🌿 n-Butyl acetate and its isomers — isobutyl acetate and sec-butyl acetate — in workplace air, gas chromatography with flame ionisation detection (GC-FID); lowest determinable concentration according to the standard 24 mg/m³, MAC (NDS) 240 mg/m³, STEL (NDSCh) 720 mg/m³ for each of the three acetates; PN-Z-04520:2020-12

Environment PN-Z-04520

Overview

WHAT THE STANDARD COVERS. Scope from the PKN card, in full: "This standard gives a method for determining n-butyl acetate (CAS no. 123-86-4) and its isomers: isobutyl acetate (CAS no. 110-19-0) and sec-butyl acetate (CAS no. 105-46-4) in workplace air using gas chromatography with flame ionisation detection. The method is used in the inspection of sanitary and hygienic conditions. The lowest concentration of n-butyl acetate, isobutyl acetate and sec-butyl acetate that can be determined under the air sampling and determination conditions described in the standard is 24 mg/m3" (our translation; no full stop at the end on the card). We did not have the text of the standard (8 pages).

ACCORDING TO THE CIOP PROCEDURE (J. Kowalska, "n-Butyl acetate and its isomers – isobutyl acetate and sec-butyl acetate. Determination in workplace air", Podstawy i Metody Oceny Środowiska Pracy 2017, no. 1(91), pp. 151–165 — read in full). The procedure was published three years before the standard, with the same range of substances and the same lowest determinable value of 24 mg/m³; we do not claim that the standard repeats it. In the procedure: tubes with two layers of activated carbon (100/50 mg), up to 10 l of air at a flow rate not exceeding 200 ml/min, samples stable in a freezer for 7 days; desorption with 1 ml of carbon disulfide for 30 min; GC-FID, capillary column 50 m × 0.32 mm with poly(ethylene glycol) modified with nitroterephthalic acid (HP-FFAP), film 0.50 µm, column temperature from 50 °C (2 min) to 110 °C at 5 °C/min; the amount in the shorter layer should not exceed 10 % of that in the longer one, otherwise the result is indicative. Measuring range 24–480 mg/m³ for 10 l of air (from 1/10 to twice the NDS), overall precision about 5.05 %, expanded uncertainty about 22.1 %; the three acetates were determined in the presence of, among others, tert-butyl, methyl, ethyl, n-amyl and 2-methoxy-1-methylethyl acetate, benzene, toluene, xylenes, ethanol, butan-1-ol, isobutanol and acetic acid. The article recalls that earlier standards (PN-Z-04023-02:1989, PN-Z-04119-2:1998, PN-Z-04119-11:2008) determined these acetates separately.

NDS VALUES (list in the annex to the regulation of 26 March 2026, Journal of Laws 2026 item 447). Item 425: "n-Butyl acetate [123-86-4]", item 426: "sec-Butyl acetate [105-46-4]" and item 431: "Isobutyl acetate [110-19-0]" — for each NDS 240 mg/m³ and NDSCh 720 mg/m³, no "skin" notation. The lowest determinable concentration according to the card, 24 mg/m³, is 10 % of the NDS.

STATUS (card as of 04.10.2026). The card of PN-Z-04520:2020-12 (Polish version) has neither the heading "Withdrawn" nor a "Withdrawal date" line: published 01-12-2020, 8 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-04520", "octanu butylu" and "octanu izobutylu" (04.10.2026) shows only this standard as current for these three acetates; PN-Z-04119-2:1998 (sec-butyl acetate) and PN-Z-04119-11:2008 (isobutyl acetate) are labelled "Withdrawn".

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 04520 appears in 11 records at 5 laboratories; in the current PCA documents (read on 03.10.2026; issues from 26.11.2025 to 08.09.2026) — in 11 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 have the form "PN-Z-04520:2020-12", in 10 of the 11 records with an accompanying document: AB 300 — instruction IN-59 issue 3 of 18.12.2025 (three items: n-butyl, sec-butyl, isobutyl); AB 882 — procedure PB-01 issue 5 of 12.01.2026 (GC-FID) and PB-10 issue 1 of 31.08.2022 (GC-MS), for isobutyl acetate also PN-Z-04119-11:2008; AB 1207 — procedure PB-06A issue 7 of 20.01.2025; AB 1854 — working instruction IR-23 issue 3 of 05.01.2023; AB 581 — no accompanying document. The "Laboratories" tab (query "PN-Z-04520") shows all 5 laboratories — checked with a tab query on the production server labcoda.pl on 04.10.2026. Consistent with this database's entry on PN-Z-04119-01 (methyl, ethyl, propyl, butyl and amyl acetates), according to which PN-Z-04520 is cited for butyl acetate by AB 300, AB 882, AB 1207 and AB 1854 — the fifth laboratory, AB 581, has it only for isobutyl acetate.

