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An optical scheme of an optical absorption gas analyzer optimized for measuring the freon content has been presented. A radiation source with a given maximum spectral density of energy luminosity in the range from 8 to 10 μm with a reference channel of 9.5 μm and a measurement threshold of 1 ppm has been developed and studied. The design of the interference filter system has been developed.

The preparation of formaldehyde gas mixtures required for metrological assurance of air pollution control is an urgent task. Methods for the preparation of gas mixtures of formaldehyde for metrological purposes are considered. The 2 μmol/mol-level gas mixtures of formaldehyde in nitrogen have been obtained by a dynamic-gravimetric method with the depolymerization of trioxane vapor. The efficiency of the trioxane conversion process was experimentally studied. The sources of uncertainty are analyzed in detail. The reference gas mixtures obtained were used for the formaldehyde mole fraction measurements during the CCQM-K90 key comparison. The relative expanded uncertainty of the measurement U = 3.3% was achieved, confi rmed by the comparison results.

Isotope ratio measurement systems based on optical spectrometers becomes widely used because of several important advantages. First is fundamental possibility to distinguish the isotopologues with the same molecular weight but different isotopic composition like 16O13C16O and 16O12C17O. Second is fundamental possibility to perform calibration free absolute measurement of different isotopologues based on ab initio calculations of line intensities [1]. Third is experimental usability, field deployability and low cost of the optical instruments.The disadvantage of the optical isotope ratio spectrometers available on the market compared to the isotope ratio mass spectrometers is still low accuracy associated not only with the capabilities of optical instruments as such, but also with the lack of high-precision measurement procedures. To improve the accuracy of the optical measurement system, the main factors affecting the measurement result should be investigated and eliminated.In this study, we used CM-CRDS carbon isotope ratio measurement system consisted of Picarro G2131i analyzer, Picarro combustion module, Picarro Caddy Universal interface, homemade system of solenoid valves Camozzi. The calibration of the measurement system was made by combustion of certified reference materials from the International Atomic Energy Agency as recommended in [2]. The linearity of the delta scale was evaluated. Non-linearity of the delta scale leads to a bias if just one or two certified reference materials are used for calibration.The measurement procedure of carbon isotope ratios in solid sample on CM-CRDS is as follows. A sample is broken down into elemental components in the combustion module. After the cleaning from interfering components, CO2 is diluted with nitrogen and analyzed by CRDS instrument. The similar procedure is performed with reference material. The issue is that even if the mass of sample and reference material are the same, the concentration of CO2 in the analyzed mixture is different. Mismatch of concentrations leads to bias in measured isotope ratios. The magnitude of concentration dependence is estimated in this study.The obtained results are discussed and ways to eliminate the abovementioned issues are proposed. [1] Polyansky, Oleg & Bielska, Katarzyna & Ghysels, Mélanie & Lodi, Lorenzo & Zobov, Nikolai & Hodges, Joseph & Tennyson, Jonathan. (2015). High-Accuracy CO2 Line Intensities Determined from Theory and Experiment. Physical Review Letters. 114. 10.1103/PhysRevLett.114.243001.[2] Willi A. Brand et al. Assessment of international reference materials for isotope-ratio analysis (IUPAC Technical Report). Pure Appl. Chem., 2014, 86(3), Pages 425–467

In Russia, the metrological traceability of certified reference materials for the composition of gas mixtures in cylinders under pressure produced by the manufacturers of certified reference materials is carried out in accordance with GOST 8.578-2014. Certified reference materials for the composition of gas mixtures in cylinders under pressure are applied in type approval testing of measuring instruments, verification, calibration and graduation of gas analytical measuring instruments intended for controlling fire and explosion hazardous gases and vapours, harmful components in the atmospheric and workplace air, emissions of vehicles and industrial enterprises, control of technological processes and quality of hydrocarbon products, etc. In this connection, ensuring the quality of commercially available certified reference materials, which number has recently amounted to about 100,000 cylinders with gas mixtures per year, is an important task. In this paper, we suggest a set of measures aimed at ensuring the quality of certified reference gas mixtures in cylinders under pressure, mass-produced by the manufacturers of certified reference materials: mandatory accreditation of reference material producers (RMPs) for compliance with the requirements of GOST ISO Guide 34-2014 and GOST ISO Guide 35-2015; constant participation of RMPs in proficiency testing programmes through interlaboratory comparisons; updating and revision of the existing set of standards defining the requirements for the entire life cycle of certified reference gas mixtures in cylinders under pressure; improvement of the method for reference material certification by calculating the value of their expanded uncertainty and introducing of a new, “technological reserve”, factor.

