A new electrochemical biosensor based on DNA damage for detection of diazinon is presented. In this work, a glassy carbon electrode (GCE) was modified by MWCNTs and poly-l-lysine for immobilization a double strain DNA (ds-DNA) on the surface of the electrode. The interaction of diazinon with ds-DNA was assayed by electrochemical impedance spectroscopy (EIS) and UV–Vis spectroscopy in the first step. It was observed that Intercalation of diazinon with DNA helix causes decreasing the interfacial charge transfer resistance (Rct). By R ct difference before and after interaction was determined the diazinon concentration in real samples. Low detection limit (0.3 nmol L ?1 ), wide linear dynamic range (0.01–100.0 µmol L ?1 ), selectivity and cost-effective for diazinon determination are the advantages of the proposed method. Biosensor function was measured by analyzing diazinon in river water, agricultural wastewater, lettuce, and tomatoes.
