Voltammetric determination of Cd2+ based on the bifunctionality of single-walled carbon nanotubes-Nafion film.
Voltammetric determination of Cd2+ based on the bifunctionality of single-walled carbon nanotubes-Nafion film.
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DOI：
10.1016/j.aca.2006.08.013
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发表时间：
2007-01
影响因子：
6.2
通讯作者：
Dong Sun;X. Xie;Yuepiao Cai;Huajie Zhang;Kangbing Wu
中科院分区：
文献类型：
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作者：
Dong Sun;X. Xie;Yuepiao Cai;Huajie Zhang;Kangbing Wu
在Nafion存在下，单壁碳纳米管（SWNTs）很容易分散到乙醇中，得到均匀的SWNTs/Nafion悬浮液。蒸发乙醇后，在玻碳电极（GCE）表面制备了具有双功能性的单壁碳纳米管/全氟磺酸（SWNTs/Nafion）膜。由于Nafion强的阳离子交换能力和单壁碳纳米管的优良性能，单壁碳纳米管/Nafion膜修饰的GCE显着提高了Cd 2+的测定灵敏度。在此基础上，建立了阳极溶出伏安法测定痕量镉的电化学方法。在pH5.0的NaAc-HAc缓冲溶液中，Cd 2+首先被交换吸附到单壁碳纳米管/Nafion膜表面，然后在-1.10V电压下被还原。在正电位扫描过程中，还原态镉被氧化，在−0.84V处出现一个清晰的溶出峰，可作为镉离子的分析信号。线性范围为4.0×10 - 8 ~ 4.0×10 - 6 molL-1，最低检测浓度为4.0×10 - 9 molL-1。最后将该方法成功地应用于水样中Cd 2+的测定。
In the presence of Nafion, single-walled carbon nanotubes (SWNTs) were easily dispersed into ethanol, resulting in a homogeneous SWNTs/Nafion suspension. After evaporating ethanol, a SWNTs/Nafion film with bifunctionality was constructed onto glassy carbon electrode (GCE) surface. Attributing to the strong cation-exchange ability of Nafion and excellent properties of SWNTs, the SWNTs/Nafion film-coated GCE remarkably enhances the sensitivity of determination of Cd2+. Based on this, an electrochemical method was developed for the determination of trace levels of Cd2+by anodic stripping voltammetry (ASV). In pH 5.0 NaAc–HAc buffer, Cd2+was firstly exchanged and adsorbed onto SWNTs/Nafion film surface, and then reduce at −1.10V. During the positive potential sweep, reduced cadmium was oxidized, and a well-defined stripping peak appeared at −0.84V, which can be used as analytical signal for Cd2+. The linear range is found to be from 4.0×10−8to 4.0×10−6molL−1, and the lowest detectable concentration is estimated to be 4.0×10−9molL−1. Finally, this method was successfully employed to detect Cd2+in water samples.