Department of Chemistry, Hong Kong Baptist University, 224 Waterloo Road, Kowloon Tong, Hong Kong SAR, China.
J Chromatogr A. 2009 Nov 27;1216(48):8557-62. doi: 10.1016/j.chroma.2009.10.013. Epub 2009 Oct 12.
Capillary zone electrophoresis (CZE) has been employed to characterize nanometer-sized thiolated alpha-cyclodextrin-capped gold nanoparticles (alpha-CD-S-AuNPs). The addition of tetrabutylammonium (Bu(4)N(+)) ions to the run buffer greatly narrows the migration peak of alpha-CD-S-AuNP. The optimal run buffer was determined to be 10mM Bu(4)N(+) in 30 mM phosphate buffer at pH 12 and an applied voltage of 15 kV. The effect of various tetraalkylammonium ions on the peak width and electrophoretic mobility (mu(e)) of alpha-CD-S-AuNP was studied in detail. Bu(4)N(+) ions assist in inter-linking the alpha-CD-S-AuNPs and narrowing the migration peak in CZE. This observation can be explained by the fact that each Bu(4)N(+) ion can simultaneously interact with several hydrophobic cavities of the surface-attached alpha-CDs on AuNPs. The TEM images show that alpha-CD-S-AuNPs with Bu(4)N(+) are linked together but in the absence of Bu(4)N(+), they are more dispersed. The migration mechanism in CZE is based on the formation of inclusion complexes between Bu(4)N(+) and alpha-CD-S-AuNPs which induces changes in the charge-to-size ratio of alpha-CD-S-AuNPs and mu(e). An inverse linear relationship (r(2)>0.998) exists between the mu(e) and size of alpha-CD-S-AuNPs in the core range 1.4-4.1 nm. The CZE analyses are rapid with migration time less than 4 min. A few nanoliters of each of the alpha-CD-S-AuNP samples were injected hydrodynamically at 0.5 psi for 5s. Our work confirms that CZE is an efficient tool for characterizing the sizes of alpha-CD-S-AuNPs using Bu(4)N(+) ions.
毛细管区带电泳 (CZE) 已被用于表征纳米级巯基化α-环糊精包裹的金纳米粒子 (α-CD-S-AuNPs)。在运行缓冲液中加入四丁基铵 (Bu(4)N(+)) 离子会极大地缩窄 α-CD-S-AuNP 的迁移峰。确定最佳运行缓冲液为 10mM Bu(4)N(+) 在 30mM 磷酸盐缓冲液 pH 12 和 15kV 的应用电压。详细研究了各种四烷基铵离子对 α-CD-S-AuNP 峰宽和电泳迁移率 (μ(e)) 的影响。Bu(4)N(+) 离子有助于连接 α-CD-S-AuNP 并缩窄 CZE 中的迁移峰。这一观察结果可以解释为每个 Bu(4)N(+) 离子可以同时与 AuNP 表面附着的α-CD 的几个疏水性腔相互作用。TEM 图像显示，带 Bu(4)N(+)的α-CD-S-AuNP 连接在一起，但在没有 Bu(4)N(+)的情况下，它们更加分散。CZE 中的迁移机制基于 Bu(4)N(+)与 α-CD-S-AuNP 之间形成包合复合物，这导致 α-CD-S-AuNP 的电荷-大小比和 μ(e)发生变化。μ(e)与核心范围 1.4-4.1nm 内 α-CD-S-AuNP 的大小之间存在反比线性关系 (r(2)>0.998)。CZE 分析快速，迁移时间小于 4 分钟。通过在 0.5psi 下以 5s 的时间水力注射每种 α-CD-S-AuNP 样品数纳升。我们的工作证实，CZE 是使用 Bu(4)N(+) 离子表征 α-CD-S-AuNP 大小的有效工具。
