Quantitation of 2-chlorovinylarsonous acid in human urine by automated solid-phase microextraction–gas chromatography–mass spectrometry

Lewisite [dichloro(2-chlorovinyl)arsine] is a highly toxic chemical warfare agent with vesicant properties. The accidental exposure to lewisite or its intentional use as a chemical terrorism weapon are a public health threat and warrant investigations for the development of analytical methods to detect biomarkers of exposure to lewisite. Under aqueous conditions, lewisite rapidly hydrolyzes to the non-volatile 2-chlorovinylarsonous acid (CVAA). We have developed a sensitive, simple, and automated method for measuring CVAA in human urine. The assay is based on the use of solid-phase microextraction (SPME) and gas chromatography–mass spectrometry (GC–MS) after derivatization of the CVAA with 1,3-propanedithiol (PDT). The volatile CVAA-PDT is adsorbed onto a SPME fiber and analyzed by GC–MS. The assay was validated on human urine samples spiked with CVAA to determine the accuracy, precision, and limit of detection (LOD). The LOD was 7.4 pg in 1 ml of urine.