The determination of unsulphonated primary aromatic amines in water-soluble food dyes and other food additives
EEC directives prescribe limits for the amount of unsulphonated primary aromatic amines present in food colouring matters in general and prohibit the presence of particular carcinogenic amines in food dyes and other food additives. Integrated methods based on solvent extraction and thin-layer chromatography have been devised for identification of these amines, followed by the spectrophotometric determination of their condensation products with 4-dimethylaminocinnamaldehyde. The method is also extended to the determination of primary aromatic amines in biphenyl and to the determination of aminoazobenzenes in the dye Fast Yellow. An additional thin-layer chromatographic method is given for the differentiation between the isomers of naphthylamine as their tosyl derivatives.