Organophosphates present serious fulmination in several aspects of human life. Detection of organophosphates is frequently based on following acetylcholinesterase (AChE) inhibition. Although limit of detection and sensitivity for AChE-based assays seem to be intriguing, the identification of organophosphates is not currently efficient in this way. We introduce an improvement of AChE-based assay by reactivators using a selective come-back of AChE activity after previous inhibition. We have chosen four organophosphates: paraoxon-ethyl, paraoxon-methyl, trichlorfon, methamidophos as representative pesticides and the three most available reactivators: HI-6, obidoxime, pralidoxime. Reactivation was realized in the 96-wells photometric microplates and activity of human recombinant AChE was followed by reaction of Ellman's reagent with one of enzyme digestion product: thiocholine. Distinguishing of reactivation efficacy was judged by the independent two population t-test. The most significant identification was based on methamidophos inhibited AChE reactivation by HI-6 or pralidoxime and paraoxon-ethyl inhibited AChE by obidoxime; moreover, identification of trichlorfon and paraoxon-methyl was possible, too. Practical impact of described method is discussed.

Center of Advanced Studies Faculty of Military Health Sciences University of Defence Hradec Kralove Czech Republic

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