A good route for the fabrication of CeO2 nanoparticles （nano-CeO2）/multi-walled carbon nanotubes （MWCNTs） modified glassy carbon electrodes （GCE） was proposed. MWCNTs are used to immobilize nano-CeO2. What＇s more, with the addition of the MWCNTs, the agglomeration level of CeO2 nanoparticles can be reduced, the extremely large surface area can be obtained and the electron transfer rate can be increased. The morphological char- acterization of nano-CeOz/MWCNTs was examined by scanning electron microscopy （SEM）. The performances of the nano-CeO2/MWCNTs/GCE were characterized with cyclic voltammetry （CV）, electrochemical impedance spectroscopy （EIS） and typical amperometric response （i-t）. The potential utility of the constructed electrodes was demonstrated by applying them to the analytical determination of puerarin concentration. The catalytic oxidation of puerarin has a better result on nano-CeOz/MWCNTs/GCE because of the synergistic effect of nano-CeO2 and MWCNTs. An optimized limit of detection of 8.0 × 10^-9 mol/L was obtained at a signal-to-noise ratio of 3 and with a fast response time （within 3 s）. Additionally, the nano-CeO2/MWCNTs/GCE exhibited a wide linear range from 0.04 to 6.0 μmol/L and high sensitivity.
The preparation of a glassy carbon electrode modified by CeO2 nanoparticles was described, which was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. In pH 6.0 buffer, the CeO2 nanoparticle modified electrode （CeO2 NP/GC） gave an excellent electrocatalytic activity for the oxidation of uric acid （UA）. The catalytic current of UA versus its concentration had a good linear relation in the range of 2.0 × 10^-7-5.0 × 10^- 4 mol/L, with the correlation coefficient of 0.9986 and detection limit of 1.0 ×10^-7 mol/L. The modified electrode can be used for the determination of UA in urine, which can tolerate the interference of ascorbic acid up to 1000-fold. The method was simple, quick and sensitive.
