Key Comparison Reference Value Research Articles

Report on key comparison AFRIMETS.AUV.V-K5 and linking to CCAUV.V-K5

Main textFollowing the completion of the fifth CIPM key comparison (KC) in the area of vibration concerning sinusoidal acceleration, participating Regional Metrology Organizations (RMOs) have the responsibility to disseminate the Key Comparison Reference Values (KCRV) to non-participating National Metrology Institutes (NMIs), thereby establishing a traceable link between NMIs participating in regional comparisons and the KCRVs. The comparison results reported here have that objective. The comparison was piloted by AFRIMETS with participants from three NMIs, situated in two RMOs, namely SIM and APMP.The respective Degrees of Equivalence, linked to the KCRVs, are reported. The final report has been peer-reviewed and approved for publication by the CCAUV, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).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 https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCAUV, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Comparison of the standards for absorbed dose to water of the IAEA and the KRISS, Korea in accelerator photon beams

A bilateral comparison was conducted between the International Atomic Energy Agency (IAEA) and the Korea Research Institute of Standards and Science (KRISS) to measure the absorbed dose to water in accelerator photon beams. KRISS served as a linking laboratory to compare the IAEA standard with the key comparison reference value (KCRV) of the BIPM.RI(I)–K6 program, in which KRISS participated in 2017.Two ionization chambers from the IAEA were used as transfer instruments for the comparison. Both laboratories measured the calibration coefficients of these instruments and calculated the ratios. The ratio of the KRISS standard to the KCRV was applied to obtain the degree of equivalence of the IAEA, along with its uncertainty. The largest deviation of the IAEA measurement from the KCRV was 3.4 mGy/Gy, significantly smaller than the expanded uncertainty of 10.7 mGy/Gy (k = 2, 95% level of confidence).This study demonstrates the equivalence of IAEA's measurement standard for accelerator photon beams to other primary standard dosimetry laboratories. It provides evidence for the satisfactory operation of IAEA's quality management system and enhances the international credibility of the IAEA SSDL network, particularly in high-energy accelerator photon beams from linear accelerators.

Subsequent bilateral key comparison study - organic solvent calibration solution - gravimetric preparation and value assignment of aflatoxin B1 (AfB1) in acetonitrile (ACN)

