🧵 Detection of azo colorants releasing aromatic amines in textiles — 1 g of coloured material (disperse dyes: first extraction with xylene under reflux; other dyes and pigments: directly) is reduced with sodium dithionite in citrate buffer pH 6 at 70 °C, the released amines are transferred into tert-butyl methyl ether on a diatomaceous earth column and determined chromatographically (TLC/HPTLC, HPLC-DAD/MS, GC-FID/MS, CE-DAD) with confirmation by a second method; 22 amines from Table 1, PN-EN ISO 14362-1

Materials and NDT PN-EN ISO 14362-1

Overview

WHAT THE STANDARD COVERS. We read the text of the standard in the iTeh sample of ISO 14362-1:2017 (French version): from the title page through the contents, foreword and Clauses 1–8 up to and including 9.6.1. Outside the sample remain 9.6.2 and 9.6.3 (mixed colours), the details of Clause 10 (extraction, reduction, separation, determination, recovery check), Clauses 11 and 12 (calculation, reliability of the method, test report) and Annexes A–G. From the title page and European foreword of the SIST EN ISO 14362-1:2017 sample we take only the EN data; the further pages of that sample contain the text of the earlier ISO 24362-1:2014 and we do not use them.

ACCORDING TO THE TEXT OF ISO 14362-1:2017 AND THE FOREWORD OF EN ISO 14362-1:2017. EN ISO 14362-1:2017 was prepared by ISO/TC 38 “Textiles” in collaboration with CEN/TC 248 “Textiles and textile products” (secretariat BSI); CEN approved it on 21.12.2016, and it superseded EN 14362-1:2012. ISO 14362-1:2017 (first edition, 2017-02) replaced ISO 24362-1:2014; the foreword lists the changes: a new Clause 3 and renumbering, removal from “Principle” of the combined method because it gave inaccurate results in some cases, more explanation on sampling, xylene instead of chlorobenzene (lower toxicity), Annex C extended with examples of false positive results, and a new Annex G “Pigments”. Scope (1): detection of the use of azo colorants that may not be used in certain textile articles, accessible to the reducing agent without extraction (colouring with pigments or dyeing of cellulosic, animal and synthetic fibres) or with extraction (disperse dyes on polyester, polyamide, acetate, triacetate, acrylic, chlorofibre); the method applies to all coloured textiles, including printed and coated ones. Table 1 (Clause 4) lists 22 amines with CAS numbers — among them 4-aminobiphenyl, benzidine, 4-chloro-o-toluidine, 2-naphthylamine, o-toluidine, o-anisidine and 4-aminoazobenzene; according to footnote c these are the amines prohibited under Regulation (EC) No 1907/2006 (REACH). Amines No. 5 and 6 are further reduced to No. 18 and 19. Colorants releasing 4-aminoazobenzene give aniline and 1,4-phenylenediamine under these conditions; only aniline is detected, and with aniline above 5 mg/kg the presence of these colorants should be tested according to ISO 14362-3 (footnote b). Principle (5): with disperse dyes the colorant is extracted from the fibre with xylene under reflux (specimen suspended above the flask), the extract is concentrated and transferred with methanol into the reaction vessel, where it is reduced with sodium dithionite in aqueous citrate buffer (pH = 6) at 70 °C; if the specimen is not completely decolourised, a new specimen is tested by the method for non-extractable colorants — reduction with sodium dithionite in citrate buffer pH 6 at 70 °C in a closed vessel; the released amines pass into tert-butyl methyl ether by liquid-liquid extraction on diatomaceous earth columns, the extract is concentrated and the residue dissolved for chromatography; a detected amine must be confirmed by at least one other method. Annex E describes a screening method without the column. Safety (6): the amines of Clause 4 are known or suspected human carcinogens. Reagents (7): xylene (mixture of isomers), acetonitrile, methanol, tert-butyl methyl ether, citrate/sodium hydroxide buffer pH = 6 (citrate concentration 0,06 mol/l), aqueous sodium dithionite solution 200 mg/ml freshly prepared (use within one hour), diatomaceous earth, standards of amines 1–4 and 7–21 and of aniline and 1,4-phenylenediamine; stock solution at least 300 µg of each amine per millilitre, daily solution 15,0 µg/ml, quantification solutions from 2 µg/ml to 50 µg/ml; for GC an internal standard 1,0 mg/ml (naphthalene-d8, 2,4,5-trichloroaniline or anthracene-d10, 10 µl per millilitre) and benzidine-d8 as an indicator of interferences in the late part of the GC chromatogram; grade 3 water according to ISO 3696. Apparatus (8): extraction apparatus with coil condenser NS 29/32, hook holding the specimen and 100 ml round-bottom flask; ultrasonic bath; tightly closing reaction vessel of heat-resistant glass 20–50 ml; heat source maintaining (70 ± 2) °C; column with an inner diameter of 25–30 mm and length of 130–150 mm with 20 g of diatomaceous earth and a glass fibre filter; rotary evaporator; chromatograph to choose from: TLC or HPTLC, HPLC with gradient elution and DAD or MS detector, GC with FID or MS detector, capillary electrophoresis with DAD (PTFE filter 0,2 µm). Specimen (9): 1 g of cut material in total; from a composite article all parts are tested (main fabric, lining, pockets, embroidery, labels, cords, fasteners, imitation fur, sewing threads); identical small parts are combined; below 0,5 g the material is a minor component, below 0,2 g no analysis is performed; embroidery is weighed with the fabric. Table 2 decides extraction by fibre type (natural fibre — no extraction; man-made fibre with disperse or undetermined dye — with extraction), Table 3 — for blends; undyed fibre is not tested; with printing or pigments (or uncertainty) direct reduction (10.2) is used; all colours must be tested (9.6.1).

