Voltammetric determination of nitrates using silver electrodes

A silver disk electrode (diameter 0.2 mm) and composite silver electrode pr epared from a mixture of silver, graphite powder and methacrylate resin (20 % Ag, 20 % graphite, 60 % methacrylate resin) are described. The electrode s prepared were used for the voltammetric determination of nitrate ions in samples of natural and wastewater (detection limit 7 mg L-1). The activatio n of the electrode surface before each measurement by a rime-defined polari zation ensures the reproducibility of the results of the voltammetric analy sis. For the realization of such activation process the use of a computer-c ontrolled instrument is necessary. For the electroanalytical measurement th e advantages of the composite electrodes compared to solid silver electrode s includes simple preparation, low cost and electrochemical behavior typica l to microelectrode arrays.