the framework conditions.

4.9.2 Main phase

4.9.2.1 Chemical aspects of the main phase

This block holds the chemical aspects of the first, the main phase: moisture content, Brønsted acidity and substance category.

The essential substance conversion usually takes place in the main phase, so its chemical environment is what makes the reactivity estimable.

4.9.2.2 Moisture content of the main phase (Wet)

The selection assesses the moisture or water content of the main phase.

Water takes part in many reactions as a reaction partner, as a solvent or as a disturbance and can cause hydrolysis or shift solubilities.

4.9.2.3 Brønsted acidity of the main phase (Protonic)

Here stands the acid-base behaviour of the main phase in the sense of Brønsted theory — the ability to give up or take on protons.

The acidity can determine the reaction pathways, equilibria and solubilities of proton-dependent systems, or it can act as a catalyst or an inhibitor: whether the phase acts as a proton donor or as an acceptor is what explains its reaction behaviour.

4.9.2.4 Substance category of the main phase (Category)

Here stands the chemical category of the main phase — hard or soft acid or base in the HSAB sense, or inert. Two different acid-base concepts are meant here: the Lewis concept stresses the electron-pair acceptor/donor properties (rather with organic molecules), while the HSAB concept looks more at the charge/radius ratio and the polarisability (rather with inorganic, salt-like substances).

The category helps to estimate which reaction partners might preferentially react with one another and prompts reflection on the possible reaction behaviour of the substances during the period currently being recorded.

4.9.3 Secondary phase

4.9.3.1 Chemical aspects of the second phase

This block holds the chemical aspects of a second, a secondary phase, where the system is multiphase.

At phase boundaries separate reactions frequently run, and the secondary phase can take up or release reaction partners; without it the picture of a multiphase system stays incomplete.

4.9.3.2 Moisture content of the second phase (Wet)

The selection assesses the moisture or water content of the secondary phase (2nd phase).

A secondary phase can act as a water reservoir or as a drying agent and so shift the moisture balance of the whole system; the entry makes the distribution across both phases readable.

4.9.3.3 Brønsted acidity of the second phase (Protonic)

Here stands the acid-base behaviour of the second phase in the sense of Brønsted theory.

Between two phases of differing acidity a proton or substance transport across the phase boundary can take place; the entry makes that gradient visible. As with the main phase, the acidity of the secondary phase can determine the reaction pathways, equilibria and solubilities of proton-dependent systems, or it can act as a catalyst or an inhibitor.

4.9.3.4 Substance category of the second phase (Category)

Here stands the chemical category of the second phase — hard or soft acid or base, or inert. Two different acid-base concepts are meant here: the Lewis concept stresses the electron-pair acceptor/donor properties (rather with organic molecules), while the HSAB concept looks more at the charge/radius ratio and the polarisability (rather with inorganic, salt-like substances).

From the interplay of the categories of both phases it can be estimated whether and how they react with one another.

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4.10 Remarks on the whole observation (Notes & files)

This accordion at the end of the block holds a free text and files for the whole observation — not for a single field, but for everything the block records.

A form only ever captures what is expected, or what its author considered most important. The remark is the place for what went unconsidered, or for the unexpected: what was noticed beside the measured values — a smell, a sudden colour, a noise, an action. It stays attached to its step instead of drifting into a separate note that nobody finds again.

If something important has been forgotten, please create a ticket so that it can be improved in future versions. The place for that is the Error page.

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5 Substance input/output

5.1 Overview of the substance in/out form

This sub-form documents the addition and removal of substances (entry/exit) including weighing and stoichiometric coefficients. When entering, the principle of chronological order applies. The substance that is at the place of reaction first is also named first. The substance that is the first to be taken out of the reaction mixture by a separation operation is likewise named first.

It records which substances enter or leave the system with which amount, mass or volume, and how they relate stoichiometrically — the material basis of every preparation. The i-links of the individual fields jump to the matching detailed explanation in this overview page.

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5.2 Time duration

5.2.1 Time span of the substance transfer

This block holds the time span over which the substance transfer extends: start, end and the span calculated from them or entered by hand. Where the time unit is missing from the span, the minute (min) is assumed as the unit.

Weighing in, adding and taking off are the steps that change the composition of the batch. Only the link between such a step and a point in time makes the sequence reconstructible, and it says which observation came before an addition and which one after it. The start of the span is enough for that; the end may stay empty.

The rate of the addition belongs to the procedure: a reagent poured in within seconds reacts differently from the same reagent dripped in over an hour — the heat is distributed differently, local excess concentrations arise or fail to arise. Whoever records only the point in time loses that difference.

5.2.2 Duration (qualitative)

Every term carries its substitute value in seconds with it. The values are mean values of customary wordings, not limits — “overnight” is read as 18 h, not as the exact length of the night.

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5.3 Pressure and temperature

5.3.1 Temperature and pressure of the addition

This block holds the temperature and pressure conditions of the addition. It means the state in the addition vessel: the temperature at which the substance or the mix is added, and the pressure in the addition vessel — not the conditions in the batch it is added to.

Only what differs from room temperature or normal pressure is stated — hot water, for instance, an ice-cooled acid or a boiling-hot solution from the side strand. A substance that comes out of the bottle at room temperature needs no entry; that is why the block starts closed in the substance transfer subform.

5.3.2 Mean value or lower limit (Main)

Here stands the main value of the parameter — the governing temperature or pressure in the addition vessel. Where a range limit is given as well, this entry is the lower bound of the range.

It is the reference point by which the addition can be compared with a procedure.

5.3.3 Upper limit (Range limit)

Here stands the second limit of a range beside the main value. If a procedure says “hot water (70 to 90 °C)”, for instance, 70 °C is the main value and 90 °C goes here.

Left empty, the main value stands alone. If a hot substance or mix cools down during a slow addition, only the range of both values describes what happened.

5.3.4 Temperature (T)

Here stands the temperature at the addition — the temperature of the substance or mix in the addition vessel, not that of the batch. It is entered only where it differs from room temperature.

The temperature of the addition decides solubility, reaction rate and crystal formation: a saturated solution added hot crystallises differently on cooling than one added cold.

5.3.5 Pressure (p)

Here stands the pressure in the addition vessel under which the substance or mix is added. It is entered only where it differs from normal pressure.

Where gases are involved or material is transferred out of a closed apparatus, the pressure shifts equilibria and boiling points and is safety-relevant. Without an entry, standard pressure is presumed.

5.3.6 Qualitative temperature statement (Qual. T.)

Here stands the temperature in the addition vessel as a customary name instead of a measured value — “room temperature”, “ice bath”, “oil bath smoking”. Exactly one term is chosen; without a choice the entry stays out of the record.

5.3.7 Qualitative pressure statement (Qual. p)

Here a customary name represents the approximate, unmeasured pressure in the addition vessel. Terms such as “water-jet pump”, “standard pressure”, “high vacuum” can be used as a synonym for approximate pressure values or orders of magnitude of pressure. If nothing is selected, the entry stays empty and standard pressure (1013 hPa) is assumed.

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5.4 Receiver (receiving vessel for the reaction mixture)

This tick marks the entry as a receiver: the substance is not a portion added into the reaction mixture, it is the vessel content the mixture is added to — a solvent laid on beforehand, a quench, a cooled receiver at the condenser.

It re-reads the whole block. Without the tick, the conditions of this entry — stirring, temperature, atmosphere, drying agent — describe the substance being added. With the tick they describe the reaction mixture, because that is what is being poured in. The same fields therefore say something different, and only this tick tells the two readings apart.

The direction of the addition decides the local concentration ratio: adding a coloured liquid to a receiver of water is a different experiment from adding water to a coloured liquid, although both entries would otherwise read alike. The receiver aspect should not occur in ordinary preparations; in rare cases it matters for the description of separations.

The tick does not touch the arithmetic. Amount of substance, stoichiometric index and empirical factor are calculated exactly as for any other entry; a substance laid on as a solvent usually carries the stoichiometric index 0.

5.5 Substance addition and removal (In/out, transfer)

Here stands whether a substance is added to the reaction system or removed from it, and in what form (in brackets the sign for the addition and the one for the removal):

once, all at once (+ / −),
in several portions (++ / −−),
in small amounts, dropwise or by the spatula (⊕ / ⊖), or
continuously over a period of time (⊕⊕ / ⊖⊖).

The course of a reaction depends strongly on the manner of dosing: too rapid an addition can lead to local overheating, side reactions or a runaway, while a portionwise or slow addition keeps the heat development manageable. Adding it in one shot can, in precipitation reactions, also lead to co-precipitation.

Addition and removal are logged with their sign, so the material balance over the whole batch stays traceable — and with it which component was in the vessel at which time.

5.6 State of matter at addition

The select box states the state of matter of the substance at the moment of transfer. Conceivable are for example the phase states crystalline, solid, colloidal, liquid, aqueous solution, dissolved, supercritical or also gaseous.

The state influences reaction rate, mixing and handling. A finely divided solid reacts differently from a compact crystal, a dissolved component distributes at once, a gas demands pressure and tightness control. It is also what a dust or gas hazard is judged from.

5.7 Short name of the substance

Here stands the short name — a freely chosen brief designation under which the substance is recognised throughout the whole course protocol.

The same substance, the same mixture or the same fraction can be added, removed, observed or transformed in several steps. Without a consistent name the path of a component through the batch can hardly be followed; the short name links the separate blocks into one coherent story of the substance.

The length is advice, not a limit: up to 15 characters the name reads best in the record, beyond 30 characters the field says so — but your entry is kept in every case. Nothing is cut off, and nothing is refused.

5.8 Stoichiometric coefficient (Stoich.)

Here stands the stoichiometric coefficient — the number with which the substance appears in the balanced reaction equation, that is, the molar ratio in which it is used relative to the other reaction partners.

From it follow the theoretical yield and the limiting reaction partner. Whoever knows the molar ratio can tell whether a component is in deficit and so caps the maximum amount of product; weighed portions can then be chosen so that the intended ratio is kept as far as possible, in order to avoid wasting expensive or hazardous reagents — for the sake of the environment and of one's own costs.

