標題: | Size-fractionation of silver nanoparticles using ion-pair extraction in a counter-current chromatograph |
作者: | Shen, Ching-Wei Yu, Tiing 應用化學系 Department of Applied Chemistry |
關鍵字: | Counter-current chromatography;Silver nanoparticles;Size separation;Ion-pair;Phase transfer;Step-gradient extraction |
公開日期: | 7-八月-2009 |
摘要: | Size separation of silver nanoparticles was investigated in counter-current chromatography (CCC) based on a unique step-gradient extraction process. Carboxylate anions were modified on silver nanoparticles to produce water-dispersible nanoparticles. The aqueous nanoparticles were readily transferred to the organic phase (toluene/hexane = 1: 1, v/v) together with the phase transfer catalyst, tetraoctylammonium bromide (TOAB), owing to the ion-pair adduct formation between silver nanoparticle anions and tetraoctylammonium cations. Smaller nanoparticles were found to be more readily transferred to the organic phase compared to larger nanoparticles. Various concentrations of TOAB in the organic elution phase were used in the CCC extraction experiments. it appeared that a concentration of 0.02 mM of TOAB was adequate to achieve optimum separation and recovery for the aqueous Ag nanoparticle sample (1.5 mg) in the CCC extraction experiments. Samples of 15.8 +/- 5.3 nm were separated; the distributions of four fractions collected were 13.7 +/- 1.9, 14.1 +/- 3.5, 19.2 +/- 4.3, and 22.2 +/- 4.9 turn. Compared with the step-wise extraction performed in this study, the step-gradient extractions using CCC provided much better size discrimination. (C) 2009 Elsevier B.V. All rights reserved. |
URI: | http://dx.doi.org/10.1016/j.chroma.2009.06.002 http://hdl.handle.net/11536/6827 |
ISSN: | 0021-9673 |
DOI: | 10.1016/j.chroma.2009.06.002 |
期刊: | JOURNAL OF CHROMATOGRAPHY A |
Volume: | 1216 |
Issue: | 32 |
起始頁: | 5962 |
結束頁: | 5967 |
顯示於類別: | 期刊論文 |