Pitkänen Leena, Montoro Bustos Antonio R, Murphy Karen E, Winchester Michael R, Striegel André M
Chemical Sciences Division, National Institute of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, MD 20899, USA.
Chemical Sciences Division, National Institute of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, MD 20899, USA.
J Chromatogr A. 2017 Aug 18;1511:59-67. doi: 10.1016/j.chroma.2017.06.064. Epub 2017 Jun 27.
The physicochemical characterization of nanoparticles (NPs) is of paramount importance for tailoring and optimizing the properties of these materials as well as for evaluating the environmental fate and impact of the NPs. Characterizing the size and chemical identity of disperse NP sample populations can be accomplished by coupling size-based separation methods to physical and chemical detection methods. Informed decisions regarding the NPs can only be made, however, if the separations themselves are quantitative, i.e., if all or most of the analyte elutes from the column within the course of the experiment. We undertake here the size-exclusion chromatographic characterization of Au NPs spanning a six-fold range in mean size. The main problem which has plagued the size-exclusion chromatography (SEC) analysis of Au NPs, namely lack of quantitation accountability due to generally poor NP recovery from the columns, is overcome by carefully matching eluent formulation with the appropriate stationary phase chemistry, and by the use of on-line inductively coupled plasma mass spectrometry (ICP-MS) detection. Here, for the first time, we demonstrate the quantitative analysis of Au NPs by SEC/ICP-MS, including the analysis of a ternary NP blend. The SEC separations are contrasted to HDC/ICP-MS (HDC: hydrodynamic chromatography) separations employing the same stationary phase chemistry. Additionally, analysis of Au NPs by HDC with on-line quasi-elastic light scattering (QELS) allowed for continuous determination of NP size across the chromatographic profiles, circumventing issues related to the shedding of fines from the SEC columns. The use of chemically homogeneous reference materials with well-defined size range allowed for better assessment of the accuracy and precision of the analyses, and for a more direct interpretation of results, than would be possible employing less rigorously characterized analytes.
纳米颗粒（NPs）的物理化学特性对于定制和优化这些材料的性能以及评估NPs的环境归宿和影响至关重要。通过将基于尺寸的分离方法与物理和化学检测方法相结合，可以实现对分散NP样品群体的尺寸和化学特性进行表征。然而，只有当分离本身是定量的，即在实验过程中所有或大部分分析物从柱中洗脱出来时，才能就NPs做出明智的决策。我们在此对平均尺寸跨度为六倍的金纳米颗粒进行尺寸排阻色谱表征。困扰金纳米颗粒尺寸排阻色谱（SEC）分析的主要问题，即由于通常从柱中回收的NP较差而缺乏定量 accountability，通过仔细匹配洗脱液配方与合适的固定相化学性质以及使用在线电感耦合等离子体质谱（ICP-MS）检测得以克服。在此，我们首次展示了通过SEC/ICP-MS对金纳米颗粒进行定量分析，包括对三元NP混合物的分析。将SEC分离与采用相同固定相化学性质的HDC/ICP-MS（HDC：流体动力学色谱）分离进行了对比。此外，通过HDC结合在线准弹性光散射（QELS）对金纳米颗粒进行分析，可以在整个色谱图上连续测定NP尺寸，避免了与SEC柱中细粉脱落相关的问题。与使用表征不够严格的分析物相比，使用具有明确尺寸范围的化学均匀参考材料能够更好地评估分析的准确性和精密度，并更直接地解释结果。
