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 0.5 M 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 1 ∼ 12. The FePCNF/CPE shows excellent electrocatalytic activity toward the oxidation of ascorbic acid in 0.5 M 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 10 ∼ 120 µM. The detection limit was 4 µM. The electrode exhibited a high stability and reproducibility. [ABSTRACT FROM AUTHOR]