Chronopotentiometric method for assessing antioxidant activity: A reagentless measuring technique

A simple chronopotentiometric method designed for the estimation of the antioxidant activity of liquid samples was investigated. A carbon electrode with a thin immobilized redox mediator layer on its surface was used for detection. A two-step measuring protocol was used. Firstly, in a short potential-controlled step, the mediator was set to its oxidized state; then, in the second step, the electrode potential–time curve was recorded in open circuit mode. The initial slope of this curve served as the analytical signal. It is clear that a higher antioxidant concentration produced a higher slope. The performance of adsorbed and electropolymerized Meldola Blue redox mediator layers formed on glassy carbon electrodes was investigated and compared. L-ascorbic acid was used as a sample antioxidant in this study.