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

Abstract

La-doped ZnWO 4 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 ZnWO 4 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.

La(OH)3 Multi-Walled Carbon Nanotube/Carbon Paste-Based Sensing Approach for the Detection of Uric Acid—A Product of Environmentally Stressed Cells

“…Non-expensive and robust non-enzymatic sensors perform direct oxidation of UA on the surface of the electrode material [ 29 , 30 ]. Various materials, such as covalent organic and metal incorporated conductive polymers [ 13 , 16 , 19 , 23 ], metal oxides [ 30 , 31 , 32 ], carbon-based materials, and their composites [ 11 , 12 , 33 ], have been tested for UA detection [ 5 , 26 ]. These nanomaterials have been recognized as promising materials for the development of analytical methods for the detection not only of UA but also of numerous other biologically active compounds [ 34 , 35 , 36 , 37 ].…”

“…The use of La [ 32 , 38 , 39 ]-based electrode materials has been reported in the literature with the main applications in fuel cells [ 40 , 41 , 42 ] and sensing devices [ 43 , 44 , 45 , 46 ], while Wang et al [ 47 ] used LaFeO 3 for the simultaneous determination of dopamine, uric acid and ascorbic acid, thus proving the materials’ compatibility with these analytes. La doping can affect lattice structures and phase transformations of compounds due to its larger atomic radius and unique electron structure, thus enhancing the catalytic and electrochemical properties of La-doped materials [ 32 ]. Furthermore, Guo et al [ 48 ] suggested that the alkaline properties of La(OH) 3 contribute to the acidic analytes’ bonding.…”