🌿 Toluene-2,4-diyl diisocyanate and toluene-2,6-diyl diisocyanate (2,4-TDI, 2,6-TDI) in workplace air — high-performance liquid chromatography with fluorimetric detection (HPLC-FLD); lowest determinable concentration according to the standard 0.00014 mg/m³; MAC (NDS) for diisocyanates as the NCO group; PN-Z-04490:2017-10

Environment PN-Z-04490

Overview

WHAT THE STANDARD COVERS. Scope from the PKN card, in full: "This standard gives a method for determining toluene-2,4-diyl diisocyanate (CAS no.: 584-84-9) and toluene-2,6-diyl diisocyanate (CAS no.: 91-08-7) in workplace air using high-performance liquid chromatography with fluorimetric detection. The method is used in the inspection of sanitary and hygienic conditions. The lowest concentration of toluene-2,4-diyl diisocyanate and/or toluene-2,6-diyl diisocyanate that can be determined under the air sampling and determination conditions described in the standard is 0.00014 mg/m3." (our translation). The card gives neither the sampler nor the reagent. We did not have the text of the standard (8 pages). The CIOP index of methods from 2000–2017 lists "Toluylene diisocyanate – no. 1(87) 2016"; we did not read the article and give nothing from it.

NDS VALUES (regulation of 26 March 2026, Journal of Laws 2026 item 447). In the annex, item 177: "Diisocyanates – as the NCO group" with footnotes 14 and 16 — NDS 0.006 mg/m³, NDSCh 0.012 mg/m³, "skin" notation; footnote 14: "The substance may have a sensitising effect on the skin and respiratory system", footnote 16: NCO refers to the isocyanate functional groups, and exposure is assessed "on the basis of the sum of concentrations of the isocyanate functional groups of diisocyanate compounds" in the air. Transitional provisions (§ 2): until 8 April 2026 separate values applied — for toluene-2,4-diyl diisocyanate, toluene-2,6-diyl diisocyanate and their mixture NDS 0.007 mg/m³ and NDSCh 0.021 mg/m³ — and the value as the NCO group was not applied; from 9 April 2026 to 31 December 2028 the NDS for diisocyanates as the NCO group is 0.01 mg/m³ and the NDSCh 0.02 mg/m³; from 1 January 2029 — the values from the annex (0.006 and 0.012 mg/m³). A result for a single TDI isomer must therefore now be converted to the NCO group and summed with other diisocyanates present in the air.

STATUS (card as of 04.10.2026). The card of PN-Z-04490:2017-10 (Polish version) has neither the heading "Withdrawn" nor a "Withdrawal date" line: published 23-10-2017, 8 pages, price group D, Health, Environment and Medicine Sector, KT 159 Chemical and Dust Hazards in the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-04490" and "diizocyjanianu" (04.10.2026) shows this standard and PN-Z-04131-3:2001 (hexane-1,6-diyl diisocyanate, spectrophotometric method).

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 04490 appears in 8 records at 4 laboratories; in the current PCA documents (read on 03.10.2026; issues from 29.01.2026 to 11.06.2026) — in 7 rows at the same laboratories (AB 875 has two records in the database copy — 2,4-TDI and 2,6-TDI — and one row in PCA); 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-04490:2017-10" — AB 802, AB 875 and AB 1207; AB 886 — "PN-Z-04490:2017" (without the month). The "Laboratories" tab (query "PN-Z-04490") shows all 4 laboratories — checked with a tab query on the production server labcoda.pl on 04.10.2026.

