Quantitation of the tetrachloroethylene metabolite N-acetyl-S-(trichlorovinyl)cysteine in rat urine via negative ion chemical ionization gas chromatography/tandem mass spectrometry

Abstract

A sensitive and selective negative ion chemical ionization gas chromatographic/tandem mass spectrometric (NICI GC/MS/MS) method was developed for the determination of the tetrachlorethylene metabolite, N-acetyl-S-(trichlorovinyl)cysteine (TCVC), in rat urine. Urine samples were fortified with a 13C,D2-analog of TCVC, acidified and extracted with ethyl acetate. The extract were derivatized with methanolic HCl, and the resulting methyl esters analyzed via NICI GC/MS/MS. Detection of the TCVC analogs was performed by monitoring the Cl- product ion of M-Cl2C2HS-. The limit of detection for TCVC by this method was estimated to be 0.1 ng ml-1 urine (3 x noise). The quantitation limit was determined to be 0.3 ng TCVC per milliliter of urine. The method was found to be linear for TCVC concentrations from 0.3 to 104 ng ml-1 urine. Relative recovery of TCVC from urine ranged from 95.4% to 108.5%. Additional data are given for GC/MS and GC/MS/MS analysis of the pentafluoro-benzyl ester derivative of TCVC. Data are also presented for the isolation and analysis of this compound obtained from dosed rats.