🌿 Formaldehyde in the presence of hydrogen cyanide in workplace air — visible-light spectrophotometry with phenylhydrazine and potassium ferricyanide; the PKN card gives no limit of quantification; MAC (NDS) 0.37 mg/m³ (0.3 ppm), STEL (NDSCh) 0.74 mg/m³ (0.6 ppm), "skin" notation; PN-Z-04045-08:1990 (withdrawn 06-03-2012)
In short
Polish standard of 1990 with a spectrophotometric method for determining formaldehyde in workplace air, according to the title — in the presence of hydrogen cyanide: formaldehyde is absorbed by the action of phenylhydrazine hydrochloride (the card says "phenylhydrazone"), and the pink colour of the solution after reaction with potassium ferricyanide and hydrochloric acid is the basis of the measurement. The test is performed according to PN-Z-04045-08:1990; Ranges in accreditation scopes: AB 874: 0.03–2 mg/m³, workplace air; AB 935: 0.8–25 mg/m³, waste gases, excluding point 7; both spectrophotometry. The procedure comprises 4 steps; it is used for: Workplace air — formaldehyde — in the current scope of 1 laboratory; waste gases — in the scope of the other, excluding point 7; both despite the withdrawal of the standard, Assessment of occupational exposure against the NDS of 0.37 mg/m³ and the NDSCh of 0.74 mg/m³, "skin" notation (Journal of Laws 2026 item 447, item 260 of the list).
At a glance
- Standard: PN-Z-04045-08:1990
- Category: Environment
- Procedure steps: 4
- STATUS (card as of 05.10.2026): PN-Z-04045-08:1990 WITHDRAWN — withdrawal date 06-03-2012; the card does not indicate a replacing standard; current for formaldehyde (first 50 PKN results): PN-Z-04045-12:2006 (replaces sheet 04)
- Edition (from the PKN card): PN-Z-04045-08:1990, Polish version; published 03-02-1990, 3 pages, KT 159 Chemical and Dust Hazards in the Working Environment, ICS 13.040.30
- Method (card): absorption by the action of phenylhydrazine hydrochloride (card: "phenylhydrazone"), reaction with potassium ferricyanide and hydrochloric acid, pink colour, spectrophotometry; the card gives no limit of quantification
Overview
WHAT THE STANDARD COVERS. Scope from the PKN card, in full: "A method is established consisting in the absorption of formaldehyde by the action of phenylhydrazone hydrochloride, followed by the reaction of phenylhydrazine with potassium ferricyanide and hydrochloric acid. The pink colour of the solution is the basis of the spectrophotometric determination. The method is used for determining the content of formaldehyde in air at workplaces. General guidelines, apparatus, instruments and materials, the method of preparing reagents and solutions, the preparation of the calibration curve and standard solutions are given" (our translation; the card says "fenylohydrazonu" — phenylhydrazone — in the first sentence and "fenylohydrazyny" — phenylhydrazine — in the second; no full stop at the end). The title of the standard speaks of determination "in the presence of hydrogen cyanide"; the "Scope" field does not mention hydrogen cyanide and does not explain what this presence involves. The card gives neither the lowest determinable concentration, the air volume nor the wavelength. We did not have the text of the standard (3 pages). The CIOP index of methods from 2000–2017 lists "Formaldehyd (z próbnikami pasywnymi) – nr 3(25) 2000"; we did not read the article and give nothing from it.
NDS VALUES (list in the annex to the regulation of 26 March 2026, Journal of Laws 2026 item 447). Item 260: "Formaldehyde [50-00-0]" with footnote 7 — NDS 0.37 mg/m³ (0.3 ppm), NDSCh 0.74 mg/m³ (0.6 ppm), "skin" notation; footnote 7: "The substance may have a sensitising effect on the skin."
STATUS (card as of 05.10.2026). The card of PN-Z-04045-08:1990 (Polish version) has the heading "Withdrawn": published 03-02-1990, withdrawal date 06-03-2012, 3 pages, price group B, Health, Environment and Medicine Sector, KT 159 Chemical and Dust Hazards in the Working Environment, ICS 13.040.30; the card does not indicate a replacing standard. The PKN search for "PN-Z-04045" (05.10.2026) returns 19 items; only sheets 12, 13 and 14 are current. Among the first 50 results for "formaldehydu" (05.10.2026) the only current standard on formaldehyde is PN-Z-04045-12:2006 "Air purity protection -- Tests for aldehyde content -- Part 12: Determination of formaldehyde at workplaces by gas chromatography with passive sampling" (our translation of the title) — according to its card: published 23-08-2006, 8 pages, KT 159, paper filter coated with 2,4-dinitrophenylhydrazine, desorption with acetonitrile, gas chromatography, lowest determinable concentration 0.008 mg/m³; its card has the field "Replaces: PN-Z-04045-04:1976", not sheet 08. The systematic search term "metanalu" (methanal) returns no standard.
HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data load up to 17.09.2026, read on 05.10.2026). The number 04045-08 (with a hyphen or a full stop before the sheet number) appears in 2 records at 2 laboratories; in the current PCA documents (read on 03.10.2026; issues of 04.09.2025 and 15.06.2026 — both issued after the withdrawal of the standard) — in 2 rows at the same laboratories; a search of all PCA documents downloaded from the BIP found no laboratories outside the database copy; no item is suspended, and no document repeats pages. Forms: "PN-90/Z-04045.08" — AB 874; "PN-Z-04045-08:1990 z wyłączeniem punktu 7" (excluding point 7) — AB 935. "Laboratories" tab: "PN-Z-04045-08" — 1 laboratory, "PN-90/Z-04045.08" — 1, the same in the copy and on the labcoda.pl production server (tab queries on 05.10.2026).
WHAT THE LABORATORIES TEST (database copy and PCA documents). AB 874 — working environment, air: concentration of formaldehyde 0.03–2 mg/m³, spectrophotometric method. AB 935 — waste gases: concentration and content of formaldehyde 0.8–25 mg/m³ (8–250 µg per sample), spectrophotometric method, standard excluding point 7. Neither laboratory mentions hydrogen cyanide in its scope.
WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — status: the standard has been withdrawn since 06-03-2012, and both laboratories have it in scopes issued in 2025–2026; according to PKN the current PN-Z-04045-12:2006 replaces sheet 04, not 08 — we do not state that it is the successor of sheet 08. Second — object: the standard concerns workplace air, while AB 935 applies it to waste gases, excluding point 7, whose content we do not know — for waste gases the NDS is not a reference value. Third — hydrogen cyanide: the title links the method to the presence of hydrogen cyanide, and the laboratories' scopes do not describe this condition — the report should state whether hydrogen cyanide was present in the air. Fourth — bottom limit: the card gives no limit of quantification; AB 874 starts at 0.03 mg/m³, i.e. about 8 % of the NDS. Fifth — skin: the NDS has the "skin" notation and a footnote on the sensitising effect on the skin, and a measurement in air does not cover skin contact.
WHAT WE DO NOT GIVE. We did not have the text of the standard — we do not give the concentration or volume of the absorbing solution, the air volume and flow rate, the wavelength, the reaction conditions, the limit of quantification or calculations; we do not know what point 7 excluded by AB 935 concerns, nor what role hydrogen cyanide plays in the standard. We do not state that another standard replaced PN-Z-04045-08:1990 — PKN does not indicate one.
Method principle
Formaldehyde from workplace air is absorbed by the action of phenylhydrazine hydrochloride (the card says "phenylhydrazone"); after the reaction of phenylhydrazine with potassium ferricyanide and hydrochloric acid a pink colour forms, measured spectrophotometrically (PKN card). According to the title the method is used to determine formaldehyde in the presence of hydrogen cyanide. The result in mg/m³ is compared with the NDS of 0.37 mg/m³ and the NDSCh of 0.74 mg/m³ (Journal of Laws 2026 item 447). The standard is withdrawn (06-03-2012); WE DO NOT GIVE details — we did not have the text of the standard.
Applications
- Workplace air — formaldehyde — in the current scope of 1 laboratory; waste gases — in the scope of the other, excluding point 7; both despite the withdrawal of the standard
- Assessment of occupational exposure against the NDS of 0.37 mg/m³ and the NDSCh of 0.74 mg/m³, "skin" notation (Journal of Laws 2026 item 447, item 260 of the list)
Key parameters
| Parameter | Value |
|---|---|
| STATUS (card as of 05.10.2026) | PN-Z-04045-08:1990 WITHDRAWN — withdrawal date 06-03-2012; the card does not indicate a replacing standard; current for formaldehyde (first 50 PKN results): PN-Z-04045-12:2006 (replaces sheet 04) |
| Edition (from the PKN card) | PN-Z-04045-08:1990, Polish version; published 03-02-1990, 3 pages, KT 159 Chemical and Dust Hazards in the Working Environment, ICS 13.040.30 |
| Method (card) | absorption by the action of phenylhydrazine hydrochloride (card: "phenylhydrazone"), reaction with potassium ferricyanide and hydrochloric acid, pink colour, spectrophotometry; the card gives no limit of quantification |
| NDS / NDSCh (Journal of Laws 2026 item 447, item 260) | 0.37 mg/m³ (0.3 ppm) / 0.74 mg/m³ (0.6 ppm); "skin" notation; footnote 7 — sensitising effect on the skin |
| Ranges in accreditation scopes | AB 874: 0.03–2 mg/m³, workplace air; AB 935: 0.8–25 mg/m³, waste gases, excluding point 7; both spectrophotometry |
| Coverage in accreditation scopes (read 05.10.2026) | 2 laboratories, 2 records in the database copy, 2 rows in PCA; "Laboratories" tab: "PN-Z-04045-08" — 1, "PN-90/Z-04045.08" — 1, the same on the production server |
Standard
- Standard number
- PN-Z-04045-08:1990
- Title (PL)
- Ochrona czystości powietrza — Badania zawartości aldehydów — Oznaczanie formaldehydu w obecności cyjanowodoru na stanowiskach pracy metodą spektrofotometryczną w świetle widzialnym z fenylohydrazyną
- Title (EN)
- Air purity protection — Tests for aldehyde content — Determination of formaldehyde in the presence of hydrogen cyanide at workplaces by visible-light spectrophotometry with phenylhydrazine
Step-by-step procedure
-
Status
PN-Z-04045-08:1990 withdrawn on 06-03-2012, with no indicated successor (card as of 05.10.2026).
