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Handling undetected and low-level components in purity determination

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Abstract

Impurities expected to be present at low levels in a high-purity material may go undetected or be measured with near-zero values. This complicates assessment and reporting of uncertainty, and in particular can lead to underestimation of uncertainty, anomalies in estimating degrees of freedom, and coverage intervals, which extend outside the feasible range for the measurand. These issues are considered and appropriate remedies are suggested.

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Acknowledgment

This work was supported under contract to the UK Department of Trade and Industry as part of the Valid Analytical Measurement (VAM) programme.

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Authors and Affiliations

  1. Statistics and Bioinformatics Group, LGC Limited, Queens Road, Teddington, Middlesex, TW11 0LY, UK

    Simon Cowen & Stephen L. R. Ellison

Authors
  1. Simon Cowen
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  2. Stephen L. R. Ellison
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Correspondence to Simon Cowen.

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Papers published in this section do not necessarily reflect the opinion of the Editors, the Editorial Board and the Publisher.

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Cowen, S., Ellison, S.L.R. Handling undetected and low-level components in purity determination. Accred Qual Assur 12, 323–328 (2007). https://doi.org/10.1007/s00769-006-0250-5

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  • DOI: https://doi.org/10.1007/s00769-006-0250-5

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