Detection of paraoxon by continuous flow system based enzyme sensor

The development of an amperometric biosensor for organophosphorus insecticides based on acetylcholinesterase inhibition was studied. Enzyme was immobilized on a platinum electrode by entrapment in PVA-SbQ polymer and integrated in a continuous flow system. The system was tested using paraoxon as reference insecticide. Its detection limit was in the micromolar range and linearity extended over two concentration decades. The reactivation of the inhibited enzyme was easily obtained by pyridine-2-aldoxime methiodide solution. The stability of the biosensor was maintained over 6 months in storage conditions and about 3 weeks in operational conditions. (C) 1998 Published by Elsevier Science S.A. All rights reserved.