title: Selective detection of dopamine in the presence of ascorbic acid and uric acid by a carbon nanotubes-ionic liquid gel modified electrode.
abstract: The electrochemistry of dopamine (DA) was studied by cyclic voltammetry at a glassy carbon electrode modified by a gel containing multi-walled carbon nanotubes (MWNTs) and room-temperature ionic liquid of 1-octyl-3-methylimidazolium hexafluorophosphate (OMIMPF(6)). The thickness of gel on the surface of the electrode has to be controlled carefully because the charging currents increase with the modified layer being thicker. The anodic peaks of DA, ascorbic acid (AA) and uric acid (UA) in their mixture can be well separated since the peak potential of AA is shifted to more negative values, while that of UA is shifted to more positive values due to the modified electrode. At pH 7.08 the three peaks are separated ca. 0.20 and 0.15V, respectively; hence DA can be determined in the presence of UA and more than 100 times excess of AA. Under optimum conditions linear calibration graphs were obtained over the DA concentration range 1.0x10(-6) to 1.0x10(-4)M. The detection limit of the current technique was found to be 1.0x10(-7)M based on the signal-to-noise ratio of 3. The modified electrode has been successfully applied for the assay of DA in human blood serum. This work provides a simple and easy approach to selectively detect dopamine in the presence of ascorbic acid and uric acid.
authors.affiliation: Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing, PR China.
authors.forename: Yifang
authors.initials: Y
authors.lastname: Zhao
authors.forename: Yuqian
authors.initials: Y
authors.lastname: Gao
authors.forename: Dongping
authors.initials: D
authors.lastname: Zhan
authors.forename: Hui
authors.initials: H
authors.lastname: Liu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhao
authors.forename: Yuan
authors.initials: Y
authors.lastname: Kou
authors.forename: Yuanhua
authors.initials: Y
authors.lastname: Shao
authors.forename: Meixian
authors.initials: M
authors.lastname: Li
authors.forename: Qiankun
authors.initials: Q
authors.lastname: Zhuang
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Zhu