National Measurement Institute Research Articles

Comparison of voltage transformer measuring systems at 110 kV and 10 kV

Comparison of voltage transformer measuring systems at 110 kV and 10 kV

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).

Comparison of calibration coefficients for a vinten ionization chamber simulated using four Monte Carlo methods

The Vinten 671 ionization chamber (VIC) was modelled using Monte Carlo (MC) programs EGSnrc, Penelope, and TOPAS. Several national measurement institutes have VICs with well-characterized response relationships and have measured calibration coefficients for many radionuclides. Twelve radionuclides with various decay emissions were assessed as well as 14 monoenergetic photon sources and 10 monoenergetic electron sources. Calibration coefficients were calculated based on the energy deposited in the simulated VIC nitrogen gas volume and compared to experimental values from the literature.

Design and development of SiteHive MEMS based system for real-time vibration monitoring

Construction projects need to proactively manage their works that may cause vibration impacts to nearby structures and stakeholders. Risks of vibration include cosmetic and structural damage to buildings and threats to human comfort. The advent of MEMS accelerometers offers significant opportunities to improve on traditional vibration monitoring practices based on geophones. Geophones measure velocity which preclude acceleration based measurements and calculations like vibration dose value (the measure for human comfort), groundborne noise, and auto-levelling. The inability to capture these results means additional monitoring devices are required to capture all key measurements. MEMS-based vibration monitoring systems can be much cheaper, smaller, and more power efficient than traditional vibration monitoring systems. This enables easier installation, greater mobility, and more monitoring to be conducted. SiteHive has worked extensively with the National Measurement Institute (NMI) and the University of Technology Sydney (UTS) to test and validate the efficacy of the MEMS-based accelerometers and develop a calibration system for MEMS-based devices. This paper will outline the design research and findings that have gone into this development, results from field testing, and details on the value offered by this innovation.

Traceable S-parameter measurements up to 90 GHz in 1.35 mm coaxial

As part of a joint program three National Measurement Institutes around Europe—the National Physical Laboratory in the UK, the Physikalisch-Technische Bundesanstalt in Germany and the Laboratoire National de métrologie et d’essais in France—have each established new capabilities for the traceable measurement of S-parameters up to 90 GHz in the new 1.35 mm (E band) coaxial connector. Each institution has established their own measurement systems to access the full frequency band for the connector, utilising a variety of commercially available equipment and measurement setups. Each have also developed their own calibration techniques and verification methods using different vector network analyser calibration routines. These include optimised multi-line Through Reflect Line, multiple Offset Shorts Through and Short Open Load Reciprocal (SOLR) schemes. Uncertainties for each of these setups and calibration schemes were determined utilising theoretical models of the systems and calibration standards, or through verification methods, with different effects being derived from the dimensional characteristics for each of the different standards or verification artifacts. The different dimensional systems used to make these measurements were also developed and established previously as part of the same program. The last part of this exercise was a three-way intercomparison between the laboratories. The comparison involved the measurement of a set of four traveling standards, including both 1-port and 2-port as well as plug (male) and jack (female) devices, each with different reflection and transmission characteristics to better test and demonstrate the equivalence of the capabilities.

International comparison CCQM-K150: particle number concentration (100 to 20 000 cm-3) and particle charge concentration (0.15 to 3 fC cm-3)

Main textThis report presents the results of CCQM-K150, a key comparison between nine National Measurement Institutes (NMIs) which tested the capability of the NMIs to measure particle number concentration (in the range of 100 to 20 000 cm-3) using condensation particle counters (CPCs), and particle charge concentration (in the range of 0.15 to 3 fC cm-3) using aerosol electrometers (AEs).Measurements of aerosol particle number concentration are needed to demonstrate compliance to vehicle emission legislation and are becoming increasingly important in other areas such as ambient air and workplace monitoring. The measurements are typically carried out using condensation particle counters, which are calibrated using either reference CPCs or reference AEs.An analogous report is available for the CCQM-P189 comparison. CCQM-P189 was identical to and used the same experimental data as CCQM-K150 with one exception: data from TROPOS, which is not an NMI or Designated Institute (DI), were only included in CCQM-P189.CCQM-K150 was an amount-of-substance Track C 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 CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

International comparison CCQM-P189: particle number concentration (100 to 20 000 cm-3) and particle charge concentration (0.15 to 3 fC cm-3)

