多壁碳纳米管修饰玻碳电极选择性测定色氨酸

Selective detection of tryptophan using multiwall carbon nanotube modified glassy carbon electrode

研究了色氨酸（Trp）和酪氨酸（Tyr）在多壁碳纳米管修饰玻碳（MWNTs/GC）电极上的电化学行为.结果表明相对于玻碳电极,此修饰电极促进了色氨酸和酪氨酸的电催化.信号与背景电流比表明相对于酪氨酸此电极对色氨酸有更强的催化作用.在1.0 mol/L硫酸中此修饰电极对色氨酸和酪氨酸的分离效果最好,故可以在酪氨酸存在下选择性测定色氨酸.混合液中色氨酸的氧化峰电流与浓度在7.50×10^-6～2.00×10^-4mol/L范围内呈良好线性关系,检出限为3.29×10^-6mol/L（信噪比为3）.将此方法用于17AA复方氨基酸注射液中色氨酸的回收试验,回收率达到97%以上.

Electrochemical behaviors of tryptophan （Trp） and tyrosine （Tyr） on multi-walled carbon nanotubes modified glassy carbon （MWNTs/GC） electrode were studied. The result demonstrates that MWNTs/GC electrode greatly catalyzed the oxidation of Trp and Tyr compared with glassy carbon electrode. The ratio of signal and background current indicates that the modified electrode catalyzes more greatly Trp than Tyr. pH test result demonstrates that Trp and Tyr could be separated in 1.0 mol/L H2SO4 solution, which provides the possibility of selective detection Trp in the presence of Tyr. In the mixture, the peak current of Trp was linearly proportional to the concentration in the range from 7.50×10^-6 mol/L to 2.00×10 4 mol/L, the detection limit was 3.29×10^-6 mol/L （SPN is 3）. The method was applied to the detection of Trp in 17AA compound amino acid injection,the recovery is over 97%.