Voltammetric Determination of Insecticide Thiamethoxam on Silver Solid Amalgam Electrode

This work demonstrates the applicability of differential pulse voltammetry (DPV) for the determination of the insecticide thiamethoxam at a non-toxic mercury meniscus modified silver solid amalgam electrode (m-AgSAE). The optimum supporting electrolyte was found to be Britton-Robinson (BR) buffer, pH 10. The target compound was quantified directly in spiked drinking and river water samples in the range from 100 μmol L−1 to limits of determination (LOQs) 0.36 and 0.46 μmol L−1, respectively. After preliminary separation and preconcentration by solid phase extraction (SPE) using Lichrolut EN cartridges, quantification in spiked river and drinking water samples was possible in the range from 100 nmol L−1 to LOQs 1.3 and 1.1 nmol L−1, respectively. m-AgSAE is practically non-toxic, possesses good mechanical stability and is easy to handle and activate and thus represents a suitable alternative to the hanging mercury drop electrode (HMDE).