-
Sampling
Absorption of formaldehyde from air by the action of phenylhydrazine hydrochloride (PKN card: "phenylhydrazone"); WE DO NOT GIVE the volume.
-
Reaction and measurement
Reaction with potassium ferricyanide and hydrochloric acid, spectrophotometric measurement of the pink colour against the calibration curve (PKN card); WE DO NOT GIVE the conditions.
-
Result and assessment
Concentration in mg/m³; comparison with the NDS of 0.37 mg/m³ and the NDSCh of 0.74 mg/m³ (Journal of Laws 2026 item 447) — only for workplace air, not for waste gases.
Required equipment and apparatus
| Equipment | Example | Indicative price |
|---|---|---|
| Spectrophotometer | Measurement of the pink colour of the solution (PKN card); WE DO NOT GIVE the wavelength | — |
| Air sampling set | Absorption of formaldehyde (PKN card); WE DO NOT GIVE the absorption method, volume or flow rate | — |
Reagents, media and consumables
| Reagent | CAS | Details |
|---|---|---|
| Phenylhydrazine hydrochloride | — | For absorbing formaldehyde (PKN card: "phenylhydrazone hydrochloride"); WE DO NOT GIVE the form or concentration |
| Potassium ferricyanide and hydrochloric acid | — | For the colour reaction (PKN card); WE DO NOT GIVE the quantities |
Health and safety (OHS)
- Formaldehyde — "skin" notation and footnote on the sensitising effect on the skin in the NDS list; chemical laboratory safety rules
- TECHNICAL NOTE: standard withdrawn on 06-03-2012 with no successor in the PKN catalogue; AB 935 applies it to waste gases excluding point 7 — for them the NDS is not a reference value
Frequently asked questions
Which standard describes this test?
The test is performed according to PN-Z-04045-08:1990 — “Air purity protection — Tests for aldehyde content — Determination of formaldehyde in the presence of hydrogen cyanide at workplaces by visible-light spectrophotometry with phenylhydrazine”.
How does this method work?
Formaldehyde from workplace air is absorbed by the action of phenylhydrazine hydrochloride (the card says "phenylhydrazone"); after the reaction of phenylhydrazine with potassium ferricyanide and hydrochloric acid a pink colour forms, measured spectrophotometrically (PKN card). According to the title the method is used to determine formaldehyde in the presence of hydrogen cyanide.
What is the measuring range and accuracy?
STATUS (card as of 05.10.2026): PN-Z-04045-08:1990 WITHDRAWN — withdrawal date 06-03-2012; the card does not indicate a replacing standard; current for formaldehyde (first 50 PKN results): PN-Z-04045-12:2006 (replaces sheet 04); Edition (from the PKN card): PN-Z-04045-08:1990, Polish version; published 03-02-1990, 3 pages, KT 159 Chemical and Dust Hazards in the Working Environment, ICS 13.040.30; Method (card): absorption by the action of phenylhydrazine hydrochloride (card: "phenylhydrazone"), reaction with potassium ferricyanide and hydrochloric acid, pink colour, spectrophotometry; the card gives no limit of quantification; NDS / NDSCh (Journal of Laws 2026 item 447, item 260): 0.37 mg/m³ (0.3 ppm) / 0.74 mg/m³ (0.6 ppm); "skin" notation; footnote 7 — sensitising effect on the skin.
How long does the test take?
The procedure comprises 4 steps. The standard does not give a duration for every stage — the laboratory's own procedure decides.
What equipment is required?
Spectrophotometer, Air sampling set.
Where is this test used?
Workplace air — formaldehyde — in the current scope of 1 laboratory; waste gases — in the scope of the other, excluding point 7; both despite the withdrawal of the standard; Assessment of occupational exposure against the NDS of 0.37 mg/m³ and the NDSCh of 0.74 mg/m³, "skin" notation (Journal of Laws 2026 item 447, item 260 of the list).
What safety precautions apply?
Formaldehyde — "skin" notation and footnote on the sensitising effect on the skin in the NDS list; chemical laboratory safety rules; TECHNICAL NOTE: standard withdrawn on 06-03-2012 with no successor in the PKN catalogue; AB 935 applies it to waste gases excluding point 7 — for them the NDS is not a reference value.
Which laboratory can perform this test?
The test is performed by laboratories accredited to ISO/IEC 17025. On LabCoda you can find them by the standard number PN-Z-04045-08.