STATUS (as of 03.10.2026). The PKN search (term “PN-EN ISO 14362-1”, 03.10.2026) shows 4 items: PN-EN ISO 14362-1:2017-04 (English version, “Introduces: EN ISO 14362-1:2017 [IDT], ISO 14362-1:2017 [IDT]”) without a withdrawal note, and the withdrawn PN-EN 14362-1:2012 (replaced by PN-EN ISO 14362-1:2017-04), PN-EN 14362-1:2005 (Polish version) and PN-EN 14362-1:2004. In the iTeh catalogue (read on 03.10.2026) EN ISO 14362-1:2017 has the status “Published” (stage 60.60, 08.02.2017), and ISO 14362-1:2017 — stage 90.93 “International Standard confirmed” (start date 20.07.2022).

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, load up to 17.09.2026, read on 03.10.2026). The number 14362-1 appears in 6 records at 6 laboratories: AB 062, AB 077, AB 403, AB 910, AB 1401, AB 1573. In the current PCA documents (read on 03.10.2026, issues from 08.01.2025 to 11.08.2026) the number appears in 6 rows of the same laboratories (1 each). The form “PN-EN ISO 14362-1:2017-04” (5 laboratories), “PN-EN ISO 14362-1” without year (AB 910, flexible scope “E”, alongside among others PN-EN 71-10, PN-EN 71-11 and PN-EN ISO 14362-3). None of these items is suspended. AB 062, AB 077, AB 403, AB 910 and AB 1573 also have PN-EN ISO 14362-3 in their scopes. The “Laboratories” tab (“PN-EN ISO 14362-1”) shows the same 6 laboratories — checked with the tab query on the production server labcoda.pl on 03.10.2026.

