Supplementary comparison EURAMET.QM-S4: automotive gas mixtures

Abstract

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).

Extrapolation schemes of key comparison results in gas analysis

“…The relationship between the amount fraction and the standard uncertainty is visualised in figure 1. In the figure, also the submitted measurement results in CCQM-K3 [12], Euramet.QM-S4 [45], CCQM-K111 [13] and Euramet.QM-S1 [46] are included. The degrees of equivalence were in all cases satisfactory, i.e., the absolute value of the difference was smaller than the associated expanded uncertainty.…”

“…The relationship between the amount fraction and the standard uncertainty is visualised in figure 2. Also the measurement results submitted in Euramet.QM-S4 [45] and Euramet.QM-S1 [46] are included. Again, it is important to note that (1) the absolute value of the difference of the degree of equivalence was smaller than the associated expanded uncertainty, and (2) the calculated standard uncertainty matches well with the standard uncertainties summarised in table 2.…”

“…x 0 (mol mol The measurement results submitted in the international comparisons CCQM-K3 [12], Euramet.QM-S1 [46], CCQM-K51 [14], Euramet.QM-S4 [45] and Euramet 708 [50] have been included in the data set (see figure 4). It is important to note that (1) the degrees of equivalence were in all cases satisfactory, i.e., the absolute value of the difference was smaller than the associated expanded uncertainty in these comparisons, and…”

“…The results of the meta-analysis on the long-term stability study data are shown in table 6. The measurement results submitted in the international comparisons CCQM-K3 [12], CCQM-P41 [17,18], CCQM-K52 [15], Euramet.QM-S1 [46], Euramet.QM-S4 [45], Euramet.QM-S5 [51] and CCQM-K120 [26] are shown in figure 5. Again, it is important to note that (1) the degrees of equivalence were in all cases satisfactory, i.e., the absolute value of the difference was smaller than the associated expanded uncertainty, and (2) the calculated standard uncertainty matches well with the standard uncertainties summarised in table 6.…”