Modified Electrodes with Tungsten Oxide: Preparation Methods and Analytic Applications / Eletrodos modificados por óxido de tungstênio: Métodos de preparação e aplicações analíticas

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Thin films of non-stoichiometric tungsten oxides have been deposited onto glassy carbon surfaces by electrodeposition from acidic W (VI) solutions. At these modified surfaces, rotating disc electrode voltammetric experiments indicated that iodate is electrocatalytically reduced in a mass-transport controlled process. The influence of the film thickness on the response to iodate was investigated and the results suggested a reaction occurring at the film/solution interface. The modified electrode was employed successfully as an amperometric sensor for iodate in a flow injection apparatus. The linear response of the developed method is extended from a 5 mmol L-1 to 5 mmol L-1 iodate with a limit of detection (signal-to-noise = 3) of 210 nmol L-1. The repeatability of the method for 41 injections of an 80 mmol L-1 iodate solution was 98,3 % and the throughput was determined as 123 injections h-1. Interference from other oxidant anions such as nitrate and nitrite was not noticeable, whereas bromate and chlorate interfere at slight levels. The method was used in the determination of the iodate content in commercial salt samples.

ASSUNTO(S)

electrode electroanalytical chemistry química eletroanalitica iodate iodato amperometry eletrodo amperometria

ACESSO AO ARTIGO

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