氨甲蝶呤在Co/GC离子注入修饰电极上电化学行为及其应用研究

Studies on the Electrochemical Behavior of Methotrexate and Its Applicationat Co/GC Ion Implantation Modified Electrode

氨甲喋呤在0.1mol/LHAc-NaAc(pH=4.96)缓冲溶液中，用Co/GC离子注入修饰电极进行伏安测定，得到一良好的还原峰，峰电位为-0.95V(vs.SCE)。峰电流Ip与氨甲喋呤的浓度在2．2×10^-7-8.8×10^-6mol/L范围内呈线性关系，检出限为1．1×10^-8mol/L。建立了测定氨甲喋呤的新方法，可用于实际样品的测定，回收率在98．9％－106．2％之间，用线性扫描和循环伏安法研究了体系的电化学行为及电极反应机理。实验表明，氨甲喋呤的还原为不可逆吸附过程，并伴随两个电子和两个氢离子参与电极反应。用俄歇电子能谱（AES）和X射线光电子能谱（XPS）等表面分析技术对Co离子注入修饰电极的表面元素组成及深度分布等进行测定，表明Co离子确被注入到玻璃表面，扫速对催化效率的影响实验证明体系存在催化作用。

With Co/GC ion implantation modified electrode as the working electrode, in 0. 1mol/L HAc-NaAc (pH= 4.96) buffer solution, a sensitive reductive wave of methotrexate was obtained by linear sweepvoltammetry. The peak potential was -0. 95 V(vs. SCE). The peak current was proportional to the con-centration of methotrexate in the range of 2. 2 × 10-7~8. 8 × 10-6 mol/L with the detection limit of 1.1×10-8 mol/L. The behavior of the reduction wave was studied and applied to the determination ofmethotrexate in tablets. The reduction process was irreversible with adsorption, The composition anddepth distribution of elements on the surface of the Co/GCE were determined by Auger electron spec-troscopy and X-ray photoelectron spectroscopy. The experiments showed that Co was surely implanted in-to the surface of glassy carbon. The implanted Co catalyzed the reduction of methotrexate.