5.9 Empirical factor (Emp. factor, relative proportion)

Here stands the empirical factor — the relative proportion actually used, measured against pure stoichiometry. It says whether a reagent went in as an excess or as a deficit.

In practice one deliberately departs from the ideal coefficients: an excess of a cheap or easily separable reagent can shift an equilibrium towards the product side or force a complete conversion of the valuable partner. The factor is what makes the difference between theoretical approach and real recipe visible, and with it why a particular yield came out. An empirical factor smaller than 1 is also what one would expect for catalysts or inhibitors. An empirical factor very much greater than 1, by contrast, is what one would expect for solvents, for example, which are often also meant to absorb the heat of reaction.

What it is measured against is decided by the ✩ Emp.? tick in the substance transfer that is to be the basis: its amount of substance then is the 1, and every other factor says how many times more or less of that substance the batch holds. Without a tick the form takes the smallest turnover of all the additions — a good guess, but not a statement, and it moves along as soon as an amount changes anywhere. The reference — ticked, or chosen by the form — carries ★ beside its gear; a substance without an amount in mol carries ✪ there instead. If two blocks claim the basis, both carry ★ and no factor is computed at all: two bases are two scales, and a table in two scales is worse than one with no numbers.

5.10 Stirring conditions

This field records the stirring intensity during the substance input/output, on a fixed scale from -- rigid through undefined to ** chaotic stirring/kneading.

Optionally a metric value (number + unit) can be added as extra information; a missing unit is flagged.

5.11 Stirrer type

Here stands which stirring tool was used: a magnetic stirrer, a KPG stirrer (KPG = core-drawn precision glass apparatus; a driven glass shaft with a rigid blade) or a mixing nozzle.

The three differ not merely in strength but in the kind of motion they produce. A magnetic stir bar drives the liquid near the bottom of the vessel and stalls in viscous or heavily loaded mixtures; a KPG stirrer reaches the whole volume and tolerates suspensions; a mixing nozzle mixes by a jet instead of a rotating part and can introduce a gas or a second liquid while it does so. During a substance input the tool decides how quickly a portion is taken up: a solid dropped into an unstirred zone can cake into a lump that then dissolves for hours, and the reaction time noted afterwards belongs to the lump rather than to the chemistry.

What does not belong here: how strongly it was stirred. That is what the intensity scale and the specification beside it are for.

5.12 Stirrer specification

This free-text field holds the exact stirring tool during the substance input or output: model, speed and the geometry of the stirring element — for example “Rühry KYB 7X, 200 rpm, permanent wave”.

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5.13 Substance history

5.13.1 Origin and further use of the substance

This block links the substance input or removal to another experiment. It has one row: the direction of the link, the internal name and the version of that experiment.

This keeps traceable where a self-made substance comes from and where a product or a separated fraction goes next — without lengthening the history protocol by the steps of the other experiment.

Tip: It pays to settle on a good, uniform naming convention for follow-up experiments beforehand, for instance project code, substance and serial number (HM-Zincate-01). Then the name of the future experiment that processes this substance can already be given while the history protocol is being written.

5.13.2 Direction of the link

The selection gives the direction of the link:

⟶ — next experiment of further processing: the substance passes from this experiment into another one.
⟵ — previous experiment that produced the substance: it was made in another experiment.
● — direct supply from the manufacturer (default): the substance was bought.

With ⟶ and ⟵ the pictogram shows an arrow whose shaft separates its two rows; the tip points right (next) or left (previous). With ● there is no arrow.

5.13.3 Name of the experiment

Here stands the internal name of the previous or next experiment as it is kept in your own laboratory — for instance the title of its history protocol.

With ● (direct supply) the field may hold the manufacturer instead, if that information is available.

A uniform naming convention makes the name of a follow-up experiment predictable before it has even started.

5.13.4 Version of the experiment

Here stands the internal version number of the experiment named beside it, for instance when it was carried out more than once.

With ● (direct supply) the field may hold the manufacturer’s batch number instead, if it is available.

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5.14 Safety

5.14.1 Safety information (GHS)

This block holds the safety-relevant information on a substance: the CAS number, a pictorial representation, and the hazard and precautionary statements of the Globally Harmonised System (GHS).

The substances used can pose health, fire or environmental hazards. What stands here justifies the protective equipment, the storage and the disposal — and it is what a person reads before touching the substance, not afterwards.

5.14.2 CAS number (CAS-No)

Here stands the CAS number — a globally unique numerical key that names every chemical substance unmistakably.

Trivial and trade names are frequently ambiguous, but the same substance always bears the same CAS number. Over it, safety data sheets, physical data and literature references can be assigned to the right substance beyond doubt, and a confusion that would lead to a wrong reaction or an underestimated hazard does not arise.

5.14.3 EC number (EC-No)

Here stands the EC number — the European counterpart of the CAS number, a seven-digit key of the form 2xx-xxx-x under which a substance is listed in the EINECS, ELINCS or NLP inventory.

European law is written in it. Annex VI of the CLP regulation, the candidate list and every ECHA dossier address a substance by its EC number, not by its CAS number — whoever wants to look up whether a harmonised classification exists starts here.

A substance can carry one number without the other: newer substances have no EINECS entry, and a boiling range such as petroleum ether has neither. An empty field is therefore a statement of its own and not a gap.

5.14.4 REACH registration number (REACH-No)

The REACH registration number stands in section 1.1 of a safety data sheet and has the form 01-2119471330-49-XXXX.

Unlike the CAS and the EC number it does not belong to the substance but to the registrant: the last four digits name the individual company. Two bottles of the same substance from two suppliers therefore carry two different numbers, and a number copied from a third bottle is wrong even though it looks right.

That is why no delivered substance template fills this field. It is read off the data sheet of the container actually in hand — and it is exactly that reading which makes a record traceable back to a supplier and a batch.

5.14.5 Pictorial representation of the substance (Image)

This field records a pictorial representation of the substance, for example a structural formula or a characteristic appearance.

A visual representation is valuable, because it makes the substance graspable more quickly than a mere name and facilitates recognition in the protocol. A structural formula also makes reactive groups immediately visible.

The image thereby contributes to the understanding of the reaction: whoever has the structure before their eyes can more easily assess possible reaction sites, polarities and interactions.

5.14.6 Protective measures (P, P-statements)

Here stand the P-statements — the precautionary statements of the GHS. They describe the precautionary and protective measures for handling a hazardous substance: gloves, work under the fume hood, notes on storage and disposal.

They say concretely how the hazards a substance poses can be controlled in practice. Recorded in the protocol, the protective strategy that was planned is readable afterwards.

5.14.7 Hazard statements (H/EUH, H-statements)

Here stand the H-statements — the hazard statements of the GHS. They name the kind and severity of the hazards a substance poses: flammability, corrosive effect, toxicity, environmental hazard.

They are the basis of every hazard assessment: only from the known hazard can a sensible protective measure be derived, which is why they belong in the record before the first handling and not after it.

5.14.8 Substance links

Here stand the sources the substance data above were taken from — one link per line, and the line may name the source before the URL.

A CAS number, an EC number and an InChI are claims. A record that states them without saying where they were read cannot be checked afterwards, and it is exactly afterwards that somebody checks: when a batch is disputed, when a classification changes, when the record is read by a person who was not there.

The delivered substance templates fill the field with the openly available sources this extension also archives: the PubChem record and, where one exists, the German ICSC card of the IPCS/WHO/ILO. Both are a starting point. The legally binding classification stands in the safety data sheet of the bottle actually used — and that sheet belongs in the record as an attachment, not as a link, because a supplier's link changes with the next revision.

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5.15 Input/output

5.15.1 Weighed portion and amount of substance

This block holds the quantitative weighed portion of a substance — mass, volume, density and amount of substance — and links these quantities computationally.

Only with known amounts can the stoichiometric ratio be held and the yield be calculated. The block is the bridge between weighable reality and molar arithmetic: from a weighed mass or a measured volume, the density and the molar mass give the amount of substance used, in moles.

5.15.2 Mass (m [g])

Here stands the weighed amount of the substance, in grams or milligrams. From it and the molar mass the form calculates the amount of substance in mol; without it the mol figure stays empty.

What does not belong here: an amount that was never on a balance. For a measured volume there is the field beside it, for a statement without a number (“a knife tip”) the vague amount below.

5.15.3 Volume (V [ml])

Here stands the volume of the portion used, in millilitres — the practical measure for liquids and gases.

Together with the density, the volume gives the corresponding mass and from it the amount of substance, so a volumetric dosing keeps its link to the stoichiometric arithmetic.

What does not belong here: a weighed portion. For that the mass field stands beside it, and for an amount without a figure the vague amount below.

5.15.4 Density (ρ [g/ml])

Here stands the density — mass per unit volume, the link between the mass and the volume of a substance.

Only over the density can a volumetrically dosed reagent be turned into a mass and thus into an amount of substance. It also carries the plausibility check: whether a measured volume fits the expected mass.

5.15.5 Amount of substance (mole)

Here stands the amount of substance in moles — how many particles, atoms, molecules or formula units of the substance went in. It is calculated from mass and molar mass.

Chemical reactions run in fixed particle ratios, so the amount of substance is the central quantity of stoichiometry: only over it can two reaction partners be compared at all, and only from it follow the limiting reagent, the excess and the theoretical yield.

5.15.6 Estimated maximum amount of substance

Here stands an estimated upper bound of the amount of substance in moles. It is the last station of the amount calculation: only when neither mass and molar mass nor volume, density and concentration yield a number is this value taken as the amount of substance of the block. It never displaces a measured number — the estimate waits for the case where nothing was measured.

It is meant for samples without a sum formula: a soil, a pigment, a piece of tissue. Without an amount of substance such a block drops out of the stoichiometry and therefore out of the empirical factor — and that factor is the number by which batches are compared. A reasoned upper bound is worth more than no entry, as long as it stays recognisable as an estimate.

How to estimate. Needed are the mass of the sample, the expected mass fraction of the element in question (or of an assumed formula unit) and its molar mass:

n ≈ m · w / M

Example: 2.0 g of a soil sample, silicon fraction estimated at 25 %, M(Si) = 28.09 g/mol → n ≈ 2.0 g · 0.25 / 28.09 g/mol ≈ 0.018 mol. For an upper bound, insert the upper end of the expected fraction.

