Gas chromatographic–tandem mass spectrometric analysis of β-lyase metabolites of sulfur mustard adducts with glutathione in urine and its use in a rabbit cutaneous exposure model

• A sensitive GC–MS/MS method was established and validated for quantitation of β-lyase metabolites of sulfur mustard.
• SPE clean-up procedure was optimized in particular to yield high recoveries and very clean extracts.
• The method was applied in a rabbit cutaneous exposure model for the first time.
• The β-lyase metabolites of SM could be detected in urine from rabbits for up to 3 or 4 weeks after SM cutaneous exposure.

A method for quantitation of β-lyase metabolites of sulfur mustard (SM) adducts with glutathione has been developed and validated using gas chromatography–tandem mass spectrometry (GC–MS/MS). The linear range of quantitation was 0.1–1000 ng/mL in urine with a method detection limit of 0.02 ng/mL. The method was applied in a rabbit exposure model. Domestic rabbits were cutaneously exposed to neat liquid SM in three dosage levels, and the β-lyase metabolites in urine were determined as 1,1′-sulfonylbis[2-(methylthio)ethane] (SBMTE). The study showed that even though more than 99% of the total amount of β-lyase metabolites was excreted in the first week after exposure, the β-lyase metabolites of SM adducts with glutathione could be detected in urine from rabbits for up to 3 or 4 weeks after the SM cutaneous exposure. For high dosage group (15 mg/kg, 0.15 LD50), the mean concentration of SBMTE detected was 0.32 ng/mL on day 28. For middle (5 mg/kg, 0.05 LD50) and low (2 mg/kg, 0.02 LD50) dosage groups, the mean concentrations of SBMTE were 0.07 ng/mL and 0.02 ng/mL on day 21, respectively. The data from this study indicate that the method is sensitive and provides a relatively long time frame for the retrospective detection of SM exposure.