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.