Nafion-多壁碳纳米管复合膜修饰玻碳电极测定岩白菜素的研究

研制了以Nafion分散多壁碳纳米管的化学修饰电极,研究了岩白菜素在该修饰电极上的电化学行为和电化学动力学性质.发现修饰电极对岩白菜素有显著的电催化作用,岩白菜素的氧化过程是单电子单质子过程,岩白菜素在该修饰电极上的扩散系数、速率常数分别为6.02×10~(-6) cm~2·s~(-1)、5.54×10~(-3) mol·L~(-1)·s~(-1). 通过优化各项参数,建立了一种直接测定岩白菜素的电分析方法.该方法的线性范围为1.44×10~(-7) ～1.92×10~(-6) mol·L~(-1)和4.18×10~(-5) ～1.06×10~(-4) mol·L~(-1),检出限为1.02×10~(-7) mol·L~(-1),同支电极测定10次的相对标准偏差为4.6%,可用于岩白菜素样品的含量测定.

Determination of Bergenin Using Nafion-Multiwalled Carbon Nanotubes Composite Film Modified Glassy Carbon Electrode

A chemically modified electrode of Nafion - multiwalled carbon nanotubes coated glassy carbon electrode( Nafion - MWCNTs/GCE) was prepared. The electrochemical behaviors of bergenin and its electroanalytical method were studied. The modified electrode exhibited a remarkable catalytic and enhanced effects on the current response of bergenin. The property of kinetics were also studied. The results indicated that one - electron and one - proton transfer were involved in the electrode reac-tion process. Diffusion coefficient (D) and rate constant (k) were 6. 02 × 10~(-6) cm~2 · s~(-1) and 5. 54 × 10~(-3) mol · L~(-1) s~(-1), respectively. The experimental conditions were optimized. Under the optimal conditions, the linear calibration range for bergenin were 1. 44 × 10~(-7) - 1.92 × 10~(-6) mol · L~(-1) and 4. 18 × 10~(-5)-1.06×l0~(-4) mol · L~(-1) with a detection limit of 1.02 × 10~(-7) mol · L~(-1).The RSD(n = 10) for determination of bergenin sample were 4. 6% . This method was applied in the determination of bergenin in the real sample with satisfactory results.