Internal traceability

EURACHEM is a network of organizations in Europe, having the objective of establishing a system for the international traceability of chemical measurements and the promotion of good quality practices. It provides a forum for the discussion of common problems and for developing an informed and considered approach to both technical and policy issues. 

Co-operation on International Traceability in Analytical Chemistry Coalition of Northeastern Governors (USA)... 

Traceability in Chemical Measurement A Guide to Achieving Comparable Results in Chemical Measurement , Eurachem, Co-operation on International Traceability in Analytical Chemistry (CITAC), 2003. [http //www.eurachem.org]. 

Eurachem/ CITAC A Focus for Analytical Chemistry in Europe/ Cooperation on International Traceability in Analytical Chemistry Traceability, MU, reference materials, validation 2,3 13,14,7,15... 

Eurachem/ CITAC and EA A Focus for Analytical Chemistry in Europe/Cooperation of International Traceability in Analytical Chemistry and European Cooperation for Accreditation Method validation, Proficiency testing, QA, accreditation 2,15, 59-60... 

The results of IMEP-1 clearly pointed to the problem of lack of equivalence of measurement results and demonstrated that studies needed to use independently established quantity values. IMEP operated from the beginning under the auspices and with the support of the International Union of Pure and Applied Chemistry, EURACHEM, the Association of European Metrology Institutes, and Cooperation in International Traceability in Analytical Chemistry. 

In contrast, the ISO Guide 25 approach (updated in 1999 to ISO Guide 17025), as expanded in ref. 14 heavily focuses on good analytical practices and adequate calibration of instruments with nationally or internationally traceable standards wherever possible. 

International comparability and hence acceptance of chemical measurement results is the common central aim of all international initiatives and organizations in the field of metrology in chemistry such as the Consultative Committee for Amount of Substance (CCQM), the Co-operation on International Traceability in Analytical Chemistry (CITAC), EURACHEM, EUROM-ET and others. This is a consequence of the globalization of trade and economy and other human activities,... 

Not many terms covering concepts in measurement have circulated over the last ten years in the chemical measurement community around the world so intensely as the term trace-ability. It appears in the title of CITAC (Cooperation on International Traceability in Analytical Chemistry) since 1993. It is addressed almost yearly in Workshops of EURACHEM (A Focus for Analytical Chemistry in Europe). Documents of ILAC (International Laboratory Accreditation Cooperation) require it to be used in the process of accreditation. Standards and Guides of ISO (the International Organisation for Standardization) mention them frequently and insistingly. 

It should be clear from the above discussion that, regardless of the availability of standards, reference materials or calibration services having reference values exhibiting international traceability, the results dependent on them will not be traceable unless field laboratories are able to obtain reliable estimates of their own measurement uncertainty. This is, in fact, a requirement for accreditation to ISO 17025 but the practical difficulties of achieving it for... 

Laboratories that are accredited to ISO 17025, rather than the well-established ISO 9000 series, are using RMs and CRMs more often and are signing up for proficiency testing (PT). ISO 17025 is the standard that provides the international aspect to any laboratory measurement process and provides the control framework to assist the production of comparable measurements. ILAC (International Laboratory Accreditation Co-operation) harmonises laboratory accreditation procedures. ISO 17025 plays an important role in international traceability and in the requirements for an internationally agreed suitable CRM. 

More detailed information on the compliance requirements for the competence of calibration and testing laboratories is contained in ISO Guide 25. This guide has been interpreted to meet national requirements in some countries for example the UK Accreditation Service refers to it as UKAS MIO. Many laboratories seek accreditation to ISO Guide 25 and operate quality and testing systems which meet the requirements. The ISO Guide 25 approach heavily focuses on good analytical practices and adequate calibration of instruments with nationally or internationally traceable standards wherever possible. 

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