Electrochemical Determination of Flavonoid Fisetin in Commercial Dietary Supplements Using a Boron‐Doped Diamond Electrode

Abstract

AbstractFor the first time, a boron‐doped diamond electrode was utilized to quantitatively determine flavonoid fisetin (FST). Cyclic voltammetric studies have shown that the electrochemical oxidation of FST is irreversible and well‐separated two peaks (PA1 and PA2) in 0.1 M HNO3 solution. The effects of electrode pretreatment, solution pH, nature of the supporting electrolyte, and instrumental variables on the peak current and potentials of the FST were investigated by square‐wave voltammetry (SWV) and then optimum ones were determined. It was observed that the cathodically pre‐treated BDD (CPT‐BDD) electrode‘s performance was better than the other pre‐treatment procedures for increasing the FST oxidation signal. Under optimized conditions and using the SWV technique, the response of the first anodic peak (PA1) of the FST was proportional in a concentration range of 0.5–20.0 μg mL−1 (1.7×10−6–6.9×10−5 mol L−1) with a detection limit of 0.08 μg mL−1 (2.8×10−7 mol L−1). Also, it was successfully demonstrated that the proposed method is applicable in commercial nutritional supplement formulations.