Rapidly renewable silver amalgam annular band electrode for voltammetry and polarography

This work describes a novel type of working electrode for use in voltammetry and polarography — the renewable silver liquid amalgam film–modified silver solid amalgam annular band electrode (AgLAF–AgSAE). The electrode is produced by mechanically refreshing the silver liquid amalgam film (AgLAF) before each measurement. The main constituents of the electrode are: a specially constructed silver solid amalgam annular band electrode (AgSAE), two silicon O-rings, silver liquid amalgam and a polypropylene electrode body. Contaminants from the analyzed solution are removed and the AgSAE surface is covered with a thick layer of fresh amalgam while pulling the AgSAE into the sensor body. During movement in the reverse direction AgLAF is formed and homogenized. The time needed to refresh the film is less than 1 s. The electrode is characterized by excellent surface repeatability (～ 1%) and long-term stability (over ten thousand measurement cycles).