Main textThis report presents the results of CCQM-P189, a pilot comparison between 10 laboratories which tested the participants’ capability to measure particle number concentration (in the range of 100 to 20 000 cm-3) using condensation particle counters (CPCs), and particle charge concentration (in the range of 0.15 to 3 fC cm-3) using aerosol electrometers (AEs).Measurements of aerosol particle number concentration are needed to demonstrate compliance to vehicle emission legislation and are becoming increasingly important in other areas such as ambient air and workplace monitoring. The measurements are typically carried out using condensation particle counters, which are calibrated using either reference CPCs or reference AEs.An analogous report is available for the CCQM-K150 comparison. CCQM-K150 was identical to, and used the same experimental data as CCQM-P189 with one exception: data from TROPOS, which is not a National Measurement Institute (NMI) or Designated Institute (DI), were only included in CCQM-P189.CCQM-P189 was an amount-of-substance Track C 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 CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Bilateral Comparison of High-Voltage Capacitance and Dielectric Dissipation Factor at 50 Hz

NIM (National Institute of Metrology, China) and NMIA (National Measurement Institute, Australia) carried out a comparison program, which included low-voltage capacitance, the voltage dependence of high-voltage capacitance and the dielectric dissipation factor (DDF) at 50 Hz. The travelling standards included a low-voltage standard capacitor, a dissipation factor standard and a 100 kV compressed-gas capacitor. The capacitance and DDF of the standard capacitor, measured by the two institutes, agreed within 2 μF/F and 2×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-6</sup> , respectively, at 50 Hz and 500 V. DDF measurements at nominal values of 0.00000, 0.0001 and 0.001 agreed within 6×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-6</sup> at 50 Hz and 10 kV. The capacitance change of a 100 kV compressed-gas capacitor measured by the two institutes agreed within 2 μF/F over the voltage range from 10 kV to 100 kV. The success of the program proved comparisons using a re-filled high-voltage compressed gas capacitor and a low-voltage standard capacitor can be conveniently used to validate the complete traceability chain of the measurement of high-voltage capacitance at 50 Hz. The program also proved that DDF measurements with different implementations of traceability chain via capacitance and resistance would agree well within the uncertainties required by industrial measurements and a commercial DDF standard that has undergone international air travel would be sufficiently stable.

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).

A MATHMET Quality Management System for data, software, and guidelines

The European Metrology Network for Mathematics and Statistics (MATHMET) is creating a Quality Management System (QMS) to ensure that research outputs in the forms of data, software and guidelines are fit-for-purpose, achieve a sufficient level of quality, and are consistent with the aims of National Measurement Institutes to provide quality-assured and trusted outputs. The essential components of the QMS for all three forms of research output are discussed. On-line, interactive risk assessment tools that guide a user through the process of assigning an integrity level for the research outputs of data and software, are described. Examples of case studies that have been used to demonstrate the QMS are indicated.

Key comparison study - organic solvent calibration solution - gravimetric preparation and value assignment of deoxynivalenol (DON) in acetonitrile (ACN)

Main textThe CCQM-K154.c 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, nine NMIs/DIs participated in the Track C, Model II, Key Comparison CCQM-K154.c [Gravimetric preparation and value assignment of deoxynivalenol (DON) 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 deoxynivalenol (DON) 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 from 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.DON belongs to the large group of trichothecene mycotoxins. It is produced by certain fungi of the genus Fusarium that predominantly infect wheat, corn, oats, barley, rice, and other grains in the field or during storage. It was anticipated to provide a challenge representative for the gravimetrical preparation and value assignment of calibration solutions in the mass fraction range of 10 mg/kg to 100 mg/kg of mycotoxins with broadly similar structural characteristics.Ten participants of the MMCBKT programme were provided with a stock solution having a known DON 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 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 DON 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 DON mass fraction.The majority of the DON mass fraction KCRVs (w KCRV ) for CCQM-K154.c spanned a mass fraction range of 9.88 mg/kg to 123.45 mg/kg. The relative expanded uncertainties U(w KCRV ) ranged from 2.8 % to 6.8 %.Inspection of the degree of equivalence plots for the DON mass fraction assignments in CCQM-K154.c 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).

