Redox-Active Green Electrode: Plant-Based Betanin Immobilized on Carbon Black for Drift-Free Voltammetric and Potentiometric pH Sensor Applications.

The development of eco-friendly chemicals and material-based electrode systems with a reduced carbon footprint is a novel initiative for future technological applications. While electrochemical systems based on plant phytochemicals meet the requirements, comprehending the fundamental electron-transfer reactions and preparing stable surface-confined redox systems pose significant research challenges. In this study, we have demonstrated an in situ electrochemical reaction-assisted entrapment of redox-active betanin molecular species from native beetroot plants on a carbon black-modified glassy carbon surface (GCE/CB@Betn-Redox, where Betn-Redox stands for redox-active betanin molecular species) in a pH 2.2 KCl-HCl solution. In general, direct access to native plant phytochemicals is a formidable task due to the matrix effect. Isolating the desired phytochemicals necessitates a series of time-consuming chemical separation steps. Unlike previous literature reports on the unstable nature of Betn, GCE/CB@Betn-Redox exhibited a stable and well-defined proton-coupled electron-transfer peak at an apparent electrode potential,