| Since the discovery by Iijima in 1991, carbon nanotubes（CNTs） have developed to be hot research topic and attracted wide attention of many fields, owing to their particular structure and unique properties. In particular in the field of electrochemistry, due to the excellent conductivity, large specific surface area, good chemical stability and wide potential window of carbon nanotubes, they have become the ideal material for modifying electrodes. In recent years, in order to improve the selectivity and sensitivity of the electrodes, the attention has been focused on the fabrication of the novel modified electrodes. The construction of carbon nanotubes film modified electrodes also became the hot research focus in the field of electrochemistry. Based on plenty of literatures, this paper progresses some explorations aiming at the preparation of the electrodes modified by carbon nanotubes and carbon nanotubes composite nanomaterals. Three novel modified electrodes was prepared and used in the electrochemical determination of several active ingredients of traditional Chinese medicine. The main research are shown below:1. The stable voltammetric sensor, single-walled carbon nanotubes（SWCNTs） casted on glassy carbon electrode（GCE）, was employed in the initial electrochemical determination of naringenin. The complex electrochemical behavior of naringenin on this sensor was investigated in detail and the dynamic and thermodynamic parameters were calculated. The new electroanalytical method for naringenin was proposed with low detection limit of 2.0×10-8 mol L-1（S/N=3） and wide linear ranges from 8×10-8 to 5×10-6 mol L-1 and 5×10-6 to 1.2×10-5 mol L-1 respectively. More importantly, this sensor exhibited good reproducibility and long-term stability. Then this sensor was successfully applied for the determination of naringenin in Fructus aurantii Immaturus with satisfactory results.2. A novel voltammetric sensor was constructed by simple dripping single-walled carbon nanotubes（SWCNTs） on to the glass carbon electrode（GCE） firstly and electropolymerizing L-Citrulline film subsequently. The resulting poly（LCitrulline）/SWCNTs/GCE showed a significant voltammetric response to picroside II due to the synergistic effect of SWCNTs and poly（L-Citrulline） film. The first electroanalytical method of picroside II was proposed with detection linear range from 8.0×10-8 to 5.0×10-6 mol L-1 and a detection limit of 3×10-8 mol L-1.The high sensitivity, selectivity and long-term stability made the sensor suitable for the determination of picroside II. Moreover, based on the systematically investigation and some kinetics parameters calculated in the experimentation, the reaction mechanism of picroside II at the poly（L-Citrulline）/SWCNTs modified GCE was obtained reliably. Lastly, the proposed sensor was used for the determination of picroside II in real sample with satisfactory results. This work promoted the potential applications of amino acid materials and SWCNTs in electro-chemical sensors.3. Arctigenin was determinated by an electrochemical method for the first time based on a novel voltammetric sensor, which was prepared by simple dipping-drying of SWCNTs on glassy carbon electrode（GCE） initially and then electrochemical deposition of iodide. The resulting Iodide/SWCNTs/GCE displayed a significant voltammetric response to arctigenin due to the electrocatalytic ability of iodide for arctigenin and a large specific surface area, excellent electric conductivity of SWCNTs. Meanwhile, the redox mechanism of arctigenin on Iodide/SWCNTs/GCE was also studied. The wide linear range and low detection limit for determination of arctigenin were achieved together with high sensitivity, selectivity, good stability. To examine the practical analytical utility of the proposed electrode, the real sample Fructus Arctii was examined and the result was found satisfactory. |
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