Optimization of Mercury Thin Film Electrodes for Sono-ASV Studies

Abstract

The feasibility of using Na®on-coated mercury thin ®lm 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. Na®on-coated glassy carbon mercury thin ®lm 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 ®lm electrodes formed without Na®on. A major factor contributing to this behavior appeared to be the greater mechanical stability of the mercury thin ®lm provided by the Na®on-coating under conditions of high mass transport provided by ultrasound. In the case of iridium and platinum-based mercury thin ®lm electrodes, which showed lower sensitivity than NCGCMFE's (14 and 1.4 times more sensitive than mercury ®lms on iridium and platinum, respectively, for the determination of cadmium), the polymer-®lm became detached after short sonication times, precluding their use for analytical purposes.

Ionophore Based Bismuth Film Electrode for Lead

“…it is electroinactive, chemically inert, hydrophilic, and water insoluble. At present, Nafion has found a widespread application in conjunction with mercury film electrodes in ASV in order to increase the electrode's resistance against fouling by surface-active compounds (Hoyer, et al 2001;Brett, et al 1996;Murimboh, et al 2000;Agra-Guttierrez, et al 1999). An additional advantage associated with the use of Nafion coated mercury film electrodes is the improvement in terms of robustness towards mechanical damage (Matysik, et al 1997).…”