Square wave voltammetric analysis of polyphenol content and antioxidant capacity of red wines using glassy carbon and disposable carbon nanotubes modified screen-printed electrodes
Résumé
The polyphenols present in different French red wines were characterized electrochemically using square wave voltammetry (SWV). The voltammetric measurements were carried out using a glassy carbon electrode and disposable screen-printed carbon electrodes unmodified and modified with single- and multi-walled carbon nanotubes. The single-walled carbon nanotubes-modified screen-printed carbon electrode (SWCNTs-SPCE) showed the best results for the voltammetric analysis of polyphenols in red wine samples, allowing using disposable electrodes to perform measurements. The obtained voltammograms contained three characteristic oxidation peaks. The first peak at the lowest potential was ascribed to oxidation of catechol and galloyl groups of polyphenols (on the flavonoid B-ring), the second peak to the oxidation of malvidin anthocyanins and the third peak was due mainly to the second oxidation wave of flavonoid phenolic groups. The total polyphenols content was determined by spectrophotometric and chromatographic methods as well as antioxidant capacity by the ABTS method, and were in good agreement with the SWCNTs-SPCE results. Thus, SWV is a satisfying fast electrochemical technique for the polyphenol characterization and antioxidant capacity determination of red wine compared to the more frequently used cyclic voltammetry or differential pulse voltammetry, especially using SWCNTs-SPCE.