Electrochemical quartz crystal microbalance characterization of I - and its amperometric detection by microelectrode

Abstract

The electrochemical redox mechanism of I − ion under different concentrations on gold electrodes was studied in detail using the EQCM technique (a combination of the QCM technique and cyclic voltammetry). The redox behavior of the I − ion on a gold microelectrode when no supporting electrolyte was added was compared with a conventional gold microelectrode. Due to the small current and the very low solution iR drop of the microelectrode, the actual oxidation potential of I − on the microelectrode was much more negative than that of the conventional electrode and its anodic peak was better defined. Therefore the gold microelectode was employed for the determination of I − . A linear range of 1.0×10 −5–0.1 mol l −1 with a detection limit of 1.0×10 −6 mol l −1 was obtained on the microelectrode in pure KI aqueous solution. Two samples were measured using this method and the results were in good agreement with those indicated or calculated..