Highly Sensitive and Selective Determination of Dopamine Based on Ionic Liquid-Titanium Dioxide/Graphene Oxide Nanocomposite Modified Electrode

A composite modified voltammetric sensor for dopamine (DA) was successfully developed, which was based on in-situ electrodepositing ionic liquids (IL, [BMIM]BF4)-titanium dioxide (TiO2) nanoparticles on graphene oxide (GO) modified glassy carbon electrodes (GCE). The surface morphologies of different modified electrodes like GO/GCE, TiO2/GO/GCE, and IL-TiO2/GO/GCE were characterized by scanning electron microscopy. The electrocatalytic activities of the corresponding electrodes to dopamine (DA) were investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), indicating that IL-TiO2/GO exhibited much higher electrocatalytic oxidation activity for DA than GO/GCE and TiO2/GO/GCE. The response of the IL-TiO2/GO modified electrode to DA was linear within a range of 8.0×10-9~6.0×10-5mol⋅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.