LIQUID-CHROMATOGRAPHY ELECTROSPRAY MASS-SPECTROMETRY OF MUSTARD-RELATED SULFONIUM IONS

The detection and identification of degradation products of the chemic al blister agent bis(2-chloroethyl) sulfide, commonly known as mustard or HD, is important for the future destruction of the mustard stockpi le for safety and environmental reasons, Because stored mustard tends to degrade via intramolecular substitution forming stable sulfonium io ns, conventional gas chromatographic/mass spectrometric analysis does not give a true picture of sample composition. In this study, liquid c hromatography/electrospray ionization mass spectrometry (LC/MS) was ap plied for the detection and identification of six synthesized mustard related cyclic and open-chain sulfonium ions to demonstrate the applic ability of the technique, The technique was then applied to confirm th e identification of the major component of unknown solid heels isolate d from mustard ton containers as the six-membered ring cyclic 1-(2-chl oroethyl)-1,4-dithianium ion by comparison of spectra obtained by LC/M S and LC/MS/MS for a mustard heel and a reference standard. A mechanis m to account for this sulfonium ion formation under long-term ton cont ainer storage conditions is provided, The technique was also applied t o monitor open-chain sulfonium ion formation during the hydrolysis of 0.01 M mustard in 0.05, 2.3 and 10 vol.% thiodiglycol-water at 20 degr ees C. (C) 1997 John Whey & Sons, Ltd.