🌿 Hexavalent chromium in workplace air — paper or membrane filter, elution with sulphuric acid solution containing potassium permanganate, reaction with diphenylcarbazide, colorimetry; limit of quantification according to the standard 0.02 mg/m³ expressed as CrO₃, MAC (NDS) 0.005 mg/m³ expressed as Cr(VI); PN-Z-04126-02:1987 (withdrawn 27-11-2012)
In short
Polish standard of 1987 with a method for determining hexavalent chromium — soluble chromates and chromic acid — in workplace air: the sample on the filter is eluted with a sulphuric acid solution containing potassium permanganate, and chromium(VI) is determined colorimetrically after reaction with diphenylcarbazide. The test is performed according to PN-Z-04126-02:1987; STATUS (card as of 04.10.2026): PN-Z-04126-02:1987 WITHDRAWN — withdrawal date 27-11-2012; the card names no replacing standard; the whole PN-Z-04126 series withdrawn; the current PN-Z-04434:2011 determines total chromium. The procedure comprises 4 steps; it is used for: Workplace air — chromium(VI) compounds (soluble chromates and chromic acid) — in the current scopes of 6 laboratories, despite the withdrawal of the standard, Assessment of occupational exposure against the NDS of 0.005 mg/m³ expressed as Cr(VI) (Journal of Laws 2026 item 447, item 582 of the list).
At a glance
- Standard: PN-Z-04126-02:1987
- Category: Environment
- Procedure steps: 4
- STATUS (card as of 04.10.2026): PN-Z-04126-02:1987 WITHDRAWN — withdrawal date 27-11-2012; the card names no replacing standard; the whole PN-Z-04126 series withdrawn; the current PN-Z-04434:2011 determines total chromium
- Edition (from the PKN card): PN-Z-04126-02:1987, Polish version; published 08-09-1987, 3 pages, KT 159 Chemical and Dust Hazards in the Working Environment, ICS 13.040.30; replaced PN-Z-04055:1971
- Limit of quantification (card): 0.02 mg/m³ expressed as chromium trioxide (CrO₃)
Overview
WHAT THE STANDARD COVERS. Scope from the PKN catalogue card, in full (our translation): "The method allows soluble chromates and chromic acid to be determined. The determination consists in collecting the sample on a paper or membrane filter, eluting chromium (VI) with a sulphuric acid solution with the addition of potassium permanganate as oxidant and reaction of chromium with diphenylcarbazide in an acid medium. The red-violet colour of the complex compound formed is determined colorimetrically. Chromium (III) and large amounts of copper(II), nickel(II), vanadium(V) and iron(III) interfere with the determination. The limit of quantification expressed as chromium trioxide is 0.02 mg in 1 cubic metre of air" (no full stop at the end on the card; the card uses older Polish chemical names, which our Polish entry modernises). We did not have the text of the standard (3 pages).
NDS VALUE (list in the annex to the regulation of 26 March 2026, Journal of Laws 2026 item 447). Item 582: "Chromium(VI) compounds – expressed as Cr(VI)" — NDS 0.005 mg/m³, no NDSCh. The limit of quantification on the card is expressed as chromium trioxide (CrO₃), and the NDS as Cr(VI); to compare the two figures the units must be converted — the number 0.02 on its own is not comparable with 0.005.
STATUS (card as of 04.10.2026). The card of PN-Z-04126-02:1987 (Polish version) has the heading "Withdrawn": published 08-09-1987, withdrawal date 27-11-2012, 3 pages, price group B, Health, Environment and Medicine Sector, KT 159 Chemical and Dust Hazards in the Working Environment, ICS 13.040.30, "Replaces PN-Z-04055:1971"; the card does not name a replacing standard. The PKN search for "PN-Z-04126" and "chromu sześciowartościowego" (04.10.2026) shows the whole series "Tests for chromium and its compounds content" labelled "Withdrawn": part 00:1979 (general provisions), 01:1979 (replaced by PN-Z-04434:2011), 02:1987 (acid extraction), 03:1987 (hexavalent chromium, colorimetrically with alkaline extraction) and 5:1994 (immission). As current it returns PN-Z-04434:2011 "Determination of chromium and its compounds at workplaces by flame atomic absorption spectrometry" — in accreditation scopes (24 records at 20 laboratories in the database copy, read on 04.10.2026; the separate entry of this database on PN-Z-04434 gives, from a reading of 23.09.2026, 25 items at 21 laboratories — we did not investigate the cause of the difference between readings) it is used for metallic chromium and chromium(II), (III) and (VI) compounds together, expressed as Cr, not for chromium(VI) alone.
