| Authors: | Wang, T.; Zhao, D.; Guo, X.; Correa, J.; Riehl, B. L.; Heineman, W. R. |
| Title: | Carbon nanotube-loaded Nafion film electrochemical sensor for metal ions: europium |
| Type: | Journal Article |
| Publisher: | Analytical Chemistry |
| Year: | 2014 |
| Volume: | 86 |
| Issue: | 9 |
| Start Page: | 4354 |
| End Page: | 4361 |
| DOI: | 10.1021/ac500163f |
| WEB-link: | http://pubs.acs.org/doi/pdfplus/10.1021/ac500163f |
| Abstract: | A Nafion film loaded with novel catalyst-free multiwalled carbon nanotubes (MWCNTs) was used to modify a glassy carbon (GC) electrode to detect trace concentrations of metal ions, with europium ion (Eu(3+)) as a model. The interaction between the sidewalls of MWCNTs and the hydrophobic backbone of Nafion allows the MWCNTs to be dispersed in Nafion, which was then coated as a thin film on the GC electrode surface. The electrochemical response to Eu(3+) was found to be approximately 10 times improved by MWCNT concentrations between 0.5 and 2 mg/mL, which effectively expanded the electrode surface into the Nafion film and thereby reduced the diffusion distance of Eu(3+) to the electrode surface. At low MWCNT concentrations of 0.25 and 0.5 mg/mL, no significant improvement in signal was obtained compared with Nafion alone. Scanning electron microscopy and electrochemical impedance spectroscopy were used to characterize the structure of the MWCNT-Nafion film, followed by electrochemical characterization with Eu(3+) via cyclic voltammetry and preconcentration voltammetry. Under the optimized conditions, a linear range of 1-100 nM with a calculated detection limit of 0.37 nM (signal/noise = 3) was obtained for determination of Eu(3+) by Osteryoung square-wave voltammetry after a preconcentration time of 480 s. |
