Building nickel tungstate nanospheres anchored polyaniline conductive matrixes for trace level electrochemical determination of theobromine in food samples

In this work, a nickel tungstate nanospheres-anchored polyaniline nanocomposite (NiWO4/PANI) was prepared by using a hydrothermal route followed by a chemical oxidative polymerization route and explored as an electrode material for the determination of theobromine (TB). The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis confirm the structural-compositional details of NiWO4/PANI nanocomposite. Further, the successful fabrication of NiWO4 nanospheres perfectly anchoring on the conductive matrix of PANI is revealed by transmission electron microscope (TEM) analysis. The N2 adsorption-desorption isotherm analysis revealed the specific surface area of the composite is 28.49 m2/g. Due to the feasible multiple electroactive sites and the synergistic effect between NiWO4 and conductive PANI matrix in the NiWO4/PANI nanocomposite, it enables rapid electron migration and possesses high electrical conductivity during the sensing performances. From the amperometric i-t method, NiWO4/PANI sensor exhibits a wide linear range (0.05-1350.6 mu M) and a low detection limit (0.0079 mu M). Besides, NiWO4/PANI based sensor shows excellent stability, anti-interference ability and reproducibility, suggesting NiWO4/PANI composite-modified sensors could be a potential candidate for determining TB in food samples with suitable recovery ranges.