Nano-graphene-platelet/Brilliant-green composite coated carbon paste electrode interface for electrocatalytic oxidation of flavanone Hesperidin

Abstract

We have developed a nanodevice with the aid of adsorption strategy. The key factor being the extensive π-π interactions between sp2 carbons of nano-Graphene-platelets (nGp) and π-e- of cationic Brilliant green (Bg) at the electrode surface, that synergistically promoted Hesperidin (HES) oxidation. From our observations, electrochemical catalytic oxidation of HES significantly magnified on nGp-Bg/Modified carbon paste electrode (nGp-Bg/MCPE), under optimized experimental conditions, such as the volume of composite cast-coated, cationic active sites in the nGp-Bg film, and the pH of the buffer. Surface morphology was characterized using Field Emission Scanning Electron Microscopy (FESEM) and Electron Diffraction X-ray (EDX). Nyquist plots revealed the least charge transfer resistance at nGp-Bg/MCPE compared to other control electrodes. Further, at physiological pH, HES displayed an irreversible electrochemical charge transfer at nGp-Bg/MCPE. The cationic Bg moieties on nGp-Bg/MCPE portrayed a great affinity towards deprotonated HES and its accumulation on the electrode surface. Interactions between aromatic rings in nGp-Bg structure and HES molecules consequently enhanced total surface coverage concentration by 3.6-fold compared to control electrodes via adsorption-controlled-electron-transfer feature. We have demonstrated that the reaction capability of nGp-Bg/MCPE towards HES quantification via synergistic electrocatalytic effect, with the ability to lower the activation energy and hastened oxidation. Quantification of HES was performed using Differential Pulse Voltammetry (DPV). Gp-Bg/MCPE showed selective mediated oxidation current response with the lowest detection limit of 5.0 × 10−8 M in two linear ranges. We have successfully validated trace analysis of HES in fortified fruit juice samples, also extendable to various practical applications. Therefore, the present work has established simplicity in the principle of the novel approach in the development of an ultrasensitive voltammetric sensor for HES.