Key comparison CCQM-K45: Sn in tomato paste: final report

Key comparison CCQM-K45 was performed to demonstrate and document the capability of interested national metrology institutes in the mass fraction of Sn in a food matrix. This comparison was an activity of the Inorganic Analysis Working Group of the Comit? Consultatif pour la Qualit? de la Mati?re and was coordinated by LGC (Teddington, UK). The following laboratories participated in this key comparison (alphabetical order). KRISS (Republic of South Korea) LGC (UK) LNE (France) PTB (Germany) UME (Turkey) Good agreement was observed between the reported results of four of the participants. The other participant did not use any HCl during the sample preparation, which can affect the stability of the tin in solution, and its reported value was lower than for the other participants. It was not included in the calculation of the key comparison reference value with the agreement of the NMI concerned. The reference value was calculated as the arithmetic mean of the reported participants' results (excluding one), and is equal to 227.1 mg kg-1, with an expanded uncertainty of 2.4 mg kg-1 (1.1%). The equivalence statements were calculated on this basis. 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).