The ranges below are values of experience for orientation, not standard values, and they replace no analysis.

Typical element fractions to be expected, by class of substance
Class of substance	Typical main elements	Rough mass fractions to be expected
Organic compounds	C, H, O, N, S, halogens	C about 20–90 %, H about 1–15 %, O about 0–60 %
Proteins	C, H, O, N, S	C about 45–55 %, H about 6–8 %, N about 12–18 %, O about 20–25 %
Carbohydrates	C, H, O	C about 35–45 %, H about 5–8 %, O about 45–55 %
Fats and oils	C, H, O	C mostly 70–80 %, H 10–15 %, O 5–15 %
Silicates and glass	Si, O, Al, Ca, Na, K	O often 30–55 %, Si about 10–45 %, the remaining elements each from traces up to a few tens of percent
Metals and alloys	Fe, Al, Cu, Zn, Ni, Cr etc.	main element often 50–99 %, alloying elements about 0.01–30 %
Soil and rock samples	O, Si, Al, Fe, Ca, Mg, Na, K	O and Si usually dominate (Earth’s crust roughly 46 % O and 28 % Si); trace elements often mg/kg up to the percent range
Environmental and biological samples	C, H, O, N, S, P, metals	main elements mostly in the percent range; metals often µg/kg to mg/kg

Common ranges of the classical elemental analysis of organic samples
Element	Common range
Carbon, C	about 20–90 wt.-%
Hydrogen, H	about 1–15 wt.-%
Oxygen, O	about 0–60 wt.-%
Nitrogen, N	0–30 wt.-%
Sulfur, S	0–10 wt.-%, higher in special substances
Halogens	often 0–50 wt.-%, depending on the compound
Phosphorus, P	mostly 0–10 wt.-%
Metals	from traces up to nearly 100 wt.-%

For a first plausibility check:

C, H, N and S together — the customary CHNS elemental analysis of organic substances.
A very high oxygen fraction — possible for oxides, minerals, carbohydrates or strongly oxidised substances.
A high halogen fraction — typical of chlorinated, brominated or fluorinated compounds.
A metal fraction above 50 % — probably a metallic, mineral or organometallic sample.
Elements below about 0.01 % — trace analysis rather than classical elemental analysis.

Important: the mass fraction does not follow from the atomic mass. Hydrogen has very light atoms and still makes up only about 11.2 wt.-% of water, oxygen about 88.8 wt.-%. A sound estimate therefore needs at least the class of substance or an assumed sum formula.

Sources: BIPM, SI Brochure — definition of the mole · CIAAW — standard atomic weights of the elements · NIST Chemistry WebBook — sum formula and molar mass · FAO, Food energy: methods of analysis and conversion factors, ch. 2 — nitrogen content of proteins (factor 6.25)

5.15.7 Target amount

This row states up to which amount the addition is meant to go: up to a mass (“make up to 50 g”) or up to a volume (“fill the volumetric flask to the 100 ml mark”). It describes a goal, not a measured portion.

Both fields therefore have the character of an instruction only. The form calculates no amount of substance from them, and the amount of solvent that was added cannot be derived from them either. If that amount was measured or estimated, it still belongs in the fields m [g] and V [ml] above.

What the procedure does allow is a concentration: a known amount of substance made up to a known final volume gives c = n / V_target.

5.15.8 Target mass (max m [g])

Here stands the mass to be reached by the addition — for instance “make up to 50.0 g with water” on the balance. It means the mass of the vessel contents at the end of the addition, not the mass of the substance added.

The field has the character of an instruction only: it does not enter the amount calculation, and the amount of solvent added cannot be calculated from it. Whoever knows that amount enters it in m [g].

A concentration can be stated from it, though: the amount of the dissolved substance divided by the target mass gives its content per mass of solution (mol per kg of solution — not to be confused with the molality, which refers to the solvent alone).

5.15.9 Target volume (max V [ml])

Here stands the volume to be reached by the addition — typically “fill the volumetric flask to the mark”. It means the final volume of the solution, not the volume of the substance added.

The field has the character of an instruction only: it does not enter the amount calculation, and the amount of solvent added cannot be calculated from it. Filling to the mark takes less than the target volume, because the dissolved substance occupies space itself and volumes do not simply add up on mixing. Whoever measured the added amount enters it in V [ml].

The concentration, on the other hand, follows directly: c = n / V_target. Example: 0.500 g of sodium chloride (8.56 mmol) made up to 100 ml gives 85.6 mmol/l. This is how standard and sample solutions are prepared.

5.15.10 Mixture (mix, non-pure substance)

This tick marks the substance as a mixture, a non-pure substance.

For a mixture the molar mass cannot be derived from a sum formula. The amount of substance is therefore taken from molarity or molality instead, and the sum-formula molar mass is suppressed. That keeps the relative empirical coefficient right when an impure intermediate — a prepared solution introduced by its short name, for instance — goes into the batch.

5.15.11 Molarity (c [mol/l])

Here stands the molarity in mol/l — the amount of substance per litre of solution.

Together with the entered volume it gives the amount of substance directly, molarity × volume, without any molar mass. That is exactly what a non-pure substance or a mixture needs, and it keeps the relative empirical coefficient of the introduced fraction right.

5.15.12 Molality (č [mol/kg])

Here stands the molality in mol/kg — the amount of substance per kilogram of solution.

Together with the entered mass it gives the amount of substance directly, molality × mass, without any molar mass. It is the mass-based alternative to molarity, for the case where only a mass and no volume is known.

5.15.13 Amount of substance of the solvent (Mol solv.)

Here stands the amount of substance of the solvent — not of the substance weighed in. It is calculated, never typed, and it appears as soon as the weighing carries a concentration.

Two routes lead to it, and they differ in what they need:

Molality [mol/kg] is defined per kilogram of solvent. The mass of the solvent therefore follows from the amount of solute alone, and no density is needed.
Molarity [mol/l] is defined per litre of solution. To get from the volume of the solution to the mass of the solvent, the density is needed — and the mass of the dissolved substance has to be taken off again.

A solvent is a reactant of the medium: it decides solubility, heat capacity and, in a hydrolysis or a solvolysis, the excess that drives the reaction. Whoever wants to judge a batch has to be able to read how much solvent stood against how much substance.

Where the density is missing, the mark ? beside the field says that the number rests on a substituted value.

5.15.14 Estimate mark of the solvent amount

This mark says that the amount of solvent beside it rests on a substituted density instead of a measured one. It is set by the calculation and cannot be set by hand — an opinion about a calculation would be worth nothing.

It is ticked whenever a solvent amount could be determined although the density field held no usable value. The calculation then works with 1 g/ml, the density of water at room temperature, which is right for aqueous solutions and only roughly right for anything else.

The mark is the honest part of the entry: a number without it was derived from measured data, a number with it is an order of magnitude. Whoever repeats the batch knows which of the two they are reading.

5.15.15 Empirical factor of the solvent (Emp. factor solv.)

The empirical factor of the solvent is its relative share in the batch, measured against the same reference turnover as the factor of the substance itself: the smallest quotient of amount of substance and stoichiometric coefficient over all additions.

The solvent enters that comparison with the stoichiometric coefficient 0. That has two consequences, and both are intended:

It does not take part in determining the reference — a substance that is not part of the equation must not decide which component is the limiting one.
For its own quotient the 0 is nevertheless counted as 1, so that a relative share can be stated at all.

That is the formal reading of “takes part in the batch, not in the reaction”. For a preparation the figure answers a question every write-up asks: in what dilution was the reaction run? A factor of 40 says the solvent stood in a fortyfold excess over the limiting component.

5.15.16 Vague amount of the portion (Rough amount)

This radio list is for the case in which the procedure names no exact number for a portion — “a beaker of water”, “a knife tip of catalyst”, “until saturation”. One of the listed terms is chosen instead of inventing a figure.

Each term carries a stored average amount and a tolerance; from it the calculation derives an amount of substance, so the batch can still be compared. The figure is an order of magnitude and is marked as one.

What does not belong here: a weighed portion. Mass, volume and concentration stand in their own fields; this list is what remains when none of them can be filled in truthfully.

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5.16 Molecular aspects

5.16.1 Molecular data

This block holds the material identity features of a molecule: sum formula, molar mass and systematic IUPAC name.

They fix the substance chemically and at the same time supply the quantities the arithmetic needs: from the sum formula follows the molar mass, and the IUPAC name makes the substance unmistakably nameable.

5.16.2 Molecular formula (∑(C1H4))

Here stands the sum formula — from which elements and in what number the molecule is built up.

From it the molar mass is calculated, and it gives a first indication of composition and reactivity. Without it no amount of substance can be derived from a weighed mass.

5.16.3 Picture of the structural formula

The sum formula says what the molecule is made of — never how it is built. Two isomers share one sum formula, and whoever writes down only that leaves the later reader to choose between them.

What stands here is therefore a link to a picture of the structural formula, not an upload. The picture usually exists already — at PubChem, in Wikimedia Commons, in the group’s own drawing — and a copy in every record would multiply the same file. Where no link exists, the remark accordion at the end of the block takes an uploaded file.

The price of that decision stands openly in the field: a link rots. What it showed cannot be reconstructed from the record. In return the source stays visible in the address, and no second copy with an unsettled licence comes into being.

The field accepts only addresses that end in an image format a browser can display — svg, png, apng, webp, avif, gif, jpg, jpeg, jfif, bmp, tif, tiff, heic, heif. A link to a PDF or to a landing page is caught while it is being typed, not by the reader two years later.

5.16.4 Molar mass (M [g/mol])

Here stands the molar mass — the mass of one mole of the substance, usually in grams per mole.

It converts mass and amount of substance into each other: divided by the molar mass, a weighed mass becomes the amount of substance in moles. Yield calculations and material balances rest on it.

5.16.5 Sum formula of the solvent (Solv. ∑(C1H4))

Here stands the sum formula of the solvent — deliberately a field of its own, beside the sum formula of the substance. The entry is read by the same parser as the formula above and yields the molar mass in the field beside it; from that molar mass the amount of solvent follows.

