A composite modified voltammetric sensor for dopamine (DA) was successfully developed, which was based on in-situ electrodepositing ionic liquids (IL, [BMIM]BF 4 )-titanium dioxide (TiO 2 ) nanoparticles on graphene oxide (GO) modified glassy carbon electrodes (GCE). The surface morphologies of different modified electrodes like GO/GCE, TiO 2 /GO/GCE, and IL-TiO 2 /GO/GCE were characterized by scanning electron microscopy. The electrocatalytic activities of the corresponding electrodes to

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... ne (DA) were investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), indicating that IL-TiO 2 /GO exhibited much higher electrocatalytic oxidation activity for DA than GO/GCE and TiO 2 /GO/GCE. The response of the IL-TiO 2 /GO modified electrode to DA was linear within a range of 8.0×10 -9~6 .0×10 -5 molL -1 , and the limit of detection was found to be 9.62×10 -10 molL -1 (S/N=3). Furthermore, the fabricated electrode possessed good selectivity, reproducibility and stability, and was applied to quantitative determination of DA in human serum samples with a recovery rate of 98.6~103.2%. The accuracy of the electrode was also comparable to that of a traditional spectrophotometric method, suggesting that the proposed method was of valuable in practical application on biomedical analysis field.