An Electrochemical Method for the Determination of Antioxidant Capacities Applied to Components of Spices and Condiments

Abstract

The antioxidant activity of a set of 17 active principles present in foods is studied by using two sets of methods: i) spectrophotometric, DPPH radical scavenging method and CUPRAC assay; ii) electrochemical, using either a mercury electrode or a glassy carbon electrode covered with poly-neutral red and doped with Pt nanoparticles. The modified glassy carbon electrode assesses the scavenging activity of the antioxidants studied, improving the measurement time and easiness respect to the rest of the methods. Compared to Hg electrode, the measurements can be made in conditions close to the physiological conditions (pH 7 and aqueous medium). Using this sensor, antioxidants without activity in the DPPH radical scavenging assay can be studied. Finally, with respect to CUPRAC, the advantages of the modified electrode are the absence of organic solvent, with the consequent closeness to physiological conditions, and the lower measuring time involved. The sensitivity of this sensor is comparable with those shown by DPPH or CUPRAC.