The H2O button fills in the most common solvent of a bench in one click. It asks first where the two fields already carry something, because a solvent that was entered was entered on purpose.

What does not belong here: the formula of the substance weighed in. A solution has two molar masses, and mixing them up is the classic error of this block — the row above describes what was weighed in, this one what it was dissolved in.

5.16.6 Molar mass of the solvent (Solv. M [g/mol])

Here stands the molar mass of the solvent in g/mol. It is filled from the sum formula beside it, and a value entered by hand is kept — a solvent mixture, a deuterated solvent or a technical grade has a molar mass no formula gives. For water it is 18.02 g/mol; the H2O button sets formula and mass together.

It is the divisor of the solvent calculation: mass of the solvent divided by this molar mass gives the amount of solvent. Without it that amount stays empty, however completely the concentration is entered.

5.16.7 IUPAC name

Here stands the IUPAC name — the systematic designation of the substance, formed by international rules.

It describes a substance unambiguously and independently of language, while trivial names are often ambiguous or regionally different; from the systematic name the structure can be derived directly.

5.16.8 InChI - IUPAC International Chemical Identifier

Here stands the InChI — the machine-readable twin of the IUPAC name, a string such as InChI=1S/C3H6O/c1-3(2)4/h1-2H3 that describes the structure itself: skeleton, hydrogen positions, charge, isotopes and stereochemistry, each in a layer of its own.

It is computed and not assigned. Two people who enter the same structure obtain the same InChI without asking anybody, and that is what makes records searchable and comparable across database boundaries. A trivial name cannot do it, and a CAS number can do it only for whoever owns the register.

What does not belong here: the InChIKey. The key is a hash of the InChI — shorter, but it cannot be read back into a structure.

5.16.9 SMILES

SMILES is the third notation of the same structure — and the only one a person still types. The InChI above it is unambiguous but unreadable; the IUPAC name is readable but long. SMILES sits between them: CC(=O)C is acetone, and one can see it.

What counts in practice is that every drawing program reads and writes SMILES. Paste the line into a drawing program and the structure is on the screen; copy it out of one and it is in the record.

The field takes several lines, because a ring-rich structure runs past the width of one line. A cut SMILES is not a shorter structure but a different one.

Nothing is checked here. A SMILES parser belongs in a chemistry library, not in a record form; the field keeps what was entered and hands it on unchanged. Unlike the InChI, SMILES is not canonical — the same molecule can be written in many ways, and two different lines can mean the same substance.

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5.17 Auxiliary substance

5.17.1 Classification of the substance entry

This block classifies a substance input or removal: it records the function the substance has in the experiment — auxiliary substance, solvent, catalyst, inhibitor or indicator — and links it to a separation by name.

Auxiliary substances — precipitants, complexing agents, solubilisers — are not part of the target product and have to be documented and later removed again. The name is what says which added substance served which separation.

5.17.2 Function in the experiment

The selection ⊕! characterises the function of the substance entry for the course of the experiment:

⚙ Auxiliary substance — serves a separation procedure (washing, extracting, rinsing) and does not react itself. It is selected automatically as soon as a separation name is entered and no function has been chosen yet. Where the entry directly follows a separation, its pictogram is indented beneath that separation.
💧 Solvent — takes up the reactants without being converted itself.
⏩ Catalyst — speeds up the reaction and is present unchanged at the end.
⏸ Inhibitor — slows down or suppresses a reaction, for example as a stabiliser.
⚐ Indicator — shows a state, for example the end point of a titration.
🚿 Rinsing liquid — rinses the remainder of a substance or mixture out of a vessel so that it is transferred completely, and does not react itself. Where the entry directly follows another substance entry or the end of a strand with a Mix entry, its pictogram is indented beneath it.
Blank (undetermined) — the default: the function follows from the record, or the substance is a starting material or product.

The marking separates a process aid from the actual target substance, so that it stays recognisable which substance may remain as a removable impurity and which additional reagent the procedure needs. Only ⚙ indents the pictogram; the other functions are named in the protocol.

5.17.3 Separation name (Tn)

Here stands the identifier of the separation step (“T-3”, quick help of the separation subform) that the auxiliary substance serves. Entering a value — at least one non-whitespace character — activates the auxiliary-substance tick.

The field suggests the identifiers of all separation steps already in the history protocol — in the order of the protocol, each with its method. Free input remains possible, for instance for a step that is only inserted later.

The identifier links the added auxiliary to the separation step it belongs to and so also documents the later treatment of phases that do not serve the goal.

5.17.4 Repetitions (Rep.)

Here stands into how many portions the total amount of this substance entry is split for repetitions of the separation step — for example washing twice with 1 ml each: amount 2 ml, Rep. 2.

The field only describes the split. The amount fields (mass, volume, amount in mol) always carry the total amount of all partial steps, not the amount per portion; the amount of substance and the empirical factor are calculated from the total amount. The default is 1, that is, no split.

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5.18 Conditions of the substance transfer

5.18.1 Framework conditions of the substance transfer

This accordion holds the framework conditions under which the substance was added or removed: isolation from the laboratory atmosphere, exclusion of light, freedom from electrosmog, dryness and the drying agent used.

A batch is at its most vulnerable at the moment of transfer: the vessel is open, the substance meets air, light and moisture. What was prepared under inert gas can be spoiled by a single careless addition.

The conditions of the transfer are recorded separately from the observation and the change. A batch worked up in the dark but weighed in in daylight is only distinguishable that way.

5.18.2 Closed off from the atmosphere (▣)

Here stands that the addition or removal took place separated from the laboratory atmosphere — under inert gas, in a glovebox or on a Schlenk line.

It applies wherever substances react with oxygen or air humidity: organometallics, low-valent metal compounds, many catalysts. The transfer is the step at which inert-gas work most often fails, so the entry says the batch saw no air there either.

5.18.3 Dark environment (☀)

Here stands that the substance was added or removed with the exclusion of light.

Light-sensitive substances — silver salts, many dyes, peroxides, photolabile intermediates — decompose in daylight within minutes; the entry says that no photochemical damage was done while the vessel stood open.

5.18.4 Free of electrosmog and magnetism (¬↯)

Here stands that the transfer took place without electromagnetic fields — no stray field of a stirrer motor, no magnet, no high-frequency source nearby.

It matters with paramagnetic or ferromagnetic particles, with radical intermediates and wherever a magnetic stirring bar would drag solid along. The influence leaves no visible trace and would otherwise be sought in the chemistry.

5.18.5 Dried component and material (☂)

Here stands that the substance and the vessel used were dried before the transfer.

Residual water hydrolyses reagents, quenches organometallics and shifts the stoichiometry unnoticed — a wet spatula is enough. The entry pins the dryness to the moment of the transfer, not to some earlier point in the work.

5.18.6 Drying agent (Tm)

Here stands the drying agent over which the substance or the solvent was kept before the transfer.

The agent is the only measure of how dry dry is: molecular sieve and sodium reach residual water contents silica gel never does. It turns the tick “dry” into a comparable figure, so a repetition can choose the same degree of dryness instead of guessing.

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5.19 Remarks on the whole substance transfer (Notes & files)

This accordion at the end of the block holds a free text and files for the whole substance transfer — not for a single field, but for everything the block records.

A form only ever captures what is expected, or what its author considered most important. The remark is the place for what went unconsidered, or for the unexpected: how a substance behaved on addition, why a weighing was repeated, which vessel was used. It stays attached to its step instead of drifting into a separate note that nobody finds again.

If something important has been forgotten, please create a ticket so that it can be improved in future versions. The place for that is the Error page.

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6 System change

6.1 Overview: change

This sub-form describes the changes brought about experimentally in the reaction space. It describes the way in which a state is changed (the form of the change). The form is a compromise between describing the state and describing changes of state.

In contrast to a separation no fraction is recovered here; instead the intensive and extensive quantities of the mixture in the reaction space are converted (e.g. by heating, pressure, reaction). The i-links of the individual fields jump to the matching detailed explanation on this info page.

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6.2 Progression form

6.2.1 Progression form of the change

This block holds the temporal progression form with which a reaction condition is deliberately changed: constant, linear, S-shaped, early or late stepwise, as a peak or as a rectangular profile.

Often it is not the final value that matters but the path to it: a slow linear temperature ramp leads elsewhere than a sudden jump. The progression form is the control profile of the condition.

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6.3 Time duration

6.3.1 Time span of the change

This block holds the time span over which a change extends: start, end and the span calculated from them or entered by hand. Where the time unit is missing from the span, the minute (min) is assumed as the unit.

The speed of a change decides success or failure: too rapid heating or cooling can cause side reactions, stress cracks or an incomplete conversion. Together with the progression form the time span describes the control completely.

Together with the target value the duration fixes the rate of change. The same temperature change over ten minutes or over two hours can yield completely different products.

6.3.2 Duration (qualitative)

Every term carries its substitute value in seconds with it. The values are mean values of customary wordings, not limits — “overnight” is read as 18 h, not as the exact length of the night.

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6.4 System phase

6.4.1 Changed phase

This block describes the phase of the substance in the reaction system, and it does so twice: Main describes the phase conditions at the start of the change, Add the end point in the phase structure that the change is meant to reach.

Mostly the phase behaviour of the substances in the reactor space stays the same; then “Main” is enough, and “Add” stays closed and empty. If the change aims at a phase transition — melting, evaporating, crystallising out — “Add” describes the state aimed for. Several phase transitions in a row are better described in several sections.

6.4.2 Phase conditions at the start (Main)

Main describes the phase conditions at the start of the change: viscosity, phase, second phase and the chemical properties of both phases.

If the phase structure stays the same during the change, this is the only phase statement of the block.

6.4.3 End point of the phase structure (Add)

Add describes the end point to be reached in the phase structure during the change, with the same fields as “Main”. Together with “Main” it describes a phase transition, for instance solid → liquid when melting.

The fold is closed by default. If it stays empty, the phase structure counts as unchanged.

6.4.4 State of matter of the phase (Phase)

The select box states the current state of matter of the (main) phase in the reaction vessel. This can be, for example, solid, liquid, gaseous, aqueous or also dissolved.

Many changes aim precisely at a phase transition: the melting of a solid, the evaporation of a solution. The entry records the state the description starts from.