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 04126-02 (with a hyphen, full stop or slash before the part number) appears in 6 records at 6 laboratories; in the current PCA documents (read on 03.10.2026; issues from 26.11.2025 to 18.08.2026 — all issued after the withdrawal of the standard) — in 6 rows at the same laboratories; a search of all PCA documents downloaded from the BIP found no laboratories outside the database copy; no item with this standard is suspended and no document repeats pages. Old form "PN-87/Z-04126/02" — AB 484, AB 802, AB 849, AB 1257 and AB 1184 (next to instruction IK-804 ind. F of 14.12.2021); "PN-87/Z-04126.02" — AB 340. "Laboratories" tab: "PN-87/Z-04126/02" shows 5 laboratories, "PN-87/Z-04126.02" — 1, 6 in total, the same in the copy and on the production server labcoda.pl (tab queries of 04.10.2026). Part 03 (alkaline extraction) appears in the database copy in 12 records at 11 other laboratories — none cites both parts; part 03 is described in a separate entry of this database (chromium(VI) compounds in workplace air — filter, elution with sodium carbonate solution, reaction with diphenylcarbazide, colorimetry).
WHAT THE LABORATORIES TEST (database copy). Object: working environment — air (AB 849 and AB 1257 — air samples collected on filters). Quantity: concentration (content) of chromium(VI) compounds expressed as Cr(VI). Ranges in mg/m³: 0.00038–0.011 (AB 484), 0.000417–0.6 (AB 802), 0.0004–0.05 (AB 849), 0.001–0.2 (AB 1184), 0.001–0.050 (AB 1257), 0.0016–0.314 (AB 340). Technique: spectrophotometric method — all 6 laboratories.
WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — sensitivity against the NDS: the limit of quantification on the card (0.02 mg/m³ as CrO₃) refers to a different unit than the NDS (0.005 mg/m³ as Cr(VI)); all 6 laboratories state, expressed as Cr(VI), a bottom limit below the NDS (from 0.00038 to 0.0016 mg/m³), which requires conditions different from those in the 1987 standard — the report should name them. Second — interferences: according to the card, chromium(III) and large amounts of copper(II), nickel(II), vanadium(V) and iron(III) interfere with the determination — the report should show that they were absent or were removed. Third — what is determined: according to the card the method covers soluble chromates and chromic acid; the card does not mention insoluble chromium(VI) compounds, and part 03 of the same series (alkaline extraction) is a different method. Fourth — PN-Z-04434:2011 does not replace this standard for determining chromium(VI) — it determines total chromium. Fifth — status: the standard has been withdrawn since 27-11-2012, and the laboratories have it in scopes issued from November 2025.
WHAT WE DO NOT GIVE. We did not have the text of the standard — we do not give the air volume, the type of filter, solution concentrations, reaction conditions, the wavelength, how interferences are removed or calculations. We do not claim that another standard has replaced PN-Z-04126-02:1987 — PKN names none.
Method principle
The workplace air sample is collected on a paper or membrane filter, chromium(VI) is eluted with a sulphuric acid solution with the addition of potassium permanganate as oxidant, and after reaction with diphenylcarbazide in an acid medium the red-violet colour of the complex is measured colorimetrically. The result expressed as Cr(VI) is compared with the NDS of 0.005 mg/m³; limit of quantification according to the card — 0.02 mg/m³ expressed as CrO₃. The standard is withdrawn (27-11-2012); WE DO NOT GIVE details — we did not have the text of the standard.
Applications
- Workplace air — chromium(VI) compounds (soluble chromates and chromic acid) — in the current scopes of 6 laboratories, despite the withdrawal of the standard
- Assessment of occupational exposure against the NDS of 0.005 mg/m³ expressed as Cr(VI) (Journal of Laws 2026 item 447, item 582 of the list)
Key parameters
| Parameter | Value |
|---|---|
| STATUS (card as of 04.10.2026) | PN-Z-04126-02:1987 WITHDRAWN — withdrawal date 27-11-2012; the card names no replacing standard; the whole PN-Z-04126 series withdrawn; the current PN-Z-04434:2011 determines total chromium |
| Edition (from the PKN card) | PN-Z-04126-02:1987, Polish version; published 08-09-1987, 3 pages, KT 159 Chemical and Dust Hazards in the Working Environment, ICS 13.040.30; replaced PN-Z-04055:1971 |
| Limit of quantification (card) | 0.02 mg/m³ expressed as chromium trioxide (CrO₃) |
| Interferences (card) | chromium(III) and large amounts of copper(II), nickel(II), vanadium(V) and iron(III) |
| NDS (Journal of Laws 2026 item 447, item 582) | chromium(VI) compounds — 0.005 mg/m³ expressed as Cr(VI); no NDSCh |
| Coverage in accreditation scopes (read 04.10.2026) | 6 laboratories, 6 records in the database copy, 6 rows in PCA; "Laboratories" tab: "PN-87/Z-04126/02" — 5, "PN-87/Z-04126.02" — 1, the same on the production server; part 03 — 11 other laboratories |
Standard
- Standard number
- PN-Z-04126-02:1987
- Title (PL)
- Ochrona czystości powietrza — Badania zawartości chromu i jego związków — Oznaczanie chromu sześciowartościowego na stanowiskach pracy metodą kolorymetryczną z kwaśną ekstrakcją próbki
- Title (EN)
- Air purity protection — Tests for chromium and its compounds content — Determination of hexavalent chromium at workplaces by the colorimetric method with acid extraction of the sample
Step-by-step procedure
-
Sampling
Sample on a paper or membrane filter (PKN card); WE DO NOT GIVE the volume.
