Combining and Reporting Analytical Results

• M. Belli
• A. Fajgelj
• U. Sansone

This book contains lectures presented at the international workshopon "Combining andReporting Analytical Results - The Role of (metrological) Traceabilityand (measurement) Uncertainty for Comparing Analytical Results",held from 6 to 8 March 2006 in Rome, Italy. The IUPAC InterdivisionalWorking Party on Harmonization of Quality Assurance and the ItalianAgency for Environmental Protection and Technical Services have cooperatedin organization of this event.

The idea for this workshop originated from editors' long term experienceand observations at various meetings of different technical/scientificorganizations and groups, where analytical (measurement) results areconsidered. Almost all organizations face similar problems when theanalytical results are to be combined and reported, regardless of their "metrological level", being a field laboratory, producer ofreference materials, proficiency testing organizer or even a nationalmetrology institute. Combining measurement results obtained by one analystin one laboratory employing one measurement procedure, using one measurementtechnique is the starting point, and the two questions: "How toreport the associated measurement uncertainty and how to establish anddemonstrate the metrological traceability of combined results?"are the major points of concern. The complexity of these questions expandswith the increasing number of measurement procedure/techniques, numberof laboratories and measurement results that need to be considered.The problems described are not at all new. In recent years, however,in following the latest developments on the international measurementscene, in fulfilling requirements for laboratory accreditation accordingto international standards, e.g. ISO/IEC 17025, as well as ISO Guides34, and 43 related to formal demonstration of competence of referencematerials producers and proficiency testing organizers, more attentionhas been paid to metrological traceability and measurement uncertaintyas two important quality components of measurement results. A wide internationalinterest in the topics covered by the workshop program is reflectedin the number of cosponsoring organizations, namely: Centro SvillupoMateriali. S.p.A (CMS), the International Atomic Energy Agency (IAEA),the Consultative Committee for Amount of Substance - Metrology in Chemistry(CCQM), International Bureau of Weights and Measures (BIPM), the Co-operationon International Traceability in Analytical Chemistry (CITAC), the ISOCommittee on Reference Materials (ISO REMCO) and the United NationsIndustrial Development Organization (UNIDO). All these organizationswere represented by speakers at the workshop and have contributed papersfor this book.

The contributions in this book provide an overview of current practicesused in different laboratories from different scientific fields to combineand report measurement results, at the same time describing some basicscientific considerations as well as discussions related to legislativeaspects. Practical examples from, environmental monitoring laboratories,reference material producers, clinical chemistry, as well as from thetop metrological level, e.g. key comparisons and pilot studies organizedin support and to enable comparability of measurement and calibrationresults at world-wide level, are included. The contributions in thisbook were prepared by scientists from laboratories dealing daily withsets of measurement results, their combination and reporting. We hopethat the reader will be able to extract information for her/his ownspecific case and be able to apply it in practice. Taking into accountthat there will never be only one way of combining and reporting measurementresults, this book is not a classical text book and critical readingis required.

This is the sixth book in a series based on the work of the IUPAC Interdivisional WorkingParty on Harmonization of Quality Assurance. Also this time theIUPAC's role in achieving consensus was followed by bringing togethertechnical experts so that they could share their experience and expertise.Co-operation with other organizations is essential for making any significantprogress on an international scale. Besides the above listed co-sponsoringorganizations, substantial support and contribution to the successfulorganization of the workshop came this time from the IUPAC Secretariatand the Analytical Chemistry Division and locally from the Italian Agencyfor Environmental Protection and Technical Services (APAT) and CentroSviluppo Materiali S.p.A (CSM). We are especially grateful to Ms. S.Rosamilia, Mr. F. Falcioni, Mr. P. de Zorzi, Ms. G. Gelati, Ms. T. Guagniniand Mr. F. Babalini for the excellent conditions provided during theworkshop and Mr. A. De Maio, the Director of APAT Environmental Departmentfor his support.