6.4.5 Viscosity of the phase (Visc.)

The select box states the approximate viscosity of the (main) phase, resp. of the mixture, in the reaction vessel. Viscosity means the thickness or flowability of the mixture, that is, how easily a substance can be stirred into the mixture.

A deliberate change in viscosity, by diluting or by heating, improves or worsens mass transport and mixability, and it decides how the phase can be handled further.

6.4.6 State of matter of the secondary phase (2nd phase)

This field describes the second (secondary) phase of the substance in the reaction system at the start of the change; the same selection under “Add” describes the end point. Further phases (crystals in the reaction mixture) are to be listed in the remarks where applicable.

This is useful because the changed system can consist of more than one phase. For systematics, a main phase and a secondary phase are distinguished; further phases are not listed, even if — for example across different crystals — additional phases could exist.

6.4.7 State of matter at the end point (Phase)

Here one states the state of matter of the (main) phase that is to be reached at the end of the change. The selection is the same as under “Main”.

6.4.8 Viscosity at the end point (Visc.)

Here one states the viscosity of the (main) phase or of the mixture that is to be reached at the end of the change — for instance “viscous” after thickening.

6.4.9 State of matter of the secondary phase at the end point (2nd phase)

Here one states the state of matter of the second (secondary) phase at the end of the change — for instance crystals coming out beside a liquid main phase. Without a second phase its chemical properties stay locked.

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6.5 Pressure and temperature

6.5.1 Temperature and pressure

This block holds the targeted temperature and pressure values of the change.

Both are among the most frequently and deliberately changed reaction conditions and control rate, equilibrium and state of matter directly. As target values they are what a repeatable process control is measured against.

6.5.2 Start or base value (Main)

If the main value stands alone, it denotes the value prevailing in the reaction system during the change. It is then the primary set point. If the additional value is given as well, a span is described that states either the end value or, with the peak/rectangle type, the peak value.

If the additional value is 195 K and the main value 293 K in a peak change, the substrate was probably cooled down temporarily with dry ice. Where nothing is entered, room temperature (20–25 °C) and standard pressure (1013 hPa) are assumed.

6.5.3 End/peak value (Add)

If the field stays empty, the main value describes the conditions in the system during the change. That is mostly the case with pressures. If the additional value is given as well, a span is described that states either the end value or, with the peak/rectangle type, the peak value.

If the additional value is 373 K and the main value 293 K in a linear change, the substrate was probably heated slowly to the boiling temperature of water in a water bath.

6.5.4 Temperature (T)

The temperatures are entered in the two fields beside this. Where no value is given, a room temperature between 20 and 25 °C is assumed. If only the main value is given, it describes the temperature during the change. If main and additional value are both given, the additional value states the peak or end temperature, while the main value states the start or base temperature.

The temperature influences the reaction rate strongly and shifts equilibria; deliberate heating or cooling is one of the most effective tools of reaction control, and the target value is what makes it repeatable.

6.5.5 Pressure (p)

The pressures are entered in the two fields beside this. Where no value is given, the standard pressure of 1013 hPa is assumed. If only the main value is given, it describes the pressure during the change. If main and additional value are both given, the additional value states the peak or end pressure, while the main value states the start or base pressure.

In gas-involving reactions the pressure shifts gas equilibria, boiling points and solubilities, and it is safety-relevant. The target value makes such a change controllable and afterwards assessable.

6.5.6 Temperature (Qual. T Main, qualitative)

Here stands the temperature as a customary name instead of a measured value — “room temperature”, “ice bath”, “oil bath smoking”. Exactly one term is chosen; without a choice the entry stays out of the record. The qualitative value always ranks second and is overridden by an explicit entry in the main value.

6.5.7 Temperature at the end or peak value (Qual. T Add, qualitative)

The counterpart of “Qual. T Main” for the end or peak value of the change, just like the “Add” column beside the measured value. Exactly one term is chosen; without a choice the entry stays out of the record. An explicit entry in the additional value overrides the term.

6.5.8 Pressure (Qual. p Main, qualitative)

Here stands the pressure as a customary name instead of a measured value — “water-jet pump”, “standard pressure”, “high vacuum”. Exactly one term is chosen; without a choice the entry stays out of the record. The qualitative value always ranks second and is overridden by an explicit entry in the main value.

6.5.9 Pressure at the end or peak value (Qual. p Add, qualitative)

The counterpart of “Qual. p Main” for the end or peak value of the change, just like the “Add” column beside the measured value. Exactly one term is chosen; without a choice the entry stays out of the record. An explicit entry in the additional value overrides the term.

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6.6 Stirring parameters

6.6.1 Stirring

This block holds the stirring — how strongly the reaction mixture is moved, and with which tool.

Here stirring is a deliberately set condition like temperature or pressure: it controls heat removal, mass transfer and grain size. That is why it stands beside the intensive measured parameters and not inside them.

6.6.2 Start or base value (Main)

This column carries the start or base stirring stage: the choice on the fixed scale and, beside it, a measured value with a unit, for example 120 rpm.

The stage is coarse and therefore comparable everywhere; the number beside it is exact and holds for this device only. Together they say more than either alone.

If only the main value is given, it describes the stirring stage during the change. Otherwise the main value describes the start or base stirring stage, while the additional value describes the peak or end stirring stage.

6.6.3 End/peak value (Add)

This column carries the end or peak stirring stage — the same scale and the same measured value as on the left, but for the other end of a span.

Where the stirring differs over a period, only the pair of both stages describes the process; with steady stirring this column stays empty.

6.6.4 Stirring intensity (↺)

Here stands the stirring intensity with which the phase is moved during the change. Beside each of the two levels a measured value with a unit may stand, for example 120 rpm or 237 min⁻¹.

6.6.5 Stirrer type (⚙️)

Here stands which stirring tool was used: a magnetic stirrer, a KPG stirrer (KPG = core-drawn precision glass apparatus; a driven glass shaft with a rigid blade) or a mixing nozzle.

The three differ not merely in strength but in the kind of motion they produce. A magnetic stir bar drives the liquid near the bottom of the vessel and stalls in viscous or heavily loaded mixtures; a KPG stirrer reaches the whole volume and tolerates suspensions; a mixing nozzle mixes by a jet instead of a rotating part and can introduce a gas or a second liquid while it does so. During a change the tool determines how evenly the change reaches the whole batch: a stalled magnetic bar leaves an overheated layer at the bottom while the thermometer above it still reads the intended temperature.

What does not belong here: how strongly it was stirred. That is what the intensity scale and the specification beside it are for.

6.6.6 Stirrer specification (📝)

This free-text field holds the exact stirring tool of the change: model, speed and the geometry of the stirring element — for example “Rühry Cool Dauerwelle, 2000 rpm, induction rod”.

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6.7 Intensive measured parameters

6.7.1 Intensive

This block holds further, freely definable values for intensive parameters deliberately changed beyond temperature and pressure.

Every reaction can have control parameters of its own — irradiation, flow, field strength. They have no field of their own and are named here.

6.7.2 Start or base value (Main)

If the main value stands alone, it denotes the value prevailing in the reaction system during the change. It is then the primary set point. If, by contrast, the additional value is given as well, a span is described whose second value is either the end value or, with the peak/rectangle type, the peak value.

It is what makes an unconventional control variable recordable at all.

6.7.3 End/peak value (Add)

If this field stays empty, the main value describes the conditions in the system during the change. That is usually the case with pressures. If, by contrast, the additional value is given as well, a span is described whose second value is either the end value or, with the peak/rectangle type, the peak value.

Individual control variables, too, are often a transition between two values; the additional value carries the span of the change.

6.7.4 Freely definable parameter 1 (? - unknown)

In this text field you define the name of the intensive parameter recorded here.

If a value with a unit is given in the first field beside it only, it is taken as a constant value during the phase of change. If a value with a unit is given in each of the two further fields beside it, then, depending on the type of change, the first value is the start or base value, while the second value states the end or peak value.

6.7.5 Freely definable parameter 2 (? - unknown)

In this text field you define the name of the intensive parameter recorded here.

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6.8 System conditions

6.8.1 General conditions of the change

This block holds the special framework conditions under which the change takes place: darkness, shielding, dryness, inert gas atmosphere.

Sensitive reactions have to be protected from light, moisture, air or interference fields while they are being changed. What is recorded here is which of those influences was deliberately excluded.

6.8.2 Inert gas atmosphere (▣)

The ticked checkbox represents the framework condition that the change takes place under a protective gas atmosphere, for example under N₂ or Ar gas, whereby the gas need not necessarily be dry.

Many substances are air- or oxygen-sensitive; the entry says that oxygen and atmospheric moisture were kept out while the conditions were being moved.

6.8.3 Exclusion of light (☀)

The ticked checkbox represents the framework condition that the change is carried out with the exclusion of light.

Light-sensitive substances would decompose under light or react photochemically; the darkness rules that disturbance out.

6.8.4 Protection against electrosmog (¬↯)

The ticked checkbox represents the framework condition that the change takes place free of electromagnetic interference fields. Bear in mind that a magnetic stirrer carries a magnetic field into the system which is considerably stronger than the magnetic field of the earth and therefore counts as mild electrosmog as well.

It matters where field-sensitive processes or measurements are involved. Electromagnetic fields can moreover influence the reaction or the formation of crystals.

6.8.5 Dryness (☂)

The ticked checkbox represents the framework condition that the change is carried out with the exclusion of moisture. Otherwise an interaction with the air humidity of the laboratory sets in.

Many reagents are hydrolysis-sensitive and react undesirably with water; the exclusion keeps that out of the changed state.

6.8.6 Drying agent (Tm)

Here stands which drying agent was used, if the work was done under dry conditions according to the checkbox. From that the degree of dryness approximately reached can be estimated.

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6.9 Chemical assessment of the system phases

6.9.1 Interpretive chemical characterisation

This block holds the interpretive chemical characterisation of the changed phases, kept apart by main phase and, where present, by a second, secondary phase: moisture content, acid-base behaviour, substance category.

A change in the conditions can also shift the chemical behaviour of the phase; what is recorded here is the chemical nature of the changed state.

