制备了多壁碳纳米管修饰玻碳电极,研究了酪氨酸在该电极上的电氧化行为并优化了测定条件.试验表明:与裸玻碳电极相比,该修饰电极明显降低了酪氨酸的氧化电位,提高了酪氨酸的氧化峰电流;利用差分脉冲伏安法测定其峰电流和酪氨酸的浓度在3.0×10-6~1.0×10-4mol·L-1范围内呈线性关系,检出限(S/N=3)为1.6×10-7mol·L-1;一些常见物质对测定无干扰.此方法已应用于人尿中酪氨酸的测定,测定结果的相对标准偏差(n=6)在3.1%~4.5%之间,加标回收率在93.8%~111.8%之间.

Preparation and characterization of multi-wall carbon nanotube(MWCNT) modified glassy carbon electrode(GCE) was described and electrochemical behavior of tyrosine(TRS) at this modified electrode was studied.As shown by experimental results,the oxidation potential of TRS was lowered obviously at the modified electrode,while its oxidative peak current was increased.Linear relationship between values of peak current and concentration of TRS was found to be kept in the range from 3.0×10-6 to 1.0×10-4mol·L-1.Detection limit(S/N=3) of the method found was 1.6×10-7mol·L-1 when the enrichment time of 4 min was taken.As shown by results of test for interferences,the proposed method was proved to have good selectivity.Based on these facts a differential pulse voltammetric method for determination of tyrosine was proposed.In its application to the determination of TRS in human urine samples,values of RSD′s(n=6) obtained were in the range from 3.1% to 4.5%,and values of recovery found were in the range of 93.8%-111.8%.