🌿 Ammonium chloride in workplace air (vapours and inhalable fraction) — aerosol on a membrane filter, elution with dilute sulphuric acid, reaction of ammonium ions with Nessler's reagent, spectrophotometry; lowest determinable concentration according to the standard 1.6 mg/m³, MAC (NDS) 10 mg/m³, NDSCh 20 mg/m³; PN-Z-04265:2000 (withdrawn 25-09-2017)
In short
Polish standard of 2000 with a method for determining ammonium chloride in workplace air: the aerosol is deposited on a membrane filter, the compound is eluted with dilute sulphuric acid and the ammonium ions are determined spectrophotometrically after reaction with Nessler's reagent; the lowest determinable concentration according to the PKN catalogue card is 1. The test is performed according to PN-Z-04265:2000; Ranges in accreditation scopes: from 0.01 mg/m³ (AB 802) to 83.3 mg/m³ (AB 418); AB 719 — 0.094–9.4 mg per sample. The procedure comprises 4 steps; it is used for: Workplace air — ammonium chloride (vapours and inhalable fraction) — in the current scopes of 7 laboratories, despite the withdrawal of the standard, Assessment of occupational exposure against the NDS of 10 mg/m³ and the NDSCh of 20 mg/m³ (Journal of Laws 2026 item 447, item 86 of the list).
At a glance
- Standard: PN-Z-04265:2000
- Category: Environment
- Procedure steps: 4
- STATUS (card as of 04.10.2026): PN-Z-04265:2000 WITHDRAWN — withdrawal date 25-09-2017; the card indicates no replacing standard; no other standard in the PKN search ("chlorku amonu")
- Edition (from the PKN card): PN-Z-04265:2000, Polish version; published 25-04-2000, 5 pages, KT 159 Chemical and Dust Hazards in the Working Environment, ICS 13.040.30
- Lowest determinable concentration (card): 1.6 mg/m³
Overview
WHAT THE STANDARD COVERS. Scope from the PKN catalogue card, in full (our translation): "A method is given consisting in passing a known volume of air through a membrane filter in order to deposit ammonium chloride aerosol on it, eluting the compound with dilute sulphuric acid and reacting the ammonium ions with Nessler's reagent. The yellow-orange product formed is the basis of the spectrophotometric determination. The lowest concentrations of ammonium chloride that can be determined by this method is 1.6 mg/m3" (grammar as on the card). We did not have the text of the standard (5 pages). We found no CIOP article with a method for ammonium chloride (the 2000–2017 index of methods does not list one; search on 04.10.2026).
NDS VALUES (list in the annex to the regulation of 26 March 2026, Journal of Laws 2026 item 447). Item 86: "Ammonium chloride [12125-02-9] — vapours and inhalable fraction" — NDS 10 mg/m³, NDSCh 20 mg/m³, without the "skin" notation. Footnote 6 of the list defines the inhalable fraction according to PN-EN 481. The lowest determinable concentration according to the card, 1.6 mg/m³, is 16 % of the NDS.
STATUS (card as of 04.10.2026). The card of PN-Z-04265:2000 (Polish version) has the heading "Withdrawn": published 25-04-2000, withdrawal date 25-09-2017, 5 pages, price group C, 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-04265" and "chlorku amonu" (ammonium chloride) (04.10.2026) returns only this withdrawn standard.
HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data load up to 17.09.2026, read on 04.10.2026). The number 04265 appears in 8 records at 7 laboratories; in the current PCA documents (read on 03.10.2026; issues from 26.01.2026 to 23.07.2026 — all issued after the withdrawal of the standard) — in 8 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. All entries read "PN-Z-04265:2000"; AB 632 cites it next to instruction IB-07 edition 1 of 09.01.2024, and AB 719 in a second item, for waste gases, "excluding clause 7". The "Laboratories" tab (query "PN-Z-04265") shows all 7 laboratories — checked with the tab's query on the production server labcoda.pl on 04.10.2026.
