In Situ Renewal of Working Surfaces of Solid Indicator Electrodes and Their Use in Electroanalysis

The design of a device for the rapid regeneration of the indicator electrode surface in a test solution is discussed. The results of testing this device are presented. The device allows obtaining reproducible areas and properties of the surfaces of solid indicator electrodes by mechanically cutting 0.1–5-µm surface layers. The best reproducibility of these parameters is attained when a hexanite-R cutter is used. The serviceability of the cutter is more than 10⁵ cuts. The high-quality renewal of electrode surfaces is achieved by cutting a 4– 5-µm layer of metallic (Pt, Ag, Au, Cu, Cd, Zn, Co, Ni, etc.) electrodes and a 0.1–1.5-µm layer of graphite and graphite-based electrodes. Optimum tool angles of the cutter for all types of solid electrodes are selected. Long-term tests of the developed technique for the mechanical renewal of electrode surface confirm that the electrode surface area is well reproducible in the series of 10⁴ measurements of the analytical signal (RSD = 0.2–0.6%). Examples are given that point to the enhancement of the electrochemical activity of the surfaces of some electrodes renewed in situ in a solution without their exposure to air. It is shown that the mechanical regeneration of the electrode surface in the solution is the main condition for depositing metals under high-voltage (up to 1000 V) conditions for electroaccumulation. The advantages of the proposed technique are exemplified by determining the concentrations of cations, anions, and some organic substances by direct and stripping voltammetry.