The possibility of using the available spectroscopic databases for high-precision measurements of spectral parameters of gases has been studied. A new approach to measuring concentrations of gaseous components (НCl, CO, NO, SO2) in gas mixtures employing the HITRAN or GEISA spectroscopic databases has been proposed. A certification method of control gas mixtures using Fourier-transform IR spectroscopy has been developed to transfer the mole-fraction units to working standards in order to reduce the required number of reference standards and improve the accuracy of measurements.

The development of a new type of reference standard for carbon isotopic composition consisting of 12CO2 + 13CO2 and N2 gaseous mixtures in tanks under pressure is discussed. These standards are required for measuring the isotope ratio 13C/12C in gaseous mixtures of CO2. The procedures for preparing and verifying the reference standards are described and their stability is tested. These standard samples can be used for calibrating (testing) isotopic infrared analyzers and mass spectrometers.

The main issues and recent achievements in the field of metrological assurance of carbon isotope-ratio analysis are considered. An overview of the existing methods of carbon isotope-ratio analysis of gaseous, liquid, and solid substances is offered. Recommendations for the development of new carbon isotopic reference gaseous mixtures in vessels under pressure traceable to the international standard VPDB are given. The basic error limits required for their certification are formulated.

The survey article presents the results of work on metrological assurance of measurements using IR spectrometers, IR correlation gas analyzers and CRDS instruments. For the successful application of the existing databases in absorption spectroscopy, it is necessary to identify the most accurate data and assign uncertainty to it, based on experimental studies using reference gas mixtures. The properties of the methods that lead to a deterioration in the measurement accuracy were investigated and the ways were suggested to overcome the shortcomings of the measuring methods.

The basic principles of development of metrological assurance of quality control of products on the basis of two-phase hydrocarbon systems (stable and unstable gas condensates) are considered.

This paper presents a brief review of the developed laser technologies and lidars with hyperspectral resolution and extremely high sensitivity for the diagnosis of complex impurities in the atmosphere and hydrosphere via Raman spectra. The technological foundations of the research, exploratory, and ecological studies of hydrocarbons are developed using Raman lidars. The prospects of hybridization of Raman spectrometry and video spectrometry in remote probing are considered.

At the highest metrological level, biogas standards are commonly prepared gravimetrically as PSMs (primary standard mixtures). This international key comparison addresses the composition of biogas, to support calibration and measurement services for this renewable energy gas. The mixtures contain nitrogen, carbon dioxide, methane, ethane, propane, hydrogen and oxygen and represent the composition of biogas from landfills. The results in this Track C key comparison on the composition of biogas are generally good. Some of the datasets, especially that of oxygen, showed substantial extra dispersion, that could not be explained by the stated uncertainties. 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).

Application of CCD array photodetector technology is shown to provide record synchronously hundreds of spectral intervals, increase essentially the relative aperture and intensity of echo-signals in the input optical path as well as to reduce the mass – dimension parameters of hyperspectral Raman LIDAR as a whole for geoecological monitoring by aerial and underwater unmanned vehicles.

Measuring of absolute 13C/12C isotope amount ratios allows to explore the topical problems of the modern world, alcoholic beverages and tobacco, medical diagnostics of human health. Raman sensor is used to measure the ratio of carbon isotopes in the exhaled carbon dioxide, which is used to diagnose the human infection of Helicobacter pylori and the influence of the Helicobacter pylori bacterium on the occurrence of gastritis, gastric and duodenal ulcers. A method for the analysis of human infection with Helicobacter pylori was developed on the basis of measurements of the ratio of 13C / 12C carbon isotopes in human exhaled air with a high level of measurement accuracy. The provision of comparability of absolute 13C/12C isotope amount ratios is carried by gravimetrically prepared reference standards. The key features and emerging issues are discussed.

