DETERMINATION OF AROMATIC-AMINES ORIGINATING FROM AZO DYES BY CHEMICAL-REDUCTION COMBINED WITH LIQUID-CHROMATOGRAPHY MASS-SPECTROMETRY

Procedures were evaluated for the reductive cleavage of 16 commercial azo dyes using sodium hydrosulfite and tin(II) chloride. Identification of the reduction products were mainly based upon mass spectra obtained by particle beam high-performance liquid chromatography/mass spectrometry (HPLC/MS). Standards of the formed reduction products, when available, were employed to confirm identities. The chemical reduction methods resulted in nearly complete reduction of the azo bond to form aromatic amines. Overall, tin chloride was the more powerful reducing agent, yielding a greater number of products. The analysis of reduced industrial waste sludge extracts indicated the presence of identifiable aromatic amines which originated from the reduction of unknown dye components. While the identity of the parent dyes in these sludges could not be determined, this analytical approach appears to provide the means to assess the environmental significance of an effluent based on the presence of various amines. Therefore, reductive cleavage and HPLC/MS in tandem permits the screening of modern, complex synthetic dyes for potentially genotoxic aromatic amines without prior knowledge of the parent dye structure.