Chromatograms of glutathione conjugates of TCE. (A) S-(1,2-dichlorovinyl)-L-cysteine, (B) [13C5,15N] S-(1,2-dichlorovinyl)-L-cysteine, (C) S-(1,2-dichlorovinyl)glutathione, and (D) [13C4,15N] S-(1,2-dichlorovinyl)glutathione. Analytes were determined after extraction from control serum spiked with chemical standards: 1 nmol/ml serum for DCVC and DCVG and 0.25 nmol/ml serum for the internal standards. Arrows indicate the peaks of analytes, and chromatograms were displayed in stick mode.