6.9.2 Main phase

6.9.2.1 Chemical aspects of the phase

This block holds the chemical aspects of the changed phase: moisture content, Brønsted acidity and substance category.

They make the reaction behaviour of the phase in its changed state estimable — the chemical environment the following steps meet.

6.9.2.2 Moisture content of the phase (Wet)

The selection assesses the moisture or water content of the changed main phase.

Water takes part in many reactions as a reaction partner, as a solvent or as a disturbance, so its content decides how the changed state is to be read.

6.9.2.3 Brønsted acidity of the phase (Protonic)

Here stands the acid-base behaviour of the changed phase in the sense of Brønsted theory.

The acidity can determine the reaction pathways and equilibria of proton-dependent systems, or it can act as a catalyst or an inhibitor: whether the phase acts as a proton donor or as an acceptor.

6.9.2.4 Substance category of the phase (Category)

Here stands the chemical category of the changed phase — hard or soft acid or base in the HSAB sense, or inert. Two different acid-base concepts are meant here: the Lewis concept stresses the electron-pair acceptor/donor properties (rather with organic molecules), while the HSAB concept looks more at the charge/radius ratio and the polarisability (rather with inorganic, salt-like substances).

6.9.3 Secondary phase

6.9.3.1 Chemical aspects of the secondary phase

This block holds the chemical aspects of the second changed phase: moisture content, Brønsted acidity and substance category. It stays locked as long as no second phase is recorded.

A second phase reacts, dissolves or shields differently from the main one; without it the picture of the changed state stays incomplete.

6.9.3.2 Moisture content of the secondary phase (Wet)

The selection assesses the moisture or water content of the changed secondary phase (2nd phase).

A secondary phase can act as a water reservoir or as a drying agent and so shift the moisture balance of the whole system; the entry makes the distribution across both phases readable.

6.9.3.3 Brønsted acidity of the secondary phase (Protonic)

Here stands the acid-base behaviour of the second changed phase in the sense of Brønsted theory.

A proton exchange across the phase boundary can drive the reaction or block it; the entry says whether the secondary phase acts as a donor or as an acceptor. As with the main phase, the acidity of the secondary phase can determine the reaction pathways and equilibria of proton-dependent systems, or it can act as a catalyst or an inhibitor.

6.9.3.4 Substance category of the secondary phase (Category)

This field assigns the second changed phase to one or more chemical categories, for example according to the concept of hard and soft acids and bases or as inert. Two different acid-base concepts are meant here: the Lewis concept stresses the electron-pair acceptor/donor properties (rather with organic molecules), while the HSAB concept looks more at the charge/radius ratio and the polarisability (rather with inorganic, salt-like substances).

6.9.4 Main phase at the end point

6.9.4.1 Chemical aspects of the phase at the end point

The chemical aspects of the main phase at the end point of the change: moisture content, Brønsted acidity and substance category — the same selections as under “Main”.

6.9.4.2 Moisture content of the phase at the end point (Wet)

The moisture or water content of the main phase that is to be reached at the end of the change — for instance “dry” after drying.

6.9.4.3 Brønsted acidity of the phase at the end point (Protonic)

The acid-base behaviour of the main phase at the end point in the sense of Brønsted theory — for instance after a neutralisation.

6.9.4.4 Substance category of the phase at the end point (Category)

The chemical category of the main phase at the end point of the change; several categories can be chosen.

6.9.5 Secondary phase at the end point

6.9.5.1 Chemical aspects of the secondary phase at the end point

The chemical aspects of the secondary phase at the end point of the change: moisture content, Brønsted acidity and substance category. They stay locked as long as no second phase is recorded under “Add”.

6.9.5.2 Moisture content of the secondary phase at the end point (Wet)

The moisture or water content of the secondary phase (2nd phase) at the end of the change.

6.9.5.3 Brønsted acidity of the secondary phase at the end point (Protonic)

The acid-base behaviour of the secondary phase at the end point in the sense of Brønsted theory.

6.9.5.4 Substance category of the secondary phase at the end point (Category)

The chemical category of the secondary phase at the end point of the change; several categories can be chosen.

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6.10 Remarks on the whole change (Notes & files)

This accordion at the end of the block holds a free text and files for the whole change — not for a single field, but for everything the block records.

A form only ever captures what is expected, or what its author considered most important. The remark is the place for what went unconsidered, or for the unexpected: why a condition was altered, what the change was expected to achieve, what it actually did. It stays attached to its step instead of drifting into a separate note that nobody finds again.

If something important has been forgotten, please create a ticket so that it can be improved in future versions. The place for that is the Error page.

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7 Material list

7.1 Material list

The material list is the rig list of the working place: what stands on the bench, and how many of each.

It is not a measurement, and that is why it looks different from the other subforms. Every other block says what happened to a substance; this one says what the hands had within reach while it happened.

Two things make a written rig list worth the minutes it costs. It is the difference between “a flask” and “a 250 ml three-necked flask” when the run is repeated a year later. And read the other way round, as a clearing list, it is the check that nothing stayed on the bench.

In the future the material list could help to tell a robot, or an untrained chemist, which materials have to be made ready and which may be cleared away, washed and put back. The real idea behind the schematised record, however, is to create an easily understood, empirically grounded authoring language for chemical experiments — one that could survive even the erosion of information in a decline of civilisation brought on by a lack of energy (peak-oil crisis → fertiliser crisis → hunger crisis) and by the climate crisis. Besides, from a cognitive-psychological point of view a scheme groups information into chunks and thereby encourages thinking about the experiments and about their consequences for one’s ideas of chemistry.

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7.2 Direction of the list

7.2.1 Direction of the list

This pair of buttons says whether the material is being set out or cleared away. Exactly one of the two holds; therefore radio buttons, and “provide” is preselected.

The same list means opposite things in the two readings. Set out, it is a plan: this is what the work needs. Cleared away, it is a receipt: this went back, cleaned. Whoever notes both writes two blocks, and the difference between them is what is still standing around.

The pictogram carries the direction as an arrow into or out of the rack, so it can be read without opening the block.

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7.3 Equipment of the working place

7.3.1 Equipment of the working place

The list holds 245 items in alphabetical order, each with a tick and a piece count. The two belong together: ticking sets the count to one, a count of zero removes the tick, and a negative number is corrected to zero.

Every item belongs to exactly one of five categories — temperature & energy, separating & working up, measuring, equipment & glassware, accessories & consumables. The bar above the list narrows it down by them and stays in view while the list scrolls past. No tick means no restriction: all five are shown. Several ticks show their union.

The search field narrows further: only entries whose name contains the typed sequence of letters remain, regardless of upper and lower case. Both narrowings apply at once — the search runs within the ticked categories.

A narrowing is a view of the list, not a statement about the experiment. An entry hidden by it keeps its tick, its piece count and its line in the record, and it keeps counting in the pictogram, which tallies every category separately.

Where an item could serve two purposes it is filed by what it does in the procedure: a Liebig condenser under separating (it belongs to the distillation), a reflux condenser under temperature (it holds the boiling). Such assignments are a judgement and can be argued with.

Entries with variants are listed once per variant (“Bechergläser (250 ml)”) rather than as one entry with a free-text size. A size that is chosen from a list can be counted, compared and searched for; one that is typed in cannot.

Only the ticked entries reach the record, as an indented list under one introductory sentence.

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7.4 Note on the material list

Room for everything the list does not have: a borrowed apparatus, a defect noticed while clearing away, an item from another lab.

The list is closed on purpose — a free text field per item would make it unsearchable. What has no entry belongs here, in one place, where it can be found again.

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8 Experiment environment

8.1 Overview of the subform

This subform describes the room the experiment stood in — not what happened inside the apparatus, but what stood around it.

In the vast majority of cases the laboratory as a room and the chemical experiment itself are in close contact with each other, so environmental influences may affect the experiment. Recording the experiment environment matters only for analysing such a suspicion later on.

The surroundings act on a run whenever the reaction space is not sealed off from them: a hygroscopic substance draws water out of humid air, a rise in room temperature shifts an equilibrium, a fall in air pressure lowers a boiling point. Whoever records nothing about the room cannot tell later whether a deviation came from the prepared substance or from the day.

The room is kept apart from the observation on purpose. An observation states what the system did; this block states what stood around it. Whoever has to open a second block for it is made to notice the difference — that is the didactic reason for the separation, not a technical one.

An experiment can also take place in a sealed-off working box, such as a glove box. Then the box is the experiment environment, which is why the room conditions also list the separation from the outside atmosphere, for example by an inert gas.

8.2 Notes on the whole room

Free text and files for the whole room: everything none of the fields above asks about.

A window that stood open, a fume hood that ran, a neighbouring bench on which something was heated, the weather of the day — such things have no field of their own, and they are exactly the things one wishes one had written down when a run cannot be repeated.

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8.3 Time duration

8.3.1 Time span of the experiment environment

This block holds the time span over which the experiment environment was recorded: start, end and the span calculated from them or entered by hand. Where the time unit is missing from the span, the minute (min) is assumed as the unit.

Room temperature, air pressure and humidity change over the day; only together with a point in time do the readings say when the room was in that state. The start dates the readings of the main column, the end those of the additional column, and the span says how long the room stood in between.

When the subform is inserted, the current time is entered as the start. If start or end is changed later while a span is already filled in, the form asks whether the span is to be replaced and shows the current and the new value. A span typed by hand is taken as it is, without a warning. In an example archive start and end are deleted, because they would reveal when the author was in the laboratory; the span stays.

The pictogram shows the span as its leading entry, with the date and hour of the start below it; without a span it shows the date and the hour alone.

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8.4 Room climate

8.4.1 Room climate

The three measured readings of the room: temperature, air pressure and relative humidity.

They are the values every laboratory can read off without extra equipment, and together they fix the state of the air the experiment stood in. Each of them has two slots, so a run that lasted hours can state how the room changed while it ran.

8.4.2 Main column: the reading at the start

The main column holds the reading at the start of the run.

Whoever measures only once writes it here and leaves the second column empty; a single reading is a statement, an empty one is not.

8.4.3 Additional column: the reading at the end

The additional column holds the reading at the end of the run.

The two columns together are a span, not an average: they say how far the room moved while the experiment ran. A room that moved far is itself a finding.

