Title: Identification of nanomaterials: A validation report of two laboratories using analytical ultracentrifugation with fixed and ramped speed options.
Citation: NanoImpact vol. 10 p. 87-96
Publisher: Elsevier BV
Publication Year: 2018
JRC N°: JRC109906
ISSN: 2452-0748
URI: http://publications.jrc.ec.europa.eu/repository/handle/JRC109906
DOI: 10.1016/j.impact.2017.12.005
Type: Articles in periodicals and books
Abstract: The identification of nanomaterials for regulatory purposes in Europe requires a statistically significant comparison of the number metrics median diameter to the 100 nm criterion. Methods should be robust against minor imperfections of the implementation, transferable and reproducible between laboratories, and applicable to a wide range of diameters and material compositions. Sample preparation and metrics conversion are additional challenges that must be included in validation. Here we report on the validation of a protocol for analytical ultracentrifugation with fixed and ramped speed, specifically intended to serve the European Commission recommended definition, as relevant for REACH regulation, cosmetics and food labelling and national inventories. All the determined measurement uncertainties remain below 12% for volume and number metrics median diameters, in both laboratories. Traces of sub-100-nm particles with around 2% mass contribution (but more than 50% number contribution) were reproducibly quantified. For powders, sample preparation is a critical step, and sonication intensities above 0.4 W/mL are recommended. The ramp operation can reduce user bias by eliminating the choice of options in data acquisition. The identification of nanomaterials and non-nano-materials by AUC in either fixed or ramp speed is consistent with TEM, excluding the platelet Kaolin material, but including the monodisperse silica, multimodal silica, a nanoform and a non-nano-form of BaSO4, irregularly shaped CaCO3 and coated non-nano TiO2.
JRC Directorate:Health, Consumers and Reference Materials

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