This report presents the results of CCQM-K93, a key comparison between 13 National Measurement Institutes (NMIs), which tested the capability of the NMIs to prepare standard gas mixtures of ethanol at a nominal amount fraction of 120 µmol/mol in nitrogen. This composition is typical of the levels used to calibrate evidential breath analysers in many countries. Such standards fulfill the agreed requirements of the International Organization of Legal Metrology (OIML) for the calibration of evidential breath-alcohol analysers.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 capabilities for the preparation of certified reference materials of carbon monoxide, carbon dioxide, and propane in nitrogen have been compared. The participating national metrology institutes each submitted a gravimetrically prepared gas mixture of a specified target composition typical for the automotive industry to the coordinating laboratory. All mixtures were analyzed by the coordinating laboratory using a gas chromatograph equipped with a thermal conductivity detector in three runs under repeatable conditions. Based on the calibration curve, reference values were assigned to the amount fractions of carbon monoxide, carbon dioxide, and propane. The degrees of equivalence were established as the difference between the gas composition as calculated from preparation and the measured one, and its associated uncertainty. All participants obtained satisfactory results.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 EURAMET, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).
The key comparison CCQM-K76 was designed to test the capabilities of the participants to measure and certify sulfur dioxide in nitrogen, and to provide supporting evidence for the CMCs of these institutes for sulfur dioxide. Also, as sulfur dioxide is designated a core compound, and the 100 µmol/mol concentration is within the designated core compound concentration range, this comparison was also designed to demonstrate core capabilities of institutes which qualify under the rules of the Gas Analysis Working Group.The results of all 16 participants in this key comparison, except for three, are consistent with their key comparisons reference values. The three participants which are outside the KCRV interval are NIM, SMU and NPLI. This comparison may be used to demonstrate core analytical capabilities in accordance with the rules and procedures of the CCQM Gas Analysis Working group.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).
Main text The knowledge of natural gas composition is relevant for custody transfer operations. The determination of its composition is often used as the basis for the calculation of the calorific value. This report is a supplementary comparison organized for the Latin American region at SIM for components from methane to n-hexane, nitrogen, and carbon dioxide with a total of ten components. The traveling standards were obtained from an external source and checked for homogeneity and stability by CENAM before and after the measurements by participants and confirming the values under the involvement of two coordinating laboratories (CENAM and KRISS). The level of uncertainties of this comparison were not the traditional lower uncertainties for natural gas by long-established NMIs. Nevertheless, the results from the comparison are a useful official starting point for the SIM region. All results usually agree at levels higher than 0.6 % with the comparison reference value. The combination of the complexity of the samples being obtained from an external provider, the loss of performance of methods and instruments used by CENAM, and the use of traveling standards all contributed to the unexpectedly higher uncertainties of measurement results of this study. It should also be noted that some participating laboratories did not consider normalizing their results and did not apply all appropriate corrections. For the reference value, all normalized amount fractions have been used and uncertainties propagated appropriately. 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 https://www.bipm.org/kcdb/. 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).
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