Trace analysis of potentially carcinogenic metabolites of an azo dye and pigment in hamster and human urine as determined by two chromatographic procedures.

Analytical chemical procedures are described for determining traces of possible metabolites of two azo compounds. Direct Black 38 and Pigment Yellow 12, in hamster urine and to monitor the urine from workers who may be occupationally exposed during the manufacture or use of the dye and pigment. These methods were required for metabolism studies designed to assess the hazards that may occur if the two compounds are converted by in vivo mechanisms to potential carcinogens. Salient elements of the procedure are: extraction of the free aromatic amines and neutral compounds; alkaline hydrolysis of the aqueous phase and extraction of any hydrolyzed conjugates as free amines, and the analysis of the free amines and acetylated metabolites directly by high pressure liquid chromatography or by electron capture gas chromatography after conversion of the amines to heptafluorobutyryl derivatives. Residues of metabolites in hamster and human urine were determined at levels as low as 1 ppb. Ancillary data concerning hydrolysis of diacetylated metabolites and partition values for possible metabolites in various solvent systems are also presented.