Re-activation of an amperometric organophosphate pesticide biosensor by 2-pyridinealdoxime methochloride

Inhibitions and re-activation characteristics of a biosensor by the organophosphate pesticides were investigated. The amperometric enzyme sensor co-immobilized on a platinum electrode by crosslinking was fabricated. Inhibition of the biosensor by dimethyl 2,2-dichlorovynyl phosphate (Dichlorvos, DDVP) as a model organophosphate pesticide was tested. The relative inhibition parameter (RI) was proportional to the concentration over a wide range. It was found that a nearly reversible inhibition process was observed if the inhibition is weak. However, irreversibility was appeared when the strongly inhibition took place. In this case, only 2-pyridinealdoxime methochloride (PAM) successfully regenerated the enzyme activity. PAM treatment guaranteed almost stable recovery rate and sensitivity. The results clarified that proposed re-activation procedures could realize inexpensive and reliable continuous monitoring of organophosphate pesticides. (C) 2000 Elsevier Science S.A. All rights reserved.