Main textThe original CCQM-K154.b comparison was coordinated by the Bureau International des Poids et Mesures (BIPM) and the Chinese National Institute of Metrology (NIM) on behalf of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) for National Measurement Institutes (NMIs) and Designated Institutes (DIs) which provide measurement services in organic analysis under the 'Comité International des Poids et Mesures' Mutual Recognition Arrangement (CIPM MRA) and/or have participated in the BIPM's Mycotoxin Metrology Capacity Building and Knowledge Transfer (MMCBKT) project as part of its "Metrology for Safe Food and Feed in Developing Economies" Capacity Building Programme.Gravimetrically-prepared solutions having an assigned mass fraction of specified organic analytes are routinely used to calibrate measurement processes for the quantification of the same analytes in matrix samples. Appropriate assignments of the property value and associated uncertainty of calibration solutions thus underpin the traceability of routine analysis and are critical for accurate measurements. Evidence of successful participation in relevant international comparisons is needed to document calibration and measurement capability claims (CMCs) made by national metrology institutes and designated institutes. In total, eleven NMIs/DIs participated in the Track C, Model II, Key Comparison CCQM-K154.b [Gravimetric preparation and value assignment of aflatoxin B1 (AfB1) in acetonitrile (ACN)] for emerging areas of global interest and innovation. Participants were requested to gravimetrically prepare calibration solutions and value assign the mass fractions, expressed in mg/kg, of aflatoxin B1 (AfB1) in the acetonitrile (ACN) solution. Study samples, with assigned values and associated uncertainties were prepared by the comparison participants and sent to the coordinating laboratory for comparison. The Key Comparison Reference Values (KCRVs), calculated form values measured by the coordinating laboratory based on calibrations obtained from independent gravimetrically prepared calibrant solutions, agreed with participants reported values, within their stated uncertainties.AfB1 was selected to be representative of polar aflatoxins. Aflatoxins are a class of mycotoxins generally produced by fungi of the genus Aspergillus. It was anticipated to provide a challenge representative for the gravimetrical preparation and value assignment of calibration solutions in the mass fraction range of 2 mg/kg to 50 mg/kg of mycotoxins with broadly similar structural characteristics.In the original study CCQM-K154.b, nine participants of the MMCBKT programme were provided with a stock solution having a known AfB1 mass fraction and expanded uncertainty to use to gravimetrically prepare and value assign a calibration solution. Three NMIs/DIs also participated using their own calibration solutions. The use of in-house solutions required anadditional capacity to undertake a fit-for-purpose purity assessment. NIM was the only NMI participating using both the MMCBKT based and their own in-house assigned solutions in order to connect the two different groups.It was decided to propose separate KCRVs for each of the two ampoules provided by the participating NMIs/DIs based on the AfB1 mass fraction. This allowed participants to demonstrate the efficacy of their implementation of the approaches used to gravimetrically prepare calibrations solutions and to assess the AfB1 mass fraction.The majority of the AfB1 mass fraction KCRVs (wKCRV) for CCQM-K154.b spanned a mass fraction range of 2.02 mg/kg to 31.57 mg/kg. The relative expanded uncertainties U(wKCRV) ranged from 0.69 % to 2.93 %. Inspection of the degree of equivalence plots for the AfB1 mass fraction assignments in CCQM-K154.b indicated that there was an excellent agreement of results. Solely, the AfB1 mass fraction assignments of the INRAP (Institut National de Recherche et d'Analyse Physico-Chimique, Tunisia) did not agree with the KCRVs. It was found that the samples were altered as a result of an acid contamination.The INRAP has produced a new batch of AfB1 calibration solution using the AfB1 stock solution originally provided to MMCBKT participants to be able to demonstrate the efficacy of their implementation of the approaches used to gravimetrically prepare calibrations solutions and to assess the AfB1 mass fraction. The BIPM organized the present subsequent bilateral comparison CCQM-K154.b.1 to assess the new batch of AfB1 calibration solution of the INRAP. Inspection of the degree of equivalence plots for the AfB1 mass fraction assignments indicated that there is an excellent agreement of the INRAP results for CCQM-K154.b.1.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 https://www.bipm.org/kcdb/.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).

Update of the BIPM comparison BIPM.RI(II)-K1.Cr-51 of activity measurements of the radionuclide 51Cr to include the 2012 result of the KRISS (Rep. of Korea), the 2022 result of the POLATOM (Poland), and to link the 2022 EURAMET.RI(II)-K2.Cr-51 comparison

Main textTwo new participations in the BIPM.RI(II)-K1.Cr-51 comparison have been added to the previous results and this has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. A link has been made to the EURAMET.RI(II)-K2.Cr-51 comparison piloted by the POLATOM in 2022, who sent an ampoule from the EURAMET comparison to the International Reference System (SIR). The LNE-LNHB (France) used the EURAMET comparison to update its degree of equivalence. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table for the latest results in the BIPM.RI(II)-K1.Cr-51, and the linked EURAMET.RI(II)-K2.Cr-51. A graphical presentation is also given.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 https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

