Electro-catalytic determination of l-Cysteine using multi walled carbon nanotubes-Co3O4 nanocomposite/benzoylferrocene/ionic liquid modified carbon paste electrode

Abstract

We attempted to develop a new electrochemical sensing platform via the modification of carbon paste electrode using multi-walled carbon nanotubes-Co3O4 nanocomoisite/benzoyl ferrocene/ionic liquid (MWCNTs-Co3O4/BF/IL/CPE), with the aim of detecting l-Cysteine (l-Cys) analyte. A facile hydrothermal protocol was fulfilled to construct the nano-composite, followed by characterizing via Energy-dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM), Fourier transform-infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The electrocatalytic behavior of l-Cys was explored on the modified electrode surface through cyclic voltammetry (CV), chronoamperometry, and differential pulse voltammetry (DPV). The findings from the cyclic voltammetry highlighted an excellent catalytic activity of proposed MWCNTs-Co3O4/BF/IL/CPE towards the l-Cys oxidation in phosphate buffer solution (pH = 7.0) when comparing with other electrodes, owing to synergistic influence of fused ferrocene-derivative, ionic liquid and nanocomposite. The as-develop sensor had a narrow limit of detection of 0.04 ± 0.001 μM and a broad linear dynamic range of 0.1 μM to 100.0 μM. Notably, the MWCNTs-Co3O4/BF/IL/CPE exhibits good sensitivity of 0.1449 µA·µM−1. The practical applicability of our sensor was confirmed by sensing the l-Cys in real samples, possessing satisfactory recoveries (97.8 %-104.3 %).