Electrocatalytic Oxidation of Sulfite on a Nickel Aquapentacyanoferrate Modified Electrode: Application for Simple and Selective Determination

An electroactive metal cyanometallate complex, nickel aquapentacyanoferrate (NAPCF) was synthesized and characterized using XRD and UV‐vis spectral studies. The solid complex was then mechanically immobilized on the surface of a paraffin impregnated graphite electrode (PIGE) and the NAPCF modified electrode was characterized using cyclic voltammetry. The dependence of the modified electrode was tested in terms of supporting electrolyte, scan rate and pH of the medium. The electrocatalytic oxidation of sulfite at the modified electrode was investigated by cyclic voltammetry, hydrodynamic voltammetry and chronoamperometry techniques. It was found that the NAPCF modified electrode efficiently exhibited electrocatalytic activity for the oxidation of sulfite with relatively high sensitivity, selectivity and long life of activity. Based on the electrocatalytic oxidation, the NAPCF modified electrode was used as a sensor for the determination of sulfite. The linear working range for the determination of sulfite was 2.78×10^?6 M to 3.00×10^?3 M with a detection limit of 9.26×10^?7 M. The electrode was applied for the determination of sulfite in real samples satisfactorily.