Forensic application of carbon isotope ratio measurements of honey and honey protein to investigate the degree of adulteration with high fructose corn syrup or other C4 plant sugars is well established. These measurements must use methods that exhibit suitable performance criteria, particularly with regard to measurement uncertainty and traceability – low levels of adulteration can only be detected by methods that result in suitably small measurement uncertainties such that differences of 1‰ or less can be reliably detected. Inter-laboratory exercises are invaluable to assess the state-of-the art of measurement capabilities of laboratories necessary to achieve such performance criteria. National and designated metrology institutes from a number of countries recently participated in an inter-laboratory assessment (CCQM-K140) of stable carbon isotope ratio determination of bulk honey. The same sample material was distributed to a number of forensic isotope analysis laboratories that could not participate directly in the metrological comparison. The results from these studies have demonstrated that the majority of participants provided isotope delta values with acceptable performance metrics; that all participants ensured traceability of their results; and that where measurement uncertainties were reported; these were fit-for-purpose. A number of the forensic laboratories only reported precision rather than full estimates of measurement uncertainty and this was the major cause of the few instances of questionable performance metrics. Reporting of standard deviations in place of measurement uncertainties is common practice outside metrology institutes and the implications for interpretations of small differences in isotopic compositions are discussed. The results have also highlighted a number of considerations that are useful for organisers of similar inter-laboratory studies in the future.

We developed SRS-sensor 13C/12C isotops measurements detecting Helicobacter Pylori for medical diagnostics of human health. Measuring of absolute 13С/12С isotope amount ratios allows to explore the topical problems of the modern world, alcoholic beverages and tobacco, medical diagnostics of human health. SRS method is used to measure the ratio of carbon isotopes in the exhaled carbon dioxide, which is used to diagnose the human infection of Helicobacter pylori and the influence of the Helicobacter pylori bacterium on the occurrence of gastritis, gastric and duodenal ulcers. A method for the analysis of human infection with Helicobacter pylori was developed on the basis of measurements of the ratio of 13C / 12C carbon isotopes in human exhaled air with a high level of measurement accuracy. The article reviews the work in the field of provision comparability of absolute 13С/12С isotope amount ratios in the environment and food. The analysis of the technical and metrological characteristics of traditional and perspective instruments for measuring isotope ratios is presented. The provision of comparability of absolute 13С/12С isotope amount ratios is carried by gravimetrically prepared reference standards. The key features and emerging issues are discussed.

Glucose and creatinine are two of the most frequently measured substances in human blood/serum for assessing the health status of individuals. Because of their clinical significance, CCQM-K11 glucose in human serum and CCQM-K12 creatinine in human serum were the fourth and fifth key comparisons (KCs) performed by the Organic Analysis Working Group (OAWG). These KCs were conducted in parallel and were completed in 2001. The initial subsequent KCs for glucose, CCQM-K11.1, and creatinine, CCQM-K12.1, were completed in 2005. Measurements for the next KCs for these two measurands, CCQM-K11.2 and CCQM-K12.2, were completed in 2013. While designed as subsequent KCs, systematic discordances between the participants' and the anchor institution's results in both comparisons lead the OAWG to request reference results from two experienced laboratories that had participated in the 2001 comparisons. Based on the totality of the available information, the OAWG converted both CCQM-K11.2 and CCQM-K12.2 to 'Track C' KCs where the key comparison reference value is estimated by consensus. These comparisons highlighted that carrying out comparisons for complex chemical measurements and expecting to be able to treat them under the approaches used for formal CIPM subsequent comparisons is not an appropriate strategy. The approach used here is a compromise to gain the best value from the comparison; it is not an approach that will be used in the future. Instead, the OAWG will focus on Track A and Track C comparisons that are treated as stand-alone entities. Participation in CCQM-K11.2 demonstrates a laboratory's capabilities to measure a polar (pKow > 2), low molecular mass (100 g/mol to 500 g/mol) metabolite in human serum at relatively high concentrations (0.1 mg/g to 10 mg/g). Participation in CCQM-K12.2 demonstrates capabilities to measure similar classes of metabolites at relatively low concentrations (1 μg/g to 30 μg/g). The capabilities required for the analysis of complex biological matrices include sample preparation (protein precipitation, extraction, derivatization), gas chromatographic (GC) or liquid chromatographic (LC) separation, and quantification using an isotope dilution mass spectrometry (IDMS) approach. 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).

