Montoro Bustos Antonio R, Purushotham Kavuri P, Possolo Antonio, Farkas Natalia, Vladár András E, Murphy Karen E, Winchester Michael R
Theiss Research , 7411 Eads Avenue , La Jolla , California 92037 , United States.
Anal Chem. 2018 Dec 18;90(24):14376-14386. doi: 10.1021/acs.analchem.8b03871. Epub 2018 Dec 6.
Single particle inductively coupled plasma-mass spectrometry (spICP-MS) is an emerging technique capable of simultaneously measuring nanoparticle size and number concentration of metal-containing nanoparticles (NPs) at environmental levels. single particle ICP-MS will become an established measurement method once the metrological quality of the measurement results it produces have been proven incontrovertibly. This Article presents the first validation of spICP-MS capabilities for measuring mean NP size and number size distribution of gold nanoparticles (AuNPs). The validation is achieved by (i) calibration based on the consensus value for particle size derived from six different sizing techniques applied to National Institute of Standards and Technology (NIST) Reference Material (RM) 8013; (ii) comparison with high-resolution scanning electron microscopy (HR-SEM) used as a reference method, which is linked to the International System of Units (SI) through a calibration standard characterized by the NIST metrological atomic force microscope; and (iii) evaluation of the uncertainty associated with the measurement of the mean particle size to enable comparison of the spICP-MS and HR-SEM methods. After establishing HR-SEM and spICP-MS measurement protocols, both methods were used to characterize commercial AuNP suspensions of three different sizes (30, 60, and 100 nm) with four different coatings and surface charge at pH 7. Single particle ICP-MS measurements (corroborated by HR-SEM) revealed the existence of two distinct subpopulations of particles in the number size distributions for four of the 60 nm commercial suspensions, a fact that was not apparent in the measurement results supplied by the vendor using transmission electron microscopy. This finding illustrates the utility of spICP-MS for routine characterization of commercial AuNP suspensions regardless of size or coating.
单颗粒电感耦合等离子体质谱法（spICP-MS）是一项新兴技术，能够同时测量环境水平下含金属纳米颗粒（NPs）的纳米颗粒大小和数量浓度。一旦其产生的测量结果的计量质量得到无可争议的证明，单颗粒ICP-MS将成为一种既定的测量方法。本文首次验证了spICP-MS测量金纳米颗粒（AuNPs）平均纳米颗粒大小和数量大小分布的能力。通过以下方式实现验证：（i）基于应用于美国国家标准与技术研究院（NIST）标准参考物质（RM）8013的六种不同尺寸测量技术得出的粒径共识值进行校准；（ii）与用作参考方法的高分辨率扫描电子显微镜（HR-SEM）进行比较，该方法通过由NIST计量原子力显微镜表征的校准标准与国际单位制（SI）相关联；（iii）评估与平均粒径测量相关的不确定度，以便比较spICP-MS和HR-SEM方法。在建立HR-SEM和spICP-MS测量方案后，两种方法都用于表征三种不同尺寸（30、60和100 nm）、具有四种不同涂层且在pH 7下带有表面电荷的商用AuNP悬浮液。单颗粒ICP-MS测量结果（经HR-SEM证实）显示，在60 nm商用悬浮液中的四种悬浮液的数量大小分布中存在两个不同的颗粒亚群，这一事实在供应商使用透射电子显微镜提供的测量结果中并不明显。这一发现说明了spICP-MS在常规表征商用AuNP悬浮液方面的实用性，无论其尺寸或涂层如何。
