IUPAC

To evaluate and compile a list of isotopic reference materials. The results will be published in PAC and other journals relevant to user communities. Such publications can play a key role in encouraging funding agencies to support the development of new reference materials for elements for which there are no references available.

Recent analytical advancements (e.g. multiple collector inductively coupled plasma mass spectrometry) enable the measurement of isotope abundance variations for elements that were previously regarded as having no isotope abundance variation. Instead of reporting the isotope abundance variations of such elements relative to certified international reference materials, many research groups use in-house standards or geological materials (silicate rocks, ocean water) that do not allow inter-laboratory data comparison because these materials are not freely available or may not be isotopically inhomogeneous. Another problem is that for some of the elements, no international or other reference material is available. In addition, some reference materials used for well-established isotope abundance applications are about exhausted. For example, NBS 19 calcium carbonate, for stable carbon and oxygen isotope abundances, and "La-Jolla-Nd", for radiogenic neodynium work, are in short supply.

Inter-laboratory comparability of isotope abundance data is critical for quality assurance of data. This project includes a survey of the literature to identify the commonly used international isotopic reference materials. Clarification of the availability of these materials from international distributors (e.g. NIST, IRMM, and IAEA) is important to the user community. Institutions that prepare and distribute international reference materials will be made aware of elements that lack certified international reference materials. This is important information that can be provided to funding agencies for creation of new isotopic reference materials.

A table of recommended international reference materials for chemical elements and their availability is planned to be published in Pure and Applied Chemistry and on the web. It will include the certified isotope amount ratio data for these international reference materials.