Working and Liaison Groups

	Education & Training WG
	Measurement Uncertainty and Traceability WG
	Metrology in Chemistry WG (MetChem)
	Permanent Liaison Group (PLG)
	Proficiency Testing (EEE-PT) WG
	Proficiency Testing WG
	Qualitative Analysis WG
	Reference Materials WG

Measurement Uncertainty and Traceability WG

(joint with CITAC)

Terms of Reference

1. 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.
2. 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.
3. These guides will be developed in collaboration with EA and will be updated as experience is gained in their use.
    

Work Programme

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.
 

Members