Fabrication of Fc-SWNTs modified glassy carbon electrode for selective and sensitive determination of dopamine in the presence of AA and UA

The electrochemistry of dopamine (DA) was investigated by cyclic voltammetry (CV) and differential pulse voltammograms (DPV) at a glassy carbon electrode modified by the hybridization adducts of Fc-SWNTs. The electro-oxidation of DA could be catalyzed by Fc/Fc+ couple as a mediator and had a higher electrochemical response due to the unique carbon surface of carbon nanotubes. The anodic peaks of DA, ascorbic acid (AA) and uric acid (UA) in their mixture can be well separated by the prepared electrode. Under optimum conditions linear calibration graphs were obtained over the DA concentration range 5.0 × 10−6 to 3.0 × 10−5 M with a correlation coefficient of 0.9998 and a detection limit of 5.0 × 10−8 M based on the equation Cm = 3sb1/m. 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 DA in the presence of AA and UA.