Electrochemical quartz crystal impedance study on the overoxidation of polypyrrole-carbon nanotubes composite film for amperometric detection of dopamine.
Electrochemical quartz crystal impedance study on the overoxidation of polypyrrole-carbon nanotubes composite film for amperometric detection of dopamine.
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DOI：
10.1016/j.bios.2006.11.022
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发表时间：
2007-06
影响因子：
12.6
通讯作者：
Xinman Tu;Q. Xie;Shiyue Jiang;S. Yao
中科院分区：
文献类型：
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作者：
Xinman Tu;Q. Xie;Shiyue Jiang;S. Yao
采用电化学石英晶体阻抗（EQCI）方法研究了聚吡咯（PPy）-多壁碳纳米管（MWCNT）纳米复合薄膜在中性和碱性溶液中的过氧化情况。 PPy 在 0.10molL−1Na2SO4 和 0.20molL−1NaOH 水溶液中过氧化过程中获得的每个电子转移的摩尔质量 (M/n) 值估计为约。分别为 17 和 22gmol−1，表明在过度氧化过程中溶液 OH− 对吡咯单元的亲核攻击，以及在 NaOH 溶液中过度氧化后可能部分形成羧基。此外，在 NaOH 溶液中制备的过氧化 PPy-MWCNT 复合膜对溶解在中性磷酸盐缓冲液中的多巴胺 (DA) 的亲和力明显高于在 Na2SO4 溶液中制备的膜。与单独修饰过氧化PPy或MWCNT相比，过氧化纳米复合膜的修饰显着提高了中性磷酸盐缓冲液中DA测定的灵敏度。在含有 1.0mgmL−1MWCNT 的聚合浴中制备并在 0.20molL−1 NaOH 溶液中过氧化的 -6kHz（201 nm 厚）纳米复合膜中，DA 的差分脉冲伏安测定的峰值电流响应与 DA 浓度从 4.0×10−8 到 1.4×10−6molL−1 呈线性关系，检测下限为 1.7nmolL−1，良好的抗干扰能力，以及良好的稳定性和重现性。
The electrochemical quartz crystal impedance (EQCI) method was used to study the overoxidation of polypyrrole (PPy)–multiwalled carbon nanotubes (MWCNT) nanocomposite film in neutral and alkaline solutions. The values of molar mass per electron transferred (M/n) obtained during the overoxidation of PPy in 0.10molL−1Na2SO4and 0.20molL−1NaOH aqueous solutions were estimated to be ca. 17 and 22gmol−1, respectively, suggesting the nucleophilic attack of solution OH−to the pyrrole units during the overoxidation, and the possible partial formation of carboxylic groups after the overoxidation in the NaOH solution. Also, the overoxidized PPy–MWCNT composite film prepared in the NaOH solution showed a notably larger affinity to dopamine (DA) dissolved in a neutral phosphate buffer than that prepared in the Na2SO4solution. The modification of the overoxidized nanocomposite film improved substantially the sensitivity for DA assay in a neutral phosphate buffer, as compared with the modification of overoxidized PPy or MWCNT alone. At a −6kHz (201-nm thickness) nanocomposite film prepared in a polymerization bath containing 1.0mgmL−1MWCNT and overoxidized in 0.20molL−1aqueous NaOH, the peak current response from differential pulse voltammetric assay of DA was linear with DA concentration from 4.0×10−8to 1.4×10−6molL−1, with a lower limit of detection of 1.7nmolL−1, good anti-interferent ability, as well as good stability and reproducibility.