Analysis of urinary 1,1,2,2-tetrachloroethylene (PERC) metabolites by HPLC electrospray ionization tandem mass spectrometry (ESI-MS/MS) as potential exposure biomarkers.
Cheever-KL; Marlow-K; Ruder-A; Forrester-C; Taylor-L; Butler-M
Toxicologist 2003 Mar; 72(S-1):242
The industrial solvent and dry cleaning agent, PERC (CAS 127-18-4), produces liver tumors in mice and nephrotoxicity and renal tumors in male rats. This toxicity may involve reactive intermediates which could induce similar toxicity in workers. Bioactivation of PERC is reported to occur by oxidation by CYP2E1 and GSH. Trichloroacetic acid (TCA) and dichloroacetic acid (DCA) are reported PERC urinary metabolites and the GSH conjugate is cleaved to S-(1,2,2-trichlorovinyl)-L-cysteine (TCVC) and acetylated to N-ac-TCVC. A biomonitoring method was developed to measure urinary levels of TCA, DCA, TCVC and N-ac-TCVC with deuterated TCVC, N-ac-TCVC and DCA as internal standards. Samples were loaded onto SPE columns and PERC metabolites were eluted with acetone, dried and diluted in MeOH for HPLC ESI-MS/MS analysis on a Phenomenex Jupiter C18 column. A 10-min linear gradient (55:45 H2O:MeOH 1% acetic acid to MeOH 1% acetic acid) at 300 microL/min eluted the compounds of interest within 12 min. The mass spectrometer was operated using ESI-MS/MS, initially in the negative ion mode for detection of TCA and DCA, and subsequently in the positive ion mode for TCVC and N-ac-TCVC. Some urine samples from laundry workers with no demonstrated PERC exposure and dry cleaning workers that were potentially exposed to PERC during loading or unloading of garments contained detectable amounts of PERC metabolites in urine collected during pre or post-shift periods. The limit of detection (LOD) was 0.47 pmol for TCVC, 0.8 pmol for N-ac-TCVC, 11.45 pmol for DCA, and 7.17 pmol for TCA. A small number of samples contained amounts of PERC metabolites that exceeded the limit of quantification (LOQ) - 4.68 pmol for TCVC, 8.03 pmol for N-ac-TCVC, 114.5 pmol for DCA, and 71.73 pmol for TCA. The analysis appears to offer significant advantages over typical extraction and derivatization procedures required for GC-MS analysis of these compounds. Thus, PERC internal exposure levels may be quantified by HPLC ESI-MS/MS analysis of these metabolites.
Ionization; Solvents; Dry-cleaning-industry; Tumors; Liver-cancer; Liver-damage; Oxidation; Sampling; Metabolites
DART; DSHEFS; EID
The Toxicologist. Society of Toxicology 42nd Annual Meeting and ToxExpo, Cutting-Edge Science, Networking, New Perspectives, March 9-13, 2003, Salt Lake City, Utah