-
Elution
With a sulphuric acid solution with the addition of potassium permanganate (PKN card).
-
Reaction and measurement
Reaction with diphenylcarbazide in an acid medium, colorimetry of the red-violet complex (PKN card).
-
Result and assessment
Concentration expressed as Cr(VI); comparison with the NDS of 0.005 mg/m³ (Journal of Laws 2026 item 447); limit of quantification on the card 0.02 mg/m³ as CrO₃.
Required equipment and apparatus
| Equipment | Example | Indicative price |
|---|---|---|
| Colorimeter or spectrophotometer | Measurement of the colour of the chromium–diphenylcarbazide complex (PKN card); WE DO NOT GIVE the wavelength | — |
| Air sampling set with a paper or membrane filter | Sample collection (PKN card); WE DO NOT GIVE the volume | — |
Reagents, media and consumables
| Reagent | CAS | Details |
|---|---|---|
| Sulphuric acid solution with potassium permanganate | — | For eluting chromium(VI); permanganate as oxidant (PKN card) |
| Diphenylcarbazide | — | Colour reagent in an acid medium (PKN card: older Polish name "dwufenylokarbazyd") |
Health and safety (OHS)
- Sulphuric acid and potassium permanganate — chemical laboratory safety rules
- TECHNICAL NOTE: the limit of quantification on the card (as CrO₃) and the NDS (as Cr(VI)) are expressed on different bases; standard withdrawn on 27-11-2012
Frequently asked questions
Which standard describes this test?
The test is performed according to PN-Z-04126-02:1987 — “Air purity protection — Tests for chromium and its compounds content — Determination of hexavalent chromium at workplaces by the colorimetric method with acid extraction of the sample”.
How does this method work?
The workplace air sample is collected on a paper or membrane filter, chromium(VI) is eluted with a sulphuric acid solution with the addition of potassium permanganate as oxidant, and after reaction with diphenylcarbazide in an acid medium the red-violet colour of the complex is measured colorimetrically. The result expressed as Cr(VI) is compared with the NDS of 0.
What is the measuring range and accuracy?
STATUS (card as of 04.10.2026): PN-Z-04126-02:1987 WITHDRAWN — withdrawal date 27-11-2012; the card names no replacing standard; the whole PN-Z-04126 series withdrawn; the current PN-Z-04434:2011 determines total chromium; Edition (from the PKN card): PN-Z-04126-02:1987, Polish version; published 08-09-1987, 3 pages, KT 159 Chemical and Dust Hazards in the Working Environment, ICS 13.040.30; replaced PN-Z-04055:1971; Limit of quantification (card): 0.02 mg/m³ expressed as chromium trioxide (CrO₃); Interferences (card): chromium(III) and large amounts of copper(II), nickel(II), vanadium(V) and iron(III).
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?
Colorimeter or spectrophotometer, Air sampling set with a paper or membrane filter.
Where is this test used?
Workplace air — chromium(VI) compounds (soluble chromates and chromic acid) — in the current scopes of 6 laboratories, despite the withdrawal of the standard; Assessment of occupational exposure against the NDS of 0.005 mg/m³ expressed as Cr(VI) (Journal of Laws 2026 item 447, item 582 of the list).
What safety precautions apply?
Sulphuric acid and potassium permanganate — chemical laboratory safety rules; TECHNICAL NOTE: the limit of quantification on the card (as CrO₃) and the NDS (as Cr(VI)) are expressed on different bases; standard withdrawn on 27-11-2012.
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-04126-02.