Yong-Doo Kim

International comparison CCQM-K46: Ammonia in nitrogen

Ammonia is an important compound in the chemical industry. It is widely used and is the basis for producing other compounds containing nitrogen. Ammonia is also very hazardous, and consequently emissions of ammonia need be controlled and monitored. In the past years, several national metrology institutes have developed facilities for the preparation of Primary Standard gas Mixtures (PSMs), dynamically generated ammonia mixtures and facilities for comparing and certifying gas mixtures containing ammonia. The amount-of-substance fraction level of ammonia chosen for this key comparison is 30–50 µmol/mol. The results of this key comparison revealed that there is at present no consensus among static and dynamic techniques for gas mixture preparation for this component in this range. As key comparison reference value (KCRV), the mean of the three methods is used. In its uncertainty, no allowance is made for the observed biases. With respect to the KCRV, only two laboratories report consistent results. When grouped in accordance with the employed methods, the results are consistent. Further experimental work is needed. 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).

International Comparison CCQM-K41: Hydrogen sulfide in nitrogen

This key comparison was intended to compare the capabilities for the preparation and value assignment of gas standards for hydrogen sulfide in nitrogen, maintained at the participating national metrology institutes. The range of the nominal amount-of-substance fractions of the comparison standard is 10 µmol/mol, which is close to regulatory levels in most countries. The measurements in this key comparison took place in 2005. There were 7 participants. The KCRV was calculated from the participants data, and thus represents a consensus value. This was necessary due to the fact that the cylinders could not be prepared gravimetrically as hydrogen sulfide may be absorbed onto the walls of the cylinder, and has been shown to be unstable in cylinders at the comparison concentration. Thus the gas mixtures were procured from a vendor as a homogeneous lot of 12 cylinders, analyzed by the coordinating laboratory for 6 months to determine stability, and then those determined to be stable were shipped to the participants for analysis. After analysis, the cylinders were returned to the coordinating laboratory for reanalysis. Through this protocol the coordinating laboratory could track stability. In parallel, the coordinating laboratory also analyzed a stable reference, a hydrogen sulfide gas mixture that had been shown to be stable over many years. Using the lot stability data, the participants analytical results, and the coordinating laboratories analysis of the stable reference, a consensus value could be calculated which represents the concentration of the stable reference. The key comparison demonstrated that the results of the laboratories agreed within 0.5% relative to the consensus value. A subset of 6 participants results agreed with the consensus value to better than 0.25%. 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).

Final report on international key comparison CCQM-K65: Gas standards containing methyl and ethyl mercaptans (at the level of 20–30 µmol/mol) in methane

The key comparison CCQM-K65 was intended to compare the capabilities for the preparation and value assignment of gas standards for methyl and ethyl mercaptans in methane, maintained at the participating national metrological institutes: VNIIM (Russia), KRISS (Korea), VSL (Netherlands) and NPL (United Kingdom). The range of the nominal amount of substance fractions of the comparison gas mixtures was 20 µmol/mol to 30 µmol/mol, which is close to regulatory level (in several countries including Russia) for mercaptans in odorated natural gas. This comparison was proposed at the 12th GAWG meeting in October 2004 and was conducted in 2008. Conclusions are as follows: The results of all laboratories are consistent with the reference values. The observed differences between the reference and reported values are within ±0.9% for methyl mercaptan and ±0.75% for ethyl mercaptan relative to the gravimetric values, and do not exceed the appropriate assigned expanded uncertainties. The prepared mixtures were found to be stable during about a year within the uncertainty of the measurements. The gravimetric values were successfully validated with a dynamic method. 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).

Final Report on key comparison CCQM-K22: Benzene, chloroform, dichloromethane, trichloroethylene, tetrachloroethylene, 1,2-dichloroethane, 1,3-butadiene and vinyl chloride in nitrogen

The aim of this comparison was to compare capabilities for the preparation and value assignment of gas mixture standards for benzene, chloroform, dichloromethane, trichloroethylene, tetrachloroethylene, 1,2-dichloroethane, 1,3-butadiene and vinyl chloride in nitrogen (HAPs-8), maintained at national metrology institutes (NMIs). The measurements in this key comparison took place in 2003. There were six 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 90 nmol/mol to 110 nmol/mol. The Chemical Evaluation Research Institute (CERI, Japan) prepared gravimetric mixture samples of HAPs-8 in 10xa0L 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 analysed and then returned to the CERI. Each sample was reanalysed 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 except for 1,2-dichroloethane. These deviations were combined into the uncertainty of the comparison samples but were small enough compared to the deviations from values reported by participating laboratories and the gravimetric values of the samples. 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).

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 10xa0L 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).

International comparison CCQM-K119 liquefied petroleum gas

M L Downey, P J Brewer, E Atkins, R J C Brown, A S Brown, E T Zalewska, A M H van der Veen, D E Smeulders, J B McCallum, R T Satumba, Y D Kim, N Kang, H K Bae, J C Woo, L A Konopelko, T A Popova, A V Meshkov, O V Efremova and Y Kustikov National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK. Van Swinden Laboratorium, Chemistry Group, Thijsseweg 11, 2629 JA Delft, the Netherlands. National Measurement Institute, 36 Bradfield Rd, Lindfield NSW, 2070, Australia. Korea Research Institute of Standards and Science, 267 Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea. D.I. Mendeleyev Institute for Metrology, 19 Moskovsky Prospekt, 198005 St-Petersburg, Russia.

Final report on international key comparison APMP.QM-K41: 10 µmol/mol hydrogen sulfide in nitrogen

This report presents the results of APMP.QM-K41, a key comparison. This comparison is designed to test the capabilities of the NMIs to measure and certify hydrogen sulfide at a nominal amount fraction of 10 µmol/mol in nitrogen. This comparison provides an opportunity to the NMIs in APMP to submit supporting evidence for CMC at the same level as CCQM-K41. The results from this comparison are linked with CCQM-K41. 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).