CCQM-K160: platinum group elements in automotive catalyst

Main textThe platinum group elements (PGEs) play an important role in reducing emissions from automotive vehicles through their use in catalytic convertors but also for catalysis in the pharmaceutical industry. The immense economic value of platinum (Pt), palladium (Pd) and rhodium (Rh) highlights the importance of highly accurate measurements. Therefore, there is a need for National Metrology Institutes (NMIs) and Designated Institutes (DIs) to demonstrate measurement capability in this space.A pilot comparison (CCQM-P63) for precious metals in automotive catalyst took place in 2006, but with a limited number of institutes participating. Furthermore, this study was performed over 17 years ago. Therefore, there was a need to maintain existing capability and demonstrate new capability in a key comparison, in order to claim calibration and measurement capability claims (CMCs). With the core capability matrix, this study falls into the "Difficult to dissolve metals/metal oxides" which will support CMC categories 8 (Metal and metal alloys), 9 (Advanced materials) and 14 (Other materials).Eleven NMIs and DIs participated in the Key Comparison CCQM-K160 Platinum Group Elements in Automotive Catalyst. Participants were requested to evaluate the mass fractions of Pt, Pd and Rh in mg/kg in an unused autocatalyst material (cordierite ceramic base). The Key Comparison Reference Values (KCRVs) and Degrees of Equivalence (DoEs) were calculated utilising the NIST Decision Tree for the measurands. The participants utilised a number of sample preparation and analytical methods including hot plate digestion, microwave digestion and sodium fusion, followed by either atomic absorption spectroscopy (AAS), inductively coupled plasma optical emission spectroscopy (ICP-OES) or inductively coupled plasma mass spectrometry (ICP-MS) detection. Several calibration techniques were used, namely external calibration, standard addition, isotope dilution mass spectrometry (IDMS) and an exact matching procedure. Additionally, one participant employed instrumental neutron activation analysis (INAA) with k0 standardisation which is a direct solid analysis method. The majority of participants claimed traceability to NIST primary calibrants or their own CRMs. Furthermore, several matrix CRMs were included or spiked samples for quality control. All institutes were required to determine the dry mass fraction using the stipulated protocol.The NIST decision tree was implemented for the calculation of the KCRVs and DoEs. The participant results overall showed good agreement with the KCRV, despite the variety of dissolution procedures and measurement techniques for this highly complex matrix and challenging measurands. Successful participation in CCQM-K160 demonstrated measurement capabilities for the determination of mass fraction of Pt, Pd and Rh in the mg/kg range and will support broad scope CMC claims for a wide range of challenging matrices.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 https://www.bipm.org/kcdb/.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).

Update of the BIPM comparison BIPM.RI(II)-K1.Zn-65 of activity measurements of the radionuclide 65Zn to include the 2015 result of the LNMRI-IRD (Brazil) and the 2018 result of the LNE-LNHB (France)

Main textSince 1977, 19 laboratories have submitted 22 samples of 65Zn to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)- K1.Zn-65. The LNMRI-IRD (Brazil) and the LNE-LNHB (France) are the latest participants in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical representation is also given.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 https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

CCEM key comparison CCEM.RF-K26. Attenuation at 18 GHz, 26.5 GHz and 40 GHz using a step attenuator. Final report of the pilot laboratory

Main textThis report summarizes the results of the Key Comparison CCEM.RF-K26 Attenuation at 18 GHz, 26.5 GHz and 40 GHz using a step attenuator which has been performed from January 2015 to February 2018. Fourteen National Metrology Institutes (NMIs) participated in this key comparison, including the National Metrology Institute of Japan (NMIJ/AIST, Japan) which served as pilot laboratory, the National Institute of Metrology (NIM, China), the Physikalisch-Technische Bundesanstal (PTB, Germany), the Laboratoire national de métrologie et d'essais (LNE, France), the Swiss Federal Office for Metrology and Accreditation (METAS, Switzerland), the National Physical Laboratory of India (NPLI, India), the All-Russian Scientific Research Institute of Physico-Technical Measurements (VNIIFTRI, Russia), the Korea Research Institute of Standard and Science (KRISS, South Korea), the National Physical Laboratory (NPL, United Kingdom), the National Metrology Institute of South Africa (NMISA, South Africa), the Tubitak Ulusal Metrologi Enstitűsű (TUBITAK-UME, Turkey), the National Metrology Centre (NMC-A*STAR, Singapore), the Czech Metrology Institute (CMI, Czech Republic) and the Instituto Nacional de Tecnica Aeroespacial (INTA, Spain). The Key Comparison Reference Values (KCRVs) were determined from the measurement results of five to ten participating NMIs, depending on the attenuation and frequency.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 https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Update of the BIPM comparison BIPM.RI(II)-K1.Ge-68 of activity measurements of the radionuclide 68Ge to include the 2021 result of the NIM (China)

