Covalent grafting of three flavonoids onto the glassy carbon electrode surface by cyclic voltammetry

Electrochemical oxidation of quercetin (QR), 3-hydroxyfl avone (3HF), and baicalein (BN) and their grafting onto the glassy carbon (GC) electrode have been studied using the cyclic voltammetric (CV) technique. Electrochemical studies were performed within a one-compartment three-electrode cell at room temperature. The modification was carried out only in nonaqueous media, while the electrochemical characterization was done in both aqueous and nonaqueous media. In the nonaqueous experiments, 0.1 m tetrabutylammonium tetrafluoroborate in acetonitrile was used, whereas in the aqueous experiments, Britton-Robinson buffer solutions (pH = 2) and 0.1 m KCl solutions were. Surface modifi cations were performed by CV for all compounds. The presence of QR, 3HF, and BN at the GC electrode surface was characterized by CV, electrochemical impedance spectroscopy, contact angle measurement, ellipsometry, and atomic force microscopy.