Organizations & People
Title: A new comprehensive report on the isotopic compositions
of the elements for global user communities
Task Group Chairman: Robert
Berglund, John Karl
B. Coplen, Tiping P.
Ding, Paul De Bièvre,
John R. De Laeter,
A. M. Fouillac,
Klaus G. Heumann,
Norman E. Holden,
Hiroshi Hidaka, Kevin
J.R. Rosman, Etienne
D.P. Taylor, Thomas
Walczyk, Ying-Kai Xiao,
and Michael Wieser
Completion Date: 2007 - project completed
To design, compile and produce a new comprehensive Report on the Isotopic
Compositions of the Elements, containing updated data and in a format
suitable for the 21st Century.
In the past, CAWIA has produced several tables of the isotopic
compositions of the elements (e.g. the most recent published in 1997)
with isotopic data representing the best available measurements and
representative materials. The aim of this project is to update and
drastically upgrade this information, which has not been done in 7
years. Apart from the upgrading (incorporating new information obtained
since 1997), the data handling procedures for the future table should
also be modified to achieve recommended isotopic compositions that
are fully in line with standard atomic weights. This is not always
the case today.
With increasing importance of isotope ratio measurements in chemistry,
environmental sciences, product authentication, forensic and life
sciences, there is a need for an expanded and revised database on
isotopic abundances in normal terrestrial materials and associated
reference materials with standard atomic weights that reflect the
current knowledge of isotopic compositions. This represents a major
modification and an expansion of the present isotopic composition
compilations. It will include a computer database accessible by the
chemical community and will facilitate future updates, as new information
Project phase 1: A special core task group consisting of R.
Loss, J.K. Böhlke, K. Rosman, T. Coplen, T. Walczyk, M. Berglund,
P. Taylor will hold a 3-day workshop August 5, 6, and 7 in Ottawa
to develop guidelines for the new RICE data tables for use by the
Subcommittee for Isotope Abundance Measurements (SIAM) when reviewing
currently tabulated and subsequently reported isotopic compositions.
On August 8 and 9 in Ottawa (IUPAC GA 2003), a forum of the full Task
Group will meet to discuss the role of the new comprehensive "Report
on the Isotopic Compositions of the Elements" for global user
communities within the future structure of IUPAC, its Divisions, Subcommittees,
and Commissions. A face-to-face meeting is critical, as it is the
most cost effective way to engineer this novel system via in depth
discussions with the relevant experts in a timely manner, which is
important to this rapidly changing scientific subject. The Commission's
collective experience over the past decades is that this is only viable
approach, in view of the number of issues involved and the fact that
experts from different scientific disciplines are needed. A new layout
for the table of isotopic compositions will be drafted.
Project phase 2: By electronic communication, the core task
group will further revise and then finalise these Guidelines and make
a template for the novel table.
A novel calculation tool is available and will be distributed by
IRMM for free to the project members. This software estimates the
uncertainty of the isotope abundances from isotope ratios (and vice
versa). It takes into account natural isotopic variation (e.g., from
the IUPAC SNIF report), and it allows ratio conversion. It also allows
the user to produce a standard atomic weight for the element. The
intention is to have a hard link between the reservoir of raw literature
data stored and the end products delivered. This will drastically
improve archiving and it will allow for a more efficient review of
previous decisions made by the Commission.
(last update 29 Jan 2007)
The task group reviewed key uncertainty inputs and developed prototype
uncertainty determinations suitable for Isotopic Composition (re)determination
of published data utilizing the analysis and computational rules of
the 'ISO guide to the expression of uncertainty in measurement' as
used by the European cooperation for Accreditation of Laboratories.
These procedures were used to prepared evaluated Isotopic Composition
and Atomic Weight data for nickel, sulfur, and osmium. Unfortunately,
the prototyping rapidly revealed a myriad of unforeseen complexities
and difficulties required to complete this for all the polyisotopic
Due to user-community demand, the task group recommended reporting
evaluated isotope ratios, as well as isotopic abundances, which is
a major departure from previous reporting of only isotopic abundances.
This created major difficulties in evaluating and (re)determining
isotope-ratio uncertainties from those publications that only reported
abundances, especially those with unclear, non-standard, or even non-existent
The amount of time required to review the substantial literature
and evaluate isotope data for all of the proposed parameters was much
greater than first thought. In particular, the degree of interpersonal
interaction involved in evaluating the data clearly could not be met
within the proposed project time lines.
Recognizing the complications and difficulties involved in the full
re-evaluation of all polyisotopic elements, the task group recommended
a new project #2003-031-2-200
'Isotopic Compositions of Selected Elements'. Funded in
2004, that project has made substantial progress.
The new evaluation templates and experience gained by the task force
members in these two projects have been applied by the Commission
on Isotopic Abundances and Atomic Weights at the 43rd IUPAC General
Assembly in Beijing 2005 and resulted in fully revised atomic weight
data for 12 elements. (Pure
78(11), 2051-2066, 2006)
Last Update: 6 February 2007
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Page last modified 6 February 2007.
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