Hydrothermal Method Prepared La-Doped ZnWO₄Nanospheres as Electrocatalytic Sensing Materials for Selective and Sensitive Determination of Dopamine and Uric Acid

Abstract

La-doped ZnWO4 nanospheres were successfully synthesized by a hydrothermal synthesis method and further investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). A novel electrochemical sensor has been fabricated by carbon paste electrode (CPE) coated with the prepared La-doped ZnWO4 nanospheres. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were applied to characterize the electrochemical properties of the sensor. By using DPV method, low detection limits of DA and UA were obtained to be 0.04 μmol·L−1 and 0.03 μmol·L−1 (S/N = 3), with the linear calibration curves over the concentration ranges of 0.10∼43.03 μmol·L−1 and 0.08∼106.65 μmol·L−1, respectively. Furthermore, the sensor was employed to detect DA and UA with good selectivity and sensitivity, and the interference experiment as well as the practical sample analysis was also well performed.