🌿 Isoflurane (inhalation anaesthetic) in workplace air — adsorption of vapour on activated carbon, desorption with toluene, gas chromatography; lowest determinable concentration according to the standard 1 mg/m³, MAC (NDS) 32 mg/m³; PN-Z-04423:2011

Environment PN-Z-04423

Overview

WHAT THE STANDARD COVERS. Scope from the PKN card, in full: "A method is given consisting of adsorption of isoflurane vapour on activated carbon, desorption of the compound with toluene and analysis of the resulting solution by gas chromatography. The lowest isoflurane concentration that can be determined by this method is 1 mg/m3" (our translation; no full stop at the end on the card). The card does not give the detector. We did not have the text of the standard (7 pages).

ACCORDING TO THE CIOP PROCEDURE (M. Kucharska, W. Wesołowski, Nofer Institute of Occupational Medicine, "Isoflurane – method of determination", Podstawy i Metody Oceny Środowiska Pracy 2007, no. 1(51), pp. 133–139 — read in full). The procedure was published four years before the standard, with the same principle (activated carbon, desorption with toluene) and the same determinability of 1 mg/m³; we do not claim that the standard repeats it. In the procedure: "petroleum charcoal" activated carbon, glass tube about 100 mm with layers of 100 and 250 mg; 5 l of air at a flow rate up to 3 l/h; samples stable in a freezer for 14 days, and when other anaesthetics are present, no longer than 7 days is recommended; desorption with 1 ml of toluene for 30 min; gas chromatograph with mass detector (MSD, EI ionisation, SIM mode — masses 51, 115, 117 and 149), e.g. non-polar column 50 m × 0.2 mm, film 0.5 µm (HP-PONA), programme from 50 °C to 160 °C; calibration curve 5–375 µg in 1 ml, which for 5 l of air gives 1–75 mg/m³; the amount in the shorter layer should not exceed 10 % of that in the longer one, otherwise the result is indicative; the desorption coefficient is determined for each new batch of carbon. Validation data: limit of quantification 2.15 µg/ml, correlation coefficient 0.999, overall precision 5.16 %, total uncertainty 11.28 %. The procedure gives the NDS of 32 mg/m³ proposed at the time.

NDS VALUE (list in the annex to the regulation of 26 March 2026, Journal of Laws 2026 item 447). Item 309: "Isoflurane [26675-46-7]" — NDS 32 mg/m³, no NDSCh and no "skin" notation. The lowest determinable concentration according to the card, 1 mg/m³, is about 3 % of the NDS.

STATUS (card as of 04.10.2026). The card of PN-Z-04423:2011 (Polish version) has neither the heading "Withdrawn" nor a "Withdrawal date" line: published 12-09-2011, 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 PKN search for "PN-Z-04423" and "izofluranu" (04.10.2026) returns only this standard — the catalogue knows no 2001 edition.

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 04423 appears in 6 records at 5 laboratories; in the current PCA documents (read on 03.10.2026; issues from 29.01.2026 to 28.07.2026) — 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 is suspended and no document repeats pages. Form "PN-Z-04423:2011" — AB 875, AB 1642, AB 1207 (together with procedure PB-06D issue 7 of 20.01.2025) and AB 882 (two items: "excluding item 5.1" together with procedure PB-01 issue 5 of 12.01.2026, GC-FID; together with PB-10 issue 1 of 31.08.2022, GC-MS); AB 647 writes "PN-Z-04423:2001" — a year inconsistent with the card (2011), likewise in the PCA document (issue no. 24 of 23.07.2026). The "Laboratories" tab (query "PN-Z-04423") shows all 5 laboratories, including AB 647, because the query does not contain the year — checked with a tab query on the production server labcoda.pl on 04.10.2026.

WHAT THE LABORATORIES TEST (database copy). Object: working environment — air, samples collected on activated carbon tubes, sorbent tubes or solid sorbent; at AB 1207 the object recorded in the copy covers, besides the working environment, also samples of ambient and indoor air. Quantity: concentration (content) of isoflurane. Ranges in mg/m³: 0.17–417 (AB 1207, GC-MS), 0.78–64 (AB 647), 1.0–240.0 (AB 875, GC-MS), 1.25–80 (AB 1642), 1.41–70 (AB 882, GC-MS), 1.45–73 (AB 882, GC-FID). Technique: gas chromatography with flame ionisation detection (GC-FID) — AB 647, AB 1642 and one AB 882 item; with mass spectrometry (GC-MS) — AB 875, AB 1207 and the other AB 882 item.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — other anaesthetics: in operating theatres isoflurane occurs together with other anaesthetics (the CIOP procedure lists halothane, enflurane, sevoflurane, desflurane, methoxyflurane) — the column must separate them, and according to the procedure samples from mixtures are stored for a shorter time (up to 7 days instead of 14). Second — detector: the card does not give the detector; the CIOP procedure used a mass detector, while 3 laboratories give GC-FID with the standard — selectivity against other anaesthetics should be demonstrated. Third — standard designation: the AB 647 entry "PN-Z-04423:2001" does not match any edition in the PKN catalogue. Fourth — limit of quantification: according to the card 1 mg/m³; AB 1207 (0.17) and AB 647 (0.78) give a lower bottom limit, which requires conditions different from those in the standard. Fifth — AB 882 excludes item 5.1 of the standard, whose content we do not know.

WHAT WE DO NOT GIVE. We did not have the text of the standard — we do not give the detector, the column, the volume or flow rate of air sampling, chromatograph conditions or calculations according to the standard; data from the CIOP procedure are given as procedure data.

Method principle

Isoflurane vapour from workplace air is adsorbed on activated carbon, desorbed with toluene, and the solution is analysed by gas chromatography (PKN card); the result in mg/m³ is compared with the NDS of 32 mg/m³. The lowest determinable concentration according to the card is 1 mg/m³. WE DO NOT GIVE details of the standard — we did not have its text; the 2007 CIOP procedure (5 l of air, 1 ml of toluene, GC with mass detector in SIM mode) is described separately.

Applications

• Workplace air, especially operating theatres — isoflurane — in the current scopes of 5 laboratories
• Assessment of occupational exposure against the NDS of 32 mg/m³ (Journal of Laws 2026 item 447, item 309 of the list)

Key parameters

Standard

Standard number

PN-Z-04423:2011

Title (PL)

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

Title (EN)

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

Step-by-step procedure

1. Sampling

   Adsorption of vapour on activated carbon (PKN card); in the CIOP procedure 5 l at ≤ 3 l/h, samples up to 14 days in a freezer (up to 7 days with other anaesthetics).

2. Desorption

   With toluene (PKN card); in the CIOP procedure — each layer separately, 1 ml, 30 min.

3. Analysis

   Gas chromatography (PKN card); in the CIOP procedure — mass detector in SIM mode.

4. Result and assessment

   Concentration in mg/m³; comparison with the NDS of 32 mg/m³ (Journal of Laws 2026 item 447); lowest determinable concentration 1 mg/m³.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Toluene — according to the CIOP procedure, work with solvents in an efficient fume hood, wearing gloves and protective clothing
• TECHNICAL NOTE: with other anaesthetics in the air, chromatographic separation is required; the entry "PN-Z-04423:2001" at AB 647 has a wrong year

Frequently asked questions