Validation of dynamic light scattering and centrifugal liquid sedimentation methods for nanoparticle characterisation

A variety of techniques exists to analyse the size and size distribution of nanoparticles in a suspension. However, these nanoparticle characterisation methods have been rarely fully validated and appropriate reference materials with properly assigned SI traceable values are not easily found. This paper presents results of in-house validation studies of Dynamic Light Scattering (DLS) and Centrifugal Liquid Sedimentation (CLS) methods. During these studies, a silica nanoparticle reference material was tested under repeatability and intermediate precision conditions. The trueness of the DLS and CLS methods was investigated by measuring gold and polystyrene nanoparticle reference materials. Furthermore, for each method, an uncertainty budget has been established. Both method validation and estimation of reliable measurement uncertainties are prerequisites for the certification of new nanoparticle reference materials.