DISPOSABLE RUTHENIZED SCREEN-PRINTED BIOSENSORS FOR PESTICIDES MONITORING

A disposable choline biosensor based on ruthenized carbon screen-printed electrodes has been prepared and its use for monitoring organophosphorus pesticides and carbamates is described. The presence of 0.5% ruthenium on activated carbon mixed to form a simple graphite-based ink for the working electrode surface increased the sensitivity towards hydrogen peroxide. The choline biosensor is based on such an electrode coupled with choline oxidase immobilized by adsorption. The inhibition effect of carbamates and organophosphorus pesticides on acetylcholinesterase was detected using this biosensor. With the optimized procedure described (pH, buffer composition, incubation time, substrate concentration) we are able to detect concentrations of pesticides (carbofuran) as low as 1 nM.