Benzidine and congeners: analytical chemical properties and trace analysis in five substances

Spectrophotofluorimetric (SPF) methods are described for the trace analysis of benzidine, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, and their dihydrochloride salts in microbiological growth media, waste water, potable water, human urine, and rat blood. The salient elements of the methods for these known or suspected carcinogens are: extraction of the residues as the free amine with benzene, rapid cleanup on an alumina column, and quantification of the free amine in methanol via SPF. Potable water solutions of the salts are diluted with buffer (pH-4) and quantified directly by SPF. Ancillary analytical information concerning the solubility and stability of these compounds in water, p-values, gas chromatographic analysis of the free amines, and thin layer chromatographic data in ten solvent systems are also presented.