单壁碳纳米管和室温离子液体胶修饰电极

Single-Walled Carbon Nanotubes and Room Temperature Ionic Liquid Composite Film Modified Electrode

短单壁碳纳米管(S-SWNTs)与疏水性室温离子液体(RTIL)1-丁基-3-甲基咪唑六氟磷酸盐(BMIMPF6)以质量比1∶1研成胶,修饰在玻碳电极(GCE)上制备S-SWNT&RTIL/GCE.以铁氰化钾、抗坏血酸(AA)和亚甲基蓝(MB)为电化学探针,用伏安法表征.结果表明,该修饰电极具有优异的电催化性能和富集效应.以B-R缓冲溶液为支持电解液,单链鲱鱼精脱氧核糖核酸(ssDNA)在S-SWNT&RTIL/GCE上具有灵敏的伏安响应,于0.532和0.808V处分别出现鸟嘌呤碱基和腺嘌呤碱基的氧化峰.鸟嘌呤碱基和腺嘌呤碱基在S-SWNT&RTIL/GCE上的电极反应标准速率常数ks′分别为1.84×10-2和3.69×10-2s-1.在最佳条件下,应用微分脉冲伏安法检测,鸟嘌呤碱基的氧化峰电流与ssDNA的浓度在40μg·L-1-5.0mg·L-1范围内呈现良好的线性关系,检测限为5μg·L-1(S/N=3,信噪比).

A gel-like paste was made by mixing 1：1 （w/w） carboxylic group-fanctionalized short single-walled carbon nanotubes （S-SWNTs） and a kind of room temperature ionic liquid （RTIL）, 1-butyl-3-methylimidazolium hexafluorophosphate （BMIMPF6）. The composite film was modified on the glassy carbon electrode （GCE） to prepare the S-SWNT＆RTIL/GCE. The modified electrode showed an attractive electrocatalytic ability and could enhance the current response of electro-active molecules by employing potassium ferricyanide, ascorbic acid and methylene blue as probes. In the B-R buffer solution, ssDNA had a sensitive voltammetric response at the S-SWNT＆RTIL/GCE and the oxidative peak potentials of guanine base and adenine base were 0.532 and 0.808 V, respectively. The mechanism of electrode reaction was studied and the results showed that the heterogeneous electron transfer rate constants （ks＇） for the two bases were 1.84×10^-2 and 3.69×10^-2 s^-1, respectively. Under the optimal conditions, the differential pulse voltammetdc peak current of guanine base vs the concentration of ssDNA was linear in the range of 40 μg·L^-1-5.0 mg·L^-1 with a detection limit of 5 μg·L^-1 （S/N=3, signal/noise）.