The possibility of separating mixtures of Ag nanoparticles (NPs) with similar sizes but different surface coatings using capillary electrophoresis coupled to single particle inductively coupled mass-spectrometry (CE-SP-ICP-MS) was investigated. In two-component mixtures, it was possible to separate 40 nm sized polyvinylpirrolidone (PVP)- and citrate-coated NPs, 40 nm sized polyethylene glycol (PEG)- and citrate-coated NPs, and 60 nm sized PVP- and citrate-coated NPs. The separation of a more complex mixture containing NPs with the different coatings and sizes was successful, and each component, namely, 20, 40, and 60 nm sized citrate-coated and 40 and 60 nm sized PVP-coated NPs, could be distinguished. The theoretically expected migration order was confirmed by experimental results with selected Ag NPs. On the basis of the experimental observations, a separation mechanism that considers the effect of stable vs displaceable coatings during NP migration in CE is suggested. The ICP-MS was equipped with a prototype data acquisition system (μsDAQ) that provided 5 μs time resolution.

中文翻译：

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毛细管电泳-ICP-MS分离单涂层分离具有不同涂层的银纳米颗粒

研究了使用毛细管电泳与单颗粒电感耦合质谱法（CE-SP-ICP-MS）分离大小相似但表面涂层不同的Ag纳米颗粒（NPs）混合物的可能性。在两组分混合物中，可以分离出40 nm大小的聚乙烯吡咯烷酮（PVP）和柠檬酸盐涂层的NP，40 nm大小的聚乙二醇（PEG）和柠檬酸盐涂层的NP，以及60 nm大小的PVP和柠檬酸盐的涂层NP。成功地分离了具有不同涂层和尺寸的含NP的更复杂的混合物，并且可以区分每种组分，即20、40和60 nm大小的柠檬酸盐涂层和40和60 nm尺寸的PVP涂层NP。通过选择Ag NP的实验结果证实了理论上预期的迁移顺序。根据实验观察结果，提出了一种分离机制，该机制考虑了CE中NP迁移过程中稳定涂层与可置换涂层的影响。ICP-MS配备了原型数据采集系统（μsDAQ），可提供5 s的时间分辨率。