Metabolomics-based biomarker analysis of dihydroxypropyl mercapturic acid isomers from 3-monochloropropane-1,2-diol and glycidol for evaluation of toxicokinetics in rats and daily internal exposure in humans.

3-Monochloropropane-1,2-diol (3-MCPD), glycidol, and their esters are some major sources of risk factors during food processing. Here we showed the biomarker analysis of 2,3-dihydroxypropyl mercapturic acid (DHPMA) isomers which derived from the metabolism of 3-MCPD, glycidol, and their esters in urine of rats and humans. Iso-DHPMA, a novel urinary metabolite, was discovered and detected in urine of rats, which were orally administered with glycidol but not 3-MCPD. Using the quadrupole-orbitrap high-resolution mass spectrometry, we confirmed that iso-DHPMA appeared a specific biomarker which derived from glycidol. The limit of quantification (signal-to-noise ratio, 10:1) of the analytes in urine of rats and humans were 1.33 ng/mL and 1.56 ng/mL, respectively. Acceptable within-laboratory reproducibility (RSD<9.0%) and spiking recovery (94.7%-100.1%) substantially supported the use of current method for robust biomarker analysis, which was successfully applied to the toxicokinetic study of DHPMA in rats and short-term internal exposure to 3-MCPD and glycidol in humans.