Electrocatalytic reduction of nitrite using ferricyanide; Application for its simple and selective determination

The electrocatalytic reduction of nitrite has been studied by ferricyanide at the surface of carbon paste electrode. Cyclic voltammetry and chronoamperometry techniques were used to investigate the suitability of ferricyanide as a mediator for the electrocatalytic nitrite reduction in aqueous solution with various pH. Results showed that pH 0.00 is the most suitable for this purpose. In the optimum pH, the electrocatalytic ability about 700 mV can be seen and the homogeneous second-order rate constant (k(s)) for nitrite coupled catalytically to ferricyanide was calculated 2.75 x 103 M-1 s(-1) by Nicholson-Shain method. Also, electron transfer coefficients (alpha) for ferricyanide was determined by using various electrochemical approaches such as Tafel plot in the absence and presence of nitrite 0.556 and 0.760, respectively. The catalytic reduction peak current was linearly dependent on the nitrite concentration and the linearity range obtained was 5.00 x 10(-5) to 1.00 x 10(-3) M. Detection limit has been found to be 2.63 x 10(-5) M (2 sigma). This method has been applied as a selective, simple and precise method for determination of nitrite in real sample. (c) 2006 Elsevier Ltd. All rights reserved.