The development of reliable protocols suitable for the characterisation of the physical properties of nanoparticles in suspension is becoming crucial to assess the potential biological as well as toxicological impact of nanoparticles. Amongst sizing techniques, asymmetric flow field flow fractionation (AF4) coupled to online size detectors represents one of the most robust and flexible options to quantify the particle size distribution in suspension. However, size measurement uncertainties have been reported for on-line dynamic light scattering (DLS) detectors when coupled to AF4 systems. In this work we investigated the influence of the initial concentration of nanoparticles in suspension on the sizing capability of the asymmetric flow field-flow fractionation technique coupled with an on-line dynamic light scattering detector and a UV–Visible spectrophotometer (UV) detector. Experiments were performed with suspensions of gold nanoparticles with a nominal diameter of 40 nm and 60 nm at a range of particle concentrations. The results obtained demonstrate that at low concentration of nanoparticles, the AF4-DLS combined technique fails to evaluate the real size of nanoparticles in suspension, detecting an apparent and progressive size increase as a function of the elution time and of the concentration of nanoparticles in suspension.

中文翻译：

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通过不对称流场分级结合在线动态光散射表征纳米颗粒尺寸的局限性

开发适用于表征悬浮纳米粒子物理特性的可靠协议对于评估纳米粒子的潜在生物学和毒理学影响变得至关重要。在分级技术中，不对称流场流分馏 (AF4) 与在线粒度检测器相结合，是量化悬浮液中粒度分布的最可靠和灵活的选项之一。然而，当与 AF4 系统耦合时，在线动态光散射 (DLS) 检测器的尺寸测量不确定性已有报道。在这项工作中，我们研究了悬浮液中纳米粒子的初始浓度对不对称流场-流动分级技术结合在线动态光散射检测器和紫外-可见分光光度计 (UV) 检测器的分级能力的影响。使用标称直径为 40 nm 和 60 nm 的金纳米颗粒悬浮液在一系列颗粒浓度下进行实验。获得的结果表明，在低纳米粒子浓度下，AF4-DLS 组合技术无法评估悬浮液中纳米粒子的真实尺寸，检测到作为洗脱时间和悬浮液中纳米粒子浓度的函数的明显和渐进的尺寸增加. 使用标称直径为 40 nm 和 60 nm 的金纳米颗粒悬浮液在一系列颗粒浓度下进行实验。获得的结果表明，在低纳米粒子浓度下，AF4-DLS 组合技术无法评估悬浮液中纳米粒子的真实尺寸，检测到作为洗脱时间和悬浮液中纳米粒子浓度的函数的明显和渐进的尺寸增加. 使用标称直径为 40 nm 和 60 nm 的金纳米粒子悬浮液在一系列粒子浓度下进行实验。获得的结果表明，在低纳米粒子浓度下，AF4-DLS 组合技术无法评估悬浮液中纳米粒子的真实尺寸，检测到作为洗脱时间和悬浮液中纳米粒子浓度的函数的明显和渐进的尺寸增加.