In Langmuir 2012 DOI: 10.1021/la301351k, Caterine Minelli et al. provide a comprehensive comparison of application of different sizing techniques, including both well established such as TEM and dynamic light scattering (DLS) and new and emerging ones, such as nanoparticle tracking analysis (NTA), scanning ion occlusion sensing (SIOS), and differential centrifugal sedimentation (DCS), for characterization of Stöber silica.