8.4.4 Room temperature (T)

Here stands the temperature of the room, not that of the reaction system.

The entry is converted into kelvin, so that readings in degrees Celsius, degrees Fahrenheit and kelvin can be compared without arithmetic. The room temperature decides how fast an unthermostatted batch equalises with its surroundings, and it is the reference against which every heating and cooling of the apparatus is read.

8.4.5 Air pressure of the room (p)

Here stands the air pressure of the room.

The entry is converted into pascal; the pictogram prints it in hectopascal (hPa), the unit of a barometer and of the weather report, on the line below the temperature. Without an entry that line stays empty, symbol included. The air pressure decides boiling points: a distillation at 950 hPa boils lower than the textbook says, and a batch that foamed over in the mountains did not necessarily do so from a mistake.

8.4.6 Relative humidity (φ)

Here stands the relative humidity of the room, as a bare number between 0 and 100.

The per cent belongs to the quantity and is therefore not typed: a relative humidity is a ratio and has no other unit. An entry with a unit is refused, and so is one above 100 — supersaturated air is a mist, and a mist is an observation, not a room reading.

The humidity is what most often decides a weighing-in without anybody noticing: hygroscopic substances draw water out of the air within minutes, and a mass measured at 80 % humidity is a different mass from one measured at 30 %.

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8.5 Intensive measured parameters

8.5.1 Intensive parameters of the room

Two freely named parameters of the room, for everything the three fixed readings do not cover.

Dust load or particle count, noise, vibration, illuminance, a draught — none of them is common enough to deserve a field of its own, and each of them can decide a run. The name is written into the first column, the value with its unit into the two beside it.

The pictogram counts how many of the two rows are fully given — name and value together — and prints that count as the index under the humidity. A value without a name is a number nobody can read; a name without a value is an announcement. Neither half counts on its own.

8.5.2 Main column: the reading at the start

The main column holds the reading at the start of the run.

As with the three fixed readings: whoever measures only once writes it here and leaves the second column empty.

8.5.3 Additional column: the reading at the end

The additional column holds the reading at the end of the run.

It does not count towards the index under the humidity: a row is fully given as soon as it carries a name and its first value. The second reading refines the row, it does not open it.

8.5.4 First freely named parameter

The first freely named parameter of the room.

The example in the field suggests the case the subform was built for: the particle load of the air, in micrograms per cubic metre. Dust settles into open vessels, falsifies a weighing-in and seeds a crystallisation that should have stayed in solution. Whoever works in a room without filtered air has a reason to record the figure.

8.5.5 Second freely named parameter

The second freely named parameter of the room.

The example suggests the sound level in decibels, as a stand-in for everything mechanical the room carries: a shaker on the neighbouring bench, a pump, a passing lorry. Vibration disturbs a crystallisation and a settling separation more reliably than most people expect, and it is the disturbance nobody thinks of afterwards.

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8.6 Room conditions

8.6.1 Conditions of the room

The four conditions of the room, in the same order and behind the same marks as in every other subform.

They refer to the room, not to a working step: whether it was sealed off, kept dark, kept free of fields, kept dry. An empty block means that nothing was said about the room — not that none of the four applied.

8.6.2 Room separated from the outside atmosphere (▣)

The ticked checkbox states that the room was separated from the outside atmosphere.

A glove box, a sealed climate chamber, a room under its own atmosphere: what stands inside no longer follows the weather outside. The tick is what makes the three readings above trustworthy over hours — an unsealed room follows the day, whatever was measured at its start.

8.6.3 Room kept in the darkness (☀)

The ticked checkbox states that the room was kept in the darkness.

Not the vessel — the room. A batch wrapped in foil inside a lit room is a different statement from a batch standing open in a dark one; the second protects everything on the bench, including what was set aside for later. Light-sensitive substances decompose under daylight, and a laboratory window is daylight.

8.6.4 Room free of electrosmog and magnetism (¬↯)

The ticked checkbox states that the room was kept free of electrosmog and magnetism.

Stray fields matter wherever something is measured rather than merely mixed: a balance beside a magnetic stirrer, an electrochemical cell beside a transformer, an NMR beside a lift shaft. The tick records that the room was checked for this — which is a stronger statement than that nothing was noticed.

8.6.5 Room kept dry (☂)

The ticked checkbox states that the room was kept dry.

It is the qualitative counterpart of the humidity above: the figure says how humid the air was, the tick says that keeping it dry was intended and looked after. Whoever ticks it without a figure has still said the essential thing; whoever gives a figure of 70 % and ticks it as well has contradicted themselves, and the record shows the contradiction instead of hiding it.

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9 Citation and copied procedure

9.1 Citation and copied procedure

This subform holds where a procedure comes from. Whoever reworks a published preparation copies more than a list of amounts: they take over someone else’s reasoning, and the record should say whose.

It is a block like any other, so a run may rest on several sources — one for the preparation, one for the analysis, one for a safety note. Each gets its own block, and each stands where it was used.

Two things separate a source reference from a remark. It is checkable: the kind of source decides which details make it complete, and the form says what is still missing. And it travels with the export, so the evidence stays with the data instead of in a folder next to it.

An outlook that belongs to the accessibility: with the generative models the incentive to hold texts back is growing. Whoever publishes feeds the model that will next replace or exploit their work — so less appears, or it appears later, or behind barriers, or with the decisive details left out. Three things are therefore to be expected: less reworking, because there is less to rework; a declining capacity for innovation, because inventions live on what others have disclosed; and more hostility within the scientific community, because colleagues who learned from one another turn into parties who keep something from one another. Whoever enters the degree of accessibility here honestly at least records that development — a log full of “internal” and “on request” is a finding about the state of the field, not only about one source.

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9.2 Kind of source

9.2.1 Kind of source

The kind of source is the first choice, because it decides everything after it: which fields are shown, and which of them a complete reference needs. Twelve kinds are offered. They stand in alphabetical order (of the German caption, which is the leading one), so that a kind is found through its name and not through the group somebody once sorted it into; on a wide screen they spread over several columns.

Book — monograph, textbook, contribution to an edited volume; complete with author, title, publisher, place and year. Hearsay — who said it, and when; a spoken piece of information is a source even though nobody can look it up. Internet source — title, address, the day it was retrieved and the licence. AI prompt — a question put to a generative model. Demanded are author, title, the prompt text, the model with its version and the day; the agent with its version stands beside them and stays voluntary, because whoever asks a model through its own interface has no further agent. The answer is not the source — tomorrow it is another one — the setting in which it arose is. Patent — inventor, office and the publication number in the free field “Type”. Script — lecture notes or a laboratory manual; complete with author, title and the issuing institution, which is often the only thing that identifies it. Special — patent, standard, data sheet, software; here only the title and the type are demanded, because the identifying number differs from case to case. Stream (audio) and stream (video) — channel, address and the day of retrieval as with a web page, only with a channel in the place of a work. Academic work — Magister, diploma, bachelor’s and master’s theses and other expert reports; name, title, place and year are demanded, because a qualifying work is found through the person, the place of the university and the year, and not through a number. Journal — article in a periodical; additionally volume and pages, because without them the article cannot be found. Newspaper — title, paper, place, page and the day.

One further entry belongs to every source, and it holds for every kind: the degree of accessibility. Neither the licence nor the address says whether a reader gets at the source at all — a procedure resting on an internal report is reproducible for the house and unverifiable for everyone else. Twelve steps lead from “top secret” over “internal”, “private”, “recollection”, “semi-public”, “on request”, the two paywalls and “academic” up to “public”; the empty preselection claims nothing. The entry closes the assembled reference and thereby reaches the record.

The preselection unspecified is deliberately empty. As long as no kind is chosen, every field stays visible and nothing is demanded — an unstated kind is not a wrong kind, and the record keeps silent about it.

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9.3 Details of the source

9.3.1 Details of the source

Twenty-five details stand ready here, but never all at once: the chosen kind of source decides which of them are shown. A book has no retrieval date, a web page no publisher — a field that cannot apply is better hidden than left empty.

Three of the details belong to one single kind, the AI prompt: the prompt text, the model with its version and the agent with its version. They are what turns an answer of a machine into something one can check — not by reading it again, which is impossible, but by asking the same question of the same model through the same agent. The prompt text is the only field of the reference that spans several lines; the assembled reference folds it back into one and puts it in quotation marks near the end, where its length does not push the rest out of sight.

What the kind requires is marked with a star. That is not a lock: nothing is refused, the check merely says what is still missing. A reference that stays incomplete is still worth more than none.

The details do not reach the record one by one. The form assembles them into one reference in reading order — who, what, where, when, whence — and that single line is what the record prints. Whoever fills in a field can therefore be sure it appears; there is no detail that quietly falls out.

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9.4 Completeness check

9.4.1 Completeness check

The check reads what the chosen kind requires and names, by caption, what is still empty. It runs on every keystroke; there is no button to press and no state that could be older than the form.

What it does not do is judge the content. Whether the year is right, whether the address still resolves, whether the licence permits the copy — none of that can be decided here. The check answers one question only: is anything missing that this kind of source needs to be found again.

The verdict is recorded, not only shown. An incomplete reference reaches the record with the line of what is missing, and the pictogram carries the warning sign. That is the point: a gap that is written down can be closed later, a gap that is hidden cannot.

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9.5 Export

9.5.1 Handing the source reference on

The entries of a citation block are the same facts a reference manager keeps. The export hands them over instead of making them be typed a second time: four buttons, four files, and nothing in the form changes — the export only reads.

BibTeX (.bib) is what a LaTeX run reads. RIS (.ris) is understood by Zotero, Citavi, Mendeley and EndNote. CSL-JSON (.json) is the format of the citation styles and of Pandoc. EndNote XML (.xml) is the exchange format of EndNote itself. Which of the four is the right one is decided by the programme on the other side, not by this form.

The switch above the buttons says what is written: only this one citation, or every citation of the run. A run may rest on several sources, and each of them is a block of its own.

Nothing is invented. A field that was not filled in is missing from the file too, and a citation without a title is refused with a word instead of being written as an unusable entry — there is no style that could print it. Blocks in which nothing at all stands yet are passed over in silence.

