CCQM-K13.1 Subsequent Key Comparison: Cadmium and lead in sediment

Abstract

CCQM-K13.1 is a Subsequent Key Comparison for Cadmium and Lead in Sedimentconducted to provide the opportunity for two NMIs to demonstrate and documentimprovements in measurement capability achieved since the conduct of CCQM-K-13,Amount content of Cadmium (Cd) and Lead (Pb) in sediment. The CCQM-K13 keycomparison, completed in 2001, was a successor to CCQM-P15 (Cadmium and Lead contentin sediment) study, and was performed to demonstrate and document the capability ofinterested National Metrology Institutes to measure Cd and Pb content in a sediment sample.The P15, K13 and K13.1 comparisons were activities of the Inorganic Analysis WorkingGroup (IAWG) of CCQM. CCQM-P15 and K13 were coordinated by the Institute forReference Materials and Measurements (IRMM, Geel, Belgium) of the Joint Research Centre(JRC) of the European Commission. The majority of the participants applied isotope dilutionmass spectrometry (IDMS) using various mass spectrometry techniques. External standardcalibration was used by two participants for the Cd measurement and by one participant forthe Pb measurement.Satisfactory agreement of reported results was observed for most participants in CCQM-K13;however, two NMIs (CEMAN and PTB) wished to participate in a subsequent KeyComparison to demonstrate improved performance of their analytical capabilities. SinceNIST was in the process of certifying a new marine sediment SRM (2702), and both Cd andPb were going to be determined by the same methods used in CCQM-K13, it was decided touse this opportunity to perform a Subsequent Key Comparison (CCQM-K13.1). As NIST hadsuccessfully participated in both the pilot study and K13, it served as the anchor point towhich the other participants in the subsequent study could be compared. CENAM signed upto determine Cd only in this study, and PTB signed up for both Pb and Cd. The NIST andPTB results for Pb exhibited good overlap. However, problems were observed for Cd. TheNIST and CENAM Cd results did not overlap, and PTB could not report an official result forCd largely due to suspected isobaric interferences.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 theCCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).