Nafion-coated mercury thim film and glassy carbon electrodes for electroanalysis

Abstract

The different behavior of Na®on-coated mercury thin-®lm electrodes in anodic stripping voltammetry in nitrate and acetate buffer electrolytes has been probed by electrochemical impedance studies. Investigations concerned glassy carbon electrodes, glassy carbon coated with Na®on, mercury thin ®lm electrodes and mercury thin ®lm electrodes deposited between the glassy carbon substrate and the polymer ®lm, with values of applied potential similar to those employed in anodic stripping voltammetry. Comparison is made with results obtained using Na®on=5 % poly(vinyl sulfonic acid) coatings. In the absence of cationic reducible species, acetate buffer leads to larger impedance values than nitrate electrolyte and correlates well with better characteristics of stripping signals at Na®on-based coatings on mercury thin- ®lm electrodes.