Every analyst takes analysis context on their decision on the analysis result. If a residue of a pesticide never authorised in a crop production site is identified, extra confirmation of the finding is performed. In clinical analysis, if a specific analysis result is not supported by patient symptoms, it can be decided to repeat the Read more about The impact of analysis context on analysis quality – Bayes’ Theorem principles for qualitative analysis[…]

Applying the uncertainty propagation law (i.e. the well-known Taylor Series Method) to measurements involving a complex mathematical relation between various input quantities is difficult. The link below directs you to a video that briefly explains the principles and the implementation of the spreadsheet Kragten method for an easy and fast combination of uncertainty components from Read more about Kragten method for uncertainty propagation: Easy way of doing difficult things![…]

Many chemical parameters are determined as the difference, d, between two measured values, designated as larger (g) and lower (w) inputs, (d = g – w; where g > w) determined from independent measurements such as:   Magnesium Hardness (mg/L of CaC03) = Total Hardness – Calcium Hardness Chromium (III) = Total Chromium – Chromium (VI)   The uncertainty associated with Read more about Managing the uncertainty and limit of quantification of parameters determined by the difference between independently measured values[…]

Eurachem, together with CITAC, have published a guide on how to assess and report the performance of qualitative analyses. This guide describes some of the tools that can be used to check if qualitative analyses have fit for purpose uncertainty. The limitations of some approaches for quantifying performance are discussed. The quantification of false results Read more about Eurachem/CITAC guide on assessing the performance and uncertainty in qualitative chemical analysis[…]

Talanta paper on the top-down evaluation of the measurement uncertainty from correlated validation data following regulated validation design.  Link: https://www.sciencedirect.com/science/article/abs/pii/S0039914020306779 #Metrology #Uncertainty #Validation #AnalyticalChemistry #Crossvalidation #Correlation   Research Novelty: This work presents and cross-validates a novel top-down measurement uncertainty evaluation adapted to a common method validation design for the quantification of an impurity in active Read more about The uncertainty evaluation should adapt to the available experimental data…not the other way around![…]

Free share link: https://authors.elsevier.com/a/1bFkQ,ashxm80 (Until 7 August 2020) The assessment of long-term trends in river water composition is hampered by river composition heterogeneity, and sampling and sample analysis uncertainty. This work describes a novel methodology for the reliable detection of small river composition trends by taking all relevant uncertainty components into account. The methodology was Read more about Using sampling uncertainty to distinguish small composition variations of a large river area![…]

The new requirement of the ISO/IEC 17025 standard for discussing with the customers the impact of the measurement uncertainty in the reliability of conformity decisions and for subsequently using it in conformity assessments is not just another novelty of the standard. It represents a very important evolution of laboratory accreditation that will generalise the quantification Read more about Use the uncertainty in conformity assessments because it is…honest![…]