Covalent Modification of Glassy Carbon Electrode with an Imidazolium based Methoxysilyl Ionic Liquid Nanoparticles: Application in Determination of Redox System

Abstract

Glassy carbon (GC) is the most commonly used carbon-based electrode in the analytical laboratory. Because of the high background current and low electrode response, modification of this electrode can be done by various materials and techniques. An ionic liquid (IL), 1-methyl-3-(3-trimethoxysilyl propyl) imidazoliumbis (trifluoromethylsulfonyl) imide, was covalently cross linked onto the GC surface. GC was activated in sulfuric acid solution by cyclic voltammetry, which generate surface oxygen containing functional groups such as OH group, through which the IL was covalently bonded the surface of GC. The resulting surface was characterized by using cyclic voltammetry, differential pulse voltammetry and atomic force microscopy. Hydroquinone and ascorbic acid were the redox systems used to study the effect of ILcovalent bonding on the electron transfer rate and response decay of the GC. Compared to GC modified with a physically adsorbed layer of IL with an unstable response and decrease in peak current, the chemically IL-modified electrode showed stable and favorable response characteristics.