WHAT THE LABORATORIES TEST (database copy and PCA documents). AB 802 — samples collected on impregnated filters, 2,4-TDI, 2,6-TDI and their mixture as the NCO group, with a note on the sum of concentrations of isocyanate functional groups, 0.0000676–0.24 mg/m³; AB 1207 — impregnated filters, 2,4-TDI and 2,6-TDI as the NCO group, each 0.000036–0.50 mg/m³ (working environment), and separate items for ambient and indoor air, each isomer 0.000075–1 mg/m³; AB 875 — samples on a filter, 2,4-TDI and 2,6-TDI separately, each 0.0005–1.33 mg/m³; AB 886 — samples on sorption tubes, 2,4-TDI and 2,6-TDI, each 0.0003–0.28 mg/m³. Technique: high-performance liquid chromatography with fluorimetric (fluorescence) detection — all 4 laboratories.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — reference value: since 9 April 2026 the NDS and NDSCh for TDI are no longer separate — the values for diisocyanates as the NCO group apply, assessed as a sum; a result given only as an isomer concentration (AB 875, AB 886) must be converted and summed, and a comparison with the former 0.007 and 0.021 mg/m³ is out of date. Second — sampler: AB 802 and AB 1207 give impregnated filters, AB 886 sorption tubes; the card does not give the sampler, so we do not know which one corresponds to the standard. Third — object: AB 1207 also has items for ambient and indoor air with this standard, for which the NDS is not a reference value. Fourth — sensitisation and skin: diisocyanates have a "skin" notation and, according to footnote 14, may sensitise the skin and respiratory system; a measurement in air does not cover skin exposure.

WHAT WE DO NOT GIVE. We did not have the text of the standard, and the card does not give the sampler — we do not give the sampler and derivatising reagent, the volume and flow rate of air sampling, the column, the mobile phase, the excitation and emission wavelengths or calculations (including the conversion to the NCO group according to the standard).

Method principle

Toluene-2,4-diyl and toluene-2,6-diyl diisocyanate in workplace air are determined by high-performance liquid chromatography with fluorimetric detection (PKN card). The lowest determinable concentration according to the card is 0.00014 mg/m³. From 09.04.2026 to 31.12.2028 the result is assessed against the NDS of 0.01 mg/m³ and the NDSCh of 0.02 mg/m³ for diisocyanates as the NCO group (sum). WE DO NOT GIVE details — we did not have the text of the standard.

Applications

• Workplace air — 2,4-TDI and 2,6-TDI — in the current scopes of 4 laboratories (at AB 1207 also ambient and indoor air)
• Assessment of occupational exposure to diisocyanates as the NCO group — from 09.04.2026 to 31.12.2028 NDS 0.01 mg/m³, NDSCh 0.02 mg/m³ (Journal of Laws 2026 item 447, § 2(2); in the annex, item 177: 0.006 and 0.012 mg/m³)

Key parameters

Standard

Standard number

PN-Z-04490:2017-10

Title (PL)

Ochrona czystości powietrza — Oznaczanie diizocyjanianu tolueno-2,4-diylu i diizocyjanianu tolueno-2,6-diylu na stanowiskach pracy metodą wysokosprawnej chromatografii cieczowej z detekcją fluorymetryczną

Title (EN)

Air purity protection — Determination of toluene-2,4-diyl diisocyanate and toluene-2,6-diyl diisocyanate at workplaces by high-performance liquid chromatography with fluorimetric detection

Step-by-step procedure

1. Sampling

   WE DO NOT GIVE the sampler or volumes — the card does not give them.

2. Sample preparation

   WE DO NOT GIVE the method — we did not have the text of the standard.

3. Analysis

   High-performance liquid chromatography with fluorimetric detection (PKN card); WE DO NOT GIVE conditions.

4. Result and assessment

   Concentration of 2,4-TDI and 2,6-TDI in mg/m³; for assessment — conversion to the NCO group and summing of diisocyanates against the NDS of 0.01 mg/m³ and the NDSCh of 0.02 mg/m³ (Journal of Laws 2026 item 447, § 2(2), until 31.12.2028).

Required equipment and apparatus

Health and safety (OHS)

• Diisocyanates — "skin" notation and possible sensitisation of the skin and respiratory system (footnote 14 of the list); handle standards in a fume hood, wearing gloves
• TECHNICAL NOTE: since 09.04.2026 assessment against the NDS for the sum of diisocyanates as NCO, not against separate values for TDI

Frequently asked questions