Flow field-flow fractionation (FlFFF) with inductively coupled plasma mass spectrometric (ICP-MS) detection was applied for estimating the hydrodynamic diameter of gold nanoparticles (AuNPs). Hydrodynamic diameters of AuNPs of the same core diameter but with different surface coatings were different because the coating agents and their properties were different. The challenge of this work is due to the fact that AuNPs with various types of surface coatings exhibited different interactions in the FlFFF channel, leading to different retention behaviors. Therefore, we are interested in finding suitable FlFFF conditions for estimating the hydrodynamic diameter of AuNPs with various types of electrostatic stabilizing agents [tannic acid (TA) and citrate (CT)] and steric stabilizing agents [polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), and branched polyethylene imine (BPEI)]. Different types of carrier liquids (DI water, 0.02% FL-70, 0.05% SDS, and 30 mM Tris buffer) and membrane materials [regenerated cellulose (RC) and polyethersulfone (PES) membranes] were investigated. Generally, FlFFF was applied for size characterization of nanoparticles based on FlFFF theory but the interactions between AuNPs and membrane affected the retention and the experimentally obtained hydrodynamic diameters of AuNPs from the FlFFF system. With DI water as a carrier liquid with RC or PES membranes, the hydrodynamic diameters of negatively charged particles (TA-, CT-, PVP-, and PEG-stabilized AuNPs) from FlFFF corresponded well with the hydrodynamic diameters from dynamic light scattering (DLS). Interestingly, it was possible to estimate hydrodynamic diameters of AuNPs in the mixture by using FlFFF whereas it was not possible with the use of DLS within the size range studied. This work summarized the possible interactions between AuNPs with various coating agents and membrane materials in different carrier liquids to give guidelines on the suitable conditions of FlFFF for further applications on AuNP hydrodynamic diameter estimation.

采用感应耦合等离子体质谱（ICP-MS）检测的流场流分级分离（FlFFF）来估算金纳米颗粒（AuNPs）的流体动力学直径。具有相同核心直径但具有不同表面涂层的AuNP的流体动力学直径不同，这是因为涂层剂及其性质不同。这项工作的挑战是由于以下事实：具有各种类型表面涂层的AuNP在FFFFF通道中表现出不同的相互作用，从而导致不同的保留行为。因此，我们有兴趣寻找合适的FlFFF条件，以估计具有各种类型的静电稳定剂[单宁酸（TA）和柠檬酸盐（CT）]和空间稳定剂[聚乙二醇（PEG），聚乙烯吡咯烷酮（PVP）的AuNP的流体动力学直径），和支链聚乙烯亚胺（BPEI）]。研究了不同类型的载液（去离子水，0.02％FL-70、0.05％SDS和30 mM Tris缓冲液）和膜材料[再生纤维素（RC）和聚醚砜（PES）膜]。通常，基于FFFFF理论，将FFFFF用于纳米粒子的尺寸表征，但是AuNPs与膜之间的相互作用会影响保留率以及从FlFFF系统中实验获得的AuNPs的流体力学直径。用去离子水作为带有RC或PES膜的载液，来自FlFFF的带负电粒子（TA-，CT-，PVP-和PEG稳定的AuNPs）的流体力学直径与动态光散射（DLS）的流体力学直径很好）。有趣的是，通过使用FFFFF可以估算混合物中AuNP的流体动力学直径，而在所研究的尺寸范围内使用DLS则不可能。这项工作总结了在不同载液中AuNP与各种包衣剂和膜材料之间可能的相互作用，从而为FlFFF的合适条件提供了指导，以进一步应用于AuNP流体动力学直径估算。