Voltammetric determination of tartaric acid in wines by electrocatalytic oxidation on a cobalt(II)-phthalocyanine-modified electrode associated with multiway calibration.

The electrocatalytic oxidation of tartaric acid on a carbon paste electrode modified with cobalt (II)-phthalocyanine was demonstrated and applied to the development of a highly sensitive, simple, fast and inexpensive voltammetric sensor to determine tartaric acid. The electrochemical behavior of the modified electrode was investigated by cyclic and square wave voltammetry, and the effect of experimental variables, such as dispersion and loading of cobalt (II)-phthalocyanine, together with optimum conditions for sensing the analyte by square wave voltammetry were assessed. In addition, the absence of a significant memory effect combined with the ease of electrode preparation led to the development of a sensitive and direct method to determine tartaric acid in wines.

Flow-injection electrochemical determination of citric acid using a cobalt(II)-phthalocyanine modified carbon paste electrode.

The electrocatalytic activity of cobalt(II)-phthalocyanine immobilized in a carbon paste electrode for citric acid oxidation under a diffusion-controlled electrochemical process was employed to develop a selective flow injection amperomettric analysis method. Under optimized conditions, rapid and reliable determinations of citric acid (65 samples per hour) were achieved for analyses of commercial fruit juices with minor pretreatment of the samples. A linear response was accomplished ranging from 0.