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Evaluation of the Potential of Single Particle ICP-MS for the Accurate Measurement of Number Concentration of AuNPs of Different Sizes and Coatings



Antonio Montoro Bustos, Karen E. Murphy, Michael R. Winchester


Single particle inductively coupled plasma-mass spectrometry (spICP-MS) is an emerging technique that is capable of simultaneous measurement of size and number concentration of metal-containing nanoparticles (NPs) at environmentally relevant levels. Although spICP-MS is widely applied to different fields, challenges remain in obtaining accurate and consistent particle number concentration (PNC) measurements. This paper presents, for the first time, a rigorous assessment of spICP-MS capabilities for measuring PNC of gold NP (AuNP) suspensions of different sizes and surface coatings. Calibration of spICP-MS was accomplished with the monodispersed National Institute of Standards and Technology (NIST) AuNP Reference Material (RM) 8013, nominal diameter 60 nm. The comparability of both spICP-MS direct and derived determination of PNC and reference PNC derived based on the mean particle size or the particle size distribution obtained by different reference sizing techniques was first assessed using the monodispersed NIST AuNP RM 8012, nominal diameter 30 nm. To enable a proper assessment of the accuracy of the spICP-MS results, a comprehensive estimation of the expanded uncertainty for PNC determination was carried out. Regardless of NP size or coating, spICP-MS led to quantitative PNC recoveries (90 % - 110 %) for all the AuNP suspensions studied only when reliable in-house Au mass concentrations and thorough mean particle size determinations were included in the calculation of the expected PNCs. The use of the particle size distribution over the mean size to derive PNCs resulted in non-quantitative PNC recoveries for materials with a low contribution (< 2 %) of smaller NPs (30 nm), materials with higher polydispersity (100 nm) or with two distinct subpopulations of particles (60 nm), regardless of NP coating.
Analytical Chemistry


spICP-MS, particle number concentration, gold nanoparticles


Montoro Bustos, A. , Murphy, K. and Winchester, M. (2022), Evaluation of the Potential of Single Particle ICP-MS for the Accurate Measurement of Number Concentration of AuNPs of Different Sizes and Coatings, Analytical Chemistry (Accessed June 14, 2024)


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Created February 11, 2022