摘要
研究了维生素C在多壁碳纳米管/壳聚糖复合膜修饰玻碳电极上的电化学行为及测定。实验结果表明,在0.2 mol/L PBS(pH6.0)缓冲溶液中,修饰电极对抗坏血酸的氧化具有明显的催化和增敏效应,其氧化峰电位由+0.5 V负移至+0.1 V(vs.AgCl/Ag)。对修饰剂碳纳米管的用量、支持电解质、富集电位和富集时间等进行了优化。采用半微分伏安法进行定量测定,其线性范围为4.0×10^-6~2.0×10^-3mol/L,r=-0.998 3,检出限为1.0μmol/L。对抗坏血酸在修饰电极上的电化学行为进行了探讨,其电极反应为具有吸附特性和不可逆的电极过程,测得参加反应的质子数为2,电极反应的电子转移系数为0.59。测定了维生素C药片中抗坏血酸的含量,回收率在93%~105%。
Electrochemical behaviour and determination of vitamin C(Vc) based on multiwalled carbon nanotubes(MWCNTs)/chitosan(CS) composite film modified glassy carbon electrode were studied.The results showed that in 0.2 mol/L PBS(pH 6.0) buffer solution,the GC/CS+MWCNTs exhibited a remarkable electrocatalysis and enhancement effect on oxidation of the Vc.The oxidation peak potential of Vc shifted negatively from +0.5 V at bare GC to +0.1 V at GC/CS+MWCNTs.Some experimental conditions were optimized.The linear range between the peak current and the concentration of Vc was 4.0×10^-6-2.0×10^-3 mol/L(r=0.998 3) with a detection limit of 1.0 μmol/L by using semidifferential voltammetry.The electrochemical behaviors of the Vc were studied,and the electrode process was irreversible with adsorptive characteristics.Electron transfer coefficient(α=0.59) and proton numbers(X=2) have been determined.This method has been used to determine the content of the Vc in medical tablets.The recovery was determined to be 93%-105% by means of standard addition method.
出处
《分析测试学报》
CAS
CSCD
北大核心
2007年第5期662-666,共5页
Journal of Instrumental Analysis
基金
国家民委科研项目资助(05GX04)
广西科学基金资助项目(03420180639025)
广西高校百名中青年学科带头人资助项目(RC20060703005)
广西教育厅科研资助项目(20050712)
广西民族大学博士启动基金资助项目(0509QD015)
关键词
多壁碳纳米管
壳聚糖
化学修饰电极
维生素C
电化学行为
测定
Multiwalled carbon nanotubes
Chitosan
Chemical modified electrode
Vitamin C
Electrochemical behavior
Determination