Uncertainty Analysis on Precision Measurement for Polystyrene Nanospheres Using Dynamic Light Scattering

Abstract

Dynamic light scattering (DLS) is the most commonly used technique for measuring nanosphere sizes. In order to establish the traceability of the DLS method to SI units, relevant parameters have been measured in this study. Several studies have been reported on error sources in DLS. However, these studies lacked a systematic method of analyzing the uncertainty of DLS. In this paper we describe the DLS method and present a measurement uncertainty budget. Monodispersed polystyrene latex (PSL) spheres are selected as reference materials in the uncertainty evaluation. The measured nanosphere sizes are 20, 50, 100, 300, 500, and 1000 nm, among which the measurement results of 100, 300, and 500 nm nanospheres obtained using DLS are compared with those for an electrogravitational aerosol balance (EAB) method. The uncertainties for both methods are calculated, and the results of repeated measurements are presented with confidence levels of 95%. (C) 2010 The Japan Society of Applied Physics