Wavelength-scanned cavity ring-down spectroscopy (WS CRDS) is used in gas analysis. Calibration gas mixtures containing carbon monoxide, carbon-12 dioxide, carbon-13 dioxide, methane, and formaldehyde are used to determine the metrological characteristics of WS CRDS gas analyzers. Most experimental results are in agreement with the declared data. For gas mixtures in which the gas matrix differs from air, the broadening of spectral lines related to the interaction of particles causes significant errors in the concentration measurements. Such effects that neutralize the advantages of the WS CRDS method are studied in this work. The coefficients that can be used to correct the results of the WS CRDS gas analyzers and compensate for errors related to different gas matrices are presented.

The possibilities of the Raman method of radiocarbon measurements in the field of gas analysis are investigated. With the help of veneer gas mixtures of carbon monoxide, carbon dioxide-12, carbon dioxide-13, methane, formaldehyde, the micrometric characteristics of Raman lidars were found, which in most cases coincided with the claimed ones. When gas mixtures are supplied, the diluent gas in which differs from air, the broadening of the spectral lines associated with the interactions between the particles, the results, to significant errors in the measured concentration. These effects, which negate the advantages of the measurement method, are investigated in the framework of this paper. The results of determining the coefficients for correcting the readings of gas analyzers with the achievement of inaccuracies from various diluent gases, as well as the data of the prototype Raman lidar.

Metrological traceability is usually realized by comparing the high precision gas mixtures (reference standards (RS)) and working standards used for calibration of gas analyzers. The procedures with the use of UV absorption, FTIR, and CRD spectroscopy for the transfer of the mole fraction from the RS to the working standards are developed, in order to reduce the required number of RS and improve the accuracy of measurements. For the successful use of existing spectroscopic databases, the most accurate data was necessary to identify and attribute the uncertainty, based on our own experimental work carried out using the RS. Further on the transfer of the mole fraction from the RS to the working standards can be done without the use of the RS. In the case of CRDS, when the matrix of the studied gas mixture is different from air, the broadening of the spectral lines associated with the interactions between molecules leads to significant error in the measurement of concentration of the studied gas. The effects leveling benefits of the CRDS method are studied.

Measurement assurance in the identification of ozone-depleting substances is considered. It is indicated thatozone-depleting halogenated hydrocarbons must be monitored, and portable devices for detecting counterfeits in customs border control are needed.

It was established by the method HPLC-MS with electrospray ionization that in solutions of fullerenes C60 and C70 in some essential oils a chemical reaction occurred leading to adducts of fullerenes with unsaturated terpenes. In the course of time the quantity of the adduct in solution increased and a component originating from addition of two molecules of terpene to a molecule of fullerene is formed. This can be the reason of abnormally high solubility of light fullerenes in mixtures of terpene hydrocarbons.

SRS-sensor was developed for measuring absolute amount ratios of 13C/12C isotopes for medical application. Measuring absolute amount ratios of 13C/12C isotopes allows detection of Helicobacter pylori for medical diagnostics of human health. SRS method is used to measure the amount of carbon dioxide isotopes in exhaled air to detect Helicobacter pylori. This is used to determine influence of the bacterium on the occurrence of gastritis, gastric and duodenal ulcers. This paper includes methods and metrological characteristics for measuring isotopes ratios.

This article dwells upon the organization of the educational process at ITMO University for specialization 27.04.01 Standardization and Metrology for masters according to the individual educational standard 3++ of ITMO University. The main professional standards and areas of activity for the implementation of this specialization and the process of creating competencies based on professional standards and areas of activity are described.

This article presents the report on the supplementary comparison COOMET.QM-S4, "C2-C5 components in mixtures of liquified hydrocarbons". The objective of this comparison was assessment of the analytical capabilities of COOMET NMIs for measuring the composition of Liquid Petroleum Gas (LPG) mixtures when sampled in the liquid phase from Constant Pressure Cylinders (CPCs). KEY WORDS FOR SEARCH supplementary comparison, COOMET, Liquid Petroleum Gas, LPG, amount of substance fraction, constant pressure cylinders, ethane, propane, propene, i-butane, n-butane, 1-butene, i-pentane 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).

