A Screen-Printed Enzyme Electrode for the Determination of Organo-Phosphorous Pesticides

Evolution of a previously reported bienzymatic biosensor for the determination of organo-phosphorous pesticides are reported. This class of pesticides are detected thanks to their high reversible inhibition power towards acid phosphatase (AcP). The catalytic activity of AcP was detected by means of a screen-printed electrode, in presence of the substrate ascorbic acid 2-phosphate (A2P). The current change due to the electrochemical oxidation of the ascorbic acid as reaction product was monitored. Particularly we focused our attention to the determination of the widely diffused pesticides, i.e. Malathion. Results obtained show a high sensitivity, with a lower detection limit of about 5 ppb.