Simultaneous electrochemical determination of ascorbic acid, dopamine and uric acid with helical carbon nanotubes

Abstract

In this study we develop a sensor based on helical carbon nanotubes (HCNTs) for the simultaneous electrochemical determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). A water soluble cationic polymer, poly(diallyl dimethylammonium chloride) (PDDA), is used to functionalize the nanotubes’ surface, aiming to improve the HCNTs dispersibility and adhesion to substrates. After electrochemical pre-treatment, the PDDA@HCNTs coated glassy carbon electrodes can separate the anodic oxidation potential of AA, DA and UA with well-defined peak separation in the presence of each other. The calibration curves were obtained in the range of 25–1045μML−1 for AA, 2.5–10μML−1 for DA, and 5.0–175μML−1 for UA. Detection limits of 0.12μML−1, 0.08μML−1, and 0.22μML−1 were obtained for AA, DA, and UA at pH 7.4, respectively. The analytical performance of this sensor has been evaluated for simultaneous detection of AA, DA, and UA in the fetal bovine serum samples.