WHAT THE LABORATORIES TEST (database copy). Object: working environment — air, air samples collected on filters; AB 719 also general environment — waste gas samples collected into bubblers with absorbing solution. Quantity: concentration (content) of ammonium chloride — vapours and inhalable fraction (at AB 632 — inhalable fraction). Ranges in mg/m³: 0.01–40.0 (AB 802), 0.12–40 (AB 647), 0.13–40 (AB 746), 0.13–60 (AB 849), 0.13–83.3 (AB 418), 0.436–41.43 (AB 632); AB 719 — 0.094–9.4 mg per sample (workplace air and waste gases). Technique: spectrophotometric method — all laboratories.
WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — status: the standard has been withdrawn since 25-09-2017 and the card indicates no successor; the laboratories have it in scopes issued in 2026 — the customer should know that the result is produced according to a standard withdrawn from the PKN catalogue. Second — limit of quantification: according to the card the lowest concentration determinable by this method is 1.6 mg/m³; all six laboratories with a range in mg/m³ state a lower bottom limit (from 0.01 to 0.436 mg/m³), which requires conditions different from those in the standard — the report should name them. Third — what is measured: according to the card the basis of the determination is the reaction of ammonium ions with Nessler's reagent; the card does not say how to distinguish ammonium chloride from other sources of ammonium ions in the sample, and WE DO NOT GIVE this. Fourth — form: the NDS applies to vapours and the inhalable fraction together, while the card speaks of depositing the aerosol on a filter — how the method covers the vapours does not follow from the card. Fifth — object: the AB 719 item for waste gases concerns the general environment, while the NDS applies only to workplaces.
WHAT WE DO NOT GIVE. We did not have the text of the standard — we do not give the volume or flow rate of air sampling, the type of filter, the concentration of sulphuric acid, the composition of Nessler's reagent, the wavelength, the calibration curve, calculations or the content of clause 7 excluded by AB 719. We do not claim that another standard has replaced PN-Z-04265:2000 — PKN indicates none.
Method principle
A known volume of workplace air is passed through a membrane filter on which ammonium chloride aerosol is deposited. The compound is eluted with dilute sulphuric acid, and the ammonium ions react with Nessler's reagent to give a yellow-orange product whose absorbance is measured spectrophotometrically; the result in mg/m³ is compared with the NDS of 10 mg/m³ and the NDSCh of 20 mg/m³. Lowest determinable concentration according to the card — 1.6 mg/m³. The standard is withdrawn (25-09-2017); WE DO NOT GIVE details — we did not have the text of the standard.
Applications
- Workplace air — ammonium chloride (vapours and inhalable fraction) — in the current scopes of 7 laboratories, despite the withdrawal of the standard
- Assessment of occupational exposure against the NDS of 10 mg/m³ and the NDSCh of 20 mg/m³ (Journal of Laws 2026 item 447, item 86 of the list)
Key parameters
| Parameter | Value |
|---|---|
| STATUS (card as of 04.10.2026) | PN-Z-04265:2000 WITHDRAWN — withdrawal date 25-09-2017; the card indicates no replacing standard; no other standard in the PKN search ("chlorku amonu") |
| Edition (from the PKN card) | PN-Z-04265:2000, Polish version; published 25-04-2000, 5 pages, KT 159 Chemical and Dust Hazards in the Working Environment, ICS 13.040.30 |
| Lowest determinable concentration (card) | 1.6 mg/m³ |
| NDS / NDSCh (Journal of Laws 2026 item 447, item 86) | 10 mg/m³ / 20 mg/m³ — vapours and inhalable fraction |
| Ranges in accreditation scopes | from 0.01 mg/m³ (AB 802) to 83.3 mg/m³ (AB 418); AB 719 — 0.094–9.4 mg per sample |
| Coverage in accreditation scopes (read 04.10.2026) | 7 laboratories, 8 records in the database copy, 8 rows in PCA; "Laboratories" tab ("PN-Z-04265") — 7, the same on the production server |
Standard
- Standard number
- PN-Z-04265:2000
- Title (PL)
- Ochrona czystości powietrza — Oznaczanie chlorku amonu na stanowiskach pracy metodą spektrofotometryczną
- Title (EN)
- Air purity protection — Determination of ammonium chloride at workplaces by spectrophotometry
Step-by-step procedure
-
Status
PN-Z-04265:2000 withdrawn 25-09-2017, no successor indicated (card as of 04.10.2026).
