| Summary: | The feasibility of using Nafion-coated mercury thin film electrodes on glassy carbon, iridium and platinum as substrates for anodic stripping voltammetric determination of cadmium and lead in the presence of ultrasound is examined. Glassy carbon was found to be the most appropriate substrate material for these electrodes. Nafion-coated glassy carbon mercury thin film electrodes, NCGCMFE's, were mechanically resistant under sonication, as shown by AFM imaging. These electrodes showed higher sensitivity (up to 170 times higher for cadmium depending upon deposition times) for the determination of cadmium and lead than glassy carbon mercury thin film electrodes formed without Nafion. A major factor contributing to this behavior appeared to be the greater mechanical stability of the mercury thin film provided by the Nafion-coating under conditions of high mass transport provided by ultrasound. In the case of iridium and platinum-based mercury thin film electrodes, which showed lower sensitivity than NCGCMFE's (14 and 1.4 times more sensitive than mercury films on iridium and platinum, respectively, for the determination of cadmium), the polymer-film became detached after short sonication times, precluding their use for analytical purposes.
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