New modified multiwalled carbon nanotubes paste electrode for electrocatalytic oxidation and determination of warfarin in biological and pharmaceutical samples

A novel sensor for the determination of warfarin based on a simple and sensitive method was developed on multiwalled-carbon-nanotube modified ZnCrFeO4 carbon paste electrodes (MWCNT/ZnCrFeO4/CPEs). Cyclic voltammetry, differential pulse voltammetry, chronoamperometry, and electrochemical impedance spectroscopy were used to investigate the electrochemical behavior of warfarin at the chemically modified electrode. According to the results, MWCNT/ZnCrFeO4/CPEs showed high electrocatalytic activity for warfarin oxidation, producing a sharp oxidation peak current at about +0.97 vs Ag/AgCl reference electrode at pH = 4.0. The peak current was linearly dependent on warfarin concentration over the range of 0.02–920.0 μmol/L with a detection limit of 0.003 μmol/L. In addition, chronoamperometry was also used to determine warfarin's catalytic rate constant and diffusion coefficient at MWCNT/ZnCrFeO4/CPEs.

Graphical AbstractThe modification of a carbon paste electrode with ZnCrFeO4 nanoparticles and multiwalled carbon nanotubes was studied for electrocatalytic determination of warfarin in pharmaceutical and biological samples.Figure optionsDownload full-size imageDownload as PowerPoint slide