Desenvolvimento e caracterização de sensores quimicamente modificados para análise de sulfeto

• Autor(a) principal: MATIAS, Ana Elisa Barreto
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tde/639
• topic: Sulfeto; sensor eletroquímico; azul de metileno; eletroanalítica; sulfide; electrochemical sensor; methylene blue; eletroanalytical; CNPQ::ENGENHARIAS

The developmental impulse of the present time has caused a continuous degradation of the environment, which increases the need of monitoring the contaminant levels launched in the natural water courses and industrial effluents. In this context, it is crucial to develop new methodologies of determination and quantification of various types of pollutants, with rapidity, selectivity and sensitivity, characteristics which were found in the chemically modified electrodes (CMEs). Many industrial processes are polluting the sources of water resources, such as the petrochemical industries and paper and cellulose industries. From those, sulfide is frequently set free causing serious demages due to its high toxicity, even in low concentrations, which suggests methods of detention of sulfide of high sensitivity, reduced time and low cost. Some analytical methodologies for the detention of sulfide are based on the reaction with methylene blue, which has recognized mediating electron capacity. Accordingly, the development and characterization of CMEs, modified with silica-niobium-methylene blue possess promising characteristics and great potential of use in these analyses. Studies of the voltametric behavior of CMEs had been carried through with different concentrations of SNAM. Beyond the effect of the paste composition, also the effect of the type of electrolyte support and of the pH had been investigated. The CMEs had been studied by cyclic voltammetry, linear voltammetry and chronoamperometry technique, presenting good reply to the ion sulfide in the linear response range between 7.59 x 10¬6 and 6,34 x 10¬5 moI L¬ 1, with correlation coefficient (r) of 0, 9979, detection limit of 2,03 x 10-6mol L-1 and quantification limit of 6,77 x 10¬6 moI L¬ 1. The results gotten in this work has allowed to conclude that the carbon paste modified with SNAM presents a good analytical performance for analysis of sulfide in samples of environmental interest