Simultaneous Detection of Dopamine and Ascorbic Acid at Cobalt Schiff Base Complex/Surfactant-Modified Carbon Paste Electrode

The complex N,N'-bis(5-Chloro salicylidene) 2,2-dimethyl-1,3-propandiamino cobalt (II) chloride (CoClSal) and 1-octanaminium,N,N,N-trioctyl bromide (as a cationic surfactant) are used for the preparation of the modified carbon paste electrode (CPE). The cyclic and differential pulse voltammetric methods (CV and DPV) used to study of the electrochemical behavior of ascorbic acid (AA) and dopamine (DA) at the surface of the cobalt Schiff base complex-modified CPE containing different percents of cationic surfactant. The effects of the buffered solution pH and potential sweep rate on the electrode response and the resolution between the anodic peaks of AA and DA are studied by CV and DPV. Using the modified electrode, the best peak separation (344 mV) for these compounds is obtained in solutions with pH 5.0. Surface regeneration and the very easy preparation of the modified CPE together with the efficient electrocatalytic property, very good peak resolution and reproducibility of its voltammetric responses designate the modified CPE in this work appropriate for simultaneous voltammetric determination of DA and AA.