Electrochemical reduction of metal ions catalysed by preconcentrated adsorbed ligands: the system Ni(II)-thiabendazole

Abstract

The electrochemical reduction of Ni(II) at mercury electrodes catalysed by the fungicide thiabendazole, has been studied in a sodium acetate solution. The electrode process includes the formation of a catalytic complex between aquo-Ni(II) or acetate-Ni(II) ions and unprotonated thiabendazole adsorbed on the electrode surface. At low thiabendazole concentrations the surface excess of the catalytic ligand was substantially increased by convective mass transport from solution to the surface of the hanging mercury drop electrode. Thus, adsorptive preconcentration of thiabendazole allows a significant enhancement in sensitivity in the determination of the fungicide based on the electrocatalytic reduction of Ni(II)