Determining what really counts: modeling and measuring nanoparticle number concentrations

Abstract

This paper describes a comprehensive investigation of particle number concentrations including a multi-method comparison, theoretical modeling, and cellular dosimetry.

Particle size distributions for cellulose nanocrystals measured by atomic force microscopy: an interlaboratory comparison

“…Recent ILC studies of other nano-objects have tested a variety of distribution models in an attempt to better represent the overall central location and breadth/shape of the distributions. These studies have investigated TEM data for particles with irregular shapes and high polydispersity such as gold nanorods, titanium dioxide and carbon black as well as electron microscopy and ICP-MS data for spherical particles (Montoro Bustos et al 2015;Grulke et al 2017Grulke et al , 2018aPetersen et al 2019). The models and approaches utilized in these studies include normal, lognormal and Weibull distributions as well as discrete multinomial distributions and mixtures of Gaussian distributions.…”

Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanoparticles

“…Thanks to a number of international efforts in recent years, this situation is improving. [2][3][4][5][6][7][8][9][10][11][12] Documentary standards have been developed within the International Organization for Standardisation (ISO) for a number of techniques capable of performing number concentration measurements including population-averaging methods such as: small angle X-ray scattering (SAXS), 13 dynamic light scattering 14,15 and centrifugal liquid sedimentation (CLS), 16,17 as well as particle-counting methods such as, single particle inductively coupled plasma mass spectrometry (spICP-MS), 18 particle tracking analysis (PTA), 19 differential mobility analysis with integrated condensation particle counter 20 and resistive pulse sensing (RPS). 21 Many of these standards, however, describe aspects of particle size analysis rather than measurement of number concentration.…”

Monodisperse microdroplets: a tool that advances single-particle ICP-MS measurements

“…This lack of standards has led to inconsistent measurement practices among researchers, which may cause confusion for new practitioners of sp-ICP-MS. For example, there is little consensus on signicant measurement conditions such as optimal dwell time, most accurate method to determine transport efficiency and absolute elemental sensitivities, [55][56][57][58] or robust signal-thresholding criteria for NP identication. 59 There are, indeed, many researchers working to harmonize and standardize sp-ICP-MS measurements, [60][61][62][63] but, without a suite of well-characterized reference NPs, this process remains a challenge.…”