Electrochemical Determination of Capsaicin at A Multiwalled Carbon Nanotubes/CuO Nanocomposite Modified Platinum Electrode

Herein, electrochemical detection of capsaicin (CAP) in sauce and rub samples at a Pt electrode modified with copper oxide nanoparticles (CuO NPs) incorporated with functionalized multi-walled carbon nanotubes (fMWCNTs) was reported. The spectroscopic and microscopic characterization of CuO NPs, fMWCNTs and CuO/fMWCNTs nanocomposite with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) spectroscopy and Fourier-transform infrared spectroscopy (FT-IR) spectroscopy confirmed that CuO/fMWCNTs was prepared from the nanomaterials. Electrochemical characterization of the bare Pt, the fMWCNTs-modified Pt, the CuO NP-modified Pt (Pt-CuO) and the CuO/fMWCNTs composite modified Pt (Pt-CuO/fMWCNTs) electrodes revealed that the Pt-CuO/fMWCNTs exhibited the best electron transfer capabilities. The limit of detection (LOD) and the linear range of CAP at Pt-CuO/fMWCNTs were 0.0881 and 0.357–2.73 µM, respectively. The proposed sensor offered outstanding percentage recovery of 106 and 102% when applied to the electroanalysis of CAP in spiked sauce and rub samples, respectively. Pt-CuO/fMWCNTs also retained about 88% of its initial current response when subjected to 25 cyclic voltammetry (CV) scans in the presence of CAP.