COMPARISON OF THE SQUARE-WAVE STRIPPING VOLTAMMETRY OF LEAD AND MERCURY FOLLOWING THEIR ELECTROCHEMICAL OR ABRASIVE DEPOSITION ONTO A PARAFFIN IMPREGNATED GRAPHITE ELECTRODE

Square-wave stripping voltammograms of lead and mercury mechanically transferred to the surface of a paraffin impregnated graphite electrode by abrasion are compared with the responses of these metals on the same electrode after their electrodeposition from solution. In the case of lead, the abrasion method appears to give rise to the formation of small, well-separated patches of polycrystalline metallic lead on the electrode surface. Similarly, the square-wave response for oxidation of mercury attached to the electrode by adhesion is different to that for an electrochemically deposited so-called mercury thin film electrode, implying that the nature of metal layers on the graphite surface does depend on the method of metal transfer. Despite the apparent differences in the films formed by mechanical transfer and electrochemical deposition of metals, the variation of the oxidation stripping peaks on the square wave signal parameters is independent of the accumulation method.