WHAT THE LABORATORIES TEST (items in PCA). Object: textiles, fabrics, yarn, clothing and finished products (AB 062; at AB 077 also artificial leather), textile products (AB 403), flat textile products — woven fabrics, knitted fabrics, yarn, nonwovens, coated products, finished products (AB 1573), textile products, leather and leather products (AB 1401, in the item “textile products”), toys, children’s articles and textile products that may come into contact with children, clothing (AB 910). Characteristic: content of aromatic amines released from azo colorants — with a list of 22 amines (AB 062, AB 077, AB 403, AB 1573), “presence of azo colorants splitting off carcinogenic amines” (AB 1401), “content of free amines and amines released from azo colorants” (AB 910). Ranges: (15–300) mg/kg (AB 062), (20–100) mg/kg (AB 077, AB 1573), (30–890) mg/kg (AB 403), (30–10000) mg/kg amine (AB 1401); AB 910 gives no range. Techniques: TLC and HPLC-DAD (AB 062), GC-NPD, GC-MS and HPLC-DAD (AB 077), HPLC-DAD (AB 403, AB 910), GC-MS and HPLC-DAD (AB 1401), GC-MS and GC-FID (AB 1573).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. With the choice of route: man-made fibre with disperse or unknown dye requires xylene extraction, printing and pigments — direct reduction, blends — often both (Tables 2 and 3, 9.5); a specimen not decolourised after extraction goes again by the route without extraction (5). With the specimen: all parts of the article and all colours (9.2, 9.6.1), 1 g of material, below 0,2 g no analysis. With the reagent: sodium dithionite used within one hour of preparation (7.6). With temperature: (70 ± 2) °C (8.4). With the result: an amine detected by one technique requires confirmation by another (5); amines No. 5 and 6 are not determined directly, because they are reduced to No. 18 and 19 (Table 1, footnote a); 4-aminoazobenzene is seen only indirectly as aniline — above 5 mg/kg it is checked according to ISO 14362-3 (footnote b).

WHAT WE DO NOT GIVE. We did not read the details of Clause 10 (times, volumes, reduction and extraction conditions beyond what is in the principle and reagents), the formula for the amine concentration, the data on reliability of the method (11.3, Annex B), the chromatographic conditions (Annex A), the guidance on interpreting false positive results (Annex C) or the content of the test report. Nor do we give limit values from REACH.

Method principle

Coloured textile material (1 g) is subjected to reductive cleavage of the azo bonds with sodium dithionite in citrate buffer pH 6 at 70 °C — for disperse dyes after their extraction from the fibre with xylene under reflux, for other dyes and pigments directly on the material. The released amines are transferred into tert-butyl methyl ether on a diatomaceous earth column, concentrated and determined chromatographically, and a detected amine is confirmed by a second method.

Applications

• Dyed, printed and coated textiles — cellulosic, animal and synthetic fibres (without extraction) and man-made fibres dyed with disperse dyes (with extraction) (1)
• Control of articles for aromatic amines prohibited under REACH — 22 amines from Table 1 (4)
• Textiles, clothing, leather, toys and children’s articles — items in the accreditation scopes of 6 laboratories in PCA

Key parameters

Standard

Standard number

PN-EN ISO 14362-1:2017-04

Title (PL)

Tekstylia — Metody oznaczania niektórych amin aromatycznych pochodzących z barwników azowych — Część 1: Wykrywanie zastosowania niektórych barwników azowych dostępnych metodą z ekstrakcją i bez ekstrakcji włókien

Title (EN)

Textiles — Methods for determination of certain aromatic amines derived from azo colorants — Part 1: Detection of the use of certain azo colorants accessible with and without extracting the fibres

Step-by-step procedure

1. Specimen

   1 g from each part and each colour of the article; choice of route by fibre and dye type (Tables 2 and 3). PN-EN ISO 14362-1:2017-04 without a withdrawal note (03.10.2026).

2. Extraction (disperse dyes)

   Xylene under reflux; concentrate the extract and transfer with methanol into the reaction vessel.

3. Reduction

   Sodium dithionite in citrate buffer pH 6, 70 °C, closed vessel; specimen not decolourised after extraction — new specimen without extraction.

4. Isolation of amines

   Liquid-liquid extraction on a diatomaceous earth column into tert-butyl methyl ether, concentration.

5. Determination

   Chromatography; confirm a detected amine by a second method; we do not give the details of Clauses 10–11.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• The amines of Table 1 are known or suspected human carcinogens — handling and disposal according to national regulations (6)
• Xylene, tert-butyl methyl ether, methanol and acetonitrile — flammable solvents; work in a fume hood

Frequently asked questions