Identification of Pairs of Organophosphorus Warfare Agents through Cholinesterase Reaction

Abstract

Construction of Detehit (nerve-agent detector), a colorimetric biosensor of nerve agents, enables its utilization for selective analysis of nerve agents based on the different ability of nucleophilic reagents to reactivate enzyme-inhibitor complexes in the phase before dealkylation. For this purpose mono- and bispyridinium aldoximes, common in treatment of nerve agent poisoning, are used.

For a positive identification of a pair of organophosphates, a neural network analysis was used. The analysis was processed based on spectral data of the intensity of color changes of the surface of a cotton cloth reaction zone with immobilized and stabilized enzyme acetylcholinesterase. Color changes are based on Ellman's reaction. Intensity of these changes depends on activity of the enzyme after inhibition and reactivation of enzyme-inhibitor complex. The following nerve agents were identified: sarin, soman, tabun, cyclosarin, VX, and R-33.

Keywords:

• Acetylcholinesterase reactivator
• Colorimetric biosensor
• Nerve agent
• Neural analysis

AbbreViations:

• GB, sarin
• GD, soman
• GF, cyclosarin
• GA, tabun
• VX, agent VX
• R-33, agent R-33
• VVPS, multilayer perceptron network
• RBF, Radial Basis Function-type network

Acknowledgments

VOP (Military Repair Plant) Šternberk is a state-owned company.

Notes

Measurement conditions: HI-6 reactivator at a concentration of 0.05 mg · cm⁻³ (1.393 × 10⁻⁴ M) and 10-minute treatment of acetylcholinesterase-tabun and acetylcholinesterase-VX complexes.

Linear: linear network with characterization of the layers; VVPS: multilayer perceptron network with characterization of the layers; RBF: Radial Basis Function-type network with characterization of the layers; GF: cyclosarin; VX: compound VX.

GA: tabun; GB: sarin; GD: soman; GF: cyclosarin; R-33: agent R-33; VX: agent VX.