Main textSince 2013, 6 laboratories have submitted 7 samples of 68Ge to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ge-68. Recently, the NIM (China) participated in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalencebetween each equivalent activity measured in the SIR or linked to the SIR from the CCRI(II)-K2.Ge-68 comparison and the updated KCRV have been calculated and the results are given in the form of a table. A graphical representation is also given.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 https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Update of the BIPM comparison BIPM.RI(II)-K1.Cs-137 of activity measurements of the radionuclide 137Cs to include the 2014 result of the NRC (Canada) and the 2018 result of the TENMAK-NÜKEN (Türkiye)

Main textSince 1976, 23 laboratories have submitted 45 samples of 137Cs to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Cs-137. The NRC (Canada) and the TENMAK-NÜKEN (Türkiye) participated in the comparison and the key comparison reference value (KCRV) has been updated.The degrees of equivalence between each equivalent activity measured in the SIR or linked to the SIR from the COOMET.RI(II)-K2.Cs-137 comparison and the updated KCRV have been calculated and the results are given in the form of a table. A graphical representation is also given.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 https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Update of the BIPM comparison BIPM.RI(II)-K1.Ga-67 of activity measurements of the radionuclide 67Ga to include the 2023 result of the CMI (Czechia)

Main textSince 1978, 10 laboratories have submitted 18 samples of 67Ga to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ga-67. Recently, the CMI (Czechia) participated in the comparison and the key comparison reference value (KCRV) has been fully revised. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical representation is also given.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 https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Update of the BIPM comparison BIPM.RI(II)-K1.Tb-161 of activity measurements of the radionuclide 161Tb to include the 2022 result of the NPL (United Kingdom)

Main textSince 2019, 2 laboratories have submitted 2 samples of 161Tb to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Tb-161. Recently, the NPL (United Kingdom) participated in the comparison and the key comparison reference value (KCRV) has been evaluated for the first time. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical representation is also given.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 https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Comparison of local realizations of Silver freezing-point temperatures between NMIA and NMIJ AIST

Main textThe key comparison CCT-K4.1 was initiated on the request of the National Measurement Institute, Australia (MNIA) to re-link their standards to the Consultative Committee for Thermometry (CCT) Key Comparison (KC) and facilitate the NMIA CMC submission. National Metrology Institute of Japan, Japan (NMIJ) provided the linkage to the CCT-K4 at the temperature of the freezing point of silver. At the time of the CCT-K4 NMIA (formerly CSIRO-NML) had only one silver cell and this was found to be contaminated shortly after completion. Subsequently, more silver cells were fabricated at different times to form an ensemble of five cells before the start of CCT.K4.1.In the CCT-K4.1 bi-lateral comparison, a silver cell provided by NMIA and used as the artefact and circulated in accordance with the pilot-participant-pilot scheme. It is standard practice for NMIJ to use argon at 6N purity and NMIA argon 5N purity to regulate the pressure in the silver cell. To mitigate this, the effect of different argon purity was assessed in the post-circulation measurements. First the comparison was made under 6N purity atmosphere to preserve the cell ambience after it left NMIJ then the measurement was repeated under 5N argon atmosphere.The linkage was based on the temperature of NMIJ reference Ag fixed point relative to the key comparison reference value (KCRV) of CCT-K4 at the Ag fixed point via the difference in temperature between the NMIA reference Ag fixed point and NMIJ reference Ag fixed point (links to the KCRV of the CCT-K4). The temperature difference between the standards of NMIA and the KCRV of the CCT-K4 was within the evaluated comparison uncertainties of the CCT-K4.1. This report provides detailed information on the comparison results, linkage mechanism, and the Degree of Equivalence of NMIA relative to the institutes having participated in the CCT-K4.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 https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Comparison report of the ITS-90 realization at the freezing point of silver between NIM and CMS

