Johannes Gutenberg-Universität Mainz, Department of Chemistry, Duesbergweg 10-14, Mainz 55128, Germany.
Johannes Gutenberg-Universität Mainz, Department of Chemistry, Duesbergweg 10-14, Mainz 55128, Germany.
J Chromatogr A. 2021 Jan 25;1637:461840. doi: 10.1016/j.chroma.2020.461840. Epub 2021 Jan 4.
The investigation and subsequent understanding of the interactions of nanomaterials with components of their surrounding media is important to be able to evaluate both potential use cases as well as potential risks for human health and for the environment. To investigate such interactions, asymmetrical flow field-flow fractionation (AF4) is an interesting analytical tool. This statement grounds on the fact that interactions of the analyte with the membrane and with components of the eluent are crucial for the retention behavior of the analyte within the field-flow fractionation (FFF) channel. Therefore, the investigation of the retention behavior provides an insight in the nature of the interactions between analyte, membrane and eluent. Within this publication, the influence of the composition of the eluent on the retention behavior of aqueous dispersions of two model analytes is investigated. Eluents with different types of salts and surfactants and eluents with different salt concentrations were prepared and the influence of the composition of these eluents on the retention behavior of polystyrene and polyorganosiloxane particles was compared. Three main trends were observed: Elution times increase with increasing electrolyte concentration; when comparing different electrolyte anions, the retention time increases the more kosmotropic the anion is; when comparing different electrolyte cations, the retention order depends on the surfactant. Additional dynamic light scattering (DLS) measurements were conducted to verify that the differences in retention times are not caused by actual differences in particle size. Instead, the differences in elution time can be correlated with the concentration and with the chao-/kosmotropicity of the added electrolyte ions. Therefore, AF4 proves to be sensitive to subtile changes of interaction forces on the level of Coulomb and van der Waals forces. The experimentally gathered elution times were used to develop a model describing the retention behavior, based on an enhanced version of the standard AF4 model: By introducing particle-medium-membrane interactions in the standard AF4 model via the respective Hamaker constants, the calculation of retention times was possible. The congruence of the calculated with the experimental retention times confirmed the validity of the simulation.
研究纳米材料与周围介质成分的相互作用，并了解其相互作用，对于评估其潜在用途以及对人类健康和环境的潜在风险非常重要。为了研究这种相互作用，不对称流场分级（AF4）是一种很有前途的分析工具。这一说法的依据是，分析物与膜和洗脱液成分的相互作用对于分析物在流场分级（FFF）通道中的保留行为至关重要。因此，研究保留行为可以深入了解分析物、膜和洗脱液之间相互作用的本质。在本出版物中，研究了洗脱液组成对两种模型分析物水基分散体保留行为的影响。制备了具有不同类型盐和表面活性剂的洗脱液以及具有不同盐浓度的洗脱液，并比较了这些洗脱液组成对聚苯乙烯和聚有机硅氧烷颗粒保留行为的影响。观察到三个主要趋势：洗脱时间随电解质浓度的增加而增加；当比较不同的电解质阴离子时，保留时间随阴离子亲脂性的增加而增加；当比较不同的电解质阳离子时，保留顺序取决于表面活性剂。此外，还进行了动态光散射（DLS）测量，以验证保留时间的差异不是由颗粒实际粒径差异引起的。相反，洗脱时间的差异可以与添加的电解质离子的浓度和 chaotropic/kosmotropicity 相关。因此，AF4 证明对库仑和范德华力水平上相互作用力的细微变化很敏感。实验收集的洗脱时间用于开发一种描述保留行为的模型，该模型基于标准 AF4 模型的增强版本：通过在标准 AF4 模型中通过各自的 Hamaker 常数引入颗粒-介质-膜相互作用，可以计算保留时间。计算出的保留时间与实验保留时间的一致性证实了模拟的有效性。
