Accreditation and Quality Assurance

, Volume 23, Issue 2, pp 103–108 | Cite as

Discussion on homogeneity assessment of reference materials based on uncertainty comparison method

  • Chonghua Liu
  • Zhiyong Ding
  • Yong Tian
  • Lezhou Yi
  • Ningshan Huang
Practitioner's Report


An uncertainty comparison method is proposed to assess the homogeneity of reference materials. The method compares “standard uncertainty associated with between-unit variability” (ubb) with “target standard uncertainty” (utrg) or “measurement uncertainty” (umeas) to solve the problems in assessing homogeneity of reference materials. Methods for the calculation of ubb, utrg and umeas as well as criterion for the quantitative judgment of sample homogeneity are introduced. When ubb ≤ 0.3utrg, it shows the sample is considered to be homogeneous; when 0.3utrg < ubb ≤ 0.7utrg, the sample is considered to be sufficiently homogeneous for the intended use; and when ubb > 0.7utrg, the sample is considered to be inhomogeneous. The uncertainty comparison method is compared with the F test method and shown to be more objective for the assessment of the homogeneity of certified reference materials for the chemical testing of toys.


Reference material Homogeneity assessment Uncertainty comparison method Target standard uncertainty 



Funding was provided by Guangdong Science and Technology Department (CN) (Grant No. 2014A040401066) and China National Accreditation Service for Conformity Assessment (Grant No. 2014CNAS08).


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Chonghua Liu
    • 1
  • Zhiyong Ding
    • 1
  • Yong Tian
    • 1
  • Lezhou Yi
    • 1
  • Ningshan Huang
    • 1
  1. 1.Inspection and Quarantine Technology CenterGuangdong Entry-Exit Inspection and Quarantine BureauGuangzhouPeople’s Republic of China

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