中文摘要：

将Hummers法制备的单层氧化石墨烯（GO）与多壁碳米管（MWCNT）超声混合，得到性能稳定的GO／MWCNT复合纳米材料。以此纳米材料修饰玻碳电极，构建了一种新型L＋色氨酸（L．Trp）电化学传感器。采用透射电镜（TEM）、循环伏安（CV）和交流阻抗（EIS）等方法对修饰电极进行了表征；并研究了L．Trp在修饰电极上的电化学行为和动力学性质。结果表明，L—Trp在GO／MWCNT修饰电极有一个灵敏的氧化峰（Ept=0．956V）；该氧化反应是一个2电子和2质子参与的不可逆过程，电极过程受到吸附步骤控制，其表观标准速率常数为9．613×10-4cm／s；利用该氧化峰可进行痕量L—Trp的检测。在pH6．0磷酸盐缓冲液中，当富集电位为0．600V，富集时间为25s，扫速为100mV／s时，L—Trp氧化峰电流与其浓度在1，0×10-6～1．0×10-4mol／L范围内呈良好线关系，相关系数为0．995，检出限可达3．50x10-mol／L；所制备的电化学传感器稳定性较好，用于人体血清中L-Trp的现场快速检测，加标回收率为97．8％～1042％。

英文摘要：

A single-layer graphene oxide （GO） was prepared by Hummers method, and then mixed with multiwalled carbon nanotubes （MWCNT） in ultrasound bath to form stable GO/MWCNT nanocomposites. A novel L-tryptophan （L-To） electrochemical sensor was fabricated based on GO/MWCNT modified glassy carbon electrode. The modified electrode was characterized by transmission electron microscope （TEM）, cyclic vohammetry （CV） and alternating current impedance （EIS）, and the electrochemical behaviors and kinetic properties of L-Trp on the modified electrode were also investigated. The experimental results showed that a sensitive oxidation peak of L-Trp appeared at GO/MWCNT modified electrode （Epa = 0. 956 V）, and the oxidation reaction was an irreversible process containing two electrons and two protons transfer. This electrode process controlled by the adsorption step, and the standard rate constant was 9. 613 x 10-4 cm/s. Trace levels of L-Trp can be determined by this oxidation peak. In phosphate buffer of pH 6.0, the oxidation peak currents were linearly dependent on the L-Trp concentrations in the range of 1. 00 104 - 1. 00 10-4 mol/L with accumulation time of 25 s at 0. 600 V and scan rate of 100 mV/s. The correlation coefficient was 0. 995 and the detection limit was 3.50x10-7 mol/L. The prepared electrochemical sensor had favorable stability and could be applied to the quick determination of L-Trp in human serum, and the recovery of standard addition was from 97.8% to 104.2%.