Key comparison CCQM K-28 was undertaken to assess the measurement capabilities for quantitation of (C₄H₉)₃Sn⁺ (TBT) in a prepared marine sediment by National Metrology Institutes (NMIs), which are members of the Comité Consultatif pour la Quantité de Matière (CCQM). It follows a previous pilot study, CCQM-P18. [1, 2]

This exercise was sanctioned by the 8^th CCQM meeting, 18–19 April 2002, as an activity of the Inorganic Analysis Working Group and was jointly coordinated by the Institute for National Measurement Standards of the National Research Council of Canada (NRC) and LGC, UK.

Eight NMIs initially indicated their interest, with seven ultimately submitting their results. All NMIs relied on isotope dilution mass spectrometry using a species-specific ¹¹⁷Sn-enriched TBT standard, which was supplied by LGC. No analytical methodology was prescribed for this study. As a result, a variety of extraction approaches was adopted by the participants, including mechanical shaking, sonication, accelerated solvent extraction, microwave assisted extraction and heating in combination with ethylation and direct sampling. Detection techniques included ICP-MS (coupled to GC or HPLC for the separation of Sn species) and GC-MS.

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).