Analysis of nerve agent degradation products in high‐conductivity matrices by transient ITP preconcentration and CZE separation coupled to ESI‐MS

Abstract

Preconcentration of nerve agent degradation products (alkyl methylphosphonic acids) contained in high-conductivity matrices was performed using transient ITP to enhance sensitivity of CE-ESI-MS. The separation conditions of the five studied alkyl methylphosphonic acids in CE-MS were first optimized. The presence of methanol in the separation medium was required to obtain a good separation of the analytes under counter-EOF conditions. Preconcentration by ITP was induced by the BGE acting as leading electrolyte (LE) while the terminating electrolyte (TE) was loaded before the sample because of the counter-EOF conditions. Different leading ions (formate or acetate) and LE concentrations were tested. The best results for the analysis of soil extracts fortified with the analytes were obtained with an LE composed of 30 mM CH(3)COONH(4) adjusted to pH 8.8 with ammonium hydroxide in (35:65 v/v) MeOH/H(2)O mixture. The TE consisted of 200 mM glycine adjusted to pH 10.0 with ammonium hydroxide in the same solvent mixture. The loading length of the TE zone was optimized. The initial pH of the TE, which determined the initial mobility of the terminating ion, appeared to markedly influence the resolution and the sensitivity. This transient ITP-CZE-MS method was then adapted for the analysis of rat urine samples fortified with the analytes, which required the use of a more concentrated LE (50 mM). LODs between 4 and 70 ng/mL in soil extract, and between 5 and 75 ng/mL in rat urine were reached from extracted ion electropherograms.

In situ determination of nerve agents in various matrices by portable capillary electropherograph with contactless conductivity detection

“…The prevailing CE detection methods are UV and conductivity detection, but laserinduced fluorescence [22][23][24][25], MS [26][27][28][29] and element specific detectors [30,31] have also been used. CE separation with indirect UV detection of NA degradation products was first described by Pianetti et al in 1993 [32].…”

Recent advances in CE and CEC of pollutants

“…In contrast, CEC permitted an extended electrokinetic injection time (8 min), which was not possible with MEKC, resulting in a lower LOD of 100 mg/L. Recently, Lagarrigue et al [58] applied the CE-MS/MS method for the identification of phosphonic acids present in deionized water and soil extracts (Fig. 6).…”

“…The need for fast and sensitive methods to screen large numbers of environmental samples for the presence of explosives and chemical warfare agents ensures a continuing interest in the use of CE in this field [9,40,57,58,77,84,93]. Collins and coworkers [77] investigated the ability to separate nitroaromatic and nitramine explosives in seawater samples using both MEKC and CEC.…”

“…The coupling of MEKC with MS is still in its very early stages. In the past 2 years, new CE/MEKC/CEC-ESI-MS methods have been developed for determining pharmaceuticals [49], pesticides and triazines [50,51], organic acids [52], biodegradation products from sulfonated dyes [53], dialkylphthalates [47], PAHs [54], amines [55], nitrosamines [56], explosives [57,58], and surfactants [59,60].…”

Potential of long chain ionic liquids for on-line sample concentration techniques: Application to micelle to solvent stacking

“…Stacking techniques have enjoyed considerable success in the last decade and have expanded the use of CE techniques especially to the biological, environmental and forensic fields [13][14][15][16][17][18][19][20]. Long injections were allowed by simple manipulation of the sample solution (S) such that the injected analytes were compressed or focused into narrow zones prior to separation.…”