2021 Volume 14 Issue 1 Pages 3-14
In 2015, several bladder cancer cases were reported in chemical plants in Japan, and aromatic amines including ortho-toluidine (OT) were suspected as the causative agents. The air concentration of OT was far below the occupational exposure limits recommended by Japan Society for Occupational Health but the concentration of this substance in workers’ urine was high, suggesting that the workers might have received dermal exposure to aromatic amines. In order to understand the actual exposure of aromatic amines, it is necessary to use the exposure assessment by biological monitoring. The NIOSH method 8317, a quantitative analysis of OT in urine, is the representative method for the biological monitoring of OT exposure. However, the method has some weak points; it has not been verified whether the method could analyze the urine from workers co-exposed to several kinds of aromatic amines, and the effect of urine constituents (matrix effect) on the analysis.
In this study, we developed a new analytic method in biological motoring for aromatic amines with offset matrix effect using liquid chromatography-tandem mass spectrometry. We examined whether we could analyze six kinds of aromatic amines used in the factories with the occurrence of bladder cancer, including OT, aniline (ANL), 2,4-dimethylaniline (DMA), ortho-anisidine (ANS), ortho-chloroaniline (OCA), para-toluidine (PT) and their metabolites using our new method. The sensitivity of this method is good for the five aromatic amines except OCA, and OT, ANL, DMA and ANS were detected in the urine samples of workers. In conclusions, we developed a new quantitative analysis method of urine samples which is useful for the biological monitoring of co-exposure to several kinds of aromatic amines.
