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The CCQM-K97 key comparison was organized by the inorganic analysis working group (IAWG) of CCQM as a follow-up to completed pilot study CCQM-P96 and P96.1 to test the abilities of the national metrology institutes to accurately quantitate the mass fraction of arsenobetaine (AsB) in standard solution and in fish tissue. A pilot study CCQM-P133 was parallelized with this key comparison. National Institute of Metrology (NIM), China and National Metrology Institute of Japan (NMIJ) acted as the coordinating laboratories. Six NMIs participated in CCQM-K97 and two institutes participated in CCQM-P133, and all of them submitted the results. Some NMIs submitted more than one results by different methods. The results were in excellent agreement with each other, and obviously better than those of previous P96 and P96.1. Therefore the calibrant which each NMI used was comparable. It shows that the capabilities of some of the participants have been improved after the previous pilot studies. 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 (CIPM MRA).

The CCQM-K96.1 key comparison was a subsequent bilateral comparison to the CCQM-K96 'Determination of amount content of dichromate'. The comparisons were organized jointly by the inorganic analysis and electrochemical analysis working groups of the CCQM to test the abilities of the metrology institutes to measure the content amount of dichromate. The NIM China has obtained unsatisfactory results from the CCQM-K96. The NIM requested a bilateral comparison to demonstrate its capability after improvement. The KRISS acted as the coordinating laboratory and served as a link to the reference value of CCQM-K96. Both participants used high-accuracy constant current coulometry. A good agreement of the results was observed. 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 CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The key comparison CCQM-K96 was organized jointly by the inorganic and electrochemistry working groups of CCQM to test the abilities of the metrology institutes to measure the amount content of dichromate. Slovak Institute of Metrology with help of KRISS acted as the coordinating laboratories. Eight NMIs took part in the comparison. All participants used high accuracy constant current coulometry. Good agreement of the results was observed. 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 (CIPM MRA).

This key comparison (KC), CCQM-K73, was performed to demonstrate the capability of the participating National Metrology Institutes (NMIs) to measure the amount content of H+, νH+, in an HCl solution with a nominal νH+ of 0.1 mol kg−1. The comparison was a joint activity of the Electrochemical Working Group (EAWG) and Inorganic Analysis Working Group (IAWG) of the CCQM and was coordinated by NIST (USA) and CENAM (Mexico). The agreement of the results was not commensurate with the claimed uncertainties of the subset of participants that claimed small uncertainties for this determination. A workshop on technical issues relating to the CCQM-K73 measurements was conducted at the joint IAWG-EAWG meeting at the Bureau International des Poids et Mesures (BIPM), Paris (Sevres) in April 2010. Several possible sources of bias were investigated, but none could explain the observed dispersion among the participants' results. In the absence of a specific cause for the dispersion, the IAWG and EAWG decided to assign a Key Comparison Reference Value, KCRV, and standard uncertainty of the KCRV, uKCRV, based on the DerSimonian–Laird statistical estimator. The uKCRV is dominated by the between-laboratory scatter of results in CCQM-K73. The uncertainty estimates from the participants with the lowest reported uncertainties remain unsupported by this KC. 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 (CIPM MRA).

The key comparison CCQM-K34 was organized jointly by the inorganic and electrochemistry working groups of the CCQM as a follow-up to the pilot study CCQM-P36 to test the abilities of the metrology institutes to measure the amount content of acid in solid weak acids. The Slovak Institute of Metrology acted as the coordinating laboratory, and seven NMIs expressed interest in participation. All participants used constant current coulometry at different levels of sophistication. In general very good agreement of the results was observed; some possible problems were highlighted. 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.