An Electrode Based on Electropolymerized Naringin for Voltammetry
The working conditions of naringin electropolymerization on the glassy carbon electrode modified with multi-walled carbon nanotubes (MWNT/GCE) under the conditions of potentiodynamic electrolysis have been found. The effect of monomer concentration, polarization window, potential scan rate, and number of cycles on the electrochemical properties of the polynaringin-modified electrode has been evaluated using hexacyanoferrate(II) ions as a redox standard. The best results have been observed for the polymeric coverage obtained from 0.20 mM naringin by tenfold potential cycling in the range of 0.2-0.8 V at a scan rate of 75 mV/s in the Britton-Robinson buffer solution, pH 8.0. The surface of the glassy carbon and modified electrodes has been characterized by scanning electron microscopy, cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. The high porosity of the polynaringin layer leads to an increase of the electrode effective surface area in comparison to GCE (8.2 ± 0.3 and 12.6 ± 0.6 mm<sup>2</sup> for GCE and polynaringin/MWNT/GCE, respectively). The electrochemical impedance spectroscopy data indicate an increase of the electron transfer rate on the polynaringin-modified electrode in comparison to GCE and MWNT/GCE (6.0 ± 0.5 kΩ vs . 181 ± 5 and 6.8 ± 0.3 kΩ, respectively).