Electrochemical oxidation of bentazon at a glassy carbon electrode Application to the determination of a commercial herbicide.

The electrochemical methods cyclic, differential pulse and square wave voltammetry were applied to develop an electroanalytical procedure for the determination of the herbicide bentazon in a commercial product, containing bentazon as the active ingredient, used to treat rice and corn crops. The oxidation mechanism is complex, consisting of an electrochemical step followed by chemical dimerization reaction of the products, which causes severe adsorption problems and consequent poisoning of the electrode surface. The effect of adding Triton surfactant is to enable determinations with good reproducibility to be carried out; the analytical conditions were studied and optimized. The limit of detection obtained was 10(-5) M.