Organizations & People
Title: Evaluated published isotope
ratio data (2005-2007)
Karl Böhlke, Tyler
B. Coplen, Paul
De Bièvre, John
R. De Laeter, Tiping
P. Ding, Roberto
E. Holden, Robert
D. Loss, Kevin J.R.
Rosman, Etienne Roth,
Mo-tian Zhao, and
Xiang Kuo Zhu
Evaluate isotope ratio publications between 2005 and early 2007,
to determine "best isotope ratio measurements" for compilation
and publication in a 2009 TICE, recommend "new" standard
atomic weights, and publish "Atomic Weights of the Elements
2007" in Pure and Applied Chemistry, which will also
include a table of relative atomic masses and half-lives of selected
The aim of the task group is to evaluate isotope ratio publications
between early-2005 and early 2007. The evaluated data will be incorporated
into the CIAAW* Table of Isotopic Composition of the elements (TICE)
and Table of Standard Atomic Weights. This project is an interim
step in the evaluation of isotopic data production for the next
proposed publication of TICE in 2009.
*see CIAAW actvities
The Subcommittee on Isotopic Abundance Measurements (SIAM) recognizes
that there are a number of elements that need particular attention
and for which significant publications are expected. These include
Zn, Ca, Mg, and Si: for which two, significantly different, high
precision publications have recently been assessed by IUPAC, is
in the process of being resolved and will require evaluation.
The task group will evaluate recently published isotope ratios
and resulting atomic-weights. Detailed discussions and calculations
will be carried out on any chemical element for which new isotope
ratio information exists. Particular attention will be paid to authors'
evaluations of uncertainty, the selection of materials for analysis,
and the variability of isotope ratio measurements in these materials.
The task group will than present their recommendations for adoption
of best isotopic ratios and new standard atomic weights to the Commission
on Isotopic Abundances and Atomic Weights at the General Assembly
Subsequently, a publication titled "Atomic Weights of the
Elements 2007" will be prepared for Pure and Applied Chemistry.
Subsequently, publication in J. Phys. Chem. Ref. Data is
August 2007 - The task group evaluated isotope ratio data
for 13 elements (Ar, Br, C, Cl, Cd, Lu, Mo, Ni, O, Si, Ti, Zn, Yb)
in 16 publications reported between mid-2005 and mid 2007. Particular
attention was paid to evaluations of uncertainties, the types of
materials analysed, and the variability of isotope ratio measurements
Of equally importance to the approval
of the new data was the attention paid by the task group to high
precision isotopic ratio measurements reported for elements such
as Cd, Ti, and Ni for which changes to best measurements were not
made. This highlighted the need for specialist analysts to be called
on to address issues related to specific analytical techniques.
Final uncertainty calculation and expansions
were performed using the principles and procedures proposed by IUPAC
project number 2003-031-2-200 (RICEII) using full GUM procedures.
For the elements requiring changes, appropriate uncertainty expansion
factors were used to ensure compatibility with current CIAAW accepted
evaluation procedures. A full implementation of RICEII proposals
in this type of work awaits CIAAW approval.
At the 24-27 July 2007 Pisa meeting of
the Subcommittee on Isotopic Abundance Measurements the new "best
isotope ratio" data for Ar, Lu, Mo, Yb and Zn were recommended
to CIAAW for inclusion in the next (2009) CIAAW Table of Isotopic
Composition of the elements (TICE). In addition, new Standard Atomic
Weights were also recommended for Lu, Mo, Ni, Yb and Zn to be published
in "Atomic Weights of the Elements 2007" prepared for
Pure and Applied Chemistry. A subsequent, publication in
J. Phys. Chem. Ref. Data is also anticipated. Details of
the evaluations and the recommendations are shown in the attached
minutes of the SIAM meeting.
Last update: 20 August 2007
<project announcement to be published
in Chem. Int. >
want to update this information, contact us by e-mail
Do not forget to include the Project Number,
your name and relation with that project
Page last modified 20 August 2007.
Copyright ©1997-2007 International Union of Pure and Applied Chemistry.
Questions or comments about IUPAC, please contact, the Secretariat.
Questions regarding the website, please contact Web