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Separation and detection of VX and its methylphosphonic acid degradation products on a microchip using indirect laser‐induced fluorescence
Author(s) -
HelegShabtai Vered,
Gratziany Natzach,
Liron Zvi
Publication year - 2006
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200500683
Subject(s) - chemistry , empa , chromatography , fluorescence , detection limit , nerve agent , degradation (telecommunications) , analytical chemistry (journal) , organic chemistry , telecommunications , physics , mineralogy , quantum mechanics , electron microprobe , computer science , acetylcholinesterase , enzyme
The application of indirect LIF (IDLIF) technique for on‐chip electrophoretic separation and detection of the nerve agent O ‐ethyl S ‐[2‐(diisopropylamino)ethyl] methylphosphonothiolate (VX) and its major phosphonic degradation products, ethyl methylphosphonic acid (EMPA) and methylphosphonic acid (MPA) was demonstrated. Separation and detection of MPA degradation products of VX and the nerve agent isopropyl methylphosphonofluoridate (GB) are presented. The negatively charged dye eosin was found to be a good fluorescent marker for both the negatively charged phosphonic acids and the positively charged VX, and was chosen as the IDLIF visualization fluorescent dye. Separation and detection of VX, EMPA, and MPA in a simple‐cross microchip were completed within less than a minute, and consumed only a ˜50 pL sample volume. A characteristic system peak that appeared in all IDLIF electropherograms served as an internal standard that increased the reliability of peak identification. The negative peak of both VX and the MPAs is in agreement with indirect detection theory and with previous reports in the literature. The LOD of VX and EMPA by IDLIF was 30 and 37 µM, respectively. Despite the fact that the detection sensitivity is relatively low, the rapid simultaneous on‐chip analysis of both VX and its degradation products as well as the separation and detection of the MPA degradation products of both VX and GB, increases detection reliability and may present a choice when sensitivity is not critical compared with speed and simplicity of the assay.