scope:

This International Standard specifies a method for the colorimetric determination of cystine plus systeine in wool hydrolysates. The method is applicable to all-wool textiles in any form; namely loose fibre, sliver, roving, yarn or cloth. Dyes when present may interfere with the colorimetric measurement. The method is not applicable to oxidized or reduced wool because the products of these reactions may undergo side reactions during hydrolysis, thus leading to erroneous results. The method is therefore primarily applicable to the determination of cystine plus cysteine in washed wool, tops, yarn or cloth that have been reduced or oxidized. Metal-complexing agents such as EDTA and cyanide should be absent from the wool, since the reaction is copper catalysed.