Evaluation of ionic natural deep eutectic solvents (NADES) modified binders towards the chemical properties of carbon paste electrodes

Abstract

This paper presents a new approach towards the modification of carbon paste electrodes with natural deep eutectic solvents (NADES) as a modified binder. The cyclic voltammograms with the NADES modified carbon paste electrode presented improved conductivity and charge transfer rate when compared to the bare carbon paste, evinced by the smaller peak potential separation. The incorporation of KCl solution into the NADES modifier reduced the binder layer viscosity, improving the diffusion of the probe to the graphite surface. The aforementioned effect is sustained by the reduction of the Rct values for graphite and the smaller value of the Gerischer parameter associated with the diffusion in thin layers. The reline modified carbon paste electrode also presented superior performance for the oxidation of dopamine and ascorbic acid, increasing the peak current values and reducing both the half peak width and potential peak separation for dopamine. Therefore, the results presented in this work are a first promising step of the application of NADES as a binder modifier that can be further enhanced with the modification of the modifying agent with molecular catalysts or nanomaterials. Keywords: Natural deep eutectic solvents, NADES, Carbon paste electrode, Binder, Electrochemical impedance spectroscopy