Electrocatalytic oxidation of acetylsalicylic acid at multiwalled carbon nanotube-alumina-coated silica nanocomposite modified glassy carbon electrodes

Abstract

Electrocatalytic oxidation of acetylsalicylic acid (ASA) at the multiwalled carbon nanotube-alumina-coated silica (MWCNT-ACS) nanocomposite modified glassy carbon electrode was investigated by cyclic voltammetry and square-wave voltammetry. The morphology of the MWCNT-ACS nanocomposite was characterized by field emission scanning electron microscopy. MWCNTs were well dispersed in the MWCNT-ACS nanocomposite. In cyclic voltammetric responses, the enhanced current response and the lower oxidation potential were obvious evidence for the electrocatalytic ability of MWCNTs toward ASA oxidation. The anodic peak currents varied linearly with the square root of scan rates over the range of 0.025-0.3 V s(-1), which suggested a diffusion-controlled process for the electrochemical reaction. The determination of ASA at the MWCNT-ACS nanocomposite modified glassy carbon electrode with square-wave voltammetry displayed a high sensitivity of 81.4 A M(-1) cm(-2) and a low detection limit of 3.77 mu M (S/N = 3). The sensitivity of the MWCNT-ACS nanocomposite modified glassy carbon electrode for the detection of ASA was almost 100 times of magnitude as compared to the bare glassy carbon electrode. The proposed methodology was successfully applied to the detection of ASA in pharmaceutical drugs with satisfactory results. (C) 2010 Elsevier B.V. All rights reserved.