Platinum electrode regeneration and quality control method for chronopotentiometric and chronoamperometric determination of antioxidant activity of biological fluids

The state of the indicator electrode surface, its quality control and regeneration methods play a major role in electroanalysis results. It is especially important in in the analysis of biological fluids and tissue, because the adsorption of biological matrix components may distort analytical signals and results of the analysis. This article describes an integrated approach to resolving the problem, which includes the selection of regeneration and quality control methods evaluation of availability of platinum screen-printed electrodes for chronopotentiometric and chronoamperometric analysis, as well as their use for determining antioxidant activity of blood serum and ejaculate. The electrodes are treated with solvents (acetone or ethanol) or subjected to annealing. Sources of information about the availability of electrodes for measurements are chronopotentiograms, chronoamperograms and cyclic voltammograms. For chronopotentiometric and chronoamperometric analyses, the most effective regeneration method is annealing at 750 °C for 1 h. Satisfactory regenerated platinum screen-printed electrodes are used as indicator electrodes for evaluating antioxidant activity of blood serum and ejaculate with the use of chronopotentiometry and chronoamperometry. The role of indifferent electrolyte in analytical signal formation is considered. Composition of solution used for different biological fluids (blood serum/plasma, ejaculate) was optimized and unified. The obtained results demonstrate a strong correlation: r = 0.91 for blood serum and r = 0.80 for the ejaculate.