Main textThe APMP key comparison APMP.T-K4.1 was initiated on the request of the Center for Measurement Standards, Taiwan (CMS) to link their standards to the Consultative Committee for Thermometry (CCT) Key Comparison (KC) and facilitate the CMS CMC submission. National Institute of Metrology, China (NIM) provided the linkage to the CCT-K4 at the temperature of the freezing point of silver. In the APMP.T-K4.1, one high temperature standard platinum resistance thermometer (HTSPRT) was chosen as the transfer instrument and was calibrated at the freezing point of silver. The comparison was carried out in a participant-pilot-participant sequence where NIM served as the pilot. The linkage was based on the temperature of CMS reference Ag fixed point relative to the key comparison reference value (KCRV) of CCT-K4 at the Ag fixed point via the difference in temperature between the NIM reference Ag fixed point and NIM reference Ag fixed point (links to the KCRV of the CCT-K4). The temperature difference between the standards of CMS and the KCRV of the CCT-K4 was within the evaluated comparison uncertainties of the ATPM.T-K4.1. This report provides detailed information on the comparison results, linkage mechanism, and the Degree of Equivalence of the CMS relative to the institutes having participated in the CCT-K4.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 https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Spectral analysis of deviations from key comparison reference values

When studying the results of the key comparisons of spectral quantities, it appears that in many cases participants’ results systematically deviate from the key comparison reference values over a limited spectral range. We carried out spectral analysis of such deviations in seven key comparisons of optical radiometry. The results reveal an approximate outcome that, on the average, each harmonic amplitude is inversely proportional to the order of the harmonic in all studied key comparisons. This new finding gives important information on the characteristics of spectral correlations. The result can be used in the uncertainty evaluation of spectral integrals, where the effect of unknown spectral correlations has earlier been challenging to assess quantitatively.

A bilateral comparison between LNHB and PTB to determine the activity concentration of the same 125I solution

A bilateral comparison to determine the activity concentration of the same 125I solution was organized. As electron-capture radionuclide with a rather high atomic number, 125I must be regarded as difficult to measure. The situation is partly exacerbated by the fact that some established standardization methods, like photon-photon coincidence counting, can no longer be applied due to the unavailability of appropriate equipment and expertise.One aim of this work is to compare modern liquid scintillation counting methods for the standardization of 125I. Both participating metrology institutes have used their custom-built triple-to-double-coincidence ratio (TDCR) counters and the determined activity concentrations are in excellent agreement even though the ways to analyze the data and to compute counting efficiencies were widely independent. The results also agree with the outcome of 4π-γ counting that was carried out at LNHB.In both laboratories, the measurements were complemented by measurements with several secondary standardization methods which even allow to establish a link to the CCRI(II)–K2.I-125(2) comparison started in 2004. A good agreement between the TDCR results and the key comparison reference value of the 2004/2005 comparison was obtained.

