TY - GEN A1 - Vogl, Jochen T1 - Roadmap for the purity determination of pure metallic elements – Basic rinciples and helpful advice T2 - BIPM Webpage N2 - High purity materials can serve as a realisation of the Système International d’Unitès (SI) unit amount of substance for the specific element. Solutions prepared from such high purity materials using gravimetric preparation and the concept of molar mass are used as calibration solutions in many fields of analytical chemistry. Calibration solutions prepared this way provide the traceability to the SI and are the metrological basis in elemental analysis. The preparation and characterization of such primary pure substances, representing the realisation of the SI unit amount of substance, is undertaken only by a small number of National Metrology Institutes (NMI) and Designated Institutes (DI). Many other NMIs and DIs, however, prepare elemental calibration solutions as calibrants for their measurement services, such as the certification of matrix Reference Materials or the provision of reference values for Proficiency Testing schemes. The elemental calibration solutions used for this purpose are not a direct service to customers, such as preparing secondary calibration solutions, but provide the source of traceability for the other services. Hence, it is necessary for the NMI or DI to obtain data on the purity of the pure metals or other materials used to prepare the solutions with measurement uncertainties meeting the needs of the above described services. This is commonly undertaken as a “fit for purpose” assessment, appropriate for the uncertainty requirement of the service provided to customers. As a consequence, total purity measurements are a long-term strategy of CCQM-IAWG. Several studies were conducted (CCQM-P107, CCQM-K72 and CCQM-P149) on the measurement of the purity of zinc. From these studies, several conclusions can be drawn for the purity assessment of a pure (metallic) element. These conclusions will be put together in this document in order to assist all NMIs/DIs in performing a purity assessment, whenever needed. KW - Purity assessment KW - Metal assay approach KW - Impurity assessment approach KW - Traceability PY - 2018 UR - https://www.bipm.org/wg/CCQM/IAWG/Allowed/April_2017/CCQM-IAWG17-28.pdf.pdf SP - 1 EP - 9 CY - Sevre AN - OPUS4-46834 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -