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

Abstract

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.