New approach to inter-technique comparisons for nanoparticle size measurements; using atomic force microscopy, nanoparticle tracking analysis and dynamic light scattering

The ability to reliably determine the size distributions of commercially produced nanoparticle batches is key for the continuing innovation and safety of nano-enabled materials. One of the major roadblocks is that there are no standard techniques or transfer artefacts for nanoparticle size measurements. Worst many different techniques are used all of which are based on specific physical affects and will inevitably give different results. In this paper the size of standard and industrially produced near spherical nanoparticles have been determined using both single particle (transmission electron and atomic force microscopy) and ensemble methods (dynamic light scattering and nanoparticle tracking). It has been demonstrated that these techniques give different results but these are all consistent considering the exact nature of each measurand and their physical conditions. This approach leads the way for improvement in nanoparticle size measurement by allowing the results from different techniques to be compared directly.

Nanoparticle size measurements; AFM analyses individual particles with agglomerates not detected, whilst NTA detects both. Combining the two allows the affect of agglomerates on DLS to be quantified.Figure optionsDownload as PowerPoint slideHighlights
► AFM measurements on the size distribution of nanoparticles with 0.4 nm accuracy.
► Procedure for determining size distribution from nanoparticle tracking analysis.
► Uncertainty analysis of DLS measurements plus the affect of agglomerates.
► Direct inter-comparison of all 3 techniques with uncertainty limits.