This document (EN 14362-3) has been prepared by Technical Committee CEN/TC 248 "Textiles and textile products", the secretariat of which is held by BSI (United Kingdom). The committee responsible for this standard is NA 062-05-12 AA "Textilchemische Prüfverfahren und Fasertrennung" ("Testing methods for separation and chemistry of textile fibres") of the Material Testing Standards Committee (NMP) at DIN.
Azo colorants that are able to form 4-aminoazobenzene, generate under the conditions of EN 14362-1 the amines aniline and 1,4-phenylenediamine. The presence of these 4-aminoazobenzene colorants cannot be reliably ascertained without additional information (for example, the chemical structure of the colorant used) or without a special procedure. This part of EN 14362 is supplementary to Part 1 and describes a special procedure to detect the use of certain azo colorants in commodities, which may release 4-aminoazobenzene, - accessible to reducing agent without extraction, particularly concerning textiles made of cellulose and protein fibres (for example, cotton, viscose, wool, silk); - accessible by extracting the fibres (for example, polyester or imitation leather). For certain fibre blends both parts of this standard (without or with extraction) may need to be applied. The procedure detects as well 4-aminoazobenzene (Solvent Yellow 1) which is already available as free amine in commodities without reducing pre-treatment. The use of certain azo colorants, which may release by reductive cleavage of their azo group(s) one or more of the other aromatic amines listed in the Regulation (EC) No 1907/2006 of the European Parliament and of the Council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) as regards Annex XVII, except 4-aminoazobenzene, cannot be determined quantitatively with this method. After selection of a coloured test specimen from the textile article, the test specimen is tested according to the method of the colorant extraction for disperse dyes and/or the method of the direct reduction for the other classes of the dyes (see EN 14362-1). The textile sample or the residue of the sample extraction is treated with sodium dithionite in an alkaline solution at 40 °C in a closed vessel. 4-aminoazobenzene, which is released in the process, is transferred to a t-butyl methyl ether phase by means of liquid-liquid extraction. An aliquot of the t-butyl methyl ether phase is used for analysis. The detection and determination of 4-aminoazobenzene can be performed using chromatography. If 4-aminoazobenzene is detected by one chromatographic method, then confirmation shall be made using one or more alternative methods.