. . . . . . "An enzyme electrode for the detection of V-type nerveagents, VX (O-ethyl-S-2-diisopropylaminoethyl methylphosphonothioate) and R-VX (O-isobutyl-S-2-diethylaminoethyl methylphosphonothioate), is proposed. Theprinciple of the new biosensor is based on the enzyme-catalyzed hydrolysis of the nerve agents and amperometricdetection of the thiol-containing hydrolysis products atcarbon nanotube-modified screen-printed electrodes.Demeton-S was used as a nerve agent mimic. 2-(Diethylamino)ethanethiol (DEAET) and 2-(dimethylamino)ethanethiol (DMAET), the thiol-containing hydrolysis product and hydrolysis product mimic of R-VX and VX,respectively, were monitored by exploiting the electrocatalytic activity of carbon nanotubes (CNT). As low as 2\u03BCM DMAET and 0.8 \u03BCM DEAET were detected selectivelyat a low applied potential of 0.5 V vs Ag/AgCl at a CNT-modified mediator-free amperometric electrode. Further,the large surface area and the hydrophobicity of CNT wasused to immobilize organophosphorus hydrolase mutantwith improved catalytic activity for the hydrolysis of theP\u2212S bond of phosphothiolester neurotoxins including VXand R-VX nerve gases to develop a novel, mediator-free,membrane-free biosensor for V-type nerve agents. Theapplicability of the biosensor was demonstrated for direct,rapid, and selective detection of V-type nerve agents'mimic demeton-S. The selectivity of the sensor againstinterferences and application to spiked lake water sampleswas demonstrated." . . . . . . . . . . "V-Type Nerve Agent Detection Using a CarbonNanotube-Based Amperometric Enzyme Electrode" . . . . . . . . . .