Renewable Silver-Amalgam Film Electrode for Rapid Square-Wave Voltammetric Determination of Thiamethoxam Insecticide in Selected Samples

Abstract

The paper presents the use of a renewable silver-amalgam film electrode (Hg(Ag)FE) for the determination of the insecticide thiamethoxam (TMO) in Britton-Robinson buffer pH7.0 (LOD=0.25μgmL-1, LOQ=0.70μgmL-1) by direct cathodic square-wave voltammetry (SWV). The voltammetric response for TMO obtained at this electrode was the same as that obtained with a hanging mercury drop electrode, represented by two distinct reduction peaks. Since the electron transfer processes are coupled with chemical reactions involving protons, the SWV signals strongly depend on the pH of the supporting electrolyte. The developed Hg(Ag)FE-SWV method was tested for the determination of TMO in spiked honey and river water samples, as well as for the determination of its content in the commercial formulation Actara 25 WG. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.