Sensitive detection of pesticide using ENFET with enzymes immobilized by cross-linking and entrapment method

Trichlorfon as a common pesticide is detected using a BuChE-FET sensor whic h is prepared either with cross-linked BSA-glutaraldehyde membrane or photo cross-linkable PVA/SbQ (poly(vinyl alcohol) containing styrylpyridinium) me mbrane. On the basis of these BuChE-FET sensors, a biochemical test for tri chlorfon in liquid was developed by enzyme inhibition. PVA/SbQ membrane sho ws better characteristics compared to BSA membrane: larger linear dynamic r ange in kinetic mode, better reproducibility, and above all, better stabili ty in storage. Nevertheless, the both membranes present the same detection limit for trichlorfon: 10(-6) M. The biosensor response after the enzyme in hibition can be partially recovered by using 2-methiodide pyridaldoxime, an d the degree of enzymatic reactivation depends on the concentration of pest icides and on the time of incubation. (C) 1999 Elsevier Science S.A. All ri ghts reserved.