多壁碳纳米管过氧化氢酶电极的研制及其电化学性能研究

研究对比了将过氧化氢酶(CAT)固定在多壁碳纳米管(MWCNT)-Nafion膜中,制备MWCNT-Nafion/CAT电极的方法,发现固定在Nafion膜中的MWCNT能在CAT和玻碳电极之间有效地传递电子,能实现MWCNT修饰电极上CAT的直接电子转移.CV测定表明:在磷酸盐缓冲溶液中可得到一对过氧化氢酶辅基血红素Fe(III)/Fe(II)氧化还原峰,其峰电流随扫描速度(0.050~0.210 V/s)呈良好的线性关系,其氧化峰电位(Epa)、还原峰电位(Epc)、式量电位(E0)′均随着溶液的pH值增加而负移,且呈线性关系,但其斜率不同,表明CAT的电子传递过程中质子化作用不是简单过程.用计时电流法考察MWCNT-Nafion/CAT电极对H2O2的响应速度和检测灵敏度,结果良好,且实验表明,该电极于4℃保存20天后,其伏安响应仍能保持80%左右.

Multi-Wall Carbon Nanotubes-Nafion/Catalse Electrode's Preparation and Its Electrochemical Performance Research

The author studied and compared the method of fabricating the MWCNT-Nafion/CAT electrode through immobilizing catalase in the MWCNT-Nafion film,finding that MWCNT immobilized in Nafion film can effectively accelerate electron transfer between CAT and the surface of glassy carbon electrode(GCE) and realize direct electron transfer of CAT on the MWCNT modified electrode.The CV determination indicates that there is a pair of redox peaks of CAT accessorial group-hemachrome Fe(III)/Fe(II) in the phosphate buffer solution,their peaks current linearly increase while scan rates increasing and their cathodic peak potential,anodic peak potential and formal potential all shift linearly to negative direction with the increase of pH value,but their slopes are different.This indicates that proton action is not a simple process.The author saw out the MWCNT-Nafion/CAT electrode response speed and measuring sensitivity,and the experiment further indicates the enzyme electrode's voltammograms response still retains about 80% after conserved for 20 days at 4℃.