Electrochemical study on cobalt film modified glassy carbon electrode and its application

A novel electroactive material for ascorbic acid (AA) determination was successfully prepared by plating/potential cycling method. The cobalt film was first deposited on the surface of glassy carbon electrode (GCE) in CoSO4 solution by potential cycling, and then a cobalt film on the surface of GCE was activated by potential cycling in 0.1 mol L-1 NaOH. The electrochemical performance of the resulted film (Co/GCE) and factors affecting its electrochemical activity were investigated by cyclic voltammetry and amperometry. This film electrode exhibited good electrocatalytic activity to the oxidation of AA. This biosensor had a fast response of AA less than 3 s and excellent linear relationships were obtained in the concentration range of 3 x 10(-7) to 1 x 10(-4) mol L-1 with a detection limit of 2 x 10(-7) mol L-1 (S/N = 3) under the optimum conditions. Moreover, the selectivity, stability and reproducibility of this biosensor were evaluated with satisfactory results. (C) 2010 Elsevier Ltd. All rights reserved.