Electrochemical Nanobiosensor Based on Immobilization of Acetylcholinesterase to Multiwall Carbon Nanotube Modified Glassy Carbon Electrode for Determination of Triethylthiophosphate

A simple method has been developed for immobilization of acetylcholinesterase (AChE) covalent bonding to a multiwall carbon nanotube (MWNT) modified glassy carbon electrode and a sensitive biosensor for rapid determination of triethylethiophosphate (nerve agent (VX) simulant) is proposed. MWNT improved the interface enzymatic hydrolysis reaction and increased the voltammetric response of the sensor. Under optimum conditions, the inhibition of triethylethiophosphate on AChE increased linearly to triethylethiophosphate in the 0.13 to 0.44 nM concentration range. The detection limit was 0.093 nM taken as the concentration equivalent to 10% of inhibition. The reproducibility of the biosensors obtained under optimum condition was good: RSD of 3% was observed for five replicates using the same biosensor. The sensor was found to be stable for over 2 months.