Organic Phase Amperometric Biosensor for Detection of Pesticides

Abstract

A rapid, simple, and sensitive acetylcholinesterase (AChE) amperometric 
biosensor for direct measurement of organophosphorus compounds (OPCs) in organic solvent was developed. The biosensors were based on a graphite electrode and on thiocholine-hexacyanoferrate reaction. The enzyme (AChE) was co-immobilized with an electron mediator, Prussian Blue, on the surface of the electrode. The effect of organic solvents on acetylcholinesterase activity was estimated in the presence of polar (hydrophilic) and non-polar (hydrophobic) organic solvents in the range of 0.01-100%. The ability of the AChE biosensors to assay pesticides was demonstrated by quantitative determination of dichlorvos, fenthion and diazinon in ethanol. The assay allows determination of OPCs in sub-micromolar concentration ranges with an overall assay time of 10 minutes. The method allows adapting the biosensor for detection of pesticides in actual water samples, avoiding the procedures of evaporation and resolution.