Investigation of Voltammetric Behaviour of Insecticide Chlorpyrifos on a Mercury Meniscus Modified Silver Solid Amalgam Electrode

This paper is devoted to the study of electrochemical behaviour of insecticide chlorpyrifos with proved endocrine disruptor properties and to the finding of the optimum conditions for its determination using differential pulse voltammetry (DPV) at a mercury meniscus modified silver solid amalgam electrode (m-AgSAE). It was confirmed that the electrochemical reaction is based on the reduction of H+ ions catalysed by chlorpyrifos adsorbed on the surface of the m-AgSAE. Two variants of the m-AgSAE were tested: i) freshly prepared m-AgSAE for each set of measurements with a classical previously published electrochemical activation (5 min at −2.2 V in 0.2 mol.L−1 KCl under stirring and in the presence of oxygen) for which the optimal base electrolyte was found to be the acidic part of the Britton-Robinson (BR) buffer (pH 1.82) containing 15% of methanol and ii) freshly prepared m-AgSAE for each set of measurements with a newly developed simplified electrochemical activation (10 s at −2.2 V in the stirred base electrolyte alone in the presence of oxygen) for which the optimal base electrolyte was found to be the acidic part of the BR buffer (pH 1.82) containing 30% of methanol.