In this article, we will describe how nanoscale particles may be individually visualised (but not imaged) in liquids and from which higher resolution particle size distribution profiles can be obtained compared to other light scattering techniques. The method is called Nanoparticle Tracking Analysis (NTA)

Sample preparation is minimal, requiring only dilution with a suitable solvent to an acceptable concentration range (between 10 and 1010 particles per ml depending on sample type). Accurate and reproducible analyses can be obtained from video images of only a few seconds duration and the results allow particle number concentration to be recovered. Given the close to real-time nature of the technique, particle-particle interactions are accessible as is information about sample aggregation and dissemination. All particle types can be measured and in any solvent type providing that the particles scatter sufficient light to be visible (i.e. are not indexed matched).