CCQM-K120.a comparison involves preparing standards of carbon dioxide in air which are fit for purpose for the atmospheric monitoring community, with stringent requirements on matrix composition and measurement uncertainty of the CO2 mole fraction. This represents an analytical challenge and is therefore considered as a Track C comparison. The comparison will underpin CMC claims for CO2 in air for standards and calibrations services for the atmospheric monitoring community, matrix matched to real air, over the mole fraction range of 250 μmol/mol to 520 μmol/mol. CCQM-K120.b comparison tests core skills and competencies required in gravimetric preparation, analytical certification and purity analysis. It is considered as a Track A comparison. It will underpin CO2 in air and nitrogen claims in a mole fraction range starting at the smallest participant's reported expanded uncertainty and ending at 500 mmol/mol. Participants successful in this comparison may use their result in the flexible scheme and underpin claims for all core mixtures This study has involved a comparison at the BIPM of a suite of 44 gas standards prepared by each of the participating laboratories. Fourteen laboratories took part in both comparisons (CCQM-K120.a, CCQM-K120.b) and just one solely in the CCQM-K120.b comparison. The standards were sent to the BIPM where the comparison measurements were performed. Two measurement methods were used to compare the standards, to ensure no measurement method dependant bias: GC-FID and FTIR spectroscopic analysis corrected for isotopic variation in the CO2 gases, measured at the BIPM using absorption laser spectroscopy. Following the advice of the CCQM Gas Analysis Working Group, results from the FTIR method were used to calculate the key comparison reference values. KEY WORDS FOR SEARCH FTIR, CO2, GC-FID, Carbon dioxide at background level, Carbon dioxide at urban level, Delta Ray, CO2 gas standards 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).

The management of the production of calibration specimens (of approved type and enterprise-wide) of a composition of hydrocarbon mixtures is considered; special attention is paid to the traceability of the standards to GET 154–2011, the state primary standard of the unit of mole fraction and unit of mass concentration of components in gaseous media.

Design and functional subsystems of a lidar sensor for the remote detection of isotopes of iodine, indicators of radioactive contamination was developed. CARS-lidar allows to register the radionuclide with a concentration level of 3÷10 molecules has been shown.

A summary is presented of the metrological verification of alcohol breathalyzers used for the examination of motorists for alcohol intoxication. The state verification scheme is provided for instruments measuring ethanol content in gaseous and liquid media along with the basic metrological characteristics of alcohol breathalyzers and working standards. A description is given for the calibration and measurement capabilities in the Russian Federation included in the international database for analytical chemical measurements in the category “Forensic control of ethanol.”

A metrological complex is developed for provision of measurement unification during production of carbon nanomaterials, i.e., fullerenes, including measurement chromatographic and mass-spectrometric equipment, a set of procedures for certifying reference standards and state standard specimens, and technological regulations for preparing high-purity fullerenes C60 and C70.

The organizational principles of the international system of uniformity of analytic chemical measurements implemented by the International Bureau of Weights and Measures and the Consultative Committee on Quantity of a Material – Metrology in Chemistry are described. The degree of participation of Russian metrological institutes in the implementation of the international agreement on mutual recognition of national standards and calibration certificates is considered. An estimate of the level of measurement and calibration capabilities of Russian metrological institutes is presented.

A complex of studies on the development of a system of metrological assurance of measurement technologies in the recovery, transportation, and delivery of gas to customers in the Russian Federation is considered. A system of metrological assurance for quality control of natural gas developed at the Gazprom company that supports the traceability of the results of measurements to the state primary standard of units of mole fraction and mass concentration of the components in gaseous media (GET 154-01) and renders the results of quality control of natural gas internationally recognizable is presented.

Results are provided for pilot comparisons between the Mendeleev All-Russia Research Institute of Metrology (VNIIM) and the All-Russia Research Institute of Physicotechnical and Radio Measurements (VNIIFTRI) in the field of particle size measurement within the framework of COOMET Project No. 378/RU/06. The research area is spherical particles with an average diameter in the range 0.5–1.5 μm. Measurements are performed by optical and electron microscopy, and a diffraction method.

Methods and instruments for ensuring unity of measurements of the ozone content in the surface layer of the atmosphere are described. The uncertainty budget of the standard photometric system based on an SRP-type photometer, forming part of the State Primary Standard of the units of molar fraction and mass concentration of the components in gaseous media (GET 154-01) is presented. The results of international key comparisons carried out under the aegis of the BIPM are presented.

