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Since a comprehensive survey published in 1999 [1] much work was done in standardizing measuring methods to characterize the surface geometry of dispersed and/or porous solids and to certify reference materials. The present paper is an extension of a short communication [2]. It gives a survey on existing standards and reports on new drafts and proposals.
In vielen industriellen High-Tech Verfahren und Prozessen, Forschung und Wissenschaft, Medizin und Umwelttechnik werden Sondergase eingesetzt.
Als Gattungsbegriff umfasst diese Bezeichnung ein ansehnliches Spektrum höchster Qualitäten an Gasen. Dazu gehören u. a. Reinstgase mit besonders hohen Anforderungen an ihre Reinheit, Gasgemische genau definierter Zusammensetzung und Isotopengemische. Wie genau kann man Gaszusammensetzungen heute messen? Wie schafft man es, dass alle dasselbe messen? Welche Techniken kommen dabei zum Einsatz?
A major requirement for the validation of methods assessing the risk associated with engineered nanoparticles (ENPs) is the use of reference materials (RMs). In the present contribution we review available RMs, ongoing projects and characterisation trends in the field. The conclusion is that actual approaches to RMs mostly deal with metrological considerations about single properties of the ENPs, typically their primary size, which can hardly be representative of nanoparticles characteristics in real testing media and therefore, not valid for reliable and comparable toxicological studies. As an alternative, we discussed the convenience and feasibility of establishing multi-parametric RMs for a series of ENPs, focusing on silica nanoparticles (SNPs). As a future perspective, the need to develop RMs based on hybrid nanoparticles is also discussed.
Quantification of energy dispersive SRXRF for the certification of reference materials at BAMline
(2010)
The certification of reference materials (CRMs) is one of the main tasks of the BAM Federal Institute for Materials Research and Testing. In this context CRMs for analytical chemistry play the dominant role. Traditionally, energy dispersive X-ray fluorescence (EDXRF) has been excluded from the final certification scheme. It has lacked the proof to be reliable enough due to peak overlapping and risks of incorrect background subtraction leading to unacceptable uncertainty and bias of the results. The development described aims at enabling ED-SRXRF to really contribute to certification by the aid of synchrotron radiation. This has been partly shown for macrocontents and has been successfully demonstrated for trace elements and thin layers. The method is based on a combination of measurements of pure elements or stoichiometric compounds as comparator materials and Monte Carlo simulations. Measurements have been performed at the BAMline, the hard X-ray beam line of the BAM at the synchrotron BESSY II in Berlin.