Voltammetric determination of methidathion insecticide

An electroanalytical method has been developed for the determination of methidathion by squarewave voltammetry on a Nafion (R)-coated glassy carbon electrode in aqueous solutions with 0.05 M acetate buffer as a supporting electrolyte. The best voltammetric conditions were found to be pH 4.0, a preconcentration potential of 0.45 V, and a preconcentration time of 60 s. The experimental parameters, such as pH, film thickness, preconcentration potential, preconcentration time, and square-wave voltammetric parameters, were optimized. Using this method, the calibration curve is linear in the range 5 x 10(-8)-7 x 10(-7) M with a detection limit (S/N = 3) of 30 nM.