Detection of additives in food using conducting polymer/CuO modified electrodes

Abstract

This study describes the modification of electrochemical sensors of the copper oxide nanoparticles incorporated with the functionalized multi-walled carbon nanotubes (CuOch/fMWCNTs and CuOgr/fMWCNTs) embedded on the platinum electrode (PtE) towards the detection of capsaicin(CAP). Prior to the fabrication of the PtE, numerous spectroscopic and microscopic techniques were utilized for the characterization of the nanomaterials; these includes the ultraviolet-visible spectroscopy (UV-Vis), fourier transform infrared spectroscopy (FTIR), x-ray diffractogram spectroscopy (XRD), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), and transmission electron microscopy (TEM). For the electrochemical characterization of the Pt-Bare, Pt-CuOch NPs, Pt-CuOgr NPs, Pt-fMWCNTs, Pt-CuOch/fMWCNTs, and PtCuOgr/fMWCNTs electrodes, the cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and square-wave voltametry (SWV) techniques were utilized. Both nanocomposite (Pt-CuOch/fMWCNTs, and Pt-CuOgr/fMWCNTs) electrodes demonstrated better electron transfer compared to other electrodes. On the detection of capsaicin, the PtCuOch/fMWCNTs electrode demonstrated a limit of detection (LOD) of 0.0765 µM with a linearrange of concentration for 0.357 to 2.7 µM while the Pt-CuOgr/fMWCNTs electrode displayed the LOD of 0.0881 µM with the linear range of concentration for 0.357 to 2.7 µM. Both proposed electrodes showed good reproducibility and excellent anti-interference capabilities. Real sample analysis was conducted using the sauce and rub, for the sauce, the Pt-CuOch/fMWCNTs showed the recovery percentages of 98 to 110 % with an average RSD value of 5.77 (n=3) and PtCuOgr/fMWCNTs gave the recovery percentage of 100-116 % with an average RSD value of 8.24(n=3). While for the rub, the Pt-CuOch/fMWCNTs showed the recovery percentages of 84-106 %with an average RSD value of 12.18 (n=3) and Pt-CuOgr/fMWCNTs gave the recovery percentage of 98 to 105 % with an average RSD value of 3.36 (n=3)