Recommendations on quantities, symbols and measurement units for publications in ACQUAL: reporting measurement uncertainty in chemical analysis

Abstract

Measurement uncertainty is an integral part of a measurement result. Without a statement of uncertainty a measurement result is not complete. Concluding about compatibility with other measurement results obtained for the same measurand or with compliance limits is not possible and the measurement result does therefore, not serve its purpose. The measurement uncertainty is a quality criterion, which is important for the use of the result, in particular if decisions are to be based on that result. The Guide to the Expression of Uncertainty in Measurement (GUM), ISO 1995, and the CITAC/EURACHEM document Quantifying Uncertainty in Analytical Measurement (QUAM), 2001, an introduction to the GUM for chemists, are useful guides for evaluating measurement uncertainty in chemical analysis. These guides and their recommendations on how to report measurement results together with the associated uncertainty serve as the basis for the following. The final measurement result obtained after corrections for all known systematic effects is regarded as the best estimate y of the measurand Y within the range of values which could reasonably be attributed to the measurand under the given conditions of measurement. It is reported in the form: Y 1⁄4 y U with U 1⁄4 kuðyÞ