Quasi-continuous dc voltage standard using sinusoidal and pulse-driven Josephson junction arrays

Josephson voltage standards (JVSs) provide a primary realization of the volt, the unit of electromotive force. They generate direct current (dc) voltages up to 10 V and show agreement better than 1 nV V−1 at 10 V. For JVSs based on Josephson junction arrays (JJAs) that are driven by sinusoidal radiofrequency (RF) power, commonly referred to as continuous wave-driven JJAs (CWD JJAs), the minimum voltage that can be generated is limited to the voltage across one Josephson junction (JJ) for practical devices. To achieve this resolution, they may require a perfect JJA chip. JVSs based on a pulse-driven (PD) JJA require high performance electronics (i.e. high bandwidth, low distortion and jitter, pulse shaping filters and large memory) to achieve their minimum and maximum voltage. We have combined two CWD JJAs and two PD JJAs driven by two microwave inputs to one chip to generate quasi-continuous dc voltages up to the sum of the full-scale voltages of both JJAs that are robust to the imperfections of the JJs and have relaxed requirements on the RF electronics driving the JJA, compared to the existing CWD JVSs and PD JVSs, respectively. By use of the JJA chip at the National Measurement Institute Australia, we demonstrate its feasibility to generate voltages up to 1 V. Preliminary evaluation of the system shows that the voltage uncertainty can be 11 nV (k = 2) or better and the theoretical resolution is better than 1 nV from 0 V to 1 V. The main requirement is that all the JJs must have quantum locking ranges with respect to the power and frequency of the RF bias and for the PD JJAs to have a constant voltage over a range of dc bias current. Although this development is not a replacement for existing state-of-the-art JVSs, we anticipate that it will be an alternative fit-for-purpose solution for metrological applications under non-ideal operating conditions or when the components of the state-of-the-art solutions are not available.

International co-validation on absolute quantification of single nucleotide variants of KRAS by digital PCR.

The precise quantification of KRAS single nucleotide variant (SNV) is critical for the treatment and prognosis of lung and colorectal cancer. Validation of digital PCR (dPCR) as a method for accurate quantification of KRAS SNV has great clinical importance. An international co-validation on absolute quantification of KRAS SNV by dPCR was conducted among three national measurement institutes (NMIs) from China (NIM), South Korea (KRISS), and Japan (NMIJ). A candidate reference material (RM) was provided by NIM and three measurands were reported: copy number concentration (Tc) of KRAS G12A mutation and wild type and KRAS G12A fractional abundance (FA). Homogeneity and stability assessment showed that the study materials provided by NIM were sufficiently homogeneous and stable during the study period. En number performance statistics was used to evaluate equivalence of the study among the three NMIs. All En values for both Tc and KRAS G12A FA≤1 showed good agreement and consistency with the reference value within the expanded uncertainty. This indicates that dPCR with full uncertainty evaluation can serve as a candidate primary reference measurement procedure (PRMP) for the KRAS SNV measurement and value assignment of reference materials.

New traceability chain for spectral irradiance measurement at LNE-Cnam

LNE-Cnam has changed its traceability chain for measuring the spectral irradiance of a light source. This facility allows calibration of spectral irradiance of a standard lamp based on a comparison with a high temperature blackbody (HTBB). The reference spectral irradiance is determined by measuring the temperature of the HTBB with a filter radiometer calibrated against our radiant flux reference. This traceability scheme differs from the one used in our former setup, which was mainly based on the International Temperature Scale, ITS-90. Both principles are used in National Measurement Institutes. Our facility uses well known methods adapted to our best capabilities as well as a particular development in optical arrangement and filter radiometer calibration. Thanks to this new measurement setup, our spectral irradiance reference is now traceable to radiometric reference, i.e. our cryogenic radiometer. We have extended our measurement capability to cover the spectral range from 250 nm to 2500 nm. We have simplified the process by reducing the number of benches (three in one) and the number of operations, and we have designed a compact measuring setup through the use of a rotating integrative sphere. This allows us to reduce by at least a factor two our measurement uncertainties over almost the entire spectral range. With this new measurement facility, France participates in the ongoing CCPR k1.a key comparison. This is a key comparison of the Consultative Committee of Photometry and Radiometry for Spectral irradiance from 250 nm to 2500 nm of tungsten halogen lamps. This communication shows the method used, and its validation.

High polarity analyte(s) in aqueous media: determination of L-PFOA and L-PFOS in ground water

