Johnson Monique E, Montoro Bustos Antonio R, Winchester Michael R
Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899-8391, USA.
Anal Bioanal Chem. 2016 Nov;408(27):7629-7640. doi: 10.1007/s00216-016-9844-x. Epub 2016 Aug 8.
Single particle inductively coupled plasma mass spectrometry (spICP-MS) is shown to be a practical technique to study the efficacy of rate-zonal sucrose density gradient centrifugation (SDGC) separations of mixtures of gold nanoparticles (AuNPs) in liquid suspension. spICP-MS enabled measurements of AuNP size distributions and particle number concentrations along the gradient, allowing unambiguous evaluations of the effectiveness of the separation. Importantly, these studies were conducted using AuNP concentrations that are directly relevant to environmental studies (sub ng mL). At such low concentrations, other techniques [e.g., dynamic light scattering (DLS), transmission and scanning electron microscopies (TEM and SEM), UV-vis spectroscopy, atomic force microscopy (AFM)] do not have adequate sensitivity, highlighting the inherent value of spICP-MS for this and similar applications. In terms of the SDGC separations, a mixture containing three populations of AuNPs, having mean diameters of 30, 80, and 150 nm, was fully separated, while separations of two other mixtures (30, 60, 100 nm; and 20, 50, 100 nm) were less successful. Finally, it is shown that the separation capacity of SDGC can be overwhelmed when particle number concentrations are excessive, an especially relevant finding in view of common methodologies taken in nanotechnology research. Graphical Abstract Characterization of the separation of a gold nanoparticle mixture by sucrose density gradient centrifugation by conventional and single particle ICP-MS analysis.
单颗粒电感耦合等离子体质谱法（spICP-MS）被证明是一种实用技术，可用于研究速率区带蔗糖密度梯度离心法（SDGC）对液体悬浮液中金纳米颗粒（AuNP）混合物的分离效果。spICP-MS能够测量沿梯度方向的AuNP尺寸分布和颗粒数浓度，从而对分离效果进行明确评估。重要的是，这些研究使用的AuNP浓度与环境研究直接相关（低于纳克/毫升）。在如此低的浓度下，其他技术[如动态光散射（DLS）、透射和扫描电子显微镜（TEM和SEM）、紫外可见光谱、原子力显微镜（AFM）]灵敏度不足，凸显了spICP-MS在此类及类似应用中的固有价值。就SDGC分离而言，一种包含三种平均直径分别为30、80和150纳米的AuNP群体的混合物被完全分离，而另外两种混合物（30、60、100纳米；以及20、50、100纳米）的分离效果较差。最后，研究表明，当颗粒数浓度过高时，SDGC的分离能力可能会不堪重负，鉴于纳米技术研究中常用的方法，这是一个特别相关的发现。图形摘要 通过传统方法和单颗粒ICP-MS分析对蔗糖密度梯度离心法分离金纳米颗粒混合物的表征。
