Characterization and semiquantitative estimation of organophosphorus compounds based on inhibition of cholinesterases

A rapid and simple spectrophotometric method is presented for the characterization and semiquantitative determination of toxic organophosphorus compounds. The method relies on the inhibition of various cholinesterases and involves calculation of bimolecular rate constants for reactions of compounds with cholinesterase preparations from different animal tissues. In experiments with sarin, soman, tabun, diisopropyl fluorophosphate and 2,2′-dichlorovinyldimethyl phosphate, the mean relative standard deviation obtained for the rate constants was 9%. The detection limits for the compounds were at the picogram level. The amount of compound needed for characterization, which depends on both the set of enzymes and the compound itself, was at the pg- or ng-level. As a test of the method, a concentrate of urban air spiked with sarin was examined.