HighlightsThe article presents pioneering research of textile chemiresistors on Evolon and Polyester substrates equipped with graphite electrodes and in-situ polymerized poly(tetrabutylphosphonium 3-sulfopropylacrylate) or poly(tributylhexylphosphonium 3-sulfopropylacrylate) sensitive layers. The DC-and AC-responses to 10 ppm of methanol, nitrogen dioxide, 4-bromoacetophenone, diethylmalonate and yperite were then investigated at laboratory temperature -the reference was "pure" synthetic air. Under these circumstances the DC-responses (SDC) varied from 0.48 to 1.36 and maximum AC-responses (Spa) from 8 to 26 deg. It was shown that sensor dynamics depends mainly on molecular weight of the analytes. Moreover, the magnitude of AC-responses correlated both qualitatively and quantitatively with the dipole moments of the analyzed molecules.

We studied issues of organophosphorus agents' analysis. Immobilised enzyme-inhibitors complexes (e.g. acetylcholinesterase-organophosphate nerve agent) were studied with modified Ellman's biochemical method utilised for assessment of acetylcholinesterase activity. Biochemical reactions are widespread and they are the most frequent used analytical methods for determination of nerve agents. This modified method is based on the nucleophilic reactions of mono-and bispyridinium aldoximes of a type 2-PAM, MMB-4 and HI-6, their homologues and isomers with enzyme-inhibitor complexes. The procedure for a gradual analysis of G and V type, Sarin, Cyclohexylsarin, Soman, Tabun, agent VX and R-33 was proposed in terms of studied nucleophilic substitution reactions quantification results. This method enables selective determination of these chemical warfare agents. A gradual analysis was evaluated by statistic method of probabilistic calculus. This type of analysis can be used for assessment of acetylcholinesterase inhibitors in very low concentrations close to hygienic limits.

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Using an immobilized acetylcholinesterase-tabun enzyme-inhibitor complex, the reactivation efficacy of a homologous series of bispyridinium reactivators with increasing length of the alkylene chain between the pyridinium rings has been studied. The number of the alkylene groups in the chain ranged from one to six. N,N'-Monomethylenebis(4-pyridiniumaldoxime) dibromide (MMB-4) and N,N'-trimethylenebis(4-pyridiniumaldoxime) dibromide (TMB-4) are the most efficient reactivators of the series.

Reactivation efficacy of three homologous and three isomeric series of pralidoxime-type reactivators with aldoxime group in position 2, 3 and 4 of the heterocycle was tested in reactivation of tabun-inhibited AChE. The experiments were performed with immobilized and stabilized porcine brain AChE. The enzyme activity was measured by Ellman method. Reactivation efficacy was determined by measurement of indicator fabric coloration intensity as a measure of AChE activity. Of the studied group of nine reactivators, isomers with the functional group in position 2 were the most effective. The highest value (30 %) for reactivation of inhibited AChE was found for 2PAE after treatment for 15 min at concentration 0.5 mg/cm(3). The efficacy of the isomers decreased in the order ortho > para > meta. No marked effect on the efficacy of the reactivators was observed on prolongation of the reactivation time. The reactivators efficacy decreased with decreasing concentration of their solutions.

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Reactivation with bis quaternary aldoxime HI-6, chemical formula 1-(2-hydroxyamino-methylpyridinium)-3-(4-carbamoylpyridinium)-2-oxapropane dichloride of immobilized enzyme acetylcholinesterase inhibited by nerve agent type "G" was studied. This aldoxime is effective in reactivation of sarin-inhibited acetylcholinesterase. Substantially lower reactivation potency was observed with cyclosarin-inhibited enzyme and almost no effect was found for that acetylcholinesterase is the enzyme complex. HI 6 is completely ineffective towards the soman-inhibited enzyme: After a 2-minute inhibition of the enzyme with soman no ability to define reactivator the inhibited enzymes and complexes.

A simple colorimetric biosensor, which uses the modified Ellman's reaction, enables selective analysis of nerve agents based on a different ability of bispyridinium oximes to reactivate enzyme-inhibitor complexes in the phase before dealkylation. The analysis was made based on spectral data of reflectance of the surface of a cotton cloth reaction zone of biosensor with immobilized and stabilized enzyme after inhibition and subsequent reactivation. The evaluation of measured data was made based on a method of artificial neuronal networks. The individual inhibitors from the groups of three nerve agents were identified: sarin, soman, tabun, cyclosarin, agent VX and its Russian analogue, R-33.