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Validation of Single Particle ICP-MS for Nanoparticle Size Distribution Measurements and Evaluation of its Potential to Assess the Influence of the Coating on the Stability of Gold Nanoparticles in Suspension
A.R. Montoro Bustos, K.P. Purushotham, A.E. Vladár, K.E. Murphy, M.R. Winchester
National Institue of Standards and Techonlogy, US
Keywords: single particle ICP-MS, HR-SEM, method validation, nanomaterial characterization, gold nanoparticles
Summary:
Single particle inductively coupled plasma-mass spectrometry (spICP-MS) is considered an emerging analytical technique for the ultrasensitive detection and characterization of metal-containing nanoparticles (NPs). Particularly, spICP-MS provides information about particle size, agglomeration/aggregation state, and particle number concentration, at mass concentration levels down to ng L-1. Simultaneous detection of dissolved, pristine NPs, and their agglomerated/aggregated species can be carried out in a single analysis by using spICP-MS. However, as spICP-MS cannot be still considered a mature methodology its validation for measuring NP size and size distribution is required. The main limitation to validation is the near total lack of NP with reliable reference information. This communication explores the usefulness of high-resolution scanning electron microscopy (HR-SEM) as reference technique for spICP-MS size validation. Test specimens include NIST reference materials RM 8012 and RM 8013, which are gold nanoparticles (AuNPs) with nominal diameters of 30 nm and 60 nm, as well as several coated commercial AuNPs. The capabilities of spICP-MS for the quantitative evaluation of the influence of different coatings on the stability of AuNPs are evaluated. It is expected that spICP-MS information attainable could offer a better understanding of the role of the coating in the behavior of AuNPs in suspension.
