Study of quinine hydrochloride detection using boron-doped diamond electrodes

Abstract

This study investigates the electrochemical properties of quinine hydrochloride (QH) using boron-doped diamond (BDD) electrodes. The redox behavior of QH was analyzed and compared in phosphate buffer solution (PBS) and potassium perchlorate (KClO₄) electrolyte, observing an increase in current response with hydrogen-terminated BDD (H-BDD) electrodes. A cyclic voltammogram of QH in 0.1 M PBS and 0.1 M KClO₄ shows a reduction peak at −1.14 V (vs. Ag/AgCl). The scan rate dependence was examined to understand the reduction mechanism involving two electrons. A linear calibration curve was noted from 2 μM to 25 μM range (R² = 0.99) with detection limits of 0.18 μM in PBS and 0.16 μM in KClO₄. The BDD electrodes demonstrated good selectivity in tonic water with sharp oxidation potentials for QH, confirming their stability for QH detection.