Potentiometric sensor system based on modified screen-printed electrodes for determining antioxidant activity

Abstract

A potentiometric sensor system (PSS) was developed to assess antioxidant activity (AOA) using the potassium hexacyanoferrates ([Fe(CN)6]3–/4–) mediator system. The screen-printed indicator electrode was made of carbon ink modified with multi-walled carbon nanotubes (MWCNTs). The screen-printed silver electrode was potentiostatically modified with a silver chloride/ferricyanide precipitate and served as a reference electrode. The resulting PSS based on modified screen-printed electrodes was tested in the analysis of antioxidants and beverages. Beverage analysis results obtained using PSS and the Folin-Ciocalteu spectrophotometric method have a high positive correlation (r = 0.97, p = 0.002). The proposed PSS can be recommended for the analysis of pharmaceutical, cosmetic and clinical samples.