title: How reliably can a material be classified as a nanomaterial? Available particle-sizing techniques at work.
abstract: Currently established and projected regulatory frameworks require the classification of materials (whether nano or non-nano) as specified by respective definitions, most of which are based on the size of the constituent particles. This brings up the question if currently available techniques for particle size determination are capable of reliably classifying materials that potentially fall under these definitions. In this study, a wide variety of characterisation techniques, including counting, fractionating, and spectroscopic techniques, has been applied to the same set of materials under harmonised conditions. The selected materials comprised well-defined quality control materials (spherical, monodisperse) as well as industrial materials of complex shapes and considerable polydispersity. As a result, each technique could be evaluated with respect to the determination of the number-weighted median size. Recommendations on the most appropriate and efficient use of techniques for different types of material are given.
authors.affiliation: Research Group of Mechanical Process Engineering, Institut für Verfahrenstechnik und Umwelttechnik, Technische Universität Dresden (TUD), 01062 Dresden, Germany.
authors.forename: Frank
authors.identifier: 0000-0001-5958-2111
authors.initials: F
authors.lastname: Babick
authors.affiliation: Division 6.8 Surface Analysis and Interfacial Chemistry, Bundesanstalt für Materialforschung und -prüfung (BAM), 12205 Berlin, Germany.
authors.forename: Johannes
authors.identifier: 0000-0003-3551-8750
authors.initials: J
authors.lastname: Mielke
authors.affiliation: Department of Material Physics, BASF SE, 67056 Ludwigshafen, Germany.
authors.forename: Wendel
authors.identifier: 0000-0003-2094-3260
authors.initials: W
authors.lastname: Wohlleben
authors.affiliation: RIKILT - Wageningen UR, 6700 AE Wageningen, The Netherlands ; Bundesinstitut für Risikobewertung (BfR), 10589 Berlin, Germany.
authors.forename: Stefan
authors.identifier: 0000-0002-4197-5758
authors.initials: S
authors.lastname: Weigel
authors.affiliation: Division 6.8 Surface Analysis and Interfacial Chemistry, Bundesanstalt für Materialforschung und -prüfung (BAM), 12205 Berlin, Germany.
authors.forename: Vasile-Dan
authors.identifier: 0000-0002-7901-6114
authors.initials: VD
authors.lastname: Hodoroaba
keywords: Characterisation techniques; Nanomaterial classification; Nanometrology; Nanoparticle; Number-weighted median size; Particle size analysis; Tiered approach