Determination of heavy metals and iodide by stripping voltammetry in sodium chloride on mercury-graphite electrodes

The behavior of Cd(II), Pb(II), Cu(II), and I− in the aqueous solutions of sodium chloride is studied by stripping voltammetry. A new version of using an indicator electrode from carbon glass ceramics modified with mercury for the consecutive stripping determination of Cd(II), Pb(II), Cu(II), and iodide is proposed. The mercury-graphite electrode was formed in the solution of a supporting electrolyte based on NH4Cl, HCl, 0.05 M potassium tetraoxalate (KH3C4O3 · 2H2O), and 5 × 10−5 M mercury(II). At first, Cd(II), Pb(II), Cu(II), and then iodide were determined by anodic-cathodic stripping voltammetry after adding a sample solution (table salt, 10–100 mg/mL NaCl).