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Konopelko L.A.,Dimendeleyev Institute For Metrology Vniim | Kustikov Y.A.,Dimendeleyev Institute For Metrology Vniim | Kolobova A.V.,Dimendeleyev Institute For Metrology Vniim | Shor N.B.,Dimendeleyev Institute For Metrology Vniim | And 14 more authors.

A new COOMET project no 483/RU/09 Supplementary comparison of primary standard gas mixtures: Nitrogen monoxide in Nitrogen (50 μ mol/mol), was registered in the KCDB BIPM as COOMET.QM-S1. The gas mixtures for the comparison were prepared gravimetrically in accordance with the requirements of ISO 6142 [1] and were studied regarding their composition and stability at the coordinating laboratory in accordance with requirements of ISO 6143. The preparation ?f gas mixtures for the comparison was carried out from pure substances by 3 stage dilution. Each mixture had its own slightly different reference value of NO mole fraction on the level of 50μmol/mol. 7 gas mixtures were prepared in cylinders and 6 of them were chosen as traveling standards. The pressure of mixtures in the cylinders was approximately 100 bar. The measurement protocol requested each laboratory to perform at least 3 measurements obtained under repeatability conditions including at least three separate calibrations. The protocol informed the participants about the nominal concentration. The amount of substance fractions as obtained from gravimetry and purity analysis of the parent substances were used as reference values. Long-term stability measurements did not show any change in the concentration of the target components within accuracy of these measurements, so that there was not any corrections due to instability. Source

Kim Y.-D.,Korea Research Institute of Standards and Science | Heo G.-S.,Korea Research Institute of Standards and Science | Lee S.,Korea Research Institute of Standards and Science | Han Q.,China Institute of Metrology | And 8 more authors.

A comparison was intended to compare the primary standards for hydrogen sulfide in nitrogen. It was intended to compare the capabilities of the preparation and value assignment of gas standard of H2S. This key comparison can be used to support CMC claims for hydrogen sulfide in the range from 1 μ mol/mol to 500 μ mol/mol. A set of hydrogen sulfide in nitrogen gas mixture with the nominal value of about 10 μ mol/mol were prepared gravimetrically through a 2-step dilution process and verified with a GC-AED (gas chromatography - atomic emission detector) system against a KRISS reference cylinder. After each calibration, the measurements of the gas mixture had to be recorded. Each laboratory was required to express the uncertainty on all results submitted, as expanded uncertainty. This key comparison supports the measurement capability of H2S in the range of 1 μ mol/mol to 500 μ mol/mol in air, nitrogen, or methane. Source

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