Carbon nanospheres modified with WO2-NaxWO3 nanoparticles for highly sensitive electrochemical detection of dopamine

Abstract

WO2-NaxWO3 nanoparticles modified carbon spheres (WO2-NaxWO3/CSs) composite has been successfully synthesized by simple hydrothermal synthesis and high temperature calcination, and highly selective detection of dopamine (DA) was performed. The existence of WO2-NaxWO3 was confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectrum. Meanwhile, it can be seen from transmission electron microscopy (TEM) images that WO2-NaxWO3 was modified on the surface of carbon spheres in the form of nanometer-scaled particles. Cyclic voltammetry (CV) showed that the glassy carbon electrode modified by WO2-NaxWO3/CSs composite had strong electrocatalytic activity for DA oxidation, and a non-enzyme DA electrochemical sensor based on this material was constructed. Under the best conditions, the differential pulse voltammetry (DPV) signals of proposed sensor linearly increased with the increase of DA concentration in the range of 0.004 ~ 15.4 μM and 15.4 ~ 106.4 μM, with high sensitivity of 19.335 μA·μM−1·cm−2 and 3.151 μA·μM−1·cm−2, respectively, and a low limit of detection (LOD) of 1.3 nM (S/N = 3) and a limit of quantification (LOQ) of 4.3 nM were obtained. Furthermore, the sensor had good selectivity and satisfactory reproducibility and good stability for DA detection (RSD = 2.50%). It was successfully used to detect DA in animal serums, its recovery rate was between 1.10% and 2.91%, showing potential practical application value.