An Electrochemical Sensor Based on Graphite Electrode Modified with Silica Containing 1-n-Propyl-3-Methylimidazolium Species for Determination of Ascorbic Acid Anastasiya B. Tkachenko†, Mykyta O. Onizhuk†, Oleg S. Tkachenko*†‡, Leliz T. Arenas‡, Edilson V. Benvenutti‡, Yoshitaka Gushikem§, Anton V. Panteleimonov**†§
	* Corresponding authors † Materials Chemistry Department, V. N. Karazin Kharkiv National University, 4 Svoboda Square, Kharkiv, 61022, Ukraine; *e-mail: oleg.s.tkachenko@karazin.ua; **e-mail: panteleimonov@karazin.ua ‡ LSS - Laboratory of Solids and Surfaces, Instituto de Química, UFRGS, PO Box 15003, CEP, Porto Alegre, RS, 91501-970, Brazil; § Instituto de Química, Universidade Estadual de Campinas, PO Box 6154, Campinas, SP, 13083-970, Brazil.
	Methods Objects Chem. Anal., 2019, 14(1), p. 5-14 https://doi.org/10.17721/moca.2019.5-14
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Abstract

In the present study, an electrochemical sensor based on the electrode (SiMImCl/C) consisting of graphite and silica, grafted with 1-n-propyl-3-methylimidazolium chloride was used for ascorbic acid (AA) quantification in pharmaceuticals and food formulations. Cyclic voltammetry and electrochemical impedance spectroscopy were applied for electrochemical characterization of the SiMImCl/C electrode. The cyclic voltammetry study revealed that the oxidation of AA on this electrode is an irreversible process, realized by adsorption and diffusion limited step. The differential pulse voltammetry was applied to develop a procedure for the AA determination. The linear range was found to be 0.3–170 μmol L-1 and the limit of detection – 0.1 μmol L-1. The proposed SiMImCl/C electrode has long term stability and does not show electrochemical activity towards the analytes, which commonly coexist with AA. The sensor was successfully used for quantification of AA in food and pharmaceutical formulations.

Keywords: ascorbic acid, sensor, voltammetry, organic-inorganic hybrid, ionic liquid

Article language: En