Ascorbate oxidase based amperometric biosensor for organophosphorous pesticide monitoring

An amperometric principle based biosensor containing tissues of cucumber, r ich in ascorbic acid oxidase, was used for the detection of organophosphoro us (OP) pesticide ethyl paraoxon, which inhibits the activity of ascorbic a cid oxidase. The optimal concentration of ascorbic acid used as substrate w as found to be 5.67 mM. The biosensor response was found to reach steady st ate within 2 min. A measurable inhibition (>10%) was obtained with 10 min i ncubation of the enzyme electrode with different concentrations of the pest icide. There was a linear relationship between the percentage of inhibition of the enzyme substrate reaction and the pesticide (ethyl paraoxon) concen tration in the range 1-10 ppm with a regression value 0.9942. (C) 2000 Else vier Science S.A. All rights reserved.