MALDI-ToF/MS as a diagnostic tool for the confirmation of sulfur mustard exposure

The continual threat of chemical and biological warfare has prompted the ne ed for unambiguous analytical methods for the confirmation of agent exposur e. In this paper, we have investigated the use of matrix-assisted laser des orption ionization time-of-flight mass spectrometry (MALDI-ToF/MS) as a dia gnostic tool for this purpose. Mass spectral studies of the interaction of sulfur mustard (bis-(2-chloroethyl) sulfide, HD) with hemoglobin and metall othioneine were conducted. In vitro experiments with purified proteins were performed, using both HD and chloroethylethyl sulfide (CEES), in an effort to determine the extent of alkylation and occurrence of HD cross-linking u sing the MALDI-ToF/MS technique. In a typical experiment, 50 ml of 5 mM HD in acetonitrile was added to an e qual volume of 0.5 mM hemoglobin in deionized water followed by vortexing a nd incubation at room temperature. After 24 h, the samples were analyzed by MALDI-ToF.MS. Mass spectral results indicated the presence of at least two distinct alkylation adducts for both HD and GEES experiments. These result s demonstrate that MALDI-ToF/MS is a useful analytical technique to investi gate the interaction of HD with biomolecules and may be employed potentiall y as a diagnostic tool for the confirmation of exposure to chemical warfare agents.