Stripping Voltammetric Determination of Trace Amount of Silver in Water Samples Using Melamine Modified Glassy Carbon Electrode

Melamine modified glassy carbon electrode was prepared by electrochemical deposition of melamine on glassy carbon electrode (GCE). In the determination of Ag+-ion, the test solution in HOAc-NaOAc buffer solution of pH 4.6 was pre-reduced for 60 s at -0.45 V, Ag+-ion was then stripped from the electrode by stripping voltammetry, scanning in the range from 0 to +0.6 V. Oxidation peak potential of Ag+-ion was observed at +0.27 V, at where linear relationship between values of peak current of Ag+-ion and the respective concentrations was obtained in the range of 6.0×10-9-5.0×10-7mol·L-1. Detection limit (3S/N) of the method found was 1.0×10-9mol·L-1. The proposed method has been used in the determination of silver in substantial water samples, giving values of recovery found by standard addition method in the range of 90.0%-96.0%.