Determination of Ultra-Trace Amounts of G-Type Nerve Agents in Aqueous Samples Utilizing "in Vial" Instantaneous Derivatization and LC-MS/MS Analysis

Avi Weissberg, Analytical Chemistry, IIBR, Ness Ziona, ISRAEL
Moran Madmon, Analytical Chemistry, Iibr, Ness Ziona, Israel
Maor Elgarisi, Analytical Chemistry, Iibr, Ness Ziona, Israel
Shai Dagan, Analytical Chemistry, Iibr, Ness Ziona, Israel

A novel methodology for the determination of Sarin (GB), Soman (GD) and Cyclosarin (GF) chemical warfare agents in aqueous samples, was developed. The method incorporated direct derivatization with a commercially available, water-soluble reagent, followed by LC-ESI-MS/MS analysis in the positive ion mode. Here we report the development of a new, highly reactive, sensitive and selective derivatizing agent 2-(DMAMP) for the identification and quantification of GB, GD, GF in aqueous samples. The derivatization reaction is fast (1 min), proceeds under mild conditions (ambient temperature) and the sample preparation consist only the addition of the reagent, directly into an injection vial, prior to LC-MS analysis. All 2-DMAMP derivatives were stable for at least 48 h and had unique tandem mass spectra characterized by common ions at m/z 230 and 185. Compared with other conventional GC-MS or LC-MS methods, faster reaction times, better sensitivity and selectivity were achieved by this direct derivatization and LC-MS method. The method limits of detection (LODs) and limits of quantification (LOQs) were determined in drinking water and found to be 1 pg/ml and 5 pg/ml, respectively. Due to the simplicity and the powerful of the proposed methodology it is appropriate for routine use for verification and evaluation of water origins contamination.