APLICAÇÃO DE ELETRODOS MODIFICADOS COM COBALTO COMO SENSOR ELETROQUÍMICO

• Autor(a) principal: Stadnik, Andréia
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações do UNICENTRO
• Texto Completo: http://localhost:8080/tede/handle/tede/278
• topic: gel de cobalto; eletrodo quimicamente modificado; técnicas eletroquímicas; cobalt gel; chemically modified electrodes; electrochemical techniques; CIENCIAS EXATAS E DA TERRA::QUIMICA

In this work, has changed the working electrode gel with cobalt [CoO(OH)], in order to generate an electrochemical sensor for redox analytes such as ascorbic acid (AA) and oxalic acid (OA). In the studies, tests were made with electrolytes: NaOH, LiOH and KOH and found the best results voltammetric NDE in supporting electrolyte of NaOH [0,5 Mol/L], which showed higher electrochemical response / voltammetric. Measurements were carried out cyclic voltammetry and square wave to determine the sensor sensitivity for the analytes of cobalt. For technical Microbalance Electrochemical Quartz Crystal was able to analyze the variations in mass of the modified electrode with gel electrolyte compared to the three studied: NaOH, KOH and LiOH, to find possible mechanisms of the front of the gel electrolyte chosen, NaOH. Studies for the analytes, and mixing the two, showed good responses in electroanalytical cyclic voltammetry at concentrations of 10-5 and 10-6 mol/L. The VCs had defined anodic and cathodic peaks due to oxidation/reduction of cobalt gel. We also observed increased sensitivity of cobalt against the oxalic acid with better results the technique of VC, as ascorbic acid showed better responses in the SWV. Thus, the gel electrode modified with cobalt showed selectivity, good sensitivity and reliable answers.