Estimation of measurement uncertainty in chemical analysis
10. Approach based on validation and quality control data (also known as the single-lab validation approach)
Brief summary: This section explains the so-called single-lab validation approach. We will look at the formalization of this approach published by Nordtest. [1]Therefore in this course this approach is often called “the Nordtest approach”. The single-lab validation approach, contrary to the ISO GUM modeling approach, does not go deeply into the measurement procedure and does not attempt to quantify all uncertainty sources individually. Instead uncertainty sources are quantified in large “batches” via components that take a number of uncertainty sources into account. Most of the data that are used come from validation of the analytical procedure. This is the reason for the word “validation” in the name of the approach. This type of approach is also sometimes called the “top-down” approach.
Sections 10.1 to 10.3 present the Nordtest approach step by step and explain the way of obtaining necessary data. Section 10.4 gives a “roadmap” of the Nordtest approach. Section 10.5 presents a practical example of applying the Nordtest approach in the case of determination of acrylamide in snacks by liquid chromatography mass spectrometry (LC-MS).
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[1] Handbook for Calculation of Measurement Uncertainty in Environmental Laboratories. B. Magnusson, T. Näykki, H. Hovind, M. Krysell, E. Sahlin. Nordtest technical report 537, ed. 4.0. Nordtest, 2017. Available on-line from http://www.nordtest.info/wp/2017/11/29/handbook-for-calculation-of-measurement-uncertainty-in-environmental-laboratories-nt-tr-537-edition-4/
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The slides presented in this section are available from here:
