ANALYSIS OF 1,1'-SULPHONYLBIS[2-(METHYLSULPHINYL)ETHANE] AND 1-METHYLSULFINYL-2-[2-(METHYLTHIO)ETHYLSULPHONYL]ETHANE, METABOLITES OF SULFUR MUSTARD, IN URINE USING GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

A method has been developed for the detection of 1,1'-sulphonylbis[2-(methylsulphinyl)ethane] and 1-methylsulphinyl-2-[2-(methylthio)ethylsulphonyl]ethane, which have been identified as urinary metabolites of sulphur mustard in the rat. The two metabolites were reduced to the single analyte 1,1'-sulphonylbis[2-(methylthio)ethane] by treatment of urine with acidic titanium trichloride. 1,1'-Sulphonylbis[2-(methylthio)ethane] was readily extracted from urine by passing through a C-8 reversed-phase extraction column, or by solvent extraction from a solid absorbent tube, and detected by gas chromatography-mass spectrometry using ammonia positive ion chemical ionisation. The limit of detection was 2 ng/ml for 1-ml samples of urine. There were no background levels of analyte in human or rat urine. If man metabolises sulphur mustard by a similar pathway, the detection of these metabolites should constitute firm evidence of an exposure to sulphur mustard.