Indirect Voltammetric Determination of Zn2+ ion Using Chitosan Ferrocyanide Modified Carbon Paste Electrode

In this research, a chitosan and ferrocyanide modified carbon paste electrode has been applied for indirect voltammetric determination of Zn2+ ion. In order to prepare this electrode, first, the chitosan modified carbon paste electrode (Ch/CPE) was fabricated via mixing the certain ratio of graphite powder, paraffin oil and chitosan. Then, ferrocyanide was accumulated on Ch/CPE via electrostatic attraction and as open circuit. The decrease of anodic peak current of cyclic voltammograms of ferrocyanide adsorbed on the chitosan and ferrocyanide modified carbon paste electrode (Fe/Ch/CPE) in Zn2+ ion presence was used for indirect determination of this ion. The effect of various factors on the Fe/Ch/CPE response to Zn2+ ion such as chitosan percentage in carbon paste, ferrocyanide accumulation time on the electrode surface, ferrocyanide concentration and pH solution was studied and optimized. The studies showed that the Fe/Ch/CPE response to Zn2+ ion is linear in two concentration ranges, 0.0019-0.0122 mM and 0.0122-20.00 mM respectively, and the detection limit of method is 5.02 × 10-7 M based on three times the standard deviation (3σ). Also, this method was successfully applied for Zn2+ ion determination in drug real sample.