The CCQM-K24 was performed without a pilot study prior to the key comparison in order to demonstrate and document the capability of interested National Metrology Institutes to measure the Cd amount content in a rice sample. The comparison was an activity of the Inorganic Analysis Working Group of CCQM and was piloted by the Institute for Reference Materials and Measurements (IRMM, Geel, Belgium) of the European Commission.

All participants applied isotope dilution mass spectrometry (IDMS) using thermal ionisation MS (TIMS), sector field or quadrupole inductively coupled plasma MS (ICP-MS) as analytical technique. NIST reported a combined result of IDMS and instrumental neutron activation analysis (INAA) for the Cd amount content in the rice.

The following laboratories participated in this key comparison (in alphabetical order).

BAM (Germany)
CSIR-NML (South Africa)
EMPA (Switzerland)
IRMM (European Union)
KRISS (South Korea)
LGC (United Kingdom)
NARL (Australia)
NIST (United States of America)
NMi (The Netherlands)
NMIJ (Japan)
NRC (Canada)
NRCCRM (China)

Very good agreement of reported results was observed. The Key Comparison Reference Value (KCRV) was agreed upon during the IAWG meeting in April 2002 at BIPM in Paris as the arithmetic mean of the reported participants' results. Accordingly the equivalence statements were calculated.

Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database www.bipm.org/kcdb.

The final report has been peer-reviewed and approved for publication by the CCQM according to the provisions of the Mutual Recognition Arrangement (MRA).