Electrochemical determination of levodopa using ZnO nanowire arrays/graphene foam

A three-dimensional (3D), macroporous and highly conductive grapheme foam (GF) was synthesized by chemical vapor deposition using a nickel foam as a template. ZnO nanowire arrays were vertically grown on the surface of the prepared GF using hydrothermal synthesis. The morphologies and structure of the ZnO NWAs/GF were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Raman spectroscopy. The results show that the prepared GF is high-quality and defect free, and the ZnO NWAs with uniform size vertically grows on the surface of 3D GF. The ZnO NWAs/GF was used as an elec-trochemical electrode for determining levodopa (LD). The results of electrochemical tests show that the oxidation current of LD is well linear with its concentration in the range of 0-80μmol·L^-1 with a sensitivity of 0.41μA·(μmol·L^-1)^-1, and the ZnO NWAs/GF electrode also shows good reproducibility and stability. The ZnO NWAs/GF can detect LD with high selectivity in the presence of uric acid.