Synergistic electrocatalytic effect of carbon paste electrode modified with boron phosphate-polyaniline composite on voltammetric determination of paracetamol and ascorbic acid

Abstract

Modified electrodes are of great importance for the sensitive, selective and accurate determination of a wide variety of compounds by electrochemical methods. Despite its superior electrical and catalytic properties, boron phosphate has not been investigated for electrode modification purposes to date. In this study, we mainly aimed to develop a simple carbon paste electrode modified with boron phosphate in the form of polyaniline composite that lowers the oxidation potentials of target molecules enhancing the current sensitivities. The as-prepared composites were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and BET surface area measurements. Ascorbic acid and paracetamol were studied as model compounds to examine the electrocatalytic performance of modified electrodes. The electrochemical oxidation of ascorbic acid and paracetamol was carried out by cyclic voltammetry and square wave voltammetry. Experimental conditions such as paste composition, pH and instrumental parameters were optimized to attain higher sensitivity and lower oxidation overpotential. The results confirmed that boron phosphate/polyaniline composites have significant advantages over graphite, polyaniline or boron phosphate alone. The sensitivity of the optimized boron phosphate/polyaniline modified electrode against ascorbic acid and paracetamol was found to be 158 mu A mM-1 and 105 mu A mM-1, respectively, in cyclic voltammetry measurements. In square wave voltammetric studies, the sensitivity was 53 mu A mM-1 and 17 mu A mM-1 for ascorbic acid and paracetamol, respectively. Reasonable wide linear ranges from 0.1 to 2.0 mM and 0.1-2.5 mM with a detection limit of 19 and 28 mu M were ascertained for ascorbic acid and paracetamol, respectively, in cyclic voltammetry studies. The analytical performance of the electrode were also satisfactory in their binary mixtures. Boron phosphate/polyaniline modified carbon paste electrode was successfully applied to the determination of ascorbic acid and paracetamol in commercial products with satisfactory results with 95-108% recoveries.