Electrochemical Determination of Ascorbic Acid Using a Glassy Carbon Electrode Modified With Microsphere Structured Hydrated Basic Copper Vanadate
Hongwei Du, Xiufen Ma, Zhonghua Bao, Zheng Wang, Tongtong Li, Ke Li, Qingwei Ren, Haidong LiABSTRACT
Microsphere structured hydrated basic copper vanadate (CuVOH) was synthesized through a simple solvothermal approach, where sodium metavanadate and copper chloride hexahydrate served as the starting reagents, and benzoic acid acted as a coordination additive to adjust particle morphology and grain dimension. The obtained products were thoroughly analyzed through x‐ray diffraction (XRD), scanning electron microscopy (SEM), and high‐resolution transmission electron microscopy (HRTEM). According to XRD analysis, all samples crystallized in a monoclinic single Cu 3 V 2 O 7 (OH) 2 ·2H 2 O, while SEM and TEM images revealed irregularly spherical particles whose average size gradually increased with higher benzoic acid concentration. The electrochemical behavior was assessed using cyclic voltammetry (CV). The CuVOH‐coated glassy carbon electrode (GCE) demonstrated excellent electrocatalytic response toward ascorbic acid oxidation in a 0.1 M KCl medium. Among all samples, CuVOH‐4 displayed the strongest current response, indicating superior electrochemical kinetics. This electrode presented a broad linear detection interval ranging from 0.001 to 2.5 mM, with detection thresholds of 0.21 µM (cvp1) and 0.09 µM (cvp2). The maximum sensitivity reached 110.1 µA mM − 1 at cvp2, demonstrating excellent selectivity, outstanding durability, and consistent signal repeatability of the CuVOH‐based electrode.