Working electrodes from amalgam paste for electrochemical measurements

Paste electrode with paste amalgam as an active electrode material is described here for the first time. Designed electrode from silver paste amalgam (AgA-PE) is solely metallic and does not contain any organic binder. Mechanical surface regeneration of AgA-PE is performed in the same way as for classical carbon paste electrodes and reproducibility of such regeneration is about 10%. Electrochemical surface regeneration appeared very efficient for most measurements. In dependence on paste metal content, the electrode surface can be liquid (resembling a film) or rather solid. The hydrogen overvoltage on AgA-PE is high, and the electrode allows measurements at highly negative potentials. AgA-PE is well suited for study of reduction or oxidation processes without an accumulation step. Anodic stripping voltammetry of some metals tested on the electrode is influenced by formation of intermetallic compounds. The measurement based on cathodic stripping voltammetry (adenine, cysteine) and on catalytic processes from adsorbed state (complex of osmium tetroxide with 2,2'-bipyridine) can be performed on AgA-PE practically under the same conditions as found earlier for HMDE and for silver solid amalgam electrode. The working electrode from paste amalgam combines the advantages of paste and metal electrodes.