The influence of technique on the measured particle size distribution of complex nanoparticle systems

Å.K. Jämting, M. Roy, H.J. Catchpoole, M. Lawn, B. Babic, V.A. Coleman, J. Herrmann
National Measurement Institute Australia, AU

Keywords: nanoparticles, size distribution, light scattering, microscopy, sedimentation, field flow fractionation


Accurate and reliable characterization of nanoparticles is crucial for both industrial applica-tions and studies of their toxicological and environmental impacts. Particle size distribution (PSD) has been widely recognised as one of the key parameters that should be reported and studied when considering nanoscale systems since particle size can be related to, amongst other things, product functionality, toxicological response and transport/clearance/persistence pathways in environmental and mammalian systems. Characterization of the PSD of nanoscale systems presents numerous challenges, including reso-lution and detection limits of available instrumentation, statistical relevance (in single-particle methods), required prerequisite knowledge (for example, optical properties), and accounting for or overcoming matrix effects. All characterization instrumentation has inherent advantages, limitations and biases. To best understand what these are, a combination of different measurement techniques should be applied to measurements of a well-controlled system. Here, we present results from a comprehensive comparison study of PSD measurements of four nanoparticle suspensions using six different characterization techniques. The results of this study demonstrate the strengths and weaknesses of different measurement techniques used to characterize suspensions with both mono- and more challenging bi-modal PSDs, and are important for scientists who perform and interpret size measurements on nanoscale particle systems.