Fabrication of GNPs/CDSH-Fc/nafion modified electrode for the detection of dopamine in the presence of ascorbic acid

A novel dopamine sensor was fabricated by forming the inclusion complex between mono-6-thio-beta-cyclodextrin (CD-SH) and ferrocene (Fe) functionalized gold nanoparticles (GNPs) films on a platinum electrode. The properties of the GNPs/CDSH-Fc nanocomposite were characterized by Fourier transform infrared spectra, UV-visible absorption spectroscopy, transmission electron microscopy and cyclic voltammetry. The electrochemistry of dopamine (DA) was investigated by cyclic voltammetry (CV) and differential pulse voltammograms (DPV). The electrooxidation of dopamine could be catalyzed by Fc/Fc(+) couple as a mediator and had a higher electrochemical response due to the unique performance of GNPs/CDSH-Fc. The anodic peaks of DA and ascorbic acid (AA) in their mixture can be well separated by the prepared electrode. Under optimum conditions linear calibration graphs were obtained over the DA concentration range 2.0 x 10(-6) to 5.0 x 10(-5) M with a correlation coefficient of 0.998 and a detection limit of 9.0 x 10(-8) M (S/N = 3). The modified electrode had been effectively applied for the assay of DA in dopamine hydrochloride injections. This work provides a simple and easy approach to selectively detect DA in the presence of AA. (C) 2011 Elsevier B.V. All rights reserved.