An electrochemical biosensor based on [Co(phen)3](2+) (phen = 1,10-phenanthroline) and multi-walled carbon nanotubes (MWCNTs) was developed for the determination of dopamine (DA) by using a glassy carbon electrode (GCE). The electrochemistry properties of the composite film were investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), and the electrooxidation behavior of DA on [Co(phen)3](2+)/MWCNTs/GCE was studied by amperometry. Under the optimum experimental conditions, the linear calibration curve was obtained in the range from 5 to 453 mu mol L-1 with a low detection limit of 1.76 mu mol L-1 (at a signal-to-noise ratio of 3). The experimental results also proved that several co-existing substances, including IC', Nat, etc., had no significant interference on the determination of DA. The validity of using this modified electrode to determine DA in dopamine hydrochloride injection was also demonstrated. (C) 2014 Elsevier B.V. All rights reserved.