Sweeney Scott F, Woehrle Gerd H, Hutchison James E
Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, Oregon 97403, USA.
J Am Chem Soc. 2006 Mar 15;128(10):3190-7. doi: 10.1021/ja0558241.
Purification and size-based separation of nanoparticles remain significant challenges in the preparation of well-defined materials for fundamental studies and applications. Diafiltration shows considerable potential for the efficient and convenient purification and size separation of water-soluble nanoparticles, allowing for the removal of small-molecule impurities and for the isolation of small nanoparticles from larger nanostructures in a single process. Herein, we report studies aimed at assessing the suitability of diafiltration for (i) the purification of water-soluble thiol-stabilized 3-nm gold nanoparticles, (ii) the separation of a bimodal distribution of nanoparticles into the corresponding fractions, and (iii) the separation of a polydisperse sample into fractions of differing mean core diameter. NMR, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) measurements demonstrate that diafiltration produces nanoparticles with a much higher degree of purity than is possible by dialysis or a combination of solvent washes, chromatography, and ultracentrifugation. UV-visible spectroscopic and transmission electron microscopic (TEM) analyses show that diafiltration offers the ability to separate nanoparticles of disparate core size. These results demonstrate the applicability of diafiltration for the rapid and green preparation of high-purity gold nanoparticle samples and the size separation of heterogeneous nanoparticle samples. They also suggest the development of novel diafiltration membranes specifically suited to high-resolution nanoparticle size separation.
在制备用于基础研究和应用的明确材料时，纳米颗粒的纯化和基于尺寸的分离仍然是重大挑战。渗滤在水溶性纳米颗粒的高效便捷纯化和尺寸分离方面显示出巨大潜力，能够在单一过程中去除小分子杂质，并从较大的纳米结构中分离出小的纳米颗粒。在此，我们报告旨在评估渗滤对于以下方面适用性的研究：（i）纯化水溶性硫醇稳定的3纳米金纳米颗粒；（ii）将纳米颗粒的双峰分布分离成相应的组分；（iii）将多分散样品分离成具有不同平均核心直径的组分。核磁共振（NMR）、热重分析（TGA）和X射线光电子能谱（XPS）测量表明，渗滤产生的纳米颗粒纯度比通过透析或溶剂洗涤、色谱和超速离心相结合的方法要高得多。紫外可见光谱和透射电子显微镜（TEM）分析表明，渗滤能够分离不同核心尺寸的纳米颗粒。这些结果证明了渗滤在快速绿色制备高纯度金纳米颗粒样品以及异质纳米颗粒样品尺寸分离方面的适用性。它们还表明需要开发特别适用于高分辨率纳米颗粒尺寸分离的新型渗滤膜。
