Final report of International Comparison EUROMET.QM-K1c: Comparison of measurements of nitrogen monoxide in nitrogen

Following-up the key comparison CCQM-K1c, EUROMET organized a regional key comparison involving ten laboratories. The objectives of this EUROMET key comparison were essentially the same as for the CCQM-K1c comparison: to compare the measurement capabilities of national metrological institutes (NMIs) in measuring amount of substance fractions of nitrogen monoxide in nitrogen. The nominal amount of substance fraction of the standards used for the comparison was 100 µmol/mol. The pilot laboratory in this key comparison also piloted the CCQM key comparison and has long-term experience in the behaviour of these mixtures and the technical challenges in preparing batches of very similar mixtures. Most participants used chemiluminescence as the measurement method; two participants used UV techniques and one ND-IR. The degrees of equivalence between this comparison and CCQM-K1c were calculated; four laboratories participated in both key comparisons, thus providing sufficient data for demonstrating the comparability. Main text. To reach the main text of this paper, click on Final Report. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the Mutual Recognition Arrangement (MRA).