A GC/MS method for the determination of 4,4'-diaminodiphenylmethane and substituted analogues in urine

A sensitive and specific gas chromatography/mass spectrometry (GC/MS) method has been developed for the analysis of 4,4'-diaminodiphenylmethane (DDM), 3-ethyl DDM (EDDM), and 3,3'-diethyl DDM (DEDDM) in urine. The method has been applied to the analysis of urine samples from workers exposed to a mixture of all three compounds, and the analysis has shown that EDDM and DEDDM are excreted in urine. We have also shown that there are two classes of conjugates present in urine. EDDM and DEDDM are excreted as heat labile conjugates, while DDM and EDDM are excreted, at least in part, as heat stable but alkaline hydrolyzable conjugates. It is proposed that the method described here could be used for biological monitoring of workers exposed to mixtures of DDM, EDDM, and DEDDM.