Dental amalgam, an alternative electrode material for voltammetric analyses of pollutants

Liquid mercury and liquid mercury amalgams are superior electrode materials in voltammetry for analytical purposes. This is mainly due to the high overvoltage to hydrogen, which enables the detection of heavy metals with high negative half-wave potentials. Because of the toxicity of mercury and liquid mercury compounds, their use is increasingly restricted, and cannot be included in voltammetric devices for field and on-line applications. Authors have studied properties of dental amalgam as an electrode material in voltammetry. The results show that dental amalgam acts similarly to a silver electrode. Also, it has a high hydrogen overvoltage, allowing it to be used, e.g., for detection of zinc. In addition, due to special properties of dental amalgam compared with mercury itself, it is not toxic. New in this paper is the determination of nickel and cobalt on the dental amalgam electrode using adsorptive cathodic stripping voltammetry (AdCSV). Also, some new data on detection of zinc, cadmium, lead and thallium are presented. The results show that this electrode can be used over a long period of time without any maintenance, which is important for on-line analyses of pollutants in soil and groundwater.