Chemical profiling of chemical warfare agents for forensic purposes

A program has been initiated towards the chemical profiling of chemical warfare agents, in order to support forensic investigations towards synthesis routes, production sites and suspect chemical suppliers. Within the first stage of the project various chemical warfare agents (VX, sulfur mustard, sarin) have been prepared according to well-known or more obscure quick-and-dirty synthesis protocols. After minimal work-up, the crude products were analyzed with GC-MS, affording highly useful mass spectral data sets of byproducts. The intact agents were present at moderate to high levels in most crude products. In several cases it was possible to correlate the applied synthesis route to the formation of unique byproducts, or to a characteristic ratio of byproducts. It was also assessed that for the majority of the crude products the chemical profile remained more or less intact upon prolonged storage. This was remarkable because it was expected that the crude products would decompose rather quickly because of the presence of traces of acid. In the current presentation, the focus will lie on the results obtained for VX. Inter alia, the stability of the chemical profile was assessed for the crude VX batches in/on several matrices (soil, water, wood, textile and rubber). Dependent on the matrix, VX could be detected up to several weeks after liquid extraction or thermodesorption followed by GC-MS analysis, while for some of the crude products the characteristic byproducts could still be detected.