Main textThe CCQM-K156 comparison was coordinated by TUBITAK UME 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).Perfluoro alkyl substances (PFAS) such as PFOS and PFOA have been used in numerous industrial applications and products. Because of their high stability and resistance to biodegradation, atmospheric photooxidation, direct photolysis and hydrolysis, they are extremely persistent in the environment. The European Union (EU) Water Framework Directive lists PFOS as a priority hazardous substance that poses a significant risk to the aquatic environment. The use of PFOS-containing Aqueous Film-Forming Foams (AFFFs) has been banned since June 2011 in the EU. As relatively water-soluble, effectively non-degradable compounds, PFOS and PFOA migrate to ground water. They are not removed in the conventional drinking water treatment, and therefore cause health risks in polluted areas. The EU Drinking Water Directive and the European Commission has proposed a limit value of 100 ng/L for the sum of 20 PFAS, including PFOS and PFOA.This study provides the means for assessing measurement capabilities for determination of high polarity measurands in a procedure that requires extraction, clean-up, analytical separation and detection. Successful participation in CCQM-K156 demonstrates measurement capabilities in determining mass fraction of organic compounds, with a molecular mass of 200 g/mol to 700 g/mol, having high polarity pKow > -2, in a mass fraction range from 0.5 ng/kg to 500 ng/kg in aqueous media.Nine NMIs and DIs participated in the CCQM-K156 key comparison. Seven institutes reported their results. SPE was applied in the sample pre-treatment and LC-MS was applied for detection. All participating laboratories applied isotope dilution mass spectrometry (IDMS) techniques for quantification. Participants established the metrological traceability of their results using certified reference materials (CRMs) from NMIs with stated traceability; where commercially available high purity materials were used the purity was determined in-house. The CCQM-K156 results for L-PFOA and L-PFOS range from 2.75 ng/kg to 5.50 ng/kg with a % RSD of 19.5 % for L-PFOA and from 2.04 ng/kg to 4.45 ng/kg with a % RSD of 21.3 % for L-PFOS. The KCRV was assigned using a Hierarchical Bayesian Random Effects Model (HB REM) estimator from the values reported by six of the participants. One participant result of L-PFOS and one result of L-PFOA were excluded from the KCRV for technical reasons. The KCRV was 4.9 ng/kg ± 0.4 ng/kg for L-PFOA and 3.8 ng/kg ± 0.4 ng/kg for L-PFOS. The six institutes that were included in the assignment of consensus KCRV all agreed within their standard uncertainties.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).

Supplementary comparison study - fipronil-sulfone in chicken egg powder (APMP.QM-S16)

Main textThe APMP.QM-S16 comparison was coordinated by the National Institute of Metrology, China (NIM) on behalf of the Technical Committee on Amount of Substance (TCQM) of the Asia Pacific Metrology Programme (APMP) and 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).Fipronil is a broad-spectrum insecticide attributed to the phenylpyrazole family. Due to its high toxicity to invertebrates and long persistence, it has been one of the most widely used insecticides to control household and agricultural pests since its appearance in the market. Fipronil has also shown genotoxicity and cytotoxicity to many vertebrate animals, like mammals, birds, fish, reptiles and so on. Moreover, fipronil could have negative effects on the liver, kidneys and thyroid glands of humans. Its oxidation metabolite is fipronil-sulfone that could induce even higher toxicity than fipronil. In 2017, a fipronil-in-egg scandal occurred in the European Union (EU) that involved more than 15 states. The detected concentration of the sum of fipronil and fipronil-sulfone was many times higher than the EU maximum residue limit in bird egg (5 μg/kg). Besides European countries, fipronil-contaminated eggs were also found in Asian areas like China, Hong Kong and South Korea. Systematic monitoring and control of pesticide residues are necessary to safeguard public health.Fipronil-sulfone was selected to be representative of pesticide residues in this comparison. This study provides the means for assessing measurement capabilities for determination of low-polarity measurands in a procedure that requires extraction, clean-up, analytical separation, and selective detection in a food matrix. Generally, it provides a demonstration of a laboratory's capabilities in determining the medium molecular weight analytes (mass range 300-500) with low polarity (pKow < -2) at mass fraction levels of 4 to 400 μg/kg in a high fat, high protein and low carbohydrate food matrix that falls within Sector 4 of the AOAC Food-matrix Triangle.Seven NMIs/DIs participated in the APMP.QM-S16 comparison. Different methods such as liquid-liquid extraction, QuEChERS and SPE were applied in the sample pre-treatment and HPLC-MS/MS, HPLC-HRMS, and GC-MS/MS were applied for detection by the participants. Most participating laboratories applied isotope dilution mass spectrometry (IDMS) techniques with fipronil-sulfone-13C4,15N2 as internal standard, except EC-JRC-Geel which used matrix matched external calibration method. In the aspect of the traceability for the measurement results, most participants either used their own CRMs, other NMIs' CRMs or the pure materials assessed in-house to guarantee traceability to SI unit. One lab was excluded from the SCRV evaluation, as they did not meet the CIPM metrological traceability requirements. As a result, six sets of valid results were used for the estimation of the SCRV. Finally Hierarchical Bayes was considered to be the appropriate estimator to calculate SCRV, which was determined as 121.82 μg/kg with a standard uncertainty of 1.77 μg/kg. Inspection of the degree of equivalence plots for the fipronil-sulfone mass fraction assignments in APMP.QM-S16 indicated that there was 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).

