title: Reactive desorption electrospray ionization for selective detection of the hydrolysis products of phosphonate esters.
abstract: Reactive desorption electrospray ionization (reactive DESI) is demonstrated to be a rapid and sensitive method for the direct detection of alkyl methylphosphonic acids, the hydrolysis products and metabolites of the chemical warfare (CW) agents VX (S-2-diisopropylaminoethyl-O-ethyl methylphosphonothiolate) and GB (sarin, isopropylmethyl phosphonofluoridate). Rapid and sensitive detection of these compounds is readily achieved by performing DESI from a solid surface; detection specificity is enhanced by implementation of a heterogeneous ion/molecule reaction using boric acid in the spray solvent. The reagent ion H(2)BO(3) (-) generated in the spray readily reacts with condensed-phase alkyl MPA to form anionic adducts. The specificity of this chemical reaction, together with the characteristic fragmentation patterns of the reaction products, supplies a highly discriminatory detection method for methylphosphonic acid (MPA), ethylphosphonic acid (EMPA) and isopropyl methylphosphonic acid (IMPA) in complex matrices.
authors.affiliation: Department of Chemistry, 560 Oval Drive, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Yishu
authors.initials: Y
authors.lastname: Song
authors.forename: R Graham
authors.initials: RG
authors.lastname: Cooks