Use of Quality Control Measurements to Determine Measurement Uncertainties according to ISO and EURACHEM Guides

摘要

Statements of analytical measurement results are not complete without sufficient information aboutthe measurement uncertainty. Standard methods for evaluating and expressing measurementuncertainties require detailed knowledge of the error structure in terms of individual uncertaintycomponents associated with each step of an analytical procedure and their mutual correlation. Manyuncertainty components must be determined experimentally by the laboratory and are only valid forthe particular setting. Frequently, this relies on repeated determinations of reference materialsduring the validation of a method and during its ongoing quality control. The validity of suchestimates is limited by the reliability of the reference materials and the degree to which they arerepresentative for the actually tested materials. The structure and assessment of uncertainties ofreference materials is not always sufficiently stated.The paper demonstrates the evaluation of the measurement uncertainties for the elemental assay ofplutonium by IDMS, with special regard to the mentioned problems.