A New Type of Large-Surface Bismuth Film Electrode on a Silver Solid Amalgam Substrate and its Application for the Voltammetric Determination of 5-Nitrobenzimidazole

摘要

A novel type of large-surface bismuth film electrode prepared by electrochemical deposition ofbismuth on a silver solid amalgam electrode (LSBiF-AgSAE) was developed. A silver solid amalgamsubstrate with a diameter of 2.64 mm was used to achieve larger surface of this electrode resulting inhigher sensitivity in the voltammetric analysis. The larger electrode surface required longer time (i.e.,1800 s) for the electrochemical deposition of the bismuth film. The electrode surface of thus preparedelectrode was characterized by atomic force microscopy (AFM) which confirmed that the bismuth filmwas not grown uniformly over the supporting surface, but created three-dimensional higher formationswhich cover only a fraction of the surface. To verify the practical application of the new LSBiF- AgSAE, the voltammetric behavior of genotoxic 5-nitrobenzimidazole (5-NBIA) was investigatedusing direct current voltammetry (DCV) and differential pulse voltammetry (DPV), and optimum conditions were found for its determination in the concentration range from 0.2 to 1000 mol L in the Britton揜obinson buffer solution (pH 7.0), with the limits of quantification (LQs) 0.37 mol L (DCV) and 0.07 mol L (DPV). An attempt to increase the sensitivity using adsorptive strippingDCV or DPV at the BiF-AgSAE was not successful. The practical applicability of the newlydeveloped electrode was verified on direct determination of 5-NBIA in tap and mineral water model samples, with LQs 0.1mol L mol L .