🌿 Isopentane (2-methylbutane) in workplace air — adsorption of vapours on activated carbon, desorption with carbon disulphide, gas chromatography; lowest determinable concentration according to the standard 150 mg/m³, MAC (NDS) 3000 mg/m³; PN-Z-04376:2010

Environment PN-Z-04376

Overview

WHAT THE STANDARD COVERS. Scope from the PKN card, in full: "A method is given consisting in the adsorption of isopentane vapours on activated carbon, desorption of the compound with carbon disulphide and analysis of the obtained solution by gas chromatography. The lowest concentration of isopentane that can be determined by this method is 150 mg/m3" (our translation; on the card without a full stop at the end). The card gives neither the detector nor the air volume. We did not have the text of the standard (7 pages). The CIOP index of methods from 2000–2017 lists "Izopentan – nr 4(38) 2003"; 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 311: "Isopentane [78-78-4]" — NDS 3000 mg/m³, without NDSCh and without the "skin" notation; pentane has a separate item in the list (item 457, NDS 3000 mg/m³). The lowest determinable concentration according to the card, 150 mg/m³, is 5 % of the NDS.

STATUS (card as of 05.10.2026). The card of PN-Z-04376:2010 (Polish version) has neither the heading "Withdrawn" nor a "Withdrawal date" line: published 16-11-2010, 7 pages, price group D, Health, Environment and Medicine Sector, KT 159 Chemical and Dust Hazards in the Working Environment, ICS 13.040.30; the card has no "Replaces" field. The PKN search for "PN-Z-04376" (05.10.2026) returns only this 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 04376 appears in 2 records at 2 laboratories; in the current PCA documents (read on 03.10.2026; issues of 08.01.2026 and 28.07.2026) — 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. The form "PN-Z-04376:2010" — AB 1144 and AB 1642, without procedures. The "Laboratories" tab (search term "PN-Z-04376") shows both laboratories — checked with a tab query on the labcoda.pl production server on 05.10.2026.

WHAT THE LABORATORIES TEST (database copy and PCA documents). AB 1144 — working environment, air samples collected on a solid sorbent: concentration and content of 2-methylbutane 1.40–7500 mg/m³ (0.00800–15.00 mg per sample); AB 1642 — air samples collected on a solid sorbent: isopentane (2-methylbutane) 0.240–6777 mg/m³ (0.00070–6.10 mg per sample). Technique: gas chromatography with flame ionisation detection (GC-FID) — both laboratories.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — limit of quantification: according to the card 150 mg/m³; AB 1144 gives 1.40 mg/m³, AB 1642 0.240 mg/m³, i.e. more than a hundred times less, which requires conditions different from those in the standard — the report should name them. Second — names: the standard and the NDS list write "isopentane", AB 1144 "2-methylbutane", AB 1642 both; when searching for a laboratory by substance name, one of them is easily missed. Third — another item of the list: pentane (item 457) has its own NDS; a result for isopentane is compared with item 311.

WHAT WE DO NOT GIVE. We did not have the text of the standard — we do not give the mass of activated carbon, the volume or flow rate of air sampling, the volume of carbon disulphide, the column, the detector required by the standard, the chromatograph conditions or calculations; we do not know the content of the 2003 CIOP article.

Method principle

Isopentane vapours from workplace air are adsorbed on activated carbon, desorbed with carbon disulphide and the solution is analysed by gas chromatography (PKN card); the result in mg/m³ is compared with the NDS of 3000 mg/m³ (Journal of Laws 2026 item 447). Lowest determinable concentration according to the card — 150 mg/m³. WE DO NOT GIVE details — we did not have the text of the standard.

Applications

• Workplace air — isopentane (2-methylbutane) — in the current scopes of 2 laboratories
• Assessment of occupational exposure against the NDS of 3000 mg/m³ (Journal of Laws 2026 item 447, item 311 of the list)

Key parameters

Standard

Standard number

PN-Z-04376:2010

Title (PL)

Ochrona czystości powietrza — Oznaczanie izopentanu na stanowiskach pracy metodą chromatografii gazowej

Title (EN)

Air purity protection — Determination of isopentane at workplaces by gas chromatography

Step-by-step procedure

1. Sampling

   Adsorption of isopentane vapours on activated carbon (PKN card); WE DO NOT GIVE the volume.

2. Desorption

   With carbon disulphide (PKN card).

3. Analysis

   Gas chromatography of the solution (PKN card); WE DO NOT GIVE the conditions.

4. Result and assessment

   Concentration in mg/m³; comparison with the NDS of 3000 mg/m³ (Journal of Laws 2026 item 447, item 311); lowest determinable concentration 150 mg/m³.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Isopentane and carbon disulphide — chemical laboratory safety rules
• TECHNICAL NOTE: the laboratories' bottom limits are more than a hundred times lower than the limit of quantification on the card (150 mg/m³); names in the scopes: isopentane and 2-methylbutane

Frequently asked questions