Project Details Assessment of Stable Isotopic Reference and Inter-Comparison Materials

Project No.:
Start Date:
01 May 2010
End Date:
01 November 2018


The objective of this project is to compile a list and evaluate isotopic composition values of available reference materials suitable for stable isotope analysis. The resulting compilation listing all relevant information for user communities will also be useful in identifying which materials are missing.

A second objective is to evaluate newly published measurements and assess the validity of new results as a means to establish new values for the community.


Isotopic abundance variations of light elements and derived delta-values are studied increasingly in a number of scientific as well as more general purpose applications. A larger number and wider range isotopic reference materials are needed to ensure the required level of day-to-day calibration of routine measurements. Part of this is due to the variety of preparation techniques necessary for increasingly wider range of materials being investigated.

The variety of materials requiring analysis makes it is necessary to ensure a proper assessment of calibration measurements of suitable reference materials. CIAAW has assembled some of the most experienced specialists in the field with the right experience in quality assurance of high precision isotope abundance ratio measurements. The same methodology will be used to make decisions regarding the best and most robust reference values for such reference materials.

The Task group will assess and determine reference values in close cooperation with the IAEA and NIST as the main distributing agencies of those reference materials. This will boost the applicability of materials and trigger and facilitate the establishment of new reference materials.

This project has the potential to remove existing discrepancies between recommended values as used by different organisations, which are thought to be due to the lengthy periods between assessments at the different organisations.

A critically evaluated table comprising recommended values for available reference materials for light elements will be prepared for publication in Pure and Applied Chemistry. The table will be up to date both at an appropriate place on the web, as well as part of the regular evaluation publication (~biennially) cycle of the Commission. This work will take several years to complete, as it involves a careful statistical treatment of all available data for each material and will need feedback from authors (if still available) of such calibration measurements. The project will be based on the compilation of reference materials for light elements as initiated by the project “Survey of International Reference Materials for Isotope Abundance Measurements”.


September 2010 – project announcement published in Chem. Int. Sep-Oct, p. 23

March 2014 – A technical report titled ‘Assessment of international reference materials for isotope-ratio analysis’ has been published in Pure and Applied Chemistry, Vol 86, No 3, pp 425-467, DOI:10.1515/pac-2013-1023

Page last update 22 Feb 2016