Bazo Antonio, Bolea-Fernandez Eduardo, Rua-Ibarz Ana, Aramendía Maite, Resano Martín
University of Zaragoza, Department of Analytical Chemistry, Aragon Institute of Engineering Research (I3A), Zaragoza, 50009, Spain.
University of Zaragoza, Department of Analytical Chemistry, Aragon Institute of Engineering Research (I3A), Zaragoza, 50009, Spain.
Anal Chim Acta. 2024 Dec 1;1331:343305. doi: 10.1016/j.aca.2024.343305. Epub 2024 Oct 5.
Single-particle ICP-mass spectrometry (SP-ICP-MS) is a powerful method for micro/nano-particle (MNP) sizing. Despite the outstanding evolution of the technique in the last decade, most studies still rely on traditional approaches based on (1) the use of integrated intensity as the analytical signal and (2) the calculation of the transport efficiency (TE). However, the increasing availability of MNP standards and advancements in hardware and software have unveiled new venues for MNP sizing, including TE-independent and time-based approaches. This work systematically examines these different methodologies to identify and summarize their strengths and weaknesses, thus helping to determine their preferred application areas.
Different SP-ICP-MS methods for MNP sizing were assessed using AuNPs (20-70 nm) and SiOMNPs (100-1000 nm). Among TE-dependent approaches, the particle frequency method was characterized by larger uncertainties than the particle size method. The results of the latter were dependent on the appropriate selection of the reference MNP, making the use of multiple reference MNPs recommended. TE-independent methods were based on external (linear and polynomial) calibrations and a relative approach. These methods exhibited the lowest uncertainties of all the strategies evaluated. External calibrations benefited from simpler calculations, but their application could be hindered by a lack of reference MNPs within the desired size range or by the need for interpolations outside the calibration range. Finally, transit time signals are directly proportional to the MNP size rather than its mass. The time-based method demonstrated adequate performance for sizing AuNPs but failed when sizing the largest SiOMNPs (1000 nm).
This work provides further insights into the application of different SP-ICP-MS methodologies for MNP sizing. Both TE-independent approaches and the monitoring of the transit time as the analytical signal are underused strategies; in this context, a Python script was developed for accurate transit time measurement. After 20 years of development, a quantitative comparison of the different methodologies, including the most novel approaches, is deemed necessary for further growth on solid theoretical ground.
单颗粒电感耦合等离子体质谱法（SP-ICP-MS）是一种用于微/纳米颗粒（MNP）尺寸测定的强大方法。尽管该技术在过去十年中取得了显著进展，但大多数研究仍依赖于基于以下两点的传统方法：（1）使用积分强度作为分析信号；（2）计算传输效率（TE）。然而，MNP标准品的日益普及以及硬件和软件的进步为MNP尺寸测定开辟了新途径，包括与TE无关的基于时间的方法。这项工作系统地研究了这些不同的方法，以识别和总结它们的优缺点，从而有助于确定它们的首选应用领域。
使用金纳米颗粒（20 - 70纳米）和硅氧化物纳米颗粒（100 - 1000纳米）评估了不同的SP-ICP-MS MNP尺寸测定方法。在依赖TE的方法中，颗粒频率法的不确定性比颗粒尺寸法更大。颗粒尺寸法的结果取决于参考MNP的恰当选择，因此建议使用多种参考MNP。与TE无关的方法基于外部（线性和多项式）校准以及一种相对方法。这些方法在所有评估策略中不确定性最低。外部校准计算更简单，但在校准范围内缺乏所需尺寸的参考MNP或在校准范围外需要插值时，其应用可能会受到阻碍。最后，渡越时间信号与MNP尺寸成正比，而不是与质量成正比。基于时间的方法在测定金纳米颗粒尺寸时表现良好，但在测定最大的硅氧化物纳米颗粒（1000纳米）尺寸时失败。
这项工作为不同的SP-ICP-MS方法在MNP尺寸测定中的应用提供了进一步的见解。与TE无关的方法以及将渡越时间作为分析信号进行监测都是未充分利用的策略；在此背景下，开发了一个Python脚本用于精确测量渡越时间。经过20年的发展，对不同方法（包括最新方法）进行定量比较对于在坚实的理论基础上进一步发展而言是必要的。
