Working and Liaison Groups
| Measurement
Uncertainty and Traceability WG |
(joint
with CITAC)
- The
EURACHEM/CITAC Measurement Uncertainty and Traceability Working Group has been
established and will operate in accordance with the Constitution agreed in the
EURACHEM Memorandum of Understanding.
- The
EURACHEM/CITAC Measurement Uncertainty and Traceability Working Group will prepare
guidance for the evaluation of uncertainties and establishment of traceability
in chemical analysis. This guidance will be applicable to all chemical analytical
laboratories and will provide guidance on the assessment of uncertainties and
establishment of traceability required for accreditation.
- These
guides will be developed in collaboration with EA and will be updated as experience
is gained in their use.
The
WG has produced the Eurachem Guide "Quantifying Uncertainty in Analytical Measurement"
(ISBN 0-948926-08-2) which was published in 1995. A draft of this guide was discussed
at a the first EURACHEM workshop on the evaluation of uncertainty held in Graz
in 1994, which was organised by Dr Wegscheider on behalf of EURACHEM Austria.
This Guide has been well received and the WG has had a large number of comments
on it. Experience with the use of the Guide was discussed at a second EURACHEM
workshop held BAM, Berlin, in September 1997. The papers presented at this workshop
have been published in Accreditation and Quality Assurance (ACQUAL)
and many other articles on the evaluation of uncertainty in chemical analysis
have also been published in this journal. Since the publication of the first edition
of the Guide the Working Group has looked at topics that were either not covered
or not covered adequately in the first edition an. A very important issue is the
relationship between method validation and uncertainty evaluation. Much of the
data required to evaluate uncertainty is or could be obtained during the collaborative
study of a method.Utilising this data reduces the work that each laboratory needs
to do itself. In many cases such data is already available and the working group
is preparing recommendations for changes to existing validation protocols so that
the necessary data is always provided. These and other topics were discussed at
the Workshop on Efficient methodology for the Evaluation of Uncertainty in Analytical
Chemistry ("Implementing the ISO Guide") which was organised by EURACHEM in co-operation
with IAEA and which was held in Helsinki June 1999. A second edition of the Measurement
Uncertainty Guide has been written on the basis of the outcome of this workshop
and is available for downloading here. A printed
version will be available soon. In
addition a web site has been set up (http://www.measurementuncertainty.org)
which contains an indexed HTML version of the Guide. This site hosts a discussion
forum on the application of the guide and has a section for the publication of
additional examples.. Measurement uncertainty and traceability are intimately
linked and terms of reference of the working group have recently been extended
to include the preparation of guidance on establishing traceability in chemical
measurement.
