PRELIMINARY STUDIES IN THE FORMATION OF ETHYL METHYLPHOSPHONOFLUORIDATE FROM RAT AND HUMAN SERUM EXPOSED TO VX AND TREATED WITH FLUORIDE ION

Abstract

A method has been developed for the analysis of a VX nerve agent biomarker in blood that is very sensitive, selective and within the capabilities of modern field mobile laboratories. A VX biomarker was found in spiked human and rat sera after treatment with fluoride ion and acetate buffer. VX was detected by the generation of its corresponding G-series derivative, ethyl methylphosphonofluoridate (VX-G). This method utilizes a C18 solid-phase extraction (SPE) followed by quantification using a gas chromatograph with either a flame photometric detector (GC-FPD) or a mass spectrometer (GC-MS). Samples are concentrated by injecting 40–400 uL of extract on a Tenax®-TA sorbent tube along with 100 pg of decadeuterated diethyl ethyl phosphonate as the internal standard followed by thermal desorption GC-FPD analysis and GC-MS confirmation. VX-G was completely resolved from sarin (GB) and the method has the potential to resolve other nerve agents in the VX series of cholinesterase inhibitors. The method detection limit was 10.5 pg of agent on column. Quality control samples were analyzed and yielded spike recoveries greater than 95%.

Keywords:

• VX
• O-Ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate
• Serum
• Chemical warfare agents
• Nerve agents
• Gas chromatography
• Flame photometric detector
• Fluoride ion

Acknowledgments