Desenvolvimento de eletrodo de filme de bismuto depositado sobre cobre para aplicações eletroanalíticas

• Autor(a) principal: Nunes, Luiza Maria da Silva
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFSCAR
• Texto Completo: https://repositorio.ufscar.br/handle/ufscar/6412
• topic: Química analitica; Eletrodeposição; Metais pesados; Eletrodo de bismuto; CIENCIAS EXATAS E DA TERRA::QUIMICA

On this work is described the development of bismuth film electrode deposited over copper substrate for electroanalytical applications. The bismuth film electrode was deposited ex situ over a copper substrate. The electrodeposition of Bi was carried out applying a constant potential of -150 mV during 300 s. The plating solution was composed by 0.02 mol L-1 Bi(NO)3 in 1.0 mol L-1 hydrochloride acid with or not 0.08 mol L-1 sodium citrate, the electrodes obtained from these solutions were nominated Bi-Cit008 and Bi-HCl, respectively. The bismuth film characterization was carried out by Field Emission Gun Scanning Electron Microscopy (FEG-SEM), Scanning Electron Microscopy with Energy Dispersive X-ray analysis (MEV-EDX) and X-Ray Diffraction analysis. The FEG-SEM and MEV-EDX analysis of bismuth film showed that the morphology of the deposits were strongly dependent of the plating solution composition. X-Ray diffraction analysis showed a single rhombohedral and cubic phase for the two bismuth film electrodes analyzed. The Bi-HCl and Bi-Cit008 electrodes showed a good cathodic potential window from -300 mV to -1200 mV. Both electrodes, exhibited a good analytical response for cadmium and lead by means of square wave anodic stripping voltammetry technique. For the lead determination, Bi-HCl and Bi-Cit008 electrodes showed a detection limit of 2.8 x 10-8 mol L-1 and 2.5 x 10-8 mol L-1, respectively in a concentration range from 9.6 x 10-6 to 5.7 x 10-5 mol L-1. For the cadmium determination, Bi-HCl and Bi-Cit008 electrodes presented a detection limit of 1.1 x 10-6 mol L-1 and 6.3 x 10-8 mol L-1, respectively in the concentration range from 1.7 x 10-5 to 12.3 x 10-5 mol L-1. Both electrodes, presented analytical response with good resolution without baseline dislocation, therefore, Bi-Cit008 had best analytical performance.