Liquefied hydrocarbon mixtures with traceable composition are required in order to underpin measurements of the composition and other physical properties of LPG (liquefied petroleum gas), thus meeting the needs of an increasingly large industrial market. This comparison aims to assess the analytical capabilities of laboratories for measuring the composition of a Liquid Petroleum Gas (LPG) mixture when sampled in the liquid phase from a Constant Pressure Cylinder. Mixtures contained ethane, propane, propene, i-butane, n-butane, but-1-ene and i-pentane with nominal amount fractions of 2, 71, 9, 4, 10, 3 and 1 cmol mol−1 respectively. 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).

The measurement of trace amounts of water in process gases is of paramount importance to a number of manufacturing processes. Water is considered to be one of the most difficult impurities to remove from gas supply systems and there is strong evidence that the presence of water contamination in semiconductor gases has a measurable impact on the quality and performance of devices. Consequently, semiconductor manufacturers are constantly reducing target levels of water in purge and process gases. As the purity of gases improves, the problem of quantifying contamination and ensuring that the gases are within specification at the point of use becomes more challenging. There are several established techniques for detecting trace water vapour in process gases. These include instruments based on the chilled mirror principle which measures the dew-point of the gas and the quartz crystal adsorption principle which measures the adsorption of water vapour into a crystal with a hygroscopic coating. Most recently, spectroscopic instruments such as those employing cavity ring-down spectroscopy (CRDS) have become available. The calibration of such instruments is a difficult exercise because of the very limited availability of accurate water vapour standards. This CCQM key comparison aims to assess the analytical capabilities of laboratories for measuring the composition of 10 μmol mol-1 water vapour in nitrogen. KEY WORDS FOR SEARCH Metrology, traceability, water vapour, process gas, advance manufacturing 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).

A requirement is substantiated for improving the accuracy of certification for gravimetric standard gas mixtures (GSGM). Principles are developed for external quality control of GSGM for working standards of the zero order with application of statistical monitoring methods for quality according to a quantified characteristic.

Developpement des methodes de transfert de fraction molaire et de la concentration en masse du polluants gazeux de la part de Etalon Primaire de Mesurage d’Etat dans une Ambiance Gazeux (GET 154-2011 [1]) a etalons de travail de zero et premiere categorie (materiau de reference) a la base de methodes de la spectroscopie absorption en UV.

The CCQM-K90 comparison is designed to evaluate the level of comparability of national metrology institutes (NMI) or designated institutes (DI) measurement capabilities for formaldehyde in nitrogen at a nominal mole fraction of 2 μmol mol−1. The comparison was organised by the BIPM using a suite of gas mixtures prepared by a producer of specialty calibration gases. The BIPM assigned the formaldehyde mole fraction in the mixtures by comparison with primary mixtures generated dynamically by permeation coupled with continuous weighing in a magnetic suspension balance. The BIPM developed two dynamic sources of formaldehyde in nitrogen that provide two independent values of the formaldehyde mole fraction: the first one based on diffusion of trioxane followed by thermal conversion to formaldehyde, the second one based on permeation of formaldehyde from paraformaldehyde contained in a permeation tube. Two independent analytical methods, based on cavity ring down spectroscopy (CRDS) and Fourier transform infrared spectroscopy (FTIR) were used for the assignment procedure. Each participating institute was provided with one transfer standard and value assigned the formaldehyde mole fraction in the standard based on its own measurement capabilities. The stability of the formaldehyde mole fraction in transfer standards was deduced from repeated measurements performed at the BIPM before and after measurements performed at participating institutes. In addition, 5 control standards were kept at the BIPM for regular measurements during the course of the comparison. Temporal trends that approximately describe the linear decrease of the amount-of-substance fraction of formaldehyde in nitrogen in the transfer standards over time were estimated by two different mathematical treatments, the outcomes of which were proposed to participants. The two treatments also differed in the way measurement uncertainties arising from measurements performed at the BIPM were propagated to the uncertainty of the trend parameters, as well as how the dispersion of the dates when measurements were made by the participants was taken into account. Upon decision of the participants, the Key Comparison Reference Values were assigned by the BIPM using the largest uncertainty for measurements performed at the BIPM, linear regression without weight to calculate the trend parameters, and not taking into account the dispersion of dates for measurements made by the participant. Each transfer standard was assigned its own reference value and associated expanded uncertainty. An expression for the degree of equivalence between each participating institute and the KCRV was calculated from the comparison results and measurement uncertainties submitted by participating laboratories. Results of the alternative mathematical treatment are presented in annex of this report. 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).