SIM.QM-S17 Ethanol in Aqueous Matrix: Supplement Key Comparison, Model 1

Main textTo establish international measurement capabilities for the determination of ethanol in aqueous matrices, the CCQM Organic Analysis Working Group (OAWG) has performed three ethanol Key comparisons (2002: CCQM-K27a for forensic aqueous ethanol and CCQM-K27b for ethanol in wine as a commodity; 2005: CCQM-K27 subsequent studies - four levels of ethanol in water; 2007: CCQM-K27.2 Subsequent 2 for forensic levels). To provide an opportunity for the NMIs and DIs within the RMOs, three Key comparisons has been conducted within SIM (SIM.QM-K1, SIM.QM-K27) and AFRIMETS (AFRIMETS.QM-K27). In addition, for the NMIs to support their ethanol in aqueous matrices measurements capabilities, a Track A Model 2 (formerly known as Track B) Key comparison CCQM-K79 (2010) has been completed to compare aqueous ethanol certified reference material (CRM) solutions certified by the participant NMIs and DIs. The current comparison is important to NMIs and DIs to maintain their ethanol in water measurement capabilities, to claim it as a new one as well as to complement their existing measurement capabilities, mainly within the range where the alcohol meter (breathalyzer) needs to be calibrated and verified.In 2017, several NMIs and DIs in SIM expressed their interest in a complementary SIM.QM-K27 comparison, therefore CENAM and INMETRO agreed to collaborate for the realization of a SIM supplement comparison, which was identified as SIM.QM-K27.2019 by the OAWG, and the final assigned name by SIM was SIM.QM-S17. The main purpose of this comparison was to offer to SIM countries and other regions an additional opportunity for the NMI and DIs to evaluate their measurements capabilities in determining mass fraction of ethanol in an aqueous matrix within the mass fraction range from 0.1 mg/g to 5 mg/g. Fourteen laboratories were registered to take part in this comparison, and thirteen sent their results. This report presents the results of the SIM Key comparison SIM.QM-S17.The measurements capabilities demonstrated by the participants in SIM.QM-S17, underpin their ability to assign reference values of ethanol content in aqueous samples for both forensic and commodities applications. Successful participation in SIM.QM-S17 demonstrates the laboratories measurement capabilities in determining mass fraction of ethanol in an aqueous matrix within the mass fraction range from 0.1 mg/g to 5 mg/g. The study material was two batches of solutions of ethanol in water prepared gravimetrically at concentrations between 0.1 mg/g - 5 mg/g by CENAM, dispensed in glass bottles of 50 mL sealed with tear off aluminum crimp seals, with rubber stoppers. In previous SIM.QM.K27 comparison, the purity-corrected gravimetric value of the aqueous ethanol solutions assigned by the coordinating NMI was used to link SIM.QM-K27 to the CCQM-K27 Key comparison reference value (KCRV), where 1 % uncertainty was assigned to the KCRV to have the same uncertainty from the CCQM-K27.2. For this comparison, SIM.QM-S17 two levels aqueous ethanol solutions, the purity assigned by CENAM was not used for KCRV as was informed initially in the protocol, instead in 5-June-2020 at the OAWG, CENAM gravimetric values were presented, as well as the participants results evaluated by four different statistical approaches to assess the candidate KCRV. For both levels of ethanol in aqueous matrix solutions, the DerSimonian-Laird Weighted mean and the Hierarchical Bayes mean methods seem to give a better estimation of the KCRV ± KCRU95 candidate and was agreed by OAWG to use the Hierarchical Bayesian mean, from where the KCRV for SIM.QM-S17 Level 1 (Low-level) and Level 2 (high-level) were (240.92 ± 1.28) mg/kg (k =2) and (389.87 ± 1.52) mg/kg (k =2), respectively. All the thirteen participants in the SIM.QM-S17, including both coordinators, demonstrated their capability to measure ethanol in aqueous matrix in the mass fraction range of 0.1 mg/g to 5 mg/g.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 https://www.bipm.org/kcdb/.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).

