Final report on CCQM-K57: Chemical composition of clay

Abstract

After the successful completion of the pilot study, CCQM-P65 [1], the Inorganic Analysis Working Group of CCQM agreed to conduct key comparison CCQM-K57, Chemical composition of clay, in Paris, April 2006. The natural mass fraction levels of five elements—Si, Ca, Fe, Al and Mg—were measured and reported as oxides in clay. Six national metrology institutes participated in CCQM K57, and CENAM (Querétaro, Mexico) coordinated.The methods employed were isotope dilution mass spectrometry (IDMS), inductively coupled plasma–mass spectrometry (ICP-MS), inductively coupled plasma–optical emission spectrometry (ICP-OES) using the dehydration method and condensation method, gravimetric analysis, neutron activation analysis (NAA), prompt gamma activation analysis (PGAA) and x-ray fluorescence spectrometry (XRF) with the reconstitution method and external calibration.This final report presents the capability of the participant institutes, based on the KCRV, which was approved at the IAWG spring meeting in 2008, and the equivalence statements regarding the KCRV, approved at its autumn meeting.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 kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).