Voltammetric Behavior and Electrochemical Determination of Ascorbic Acid at Ferrous Pentacyanonitrosylferrate Film Modified Carbon Paste Electrode

A carbon paste electrode (CPE) modified with a ferrous pentacyanonitrosylferrate (FePCNF) was prepared via two consecutive procedures. The modified electrode showed a well-defined redox couple in 0.5M KNO3 solution. The results showed that the peak potential and peak current varied with different metal cations, while anions such as [image omitted], Cl-, [image omitted], and [image omitted] at the same concentration had no effect. An extensive study showed that the response of the modified electrode was affected by pH within a range of 112. The FePCNF/CPE shows excellent electrocatalytic activity toward the oxidation of ascorbic acid in 0.5M KNO3 solution. The plot anodic peak current Ip vs. concentration of ascorbic acid was linear and has been given by the following equation: Ip=-19.7-0.38C, R=0.998 for N=13 in the concentration range 10120 mu M. The detection limit was 4 mu M. The electrode exhibited a high stability and reproducibility.