Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt Institute for Integrative Biosystems Research and Education, and Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University, 7330 Stevenson Center, Nashville, Tennessee 37235, United States.
Anal Chem. 2010 Nov 15;82(22):9268-74. doi: 10.1021/ac102175z. Epub 2010 Oct 22.
It is becoming increasingly common to use gold nanoparticles (AuNPs) protected by a heterogeneous mixture of thiolate ligands, but many ligand mixtures on AuNPs cannot be properly characterized due to the inherent limitations of commonly used spectroscopic techniques. Using ion mobility-mass spectrometry (IM-MS), we have developed a strategy that allows measurement of the relative quantity of ligands on AuNP surfaces. This strategy is used for the characterization of three samples of mixed-ligand AuNPs: tiopronin:glutathione (av diameter 2.5 nm), octanethiol:decanethiol (av diameter 3.6 nm), and tiopronin:11-mercaptoundecyl(poly ethylene glycol) (av diameter 2.5 nm). For validation purposes, the results obtained for tiopronin:glutathione AuNPs were compared to parallel measurements using nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) without ion mobility separation. Relative quantitation measurements for NMR and IM-MS were in excellent agreement, with an average difference of less than 1% relative abundance. IM-MS and MS without ion mobility separation were not comparable, due to a lack of ion signals for MS. The other two mixed-ligand AuNPs provide examples of measurements that cannot be performed using NMR spectroscopy.
使用由硫醇配体的不均匀混合物保护的金纳米粒子（AuNPs）变得越来越普遍，但由于常用光谱技术的固有局限性，许多 AuNP 上的配体混合物无法得到适当的表征。我们使用离子淌度-质谱（IM-MS）开发了一种策略，该策略允许测量 AuNP 表面上配体的相对数量。该策略用于表征三种混合配体 AuNP 样品：巯基丙氨酸：谷胱甘肽（平均直径 2.5nm）、辛硫醇：十一硫醇（平均直径 3.6nm）和巯基丙氨酸：十一巯基聚乙二醇（平均直径 2.5nm）。为了验证目的，将获得的巯基丙氨酸：谷胱甘肽 AuNP 的结果与使用核磁共振（NMR）光谱和没有离子淌度分离的质谱（MS）进行的平行测量进行了比较。NMR 和 IM-MS 的相对定量测量非常吻合，相对丰度的平均差异小于 1%。由于缺乏 MS 的离子信号，IM-MS 和没有离子淌度分离的 MS 不可比。另外两种混合配体 AuNP 提供了无法使用 NMR 光谱进行测量的示例。
