Banks Craig E, Compton Richard G
Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, UKOX1 3QZ.
Analyst. 2005 Sep;130(9):1232-9. doi: 10.1039/b508702c. Epub 2005 Aug 1.
The electrocatalytic properties of multi-walled carbon nanotube modified electrodes toward the oxidation of NADH are critically evaluated. Carbon nanotube modified electrodes are examined and compared with boron-doped diamond and glassy carbon electrodes, and most importantly, edge plane and basal pyrolytic graphite electrodes. It is found that CNT modified electrodes are no more reactive than edge plane pyrolytic graphite electrodes with the comparison with edge plane and basal plane pyrolytic graphite electrodes allowing the electroactive sites for the electrochemical oxidation of NADH to be unambiguously determined as due to edge plane sites. Using these highly reactive edge plane sites, edge plane pyrolytic graphite electrodes are examined with cyclic voltammetry and amperometry for the electroanalytical determination of NADH. It is demonstrated that a detection limit of 5 microM is possible with cyclic voltammetry or 0.3 microM using amperometry suggesting that edge plane pyrolytic graphite electrodes can conveniently replace carbon nanotube modified glassy carbon electrodes for biosensing applications with the relative advantages of reactivity, cost and simplicity of preparation. We advocate the routine use of edge plane and basal plane pyrolytic graphite electrodes in studies utilising carbon nanotubes particularly if 'electrocatalytic' properties are claimed for the latter.
对多壁碳纳米管修饰电极对NADH氧化的电催化性能进行了严格评估。研究了碳纳米管修饰电极，并将其与硼掺杂金刚石电极和玻碳电极进行比较，最重要的是，与边缘平面热解石墨电极和基底热解石墨电极进行比较。通过与边缘平面和基底平面热解石墨电极比较发现，碳纳米管修饰电极的反应活性并不高于边缘平面热解石墨电极，这使得NADH电化学氧化的电活性位点明确确定为边缘平面位点。利用这些高反应活性的边缘平面位点，采用循环伏安法和安培法对边缘平面热解石墨电极进行了NADH的电分析测定。结果表明，循环伏安法的检测限为5 microM，安培法的检测限为0.3 microM，这表明边缘平面热解石墨电极在生物传感应用中可以方便地替代碳纳米管修饰的玻碳电极，具有反应活性、成本和制备简单等相对优势。我们主张在利用碳纳米管的研究中常规使用边缘平面和基底平面热解石墨电极，特别是当声称后者具有“电催化”性能时。