WHAT THE LABORATORIES TEST (database copy). Object: working environment — air, at some laboratories samples collected on sorbent tubes; at AB 1207 the object recorded in the copy covers, besides the working environment, also samples of ambient and indoor air. Quantities: n-butyl acetate — AB 300, AB 882 (two items), AB 1207 ("butyl acetate"), AB 1854; isobutyl acetate — AB 300, AB 581, AB 882 (two items), AB 1207; sec-butyl acetate — only AB 300. Ranges in mg/m³: n-butyl 0.17–2700 (AB 1207), 0.6–1800 (AB 300), 2.0–4150 (AB 882, GC-FID), 3.47–2067 (AB 882, GC-MS), AB 1854 — 180–6500 µg in the sample; isobutyl 0.17–2700 (AB 1207), 1.11–3000 (AB 300), 1.6–2048 (AB 882, GC-MS), 2.0–5838 (AB 882, GC-FID), 3.0–450 (AB 581); sec-butyl 2.78–2100 (AB 300). Technique: GC-FID — AB 300, AB 581, AB 1854 and the GC-FID items of AB 882; GC-MS — AB 1207 and the other pair of AB 882 items.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — which acetates: the standard covers three isomers, and the laboratories have different sets of them in their scopes (sec-butyl acetate only AB 300) — it is the laboratory's scope that says which acetate is accredited, not the standard number itself. Second — limit of quantification: according to the card 24 mg/m³; all laboratories with a range in mg/m³ give a lower bottom limit (from 0.17 to 3.47 mg/m³), which requires conditions different from those in the standard — the report should name them. Third — detector: the title and the card speak of GC-FID, while AB 1207 and some AB 882 items are GC-MS according to in-house procedures, with the standard alongside. Fourth — object: at AB 1207 the same item covers ambient and indoor air, for which the NDS is not a reference value. Fifth — the NDSCh of 720 mg/m³ requires a short-term measurement; the CIOP procedure checked 3 l samples at 200 ml/min — whether the standard provides the same, WE DO NOT GIVE.

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 tube type, the solvent, the column, chromatograph conditions or calculations according to the standard; data from the CIOP procedure are given as procedure data.

Method principle

n-Butyl acetate, isobutyl acetate and sec-butyl acetate in workplace air are determined by gas chromatography with flame ionisation detection (PKN card); the result in mg/m³ is compared with the NDS of 240 mg/m³ and the NDSCh of 720 mg/m³ for each of them. The lowest determinable concentration according to the card is 24 mg/m³. WE DO NOT GIVE details of the standard — we did not have its text; the 2017 CIOP procedure (activated carbon, carbon disulfide, HP-FFAP column) is described separately.

Applications

• Workplace air — n-butyl acetate, isobutyl acetate, sec-butyl acetate — in the current scopes of 5 laboratories (11 items)
• Assessment of occupational exposure against the NDS of 240 mg/m³ and the NDSCh of 720 mg/m³ (Journal of Laws 2026 item 447, items 425, 426 and 431 of the list)

Key parameters

Standard

Standard number

PN-Z-04520:2020-12

Title (PL)

Ochrona czystości powietrza — Oznaczanie octanu n-butylu i jego izomerów: octanu izobutylu i octanu sec-butylu na stanowiskach pracy metodą chromatografii gazowej z detekcją płomieniowo-jonizacyjną

Title (EN)

Air purity protection — Determination of n-butyl acetate and its isomers isobutyl acetate and sec-butyl acetate at workplaces by gas chromatography with flame ionisation detection

Step-by-step procedure

1. Sampling

   Adsorption of vapours on activated carbon; WE DO NOT GIVE the parameters of the standard (in the CIOP procedure up to 10 l at ≤ 200 ml/min).

2. Desorption

   In the CIOP procedure — each layer separately, 1 ml of carbon disulfide, 30 min.

3. Analysis

   Gas chromatography with flame ionisation detection (PKN card); conditions in the CIOP procedure — HP-FFAP column, 50→110 °C.

4. Result and assessment

   Concentration of each acetate in mg/m³; comparison with the NDS of 240 mg/m³ and the NDSCh of 720 mg/m³ (Journal of Laws 2026 item 447); lowest determinable concentration 24 mg/m³.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Carbon disulfide and butyl acetates — flammable; according to the CIOP procedure, work with solvents in an efficient fume hood, with personal protective equipment
• TECHNICAL NOTE: a bottom limit below 24 mg/m³ requires conditions different from those in the standard; a laboratory accredits specific acetates, not always all three

Frequently asked questions