This article presents the report on the COOMET key comparison COOMET.QM-K111, which is linking to the appropriate CCQM comparison—CCQM-K111 'Propane in nitrogen 1000 μmol/mol'. CCQM-K111 was carried out in 2014–2016 and it was one of a series of key comparisons in the gas analysis area assessing core competences. 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).

Key Comparison CCQM-K36.2016 was a follow-up comparison for K36 and provided updated support for the corresponding calibration and measurement capability (CMC) entries in the BIPM CMC database. It aimed to demonstrate the capabilities of the participating NMIs to measure electrolytic conductivity of aqueous electrolyte solutions in the conductivity range 0.15 S m−1 to 1.5 S m−1 and in the conductivity range 1.5 mS m−1 to 15 mS m−1. To this end electrolytic conductivity of a potassium chloride solution (nominal conductivity 0.5 S m−1) and of a HCl solution (nominal conductivity 5 mS m−1) had to be measured. 17 NMIs participated in the comparison. The key comparison reference value (KCRV) of the KCl solution was (0.50999 +/-0.00032) S m−1 and the KCRV of the HCl solution was (4.9877 +/-0.012) mS m−1. Both values were estimated from the medians of the results considered eligible for KCRV calculation. They were given with their expanded uncertainties (95% coverage). The majority of the 0.5 S m-1 results were consistent with the KCRV. Two institutes showed a small inconsistency, one outlier was observed. The conductivity of the HCl solution showed a small, but steady linear drift of 0.00006843 mS m−1 per day during the measurement period and was corrected for KCRV calculation. Some institutes reported unstable measurement conditions for this solution. The results of seven participants have been inconsistent with the KCRV. 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).

Noble gases are one of the key elements used in the various processes of the bulbs industry, automotive industry, space industry, lasers industry, display industry as well as the semiconductor industry. Considering continuous growth, the provision of a reliable standard is required for those industries to improve their productivity. In this report, a result of the key comparison, CCQM-K113: noble gas mixture, is presented. Nominal amount-of-substance fractions of argon, neon, krypton, and xenon in helium are 20, 10, 2, and 1 cmol/mol, respectively. 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).

Carbon monoxide (CO) is reported to mainly be emitted from industries, transportation, and burnings for various usages. Its atmospheric lifetime varies from weeks to months, depending on the mixing ratio of the highly reactive hydroxyl radical. Even though the ambient level of CO varies as a function of regional sources, the mixing ratio ranges from 30 nmol/mol to 300 nmol/mol at the marine boundary layers and from 100 nmol/mol to more than 500 nmol/mol in urban areas(1). In order to study temporal trends and regional variations of the level of CO, the National Oceanic & Atmospheric Administration/Earth System Research Laboratory-Global Monitoring Division (NOAA/ESRL-GMD(2)) has played a key role as the designated Central Calibration Laboratory (CCL) within the frame of the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) program. NOAA/ESRL-GMD provides natural air standards, analyzed for CO, to WMO GAW participants. Since the structure of WMO traceability chain appears hierarchical and explicit all over the world, WMO intends to improve the CO measurement compatibility to up to 2 ppb (in case of extensive compatibility goal: 5 ppb, GAW report No. 213(3)) in order to ensure compatibility through the GAW network. Nevertheless, accurate measurement of CO at an ambient level has proven to be difficult due to the lack of stability in cylinders. For these reasons, it is necessary that measured results are compared among the values assigned by various NMIs. This key comparison was initially proposed to be aimed at a CO/N2 standard in the 2010 CCQM meeting by KRISS. With participation of FMI, NOAA, and Empa, a modified scheme of CO/air standards was developed for the purpose of atmospheric observations and co-operative support to WMO/GAW activities. Therefore, the purpose of the comparison is to support the measurement capability of CO at an ambient level of 350 nmol/mol. Further, this key comparison is expected to contribute to the establishment of traceability to a single scale of CO between NMIs by means of harmonizing the results from different national standards. The Empa result lies in a different report. 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).