CIPM key comparison CCPR-K1.a.2017 for spectral irradiance 250 nm to 2500 nm. Final report

Main textThis report describes the Key Comparison of the Consultative Committee for Photometry and Radiometry CCPR-K1.a.2017 for Spectral Irradiance in the wavelength range of 250 nm to 2500 nm. Tungsten quartz halogen lamps of the FEL type (1000 W) were used as artefacts. Each participant used its own set of lamps. The star scheme of measurements was applied with the sequence participant - pilot - participant. Twelve National Metrology Institutes participated in the comparison. Each participant's measurement data were based on a totally independent spectral irradiance scale realisation. VNIIOFI (the Russian Federation) served as a pilot. The measurements were carried out from 2017 - 2020.The analysis of the comparison was performed following the step-by-step approach described in Appendix B of the Guidelines for CCPR Key Comparison Report Preparation (CCPR-G2 Rev.4). The key comparison reference values (KCRV) were calculated independently at each wavelength as the weighted means with cut-off. The measurement data of all participants were used for the KCRV excluding just a few outliers in the wavelength range of 1700 nm to 2500 nm. The relative uncertainties of the KCRV were minimal, 0.08 %, at the wavelengths of 900 nm to 1500 nm and increasing towards the limits of the spectral range up to 0.28 % at 250 nm and 0.20 % at 2500 nm. Consistency checks were satisfied at 17 of the 28 measured wavelengths, but failed at 11 wavelengths, mostly in the infrared range. For the latter wavelengths the Mandel-Paule method was applied resulting in an additional uncertainty that varied depending on wavelength from 0.11 % to 0.89 %.In general, the measurement uncertainties submitted by the participants in this comparison were less than those submitted in the previous CCPR-K1.a comparison. This is evidenced by the values of the cut-off, which had decreased at all wavelengths by a factor of 1.2 to 3.0 depending on wavelength. However, only for seven participants the degrees of equivalence do not exceed the expanded uncertainties at almost all wavelengths. About 80 % of all results (all participants at all wavelengths) agree with the KCRV within 1 % over the whole spectral range and within 0.7 % in the visible, which is comparable with the results of the previous CCPR-K1.a comparison.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 https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Update of the BIPM comparison BIPM.RI(II)-K1.I-131 of activity measurements of the radionuclide 131I to include the 2015 results of the BEV (Austria) and the POLATOM (Poland), the 2017 result of the NMISA (South Africa), and to link the CCRI(II)-S6.I-131 comparison

Main textThree new participations in the BIPM.RI(II)-K1.I-131 comparison have been added to the previous results and this has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. A link has been made to the CCRI(II)-S6.I-131 comparison piloted by the International Atomic Energy Agency (IAEA) in 2006, based on the participation of CMI-IIR in both comparisons. One NMI used the S6 comparison to update its degree of equivalence. The results of two NMIs in the CCRI(II)-S6.I-131 comparison were superseded by a more recent APMP.RI(II)-K2.I-131 comparison. The degrees of equivalence between each equivalent activity measured in the International Reference System (SIR) and the KCRV have been calculated and the results are given in the form of a table for the latest results in the BIPM.RI(II)-K1.I-131, and the linked CCRI(II)-S6.I-131, APMP.RI(II)-K2.I-131 and EURAMET.RI(II)-K2.I-131 comparisons. A graphical presentation is also given.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 https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Key Comparison Study - Organic Solvent Calibration Solution - Gravimetric preparation and value assignment of patulin (PAT) in acetonitrile (ACN) with 0.1 % formic acid (FA)

