Methodological approaches to antioxidant content by potentiometry

Currently, the important role of the food, cosmetic, and pharmaceutical products containing antioxidants is very popular idea. Various environmental factors can cause oxidative stress increasing the reactive oxygen species level. Antioxidants (AOs) prevent oxidative stress. Some dietary supplements (DS) can be additional AOs sources. A DS based on the granular mycelium of the Hericium erinaceus is among them. Correct AOs content assessment in pharmaceuticals and DS helps to ensure their balanced dietary intake. Therefore, the task of developing new and improving existing methods for determining substances with antioxidant properties in various objects remains relevant. Due to the nature of the analysis, electrochemical methods, including potentiometric, deserve priority attention. The aim of the work was to establish the optimal conditions for potentiometry application to determine the antioxidant properties of substances (H. erinaceus extract and ascorbic acid) in the K3[Fe(CN)6]/K4[Fe(CN)6] mediator system. We found that when determining the AOs sum with adding an oxidant (hydrogen peroxide) using a mediator system with pH 6.80 and a K3[Fe(CN)6]/K4[Fe(CN)6]=0.00005/0.001 concentration ratio, well-repeating results are obtained (RSD does not exceed 5.0%). The relationship between the analytical signal and the analyte amount is linear, and the results obtained by the input–find method meet the requirement of correctness. The obtained data and the proposed methodological approaches can be useful for their application in the environmental studies of the antioxidant activity of various plant objects and the interpretation of the results.