The Atomic Medicine Initiative, University of Technology Sydney, 15 Broadway, 2007 Ultimo, NSW, Australia.
Institute for Biomedical Materials and Devices, Faculty of Science, University of Technology Sydney, 15 Broadway, 2007 Ultimo, NSW, Australia.
Anal Chem. 2020 Nov 17;92(22):15007-15016. doi: 10.1021/acs.analchem.0c02925. Epub 2020 Nov 2.
This work introduces new methods to characterize dispersions of small-diameter or low-mass-fraction nanoparticles (NPs) by single-particle inductively coupled plasma-mass spectrometry (SP ICP-MS). The optimization of ion extraction, ion transport, and the operation of the quadrupole with increased mass bandwidth improved the signal-to-noise ratios significantly and decreased the size detection limits for all NP dispersions investigated. As a model system, 10.9 ± 1.0 nm Au NPs were analyzed to demonstrate the effects of increasing ion transmission. Specifically, increasing the mass bandwidth of the quadrupole improved the size detection limit to 4.2 nm and enabled the resolution of NP signals from ionic background and noise. Subsequently, the methods were applied to the characterization of lanthanide-doped upconversion nanoparticles (UCNPs) by SP ICP-MS. Three different types of UCNPs (90 nm NaYF: 20% Yb, 2% Er; 20 nm NaGdF: 20% Yb, 1% Er; 15 nm NaYF: 20% Yb, 2% Er) were investigated. Y showed the best signal-to-noise ratios with optimized ion extraction and transport parameters only, whereas the signal-to-noise ratios of Gd, Er, and Yb were further improved by increasing the mass bandwidth of a quadrupole mass filter. The novel methods were suitable for detailed characterization of diluted UCNP dispersions including particle stoichiometries and size distributions. A Poisson model was further applied to assess particle-particle interactions in the aqueous dispersions. The methods have considerable potential for the characterization of small-diameter and/or low-mass-fraction nanoparticles.
这项工作介绍了通过单颗粒电感耦合等离子体质谱（SP ICP-MS）来描述小直径或低质量分数纳米颗粒（NPs）分散体的新方法。优化离子提取、离子传输和四极杆的操作，增加质量带宽，显著提高了信噪比，并降低了所有研究的 NP 分散体的尺寸检测极限。作为模型系统，分析了 10.9 ± 1.0nm 的 Au NPs，以证明增加离子传输的效果。具体来说，增加四极杆的质量带宽将尺寸检测极限提高到 4.2nm，并能够分辨 NP 信号与离子背景和噪声。随后，该方法应用于 SP ICP-MS 对镧系掺杂上转换纳米颗粒（UCNPs）的表征。研究了三种不同类型的 UCNPs（90nm NaYF：20%Yb，2%Er；20nm NaGdF：20%Yb，1%Er；15nm NaYF：20%Yb，2%Er）。仅优化离子提取和传输参数时，Y 表现出最佳的信噪比，而 Gd、Er 和 Yb 的信噪比通过增加四极杆质量滤波器的质量带宽进一步提高。这些新方法适用于稀释 UCNP 分散体的详细表征，包括粒子化学计量和尺寸分布。进一步应用泊松模型来评估水相分散体中粒子-粒子相互作用。这些方法在小直径和/或低质量分数纳米颗粒的表征方面具有很大的潜力。
