Plant based fabrication of CuO/NiO nanocomposite: a green approach for low-level quantification of vanillin in food samples

Abstract

Abstract Metal oxide nanoparticles have a wide range of potential applications due to their unique properties, including their high surface area-to-volume ratio, enhanced reactivity, and unique electronic and magnetic properties. They are widely used in industries such as electronics, energy, catalysis, and medicine, where their small size and unique properties can be utilized for a variety of purposes. Fabrication of bi-metal oxide nanocomposite through green synthesis routes is of great importance. The plant leaves are being used as a prominent source for reducing/capping or functionalization of metal oxide nanoparticles. Thus, engineering of CuO/NiO nanocomposite has been carried out via exploiting Java plum leaves’ extract as reducing and capping source. After successful green synthesis, the CuO/NiO nanocomposite was directed for characterization through advanced analytical tool viz XRD, FTIR and TEM. The FTIR spectra confirm the stretching frequencies of Cu–O and Ni–O bonds at 587.1 and 647.3 cm−1 which witnesses the surface functionalities of prepared nanocomposite. XRD analysis confirms the diffraction patterns of CuO/NiO nanocomposite with exceptional crystalline structure and phase purity. TEM images evaluate the nanometric size of fabricated CuO/NiO nanocomposite with nanoflower like internal texture having size below 100 nm. The as-prepared CuO/NiO nanocomposite was used as green electrocatalyst for the determination of vanillin (VN) in food samples. The redox current response and charge transfer kinetics of CuO/NiO/GCE was examined via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimal conditions such as potential window (0.2–1.3 V), PBS electrolyte pH 7, scan rate 60 mV/s, the engineered modified electrode exhibited excellent response for VN. The LOD of prepared electrocatalyst for VN was examined as 0.0087 µM. The potential of applicability of CuO/NiO/GCE was tested in ice-cream and chocolate samples. The obtained recovery values of real samples were found in acceptable range which highlights analytical potential of prepared modified electrode for VN.