Choline oxidase inhibition biosensor based on poly(brilliant cresyl blue) – deep eutectic solvent / carbon nanotube modified electrode for dichlorvos organophosphorus pesticide

Abstract

A novel electrochemical choline oxidase enzyme inhibition biosensor for dichlorvos has been developed based on poly(brilliant cresyl blue) films formed on multiwall-carbon nanotube modified glassy carbon electrodes by fixed potential and potentiodynamic cycling electropolymerisation in acid-doped ethaline deep eutectic solvent or aqueous medium. Film characterisation was done by voltammetry and scanning electron microscopy. The effect of the parameters used during potentiostatic polymerization, such as electrolyte solution (acid-ethaline or aqueous solution), polymerisation time and applied potential on the rate of growth and the electrochemical properties of the polymer films were studied. The choline oxidase enzyme inhibition biosensor for dichlorvos detection used the best polymer film formation conditions, in acid-doped ethaline. The type of reversible inhibition was determined. The new biosensor exhibited the lowest limit of detection for dichlorvos determination of those reported, 1.6 nM, excellent reproducibility and long-term stability, which makes it a promising tool for monitoring traces of organophosphorus pesticides in the environment.