Interlaboratory comparison of nanoparticle size measurements between NMIJ and NIST using two different types of dynamic light scattering instruments

Abstract

The question of how to relate particle sizes measured using a fixed-angle dynamic light scattering (DLS) instrument with those measured using a multi-angle DLS instrument is addressed. A series of nearly monodisperse polystyrene latex (PSL) particles with nominal diameters of 100 nm, 70 nm, 50 nm, and 30 nm were measured using two different types of DLS instruments: one owned by the National Metrology Institute of Japan (NMIJ) of the multi-angle type and the other owned by the National Institute of Standards and Technology (NIST) of the fixed-angle type. The mean particle size of the PSL particles was measured using the multi-angle-type instrument at various scattering angles and at various concentrations of particle suspension. These data were used to establish the functional dependence of the measured particle size on the scattering angle and particle concentration through the least-squares fitting method. The established function was then used to predict the mean particle sizes that would have been obtained if the same scattering angle and particle concentrations as those used at NIST had been selected at NMIJ. The mean particle sizes obtained at NIST and at NMIJ agreed quite well for all four PSL particle samples after compensating for the angle and concentration differences. The result of this study clearly demonstrates that consideration for the dependence of measured particle sizes on the scattering angle and particle concentration is crucial in intra-method comparisons of mean particle sizes obtained using DLS.

Angle-dependent effects in DLS measurements of polydisperse particles

“…These have mostly focused on angular and sample concentration dependence as the cause of differences in measured diffusion coefficients for latex particles of narrow size distribution. It was concluded in two such works that the dependence on angle and sample concentration for monodisperse spheres was due to the dynamic interparticle structure factor S(q) [15,16]. It is demonstrated experimentally in this work that S(q) for the low concentrations of spheres in [15] and [16] is unlikely to be the source of the angular dependence, which appears to be a slight miscalibration of angular values and possibly also finite aperture effects for a goniometer based DLS system.…”

Research Activities of Nanodimensional Standards Using Atomic Force Microscopes, Transmission Electron Microscope, and Scanning Electron Microscope at the National Metrology Institute of Japan

“…The need to accurately measure the size distribution of nanoparticles is increasing to meet the new regulations that are being implemented [49]. For example, dynamic light scattering [50,51] provides good ensemble data for particle size as long as the size distribution is narrow. For samples with a wide size distribution, although the number of observed particles is often too small to provide high-quality statistical data, microscopy (electron microscopy [52,53] or atomic force microscopy [54]) is a reliable way to estimate the distribution.…”

“…Figure 7 shows the procedure of the sandwich freezedrying method [26,51]. (1) A 100-nl suspension is placed on a 1-cm-square silicon substrate.…”

The Formulation of the N-Acetylglucosamine as Nanoparticles Increases Its Anti-Inflammatory Activities: An In Vitro Study

“…Samples from three independent preparations were analysed by a Dynamic Light Scattering (DLS, Zetasizer Ultra Malvern-Panalytical). The size was analysed at a fixed scattering angle of 633 nm, according to the Siegert relation to measuring the hydrodynamic size [ 26 ]. Each sample was analysed by using a disposable capillary cell ZSU1002, and the scattered radiation was measured using the Extended Size Range modality.…”