Changes in the Electrochemical Behavior of a Redox Mediator in the Presence of Humic Fractions

Abstract

Anthraquinone-2,6-disulfonate (AQDS) is a redox mediator that may modify the expression of different heterotrophic microbial functions. In this study, by means of cyclic voltammetry in an unbuffered, aprotic medium, the electroactive behavior of AQDS in the presence of natural redox effectors was assessed using an electroactive humic fraction model, named f50, isolated from virgin clay-limestone soil. When f50 was added to the AQDS solution, the electrochemical behavior was different, with a cathodic peak shift corresponding to AQDS.-  AQDS2- reaction towards the most negative potentials and a similar behavior in its anodic counterpart.