Chemical forensic science has recently been applied to the identification and characterization of a wide-range of chemical threat agents. These efforts on investigating chemical attribution signatures can help identify the chemical source, chemical matching, and synthetic route of the chemical threat agent. Researchers at the Chemical and Biological Forensic Analytical Center (CB-FAC) of the U.S. Army’s Edgewood Chemical and Biological Center report on the use of elemental analysis - isotope ratio mass spectrometry (EA-IRMS) technology as a unique chemical forensic technique to determine the attribution signature of sulfur mustard gas (H), which was prepared using the modified Levinstein process. The analysis of stable isotope ratios of sulfur (∂34S/32S) by EA-IRMS have demonstrated an isotopic connection of the sulfur in the chemical agent mustard (H) to the associated sulfur compounds of the immediate precursor sulfur dichloride and the elemental sulfur used to form the sulfur dichloride. Our measured values of ∂34S/32S (‰) were 9.65 +/-0.45 for H, 9.91 +/-0.64 for SCl2, and 9.27 +/-0.43 for S present a tight cluster which was readily recognized in a cluster plot. The use of EA-IRMS technique and cluster analysis could potentially benefit the chemical forensic aspects in the investigation of a criminal or terror incident involving the use of chemical threat agents. Furthermore, the construction and maintaining a searchable database of the stable isotope ratios for chemical elements and chemical compounds specifically associated with chemical threat agents and their synthesis routes would be essential and highly valued in the attribution investigation of the field of chemical forensic science.

Chemical threat agent attribution signature studies by Isotope Ratio Mass Spectrometry technology (IRMS)

253rd National Meeting (2017)

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