Key Comparison Study - Organic Solvent Calibration Solution - Gravimetric preparation and value assignment of aflatoxin B1 (AfB1) in acetonitrile (ACN)

Main textThe 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.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 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 AfB1 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 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 INRAP did not agree with the KCRVs. It was found that the samples were altered as a result of an acid contamination.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).

Synthetic origin of illicit methylamphetamine in Australia: 2011-2020.

The National Measurement Institute's Methylamphetamine Profiling Program has evolved over the last 15 years to address analytical challenges faced with changes in illicit methylamphetamine production. The program involves organic and inorganic analysis of methylamphetamine to determine the precursors and synthetic route used in manufacture. This paper discusses changes in the methylamphetamine chemical profile for samples received at this laboratory during January 2011 to December 2020. In particular, changes observed in the methylamphetamine purity, potency, synthetic route, precursor and precursor synthetic origin are discussed. Over 13,180 samples were analysed during this period consisting of samples seized on the streets and the Australian border. This paper shows correlations between methylamphetamine seizures at the Australian border with international clandestine laboratory and precursor seizures trends. As the illicit drug landscape changes so too must our approach to chemical profiling if we are to confidently determine the synthetic origin of methylamphetamine.

Measurement of Free Testosterone in Serum Using Equilibrium DialysisCoupled With ID-UHPLC-MS/MS: Comparison Between Equilibrium Devices

Free testosterone (FT) has been used as a biomarker in clinical patient care and public health research to assess and manage patients with androgenic abnormalities. The latest Endocrine Society clinical practice guideline for testosterone therapy in men with hypogonadism recommends measuring FT for those with borderline and low total testosterone concentrations, or those who have conditions that change SHBG concentrations, such as some metabolic or hormonal diseases, certain medication use, or SHBG genetic polymorphisms. Measuring FT is technically challenging and shows high variability. The CDC clinical standardization program is developing a high throughput method using the gold-standard equilibrium dialysis (ED) procedure with isotope dilution ultra-high-performance liquid chromatography tandem mass spectrometry (ID-UHPLC-MS/MS).A serum sample was dialyzed against a protein-free HEPES buffer (pH 7.4) at 37 °C until equilibrium. After isolating endogenous FT from protein-bound testosterone by ED, isotope-labeled internal standard (13C3-testosterone) was added to the dialysate for quantification. Certified pure primary reference material (National Measurement Institute M914) was used to prepare calibrators, enabling traceable quantitation and ensuring measurement trueness. FT was further isolated from the dialysate matrix using supported liquid extraction and a chromatographic separation from interfering compounds and quantitation by tandem MS. The dialysis step requires maintaining the endogenous free hormone equilibrium so that results in dialysate reflect FT concentrations in the blood without influence from dilution, temperature, or pH. The dialyzer system has a 1:1 sample-to-buffer volume and has been used in reference measurement procedures for free hormone measurements, serving as the standard for method performance comparison. Four commercially available devices designed for high throughput in a multiple well-plate format, requiring respective sample-to-buffer ratios, were evaluated for their recovery, speed, ease of automation by a liquid handling system, repeatability, and robustness. Preliminary results showed that a device with 1:1 sample-to-buffer volume had the most comparable results to those obtained from the standard dialyzer, with the mean bias less than 15%. The device with the highest sample-to-buffer ratio showed bias as high as 50%. These data suggest that controlling sample-to-buffer ratio is a critical step in ED FT method.

Full Issue Download Vol. 13 No. 1 2021 The Importance of the Measurement Infrastructure in Economic Recovery from the COVID-19 Pandemic Richard J. C. Brown , Fiona Auty, Eugenio Renedo, Mike King NCSLI Measure | Vol. 13 No. 1 (2021) | doi.org/10.51843/measure.13.1.1 Publisher NCSL International | Published February 2021 | Pages 18-21 Abstract: This paper describes the many, evidenced-based benefits

Facilitating the uptake of established methodologies for risk-based decision-making in product conformity assessment taking into account measurement uncertainty by providing dedicated software is the aim of the European project EMPIR CASoft(2018–2020), involving the National Measurement Institutes from France, Sweden and the UK, and industrial partner Trescal (FR) as primary supporter. The freely available software helps end-users perform the required risk calculations in accordance with current practice and regulations and extends that current practice to include bivariate cases. The software is also aimed at supporting testing and calibration laboratories in the application of the latest version of the ISO/IEC 17025:2017 standard, which requires that“…the laboratory shall document the decision rule employed, taking into account the level of risk […] associated with the decision rule and apply the decision rule.” Initial experiences following launch of the new software in Spring 2020 are reported.