Studying current-potential curves throughout a bipotentiometric iodometric back-titration for the determination of ascorbic acid in fruits and vegetables

A method for the determination of the ascorbic acid content in fruits and vegetables was used to introduce the principles of voltammetry. The procedure combines an iodometric back-titration with voltammetric (bipotentiometric) end point detection, which minimizes the risk of ascorbic acid oxidation, allowing for a rapid and efficient quantification of vitamin C in fruits and vegetables. A better understanding of the titration curve is achieved by analyzing the schematic current–potential curves of the anodic and cathodic half-cell reactions during the titration. Hence, not only theoretical principles of voltammetry are considered, but also the applications of these techniques to quantify a chemical species in a complex matrix. As a result, the laboratory experiment proposed is a valuable tool for analytical chemistry students to discuss electrochemistry techniques in the context of an interesting application.Fil: Verdini, Roxana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Lagier, Claudia Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentin