Basic analytical chemistry: Redox titration curves

Abstract

Redox titrations are relatively simple, fast, and low-cost analytical procedures used to determine active redox species. Analogously to cases involving acid-base systems, where the course of a titration can be followed by means of a pH curve versus the volume of the titrant (V), a titration involving a redox reaction can be monitored by observing the Potential curve (ε ) versus the volume of the titrant (V), provided that the redox system to be used fulfills all the necessary requirements for a chemical reaction to be considered suitable for use in a titration. Once these requirements are met and based on their semi-reactions, it is possible to describe a redox titration with mathematical equations and build its theoretical titration curve, as was done previously for non-redox systems. However, despite their importance, they have received relatively less attention than volumetry involving non-redox reactions. There is no specific reason that can be attributed to this observation, but it can be speculated that this is not since the use of analytical procedures involving oxidation-reduction processes requires additional theoretical knowledge and experimental care. This article seeks to provide the reader with an overview of the redox volumetry and its titration curves, drawing attention to the need for greater care when working with this technique.