Dental amalgam as an electrode material in voltammetry is provided having a very high overpotential to hydrogen. Accordingly, trace analyses can be carried out at potentials sufficiently negative to allow determination of e.g. zinc, cobalt, nickel and iron at trace levels. Such analyses have not previously been possible except by using a mercury or a mercury film electrode. Such determinations are very important for field and online analyses of pollutants in soil and groundwater, and the electrode can be used repeatedly.