Differential Pulse Anodic Stripping Voltammetric Determination of Cobalt(II) withN-p-Chlorophenylcinnamohydroxamic Acid Modified Carbon Paste Electrode

Abstract

A new preconcentration and voltammetric method was developed for the determination of Co(II) with N-p-chlorophenylcinnamohydroxamic acid (CPCHA) modified carbon paste electrode. The measurements were carried out using differential pulse anodic stripping voltammetry. The effects of several experimental parameters such as modifier composition in the carbon paste electrode, pH and concentration of supporting electrolyte, deposition potential, deposition time, and other instrumental parameters were studied for analytical application. A linear response was obtained in the concentration range 1 × 10−6– 4 × 10−5 M Co(II) with a detection limit of 3.3 × 10−7 M for a 5 min deposition time. A relative standard deviation of 3.1 % was obtained for eight successive determinations of 1 × 10−5 M Co(II). Many coexisting metal ions had little or no effect on the determination of cobalt(II). The method was applied for the determination of cobalt in vitamin B12. The new electrode offered many attractive properties such as high stability, self cleaning ability, the use of nondearated solutions and can be used repeatedly without regeneration.