The fabrication of a Co (II) complex and multi-walled carbon nanotubes modified glass carbon electrode, and its application for the determination of dopamine

•Modified materials were in a low price, and easy to be prepared.•The sensor had high selectivity and rapid current response.•Ease of construction and utilization for dopamine determination.

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 μmol L−1 with a low detection limit of 1.76 μmol L−1 (at a signal-to-noise ratio of 3). The experimental results also proved that several co-existing substances, including K+, Na+, 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.

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