This article presents the report on the COOMET supplementary comparison "Atmospheric air pollutants: CO in Nitrogen, 5 μmol/mol". Carbon monoxide (CO) is present in atmosphere due to different natural and anthropogenic sources. CO is a toxic gas and in concentrations higher than (3-5) μmol/mol it is hazardous to human health. 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).

Under the Comité Consultatif pour la Quantité de Matière (CCQM), a key comparison, CCQM-K103, was coordinated by the National Institute of Metrology (NIM) and Government Laboratory, Hong Kong, China (GLHK). The comparison was designed to demonstrate NMIs/DIs ability to analyze traces of melamine in milk and milk powder at concentration levels resulting from requirements for food safety. Seven NMIs or DIs participated in the comparison. Final reference value (KCRV) is 0.286 mg/kg, with standard uncertainty of the median as 0.011 mg/kg (3.8 %). The k-factor for the estimation of the expanded uncertainty was chosen as k = 2.57 ( t (0.05;5) ), thus the expanded uncertainty is 0.028 mg/kg (9.8%). The degrees of equivalence with melamine in milk powder KCRV for each participant were reported. The measurement results and degrees of equivalence should be indicative of the performance of a laboratory's measurement capability for IDMS in determining mass fractions in the range from 0.1 to 5.0 mg/kg of analytes with low molar mass (range 50-300 Da) with high polarity (pKow > -2.0) in milk and milk products. Extension to other analytes and matrices should be applied with care since there is a close linkage to other relevant parameters as e.g. sample preparation procedures (liquid/liquid extraction, SPE clean-up) and analytical separation techniques (e.g., GC-MS, LC-MS/MS etc). 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).

This key comparison aims to assess the core capabilities of the participants in gas analysis. Such competences include, among others, the capabilities to prepare primary standard gas Mixtures (PSMs), perform the necessary purity analysis on the materials used in the gas mixture preparation, the verification of the composition of newly prepared PSMs against existing ones, and the capability of calibrating the composition of a gas mixture. According to the Strategy for Key Comparisons of the Gas Analysis Working Group, this key comparison is classified as a track A key comparison, which means that the results of this key comparison can be used to underpin calibration and measurement capabilities using the flexible scheme, and for propane under the default scheme. The artefacts were binary mixtures of propane in nitrogen at a nominal amount-of-substance fraction level of 1000 μmol/mol. The values and uncertainties from the gravimetric gas mixture preparation were used as key comparison reference values (KCRVs). Each transfer standard had its own KCRV. The results are generally good. All results but one are within ± 0.2 % of the KCRV. 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).

In view of the need of ambient air quality control, occupational health control, authenticity of food and gases, and for medical purposes, laser gas analyzers must provide high accuracy of measurement. Development of metrological traceability of measurement for carbon monoxide, carbon dioxide, methane, formaldehyde, and carbon dioxide isotopes ratio laser gas analyzers is discussed in this presentation.

One of our recent works is development of procedures to transfer mole fraction and mass concentration of Cl2, HCl, SO2, H2S, NO, CO and to improve units transference accuracy from State Primary Measurement Standard of Mole Fraction and Mass Concentration of Components in Gas Media (GET 154-2011 [1]) to working standards of 0-th and 1-st grade (SRM) based on methods of IR spectroscopy.

The relevance of the COOMET.QM-S5 comparison is founded on tightening of requirements to a control of automobile emissions (realization of environmental standards of EURO 4, EURO-5). Participating laboratories: VNIIM, BAM, BelGIM, Ukrmetrteststandart, KazInMetr. This comparison was carried out in 2013-2014. This supplementary comparison supports CMC claims for: CO2 in the range (4–16) · 10−2 mol/mol; CO in the range (0.5–5) · 10−2 mol/mol; C3H8 in the range (0.01–0.3) · 10−2 mol/mol. Results: Component CO: All laboratories identified the values of carbon monoxide mole fraction in the gas mixture within ±0.9134%. Component CO2: All laboratories identified the values of carbon dioxide mole fraction in the gas mixture within ±0.3042%. Component C3H8: All laboratories identified the values of propane mole fraction in the gas mixture within ±0.443%. 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).