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The GeoPT Proficiency Testing Programme as a Scheme for the Certification of Geological Reference Materials

Potts, Philip J.; Webb, Peter C. and Thompson, Michael (2019). The GeoPT Proficiency Testing Programme as a Scheme for the Certification of Geological Reference Materials. Geostandards and Geoanalytical Research, 43(3) pp. 409–418.

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ISO Guide 35:2017 provides, for the first time, an alternative way of characterising certified reference materials using proficiency testing. In this paper, the properties of assigned values derived from the well-established GeoPT proficiency testing scheme are examined. This scheme, designed for laboratories that undertake the routine analysis of silicate rocks and related materials, routinely has over 100 participants contributing results. Following a detailed assessment of the metrological properties of GeoPT assigned values in relation to Guide 35 recommendations, it is demonstrated that these values may be regarded as certified values, provided a number of criteria are met. These criteria include: a demonstration of sufficient homogeneity of the candidate CRM; circulation, when judged to be appropriate of an established matrix-matched CRM for co-analysis in that round; the robust statistical analysis of data sets using GeoPT established-criteria to decide whether assigning a value is justified (based on a minimum of fifteen valid results);an expert group to manage the certification and the maintenance of appropriate records.In summary, the GeoPT proficiency testing scheme, subject to the arrangements summarised above, is considered to be competent for the certification of geological reference materials.

Item Type: Journal Item
Copyright Holders: 2019 The Authors, Geostandards and Geoanalytical Research, International Association of Geoanalysts
ISSN: 1751-908X
Keywords: certification protocol; proficiency testing; GeoPT; ISO Guide 35; assigned values; certified value
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Environment, Earth and Ecosystem Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Item ID: 59675
SWORD Depositor: Jisc Publications-Router
Depositing User: ORO Import
Date Deposited: 14 Mar 2019 12:36
Last Modified: 27 Aug 2019 08:21
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