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9.6 Kind of use

9.6.1 Kind of use

Three ways of using a source are distinguished, and the difference matters both scientifically and legally.

Verbatim means the procedure was carried out as written, and the wording is quoted below. Adapted means it was followed in substance but changed — other amounts, other apparatus, another scale; whoever reads the record later must know that the source does not say what was done. Reference means the source is named as evidence but nothing was copied from it.

Nothing is preselected. A block in which nothing has been entered yet must not claim that something was taken over word for word — an unstated way of use is not a wrong one, and the record keeps silent about it. Whoever changed something should say so here: the deviation, not the agreement, is what a later reader needs.

9.6.2 Cited section

Many sources carry several procedures on one page. The section names the part that was actually used — a heading, a paragraph, an experiment number.

Without it a reference points at a whole document, and whoever checks it has to guess which of four preparations was meant. With it the check is a matter of seconds, which is the whole purpose of citing.

9.6.3 Wording of the passage

Here stands the passage itself, in the wording of the source. A copied procedure that is only paraphrased loses exactly what makes it worth copying: the order, the reservations, the small conditions that read like decoration until they are left out.

The field is free text and stays untouched by the form — nothing is corrected, nothing is shortened. What stands here is the source speaking, not the log.

The limit is not technical but legal: a quotation must stay a quotation. A short passage with its reference is one; a whole chapter is not. Whoever wants to keep more than they may quote should note the source and leave the wording out.

9.6.4 Accessibility of the source

This choice answers a question neither the licence nor the address answers: how far does a reader get at the source at all? The licence says what one may do with it, the address says where it stands — the accessibility says whether one gets it. A procedure resting on an internal report is reproducible for the house and unverified for everybody else; the record should say so instead of leaving the reader to find out.

The entry is required for no kind of source, and it deliberately stands in the block “Takeover” and not with the source reference: it is not a detail of the source but a statement about it. Whoever copies the source reference finds the work; whether they also get to see it is said by this entry alone. That is also why it does not count in the completeness check.

The list is a ladder from closed to open, not an alphabet — the order is itself the statement. The twelve steps are told apart like this:

Unspecified (the preselection) — nothing is claimed. Not the same as “public”: whoever chooses nothing says nothing about the barrier.
⊗ Top secret — the highest level of secrecy. What separates it from “secret” is not the circle of persons but that even the existence of the source may not be named freely.
⊖ Secret — classified: the source may be named, but shown only to a named circle of persons. That circle is a list of people, not an institution.
⌂ Internal — open throughout the house (company, institute, working group), closed outside it. Unlike “secret”, the boundary is the institution and not a list of names.
⊙ Private — the source is in private hands; there is exactly one person who can hand it out. Unlike “internal”, an owner decides, not an order of things.
☁ Recollection — there is no copy at all. The steps above are locked, this one is empty: with every permission in the world there would still be nothing to look up. (It fits the kind of source “hearsay”.)
☾ Semi-public — open to anyone, but only over special networks (darknet) or closed forums. Nobody is shut out; the barrier is the way there, not the permission.
✉ On request — one gets it by asking (access to files, an archive enquiry, a question to the author). The barrier is a procedure, neither a payment nor a ban.
€€ High paywall — the source is for sale, but at a price a single person does not usually pay (standards, market studies). The difference from the next step is not one of kind but one of height — and in practice it is height that decides whether anybody checks.
€ Paywall — for sale at a customary price (an article, an e-book, a day pass).
Ⓐ Academic — reachable through a library licence. To a member of a university it feels like “public”, to everybody else like a paywall; hence a step of its own instead of one of the two.
○ Public — to be had without a barrier: no account, no payment, no application.

The chosen sign stands at the top left of the pictogram, so a closed block already shows what the evidence hangs on. Into the record the step goes as a sentence of its own (“The source stands behind a paywall.”), not as a line of the source reference.

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9.7 Notes on the citation (Note)

Free text and files for the whole block: what no field of the reference covers. A scan of the page, a note on where the copy came from, the reason why a detail is missing.

The place for a missing detail is here, not in an invented value. “The volume is not stated on the reprint” is a statement; a guessed number is not.

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10 Note

10.1 Note

This subform holds one free text and nothing else. It is the place for what belongs in the record but fits no field of any other block: a suspicion, a mishap, a question for the next run.

It is a block like any other and therefore stands WHERE it was written — between two steps, not in a collecting box at the end. That is the whole point: a remark about the third addition loses its meaning once it stands under the twentieth.

Because it has no pictogram, its closed lid shows the first three lines of the text. A run with six remarks can thus be read without opening a single one.

10.2 Wording of the note

The text itself. It is quoted in the record, not reworded: it is the wording of whoever wrote it, and a record that smooths a remark takes away the very thing it was written for.

The first three lines reach the closed lid, so the opening sentence is worth more than the rest — it is what the block is called from then on.

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11 Section start

11.1 Section start

This subform starts a new work section of the history protocol. It records that from here on a fraction from an earlier separation step is processed further — for instance the filter residue that is recrystallised, or the filtrate that is concentrated.

The subform carries three entries: the name of the fraction, its mass and its volume. The name is the reference the separation step assigns in the block “Goal / type” (“S-T-3”, “M-T-3”). In the form the block stands apart, with a gap and a double rule above it; in the reaction equation, in the brief protocol and in the history protocol a double rule likewise divides the new section from the previous one.

The history protocol supports the structuring of laboratory work only at this simplest level: it marks where a section begins and does not check whether the work can really be divided there. It is assumed that the planning has taken the structuring into account correctly.

A section start may also stand without a name — at the beginning of a work section that continues no earlier fraction, for instance when a reagent solution is prepared. As long as the name and both amounts are empty, the subform shows the button “Remove empty section start”. It folds the block away but leaves its double rule standing: the boundary of the section stays in the form and is saved with the record. A double-click on the rule — or the Delete key while the rule has focus — removes it as well. As soon as anything is entered, the button disappears.

11.2 Name of the fraction

The name of the fraction processed further — at most 20 characters. It may be typed or picked from the suggestion list; the list offers the names of all separation steps of the protocol, in the order of the protocol.

When an existing name is taken over, the form fetches mass and volume from the block “Output” of the separation step — but only if entries stand there and both fields here are still empty. If something already stands here, nothing is changed.

If the entries here differ from those of the separation step, a warning appears — in this subform and in the block “Output” of the separation step. If two separation steps carry the same name, the first one in the protocol applies.

11.3 Mass of the fraction

The mass of the fraction processed further. A unit may be written along (“0.2 kg”, “3.5 oz”); without a unit, grams apply. The entry stays as it was written; calculations use the value converted into grams.

When a name is taken over, the form fills the field from the separation step as long as mass and volume here are empty. The comparison with the separation step uses the converted values: “0.2 kg” and “200 g” agree.

11.4 Volume of the fraction

The volume of the fraction processed further. A unit may be written along (“12 cm^3”, “1 pt”); without a unit, millilitres apply. The entry stays as it was written; calculations use the value converted into millilitres.

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12 Strand

12.1 Preparation strand

Here stands that the step belongs to a preparation strand — a bracketed sequence of mixing, partial separation and purification whose product is used further in the reaction.

The membership groups the auxiliary steps that produce an intermediate and links them to the main reaction; without it they read as separate experiments.

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13 Protocol

13.1 The buttons of the protocol block

The buttons at the foot of the form turn the filled-in blocks into running text. Nothing is written on its own: the text is produced on a click, and as soon as an entry changes afterwards it is marked as outdated rather than silently rebuilt.

Protocol — The whole course as text, without the free remarks; the files attached there stand at the end.
Protocol with remarks — The same text, with every remark in its place.
Remove protocol — Takes the produced text out of the page again; nothing of the form is lost.
Copy to clipboard — Hands the finished text over to the clipboard, whole.

The head line above the text names which of the two readings it is, which form version wrote it and when — a protocol is read without the form and has to say so.

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14 Reports

14.1 The buttons of the report block

The reports do not tell the course — they read it off. All four write into the same shelf, so only one of them stands there at a time.

Reaction equation — The substances as a vertical chain, with their factors and what happened at every arrow.
Brief protocol — One line per step, each opening with the sign of its kind.
Material flow — The balance of the substances per section, over the whole record, and as the list of every input.
Condition check — One line per section: the number of its subforms once, then only the condition marks that were set, each with how often, then the drying agents that were used.
Delete report — Takes whichever report stands there out of the page again.

A minus in the material flow is not an error message: it can just as well mean that the substance came from an earlier section. It marks the place worth a second look. The condition check counts, it does not judge: a missing mark may simply mean that the condition was not needed there.

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15 Quality

15.1 The quality ring of a subform

Beside the gear of every subform stands a percentage in a ring. It says how completely this subform is filled in, measured against the quality criteria loaded for the form. What is measured is how complete the entries are, not whether they are right.

The criteria sort the entries of a subform into five groups, each with a weight:

Required — Without this entry the record is unusable.
Expected — The record remains usable without it but is incomplete.
Expected, replaceable — An expected entry that is waived when an equivalent entry is given, for example a duration instead of start and end. It then counts neither as met nor as demanded.
Optional and bonus — Additional; they raise the value but never lower it.

Every entry that is met brings its weight as points. The percentage is the sum of the points of required, expected and additional entries, divided by the points that required and expected entries demand together:

Percent = (points required + points expected + points optional + points bonus) ÷ (demanded points required + demanded points expected) × 100

It is rounded to whole percent. Because the additional entries stand only above the line, a subform can pass 100 %, up to the upper limit of the criteria file (120 % in the delivered file). They cannot make up for a missing required entry: the no-entry sign stays. A subform that demands nothing reaches 100 % with its first entry. The calculation of a single subform is shown by the ring itself when you point at it or click it.

Colour: red below 40, orange below 70, yellow below 90, green from 90. A blue 0 means nothing has been entered yet — the subform does not count towards the overall rating.

No-entry sign ⛔ — At least one required entry is missing. The sign stays as long as the entry is missing, however high the percentage is.
Warning triangle ⚠ — At least one expected entry is missing.

Which entries are meant is listed at the sign; the "Qual." box in the gear menu of the subform shows them in the form.

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