Voltammetric determination of Cd2+ based on the bifunctionality of single-walled carbon nanotubes-Nafion film.
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 Cd(2+). Based on this, an electrochemical method was developed for the determination of trace levels of Cd(2+) by anodic stripping voltammetry (ASV). In pH 5.0 NaAc-HAc buffer, Cd(2+) was firstly exchanged and adsorbed onto SWNTs/Nafion film surface, and then reduce at -1.10 V. During the positive potential sweep, reduced cadmium was oxidized, and a well-defined stripping peak appeared at -0.84 V, which can be used as analytical signal for Cd(2+). The linear range is found to be from 4.0 x 10(-8) to 4.0 x 10(-6) mol L(-1), and the lowest detectable concentration is estimated to be 4.0 x 10(-9) mol L(-1). Finally, this method was successfully employed to detect Cd(2+) in water samples.
Sun
Dong
D
Department of Pharmacy, Wenzhou Medical College, Wenzhou 325000, PR China. sun_dong11@163.com <sun_dong11@163.com>
Xie
Xiafeng
X
Cai
Yuepiao
Y
Zhang
Huajie
H
Wu
Kangbing
K
D002104:Cadmium / Q000032:analysis* / Q000737:chemistry; D004563:Electrochemistry; D005465:Fluorocarbon Polymers / Q000032:analysis* / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000032:analysis* / Q000737:chemistry
D005465:Fluorocarbon Polymers; D037742:Nanotubes, Carbon; D002104:Cadmium; C040402:perfluorosulfonic acid