Risks of a False Decision on Conformity of a Multicomponent Material and Quality of Chemical Analytical Results

Ilya Kuselman, Independent Consultant on Metrology, Modiin, Israel (ilya.kuselmam@gmail.com)
Francesca R. Pennecchi, Istituto Nazionale Di Ricerca Metrologica (INRIM), Torino, Italy
Ricardo da Silva, Faculdade De Ciências Da Universidade De Lisboa, Lisboa, Portugal
D. Brynn Hibbert, School of Chemistry, University of New South Wales (UNSW), Sydney, Australia

Comparing chemical analytical (test) results with the material specification, regulatory or acceptance limits of the component content, one should decide whether the tested sample (batch/lot) conforms or not. It is known that measurement uncertainty, which characterizes the quality of a result, leads to risks of false decisions. Evaluation of such risks for a multicomponent material or object involves calculation of probabilities of false decisions for the different components of the material or object (particular consumer’s and/or producer’s risks). At the same time, even when conformity assessment for each component of a sample is successful, the total probability of a false decision (total consumer’s risk or producer’s risk) on the conformity of the sample as a whole may still be significant. The total risk due to measurement uncertainty can be evaluated as a combination of the particular risks of conformity assessment of the sample components, whenever there is independence among their test results. Possible correlation can be viewed as a further quality parameter of the results, influencing the total risk of false decisions. It should be also taken into account at the risk evaluation.

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Short Biography of Presenting Author

Ilya Kuselman has received his Ph.D. in inorganic chemistry from Kalinin State University in 1974, and D.Sc. in analytical chemistry – from R&D Institute for Rare Metal Industry, Moscow, Russia, in 1989. Since 1991 to 2014 he was a co-worker and further Director of the National Physical Laboratory of Israel.

He has published above 200 papers in reputed journals in the fields of metrology and quality in analytical chemistry. Ilya Kuselman has been serving as an editorial board member and reviewer of Accreditation and Quality Assurance - Journal for Quality, Comparability and Reliability in Chemical Measurement (Springer) and some other journals.

He is a member of Cooperation on International Traceability in Analytical Chemistry (CITAC); of Analytical Chemistry Division of International Union of Pure and Applied Chemistry (IUPAC); of Committee on Reference Materials (ISO/REMCO) and Committee on Measurement Methods and Results (ISO/TC 69/SC 6) of International Organization for Standardization (ISO).