Final report on key comparison APMP.QM-K4.1: Ethanol in nitrogen

The aim of this comparison was to compare capabilities for the preparation and value assignment of gas mixture standards for ethanol in nitrogen, maintained at national metrology institutes (NMIs). The measurements in this key comparison took place in 2006. There were three participants and one coordinating laboratory. The key comparison reference value (KCRV) was based on the gravimetric preparation for all components. The range of the nominal amount-of-substance fractions of the comparison standard is 100 µmol/mol to 130 µmol/mol. The Chemical Evaluation Research Institute (CERI, Japan) prepared gravimetric mixture samples of ethanol in nitrogen in 10 L aluminium cylinders and the homogeneity and long-term stability of these samples were evaluated at CERI before and after the shipment of the cylinders to the participants. Each participating laboratory was shipped one cylinder to be analyzed and then returned to the CERI. Each sample was reanalyzed to verify whether the contents were stable throughout the comparison. These measurements showed no significant change in the amount fraction within the estimated uncertainty of the measurements. Two of the three participants submitted results that were within 0.1% of the relevant reference value. In these cases, the estimated uncertainty was larger than the deviation from the reference value. CERI was the link laboratory between CCQM-K4 and APMP.QM-K4. 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).