Microplate spectroscopic methods for determination of the organophosphate soman

• Published in: Journal of environmental monitoring Vol. 12; no. 6; pp. 1349 - 1354
• Main Authors: Prokofieva, Daria Stanislavovna, Voitenko, Natalia Gennadievna, Gustyleva, Lyudmila Konstantinovna, Babakov, Vladimir Nikolaevich, Savelieva, Elena Igorevna, Jenkins, Richard Owen, Goncharov, Nikolay Vasilievich
• Format: Journal Article
• Language: English
• Published: England 01.06.2010
• Subjects: Chemical Warfare Agents - analysis; Chemical Warfare Agents - chemistry; Cholinesterase Inhibitors - analysis; Cholinesterase Inhibitors - chemistry; Environmental Monitoring - methods; Soman - analysis; Soman - chemistry; Spectrum Analysis - methods
• ISSN: 1464-0325; 1464-0333
• DOI: 10.1039/b925815a

Two microplate spectroscopic methods for determination of organophosphates, based on inhibition of acetylcholinesterase activity, have been elaborated and evaluated for determination of the chemical weapon agent soman. The principal difference between the methods is that one measures reaction substrate concentration (elaborated from Hestrin), while the other measures reaction product (elaborated from Ellman). The linear ranges of the two methods were found to be similar. Although the limit of quantification was lower for the Ellman method (110 pM), the sensitivity coefficient was in favor of the Hestrin method (1.55-fold higher). The effects of the main soman hydrolysis products were consistent for the two methods: both methylphosphonic acid and pinacolyl methylphosphonic acid did not inhibit acetylcholinesterase activity. The main components of decontaminating solutions showed differential effects: while monoethanolamine had no influence upon results obtained by either method, hydrogen peroxide interfered with the Ellman method at far lower concentrations than with the Hestrin method. In practical applications involving samples containing hydrogen peroxide, the method based on Hestrin should be regarded as much more specific for OP determination than the Ellman method. In practical applications involving environmental samples containing hydrogen peroxide, the method based on Hestrin is much more specific for OP determination than that based on the Ellman method.