Title: Evaluated compilation of
international reference materials for isotope abundance measurements
Chairman: Ronny Schönberg
Berglund, Willi A. Brand, Ales
Groening, Takafumi Hirata, Robert Vocke, and Thomas
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.