Determination of aromatic amines originating from azo dyes by hydrogen-palladium reduction combined with gas chromatography/mass spectrometry

Procedures were evaluated for reductive cleavage of eight commercial azo dyes using hydrogen and palladium. The reduction was accomplished directly in a heated injector of a gas chromatograph (GC) with the resulting products separated by a capillary gas chromatography (GC) and characterized with a mass spectrometer (MS). This method resulted in nearly complete reduction of the azo bond to form aromatic amines. Standards of the formed reduction products, when available, were employed to confirm identities. For most of the tested azo dyes, the in-line H 2 -Pd reduction/ analysis procedure yielded the same or a greater number of reduced cleavage products than did reduction with SnCl 2 in solution