P6: Hair desorption of the sulphur mustard simulants methyl salicylate and 2-chloroethyl ethyl sulfide following vapour exposure

Chemical warfare agents are compounds whose toxic properties are used to kill or incapacitate people. Their synthesis, use and stockpiling are regulated by the Organisation for the Prohibition of Chemical Weapons. Despite this narrow surveillance, exposure to chemical warfare agents may still happen. Analysis of external contamination of hair could be of high interest, especially for rescue teams. It could be particularly useful to identify chemicals to which victims were exposed, or to distinguish among a large number of potentially exposed individuals those who specifically require thorough decontamination. External contamination of hair by vapours of the sulphur mustard (SM) simulant methyl salicylate has already been demonstrated (Spiandore M., Piram A., Lacoste A., Josse D., Doumenq P., External contamination of hair as a marker of exposure to chemical warfare agents, 18th Scientific Meeting of the Society of Hair Testing, Geneva, August 20-30, 2013). The main objective of this work is to determine desorption kinetics of SM simulants methyl salicylate (MeS) and blistering agent 2-chloroethyl ethyl sulfide (CEES) from hair following vapour exposure. Locks of human hair were exposed to vaporised CEES or MeS for different times and at different concentrations in order to reach concentration-time products (Ct) around 900-1500 mg. min/ m3 which corresponds to the lethal value range for SM. Desorption of MeS and CEES have been observed when transferring a contaminated lock of hair in an uncontaminated tank. Dichloromethane extracts were then analysed by GC-MS/MS operating in MRM mode. As previously shown for MeS, importance of external contamination of hair by CEES vapours increased with exposure duration or concentration. Depending on the vapour concentration or time of exposure, CEES content in hair represented 0.5 to 3 % of the exposure dose. MeS yielded in higher rates as its content retrieved in hair represented up to 15 % of the exposure dose. Both SM simulants (MeS and CEES) have been quantified in hair after they have been exposed to vapours, with a simple solvent extraction. It confirms previous results that hair could be used as a marker of vapour exposure to chemical warfare agents.