Comparison of Dynamic Light Scattering and Centrifugal Sedimentation for Nanoparticle Sizing

Abstract

To support the efforts of increasing confidence in the comparability of measurements in the field of nanotechnology, the Institute of Reference Materials and Measurements (IRMM) intends to produce reference materials with certified particle size in the nanometer range. Several techniques, which are based on different physical principles, have been developed to perform nanoparticle sizing. As a starting point in the certification of nanoparticle reference materials, IRMM is evaluating the differences between results obtained with two of the most commonly used nanoparticle sizing techniques: dynamic light scattering (DLS) and centrifugal sedimentation. The main difference between these techniques is their power to resolve multi-modal particle size distributions. Due to the separation process occurring in the disc centrifuge, centrifugal sedimentation has an excellent resolution and is able to resolve modes with a diameter ratio as low as 1.1 whereas dynamic light scattering is not able to resolve modes with a diameter lower than 4. However, dynamic light scattering is based on first principles and calibration is not needed as for centrifugal sedimentation, for which the sedimentation velocity must be calibrated. This paper will present experimental results, illustrating the advantages and drawbacks associated with each technique and it will show how these two techniques can complement each other in the certification process.JRC.D.2-Reference material