-
Sampling
Known volume of air through a membrane filter; WE DO NOT GIVE details.
-
Elution and reaction
Elution with dilute sulphuric acid, reaction of ammonium ions with Nessler's reagent; WE DO NOT GIVE the conditions.
-
Measurement, result and assessment
Spectrophotometry; concentration in mg/m³ compared with the NDS of 10 mg/m³ and the NDSCh of 20 mg/m³ (Journal of Laws 2026 item 447); lowest determinable concentration 1.6 mg/m³.
Required equipment and apparatus
| Equipment | Example | Indicative price |
|---|---|---|
| Spectrophotometer | Measurement of the coloured product of the reaction with Nessler's reagent (PKN card); WE DO NOT GIVE the wavelength | — |
| Air sampling set with a membrane filter | Deposition of ammonium chloride aerosol (PKN card); WE DO NOT GIVE the volume or flow rate | — |
Reagents, media and consumables
| Reagent | CAS | Details |
|---|---|---|
| Dilute sulphuric acid | — | For eluting ammonium chloride from the filter (PKN card); WE DO NOT GIVE the concentration |
| Nessler's reagent | — | Reaction with ammonium ions, yellow-orange product (PKN card); WE DO NOT GIVE the composition |
Health and safety (OHS)
- Nessler's reagent and sulphuric acid — chemical laboratory safety rules
- TECHNICAL NOTE: standard withdrawn on 25-09-2017; a bottom limit below 1.6 mg/m³ requires conditions different from those in the standard
Frequently asked questions
Which standard describes this test?
The test is performed according to PN-Z-04265:2000 — “Air purity protection — Determination of ammonium chloride at workplaces by spectrophotometry”.
How does this method work?
A known volume of workplace air is passed through a membrane filter on which ammonium chloride aerosol is deposited. The compound is eluted with dilute sulphuric acid, and the ammonium ions react with Nessler's reagent to give a yellow-orange product whose absorbance is measured spectrophotometrically; the result in mg/m³ is compared with the NDS of 10 mg/m³ and the NDSCh of 20 mg/m³.
What is the measuring range and accuracy?
STATUS (card as of 04.10.2026): PN-Z-04265:2000 WITHDRAWN — withdrawal date 25-09-2017; the card indicates no replacing standard; no other standard in the PKN search ("chlorku amonu"); Edition (from the PKN card): PN-Z-04265:2000, Polish version; published 25-04-2000, 5 pages, KT 159 Chemical and Dust Hazards in the Working Environment, ICS 13.040.30; Lowest determinable concentration (card): 1.6 mg/m³; NDS / NDSCh (Journal of Laws 2026 item 447, item 86): 10 mg/m³ / 20 mg/m³ — vapours and inhalable fraction.
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 with a membrane filter.
Where is this test used?
Workplace air — ammonium chloride (vapours and inhalable fraction) — in the current scopes of 7 laboratories, despite the withdrawal of the standard; Assessment of occupational exposure against the NDS of 10 mg/m³ and the NDSCh of 20 mg/m³ (Journal of Laws 2026 item 447, item 86 of the list).
What safety precautions apply?
Nessler's reagent and sulphuric acid — chemical laboratory safety rules; TECHNICAL NOTE: standard withdrawn on 25-09-2017; a bottom limit below 1.6 mg/m³ requires conditions different from those in the standard.
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-04265.