Comparison between Centrifugal Sedimentation and Dynamic Light Scattering for Nanoparticle Sizing

The Institute for Reference Materials and Measurements (IRMM) has produced and distributes a series of reference materials with certified particle size. IRMM has the intention to broaden the range of these certified particle size reference materials to the nanoparticles range. To perform nanoparticle sizing, a variety of instruments exists, each based on different physical principles. The certification process has started with an evaluation of two of the most common nanoparticle sizing techniques: centrifugal sedimentation and dynamic light scattering. The main difference between these techniques is the resolution for 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 rratio as low as 1.1 whereas dynamic light scattering is not able to resolve modes with a diameter ratio 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 the results of the comparison tests, 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