Main textThe CCQM-K154.d comparison was coordinated by the the Bureau International des Poids et Mesures (BIPM) and the Chinese National Institute of Metrology (NIM) on behalf of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) for National Measurement Institutes (NMIs) and Designated Institutes (DIs) which provide measurement services in organic analysis under the 'Comité International des Poids et Mesures' Mutual Recognition Arrangement (CIPM MRA) and/or have participated in the BIPM's Mycotoxin Metrology Capacity Building and Knowledge Transfer (MMCBKT) project as part of its "Metrology for Safe Food and Feed in Developing Economies" Capacity Building Programme.Gravimetrically-prepared solutions having an assigned mass fraction of specified organic analytes are routinely used to calibrate measurement processes for the quantification of the same analytes in matrix samples. Appropriate assignments of the property value and associated uncertainty of calibration solutions thus underpin the traceability of routine analysis and are critical for accurate measurements. Evidence of successful participation in relevant international comparisons is needed to document calibration and measurement capability claims (CMCs) made by national metrology institutes and designated institutes. In total, twelve NMIs/DIs participated in the Track C, Model II, Key Comparison CCQM-K154.d [Gravimetric preparation and value assignment of patulin (PAT) in acetonitrile (ACN) with 0.1 % formic acid (FA)] for emerging areas of global interest and innovation. Participants were requested to gravimetrically prepare calibration solutions and value assign the mass fractions, expressed in mg/kg, of PAT in ACN with 0.1 % FA solution. Study samples, with assigned values and associated uncertainties were prepared by the comparison participants and sent to the coordinating laboratory for comparison. The Key Comparison Reference Values (KCRVs), calculated form values measured by the coordinating laboratory based on calibrations obtained from independent gravimetrically prepared calibrant solutions, agreed with participants reported values, within their stated uncertainties.PAT is a mycotoxin produced by a variety of moulds, particularly by fungi of the genus Aspergillus and Penicillium. Often found in rotting apples and apple products, PAT can also occur in various other moldy fruits, grains and foods. Major human dietary sources of PAT are apples and apple juice made from affected fruit. PAT is relatively stable when given a short-acting heat-treatment, especially in an acidic environment. It was anticipated to provide a challenge representative for the gravimetrical preparation and value assignment of PAT calibration solutions in the mass fraction range of 10 mg/kg to 100 mg/kg of mycotoxins with broadly similar structural characteristics.Eight participants of the MMCBKT programme were provided with a stock solution having a known PAT mass fraction and expanded uncertainty to use to gravimetrically prepare and value assign a calibration solution. Two NMIs/DIs used reference materials for preparing their solutions while five NMIs/DIs participated using their own calibration solutions. The use of in-house solutions required an additional capacity to undertake a fit-for-purpose purity assessment. NIM was the only NMI participating using both the MMCBKT based and their own in-house assigned solutions in order to connect the two different groups.It was decided to propose separate KCRVs for each of the two ampoules provided by the participating NMIs/DIs based on the PAT mass fraction. This allowed participants to demonstrate the efficacy of their implementation of the approaches used to gravimetrically prepare calibration solutions and to assess the PAT mass fraction.The majority of the PAT mass fraction KCRVs (wKCRV) for CCQM-K154.d spanned a mass fraction range of 9.72 mg/kg to 63.40 mg/kg. The relative expanded uncertainties U(wKCRV) ranged from 2.0 % to 5.4 %.Inspection of the degree of equivalence plots for the PAT mass fraction assignments in CCQM-K154.d indicated that there was an excellent agreement of results.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 https://www.bipm.org/kcdb/.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).

ITS-90 SPRT calibration from the Ar TP to the Zn FP

Main textThis is a report to the Consultative Committee for Thermometry (CCT) on the key comparison 9 of Standard Platinum Resistance Thermometer (SPRT) calibration on the International Temperature Scale of 1990 (ITS-90) [1] from 83.8058 K (the Ar triple point) to 692.677 K (the Zn freezing point). The comparison followed a collapsed star protocol, with each of the fourteen participating laboratories shipping two standard platinum resistance thermometers (SPRTs) as transfer standards to the pilot laboratory (National Institute of Standards and Technology, NIST) for a direct comparison of SPRT calibration at the National Metrology Institute (NMI) of origin to calibration at NIST. Measurements were taken at the participating laboratories before and after measurement at NIST to assess the effect of transportation on the transfer standards. The pooled results from all laboratories were combined to calculate a key comparison reference value (KCRV).This report includes the calculation of, and comparisons to, the KCRV as well as bilateral comparisons between labs. In addition, there is space devoted to analysis of the shifts in SPRT values following travel.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 https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).