Electrochemical Determination of Gallic Acid in Red Wine, Black Tea and Green Tea Based on Choline Chloride Modified Glassy Carbon Electrode
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Date
2024-08
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Addis Ababa University
Abstract
A sensitive and selective square wave voltammetric approach for determination of Gallic acid (G.A) was developed based on choline chloride modified glassy carbon electrode (ChCl/GCE). The modification was simple and cost effective, which was performed through electrochemical deposition of choline chloride onto the glassy carbon electrode surface using cyclic voltammetry technique. Electrochemical methods including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used for characterization of the modified electrode. It was also effectively employed for the detection of G.A using cyclic voltammetry and square wave voltammetry (SWV) techniques. From the electrochemical investigation, choline chloride exhibited excellent electro catalytic behavior for the detection of G.A and increased electron transfer rate. The effects of several electro analytical experimental conditions were also optimized for sensitive determination of G.A. The irreversible electrochemical behavior of G.A at the ChCl/GCE is an adsorption controlled process involving transfer of electrons. Under the optimized conditions, the SWV result indicated that the oxidation peak current of G.A at the ChCl/GCE was directly proportional to its concentration over linear range of 1.6 μM to 240 μM with limit of detection 0.126 μM, limit of quantification 0.419 μM. The ChCl/GCE has also showed excellent selectivity, reproducibility and long-time stability towards the electrochemical oxidation of G.A. Moreover, the practical applicability of the prepared ChCl/GCE was evaluated in order to determine G.A in red wine, black tea and green tea samples with recovery ranging from 92.20 % – 1
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Keywords
Gallic Acid, Choline Chloride, Square Wave Voltammetry, Modified Glassy Carbon Electrode