AN INDIRECT VOLTAMMETRIC APPROACH FOR THE DETERMINATION OF CYANIDE AT A CHEMICALLY-MODIFIED ELECTRODE

An indirect voltammetric procedure for measuring free cyanide ions, using a chemically modified carbon-paste mercury-sensitive electrode, is described. The method is based on competitive Hg-II-complex formation reactions between an organic ligand at the electrode surface and CN- ions in solution. A linear decrease of the peak current of mercury in a solution of a defined Hg2+ concentration was observed, when the cyanide concentration was increased from 8.0 to 49.0 mg/L (0.3-1.9 x 10(-6) M). The relative standard deviation for five independent measurements was 8%.