Integration of multiwalled carbon nanotubes with cobalt oxide for smart electrochemical sensing of epicatechin in foods

•A cost-effective electrochemical sensor based on GCE/MWCNTs/Co3O4 for EC sensing in food samples is reported.•Co3O4 is synthesized from a Carica Papaya peel extract.•A wide linear dynamic range of 47.6 to 310.3 µM with 0.12 µM limit of detection is obtained on the GCE/MWCNTs/Co3O4 using SWV.•The designed sensor demonstrated good reproducibility, repeatability and excellent practicability for EC detection in actual samples (food).•Density functional theory (DFT) calculations, and Monte Carlo (MC) simulations, were performed to understand the reactive sites of EC and the electrostatic interaction of EC on electrodes surfaces, respectively.