Simultaneous detection of ascorbic acid, dopamine, uric acid and tryptophan with Azure A-interlinked multi-walled carbon nanotube/gold nanoparticles composite modified electrode

By Filik, Hayati; Avan, Asiye Asl?han; Aydar, Sevda
Published in Arabian Journal of Chemistry NULL 2016

Abstract

Abstract In this paper, multi-walled carbon nanotube/Azure A/gold nanoparticle composites (Nafion/AuNPs/AzA/MWCNTs) were prepared by binding gold nanoparticles to the surfaces of Azure A-coated carbon nanotubes. Nafion/AuNPs/AzA/MWCNTs based electrochemical sensor was fabricated for the simultaneous determination of ascorbic acid, dopamine, uric acid, and tryptophan. Cyclic voltammetry and electrochemical impedance spectroscopy were used to characterize the electrochemical properties of the modified electrodes. The modified electrode showed excellent electrocatalytic activity toward ascorbic acid, dopamine, uric acid, and tryptophan (pH 7.0). The experiment results showed that the linear response range for simultaneous detection of AA, DA, {UA} and Trp were 300-10,000 ?M, 0.5-50 ?M, 0.5-50 ?M and 1.0-100 ?M, respectively, and the detection limits were 16 ?M, 0.014 ?M, 0.028 ?M and 0.56 ?M (S/N = 3). The proposed method offers promise for simple, rapid, selective and cost-effective analysis of small biomolecules. The procedure was also applied to the determination of tryptophan in spiked milk samples.

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