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).
At the highest metrological level, biogas standards are commonly prepared gravimetrically as PSMs (primary standard mixtures). This international key comparison addresses the composition of biogas, to support calibration and measurement services for this renewable energy gas. The mixtures contain nitrogen, carbon dioxide, methane, ethane, propane, hydrogen and oxygen and represent the composition of biogas from landfills. The results in this Track C key comparison on the composition of biogas are generally good. Some of the datasets, especially that of oxygen, showed substantial extra dispersion, that could not be explained by the stated uncertainties.
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).
Nitrogen monoxide is one of the main contaminants present in the atmospheric air due to emissions of vehicles and power stations.Taking into account the positive experience of VNIIM in the pilot study CCQM-P73 (Nitrogen monoxide gas standards, 30 µmol/mol to 70 µmol/mol), a COOMET project (No 483/RU/09) on the subject was decided and registered in the KCDB as supplementary comparison COOMET.QM-S1. This involved six National Metrology Institutes, aiming to consolidate or support their Calibration and Measurement Capabilities in this field.It was found that most of the results were consistent with the reference (gravimetric) values, with observed differences not exceeding ±1.3% and not exceeding either the appropriate assigned expanded uncertainties. There was, however, one exception: the INMETRO difference from the reference value is slightly higher than the expended uncertainty.The mixtures prepared for this exercise were found to be stable during about one year within the uncertainty of the measurements.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 COOMET, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
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