BIPM Key Comparison Research Articles

APMP.M.H-S6 final report of the supplementary comparison of Vickers hardness

Main textThis report purposed the results of supplementary comparison of Vickers hardness, APMP.M.H-S6, among five National Metrology Institutes (NIMT, NMIJ/AIST, KRISS, CMS/ITRI and SASO-NMCC). The comparison was carried out during November 2015 to January 2019 in order to determine the capability of the primary Vickers hardness standard, including standard conditions of each participant, to confirm the accuracy of Vickers hardness scale HV5, HV10, HV20, HV30, HV50 and HV100 measurement declared by each participant, which includes the effect of each participant's primary indenter, and determine the degrees of equivalence of hardness scale measurement in the range 100HV to 900HV. The pilot institute was the National Institute of Metrology (Thailand), NIMT. There were 2 different types of artifacts for the comparison. The first and second set were the set of Vickers hardness comparison: hardness measurement. The third set is a set of diagonal length comparison: diagonal length measurement.The measurement results of each participant were used to compute the degree of equivalence in comparison reference value (CRV) and the uncertainty of this deviation at a 95% level of confidence. The En parameter was calculated to express the equivalence between the measurements of participants as well.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 CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Comparison of four-terminal-pair 1 pF, 10 pF, 100 pF and 1000 pF capacitance standards at frequencies of 10 kHz, 100 kHz, 1 MHz and 10 MHz (APMP.EM-S15)

Main textIn order to calibrate an LCR meter, metrological traceability of capacitance above 10 kHz becomes more and more important. For this reason, NIM (National Institute of Metrology, China)，NPLI (National Physical Laboratory, India) and NIMT (National Institute of Metrology, Thailand) have carried out research on capacitance metrology from 10 kHz to 10 MHz.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).

Final report "Key comparison CCM.FF-K1.2015 - water flow: 30 m3/h ... 200 m3/h"

Main textThe objective of the Key Comparison CCM.FF-K1.2015 for water flow measurement was to support and prove the Calibration and Measurement Capabilities (CMC) of the participating NMIs of Japan (AIST), Mexico (CENAM), Chinese Taipei (ITRI), Korea (KRISS), P.R. China (NIM), Germany (PTB), USA (NIST), Sweden (RISE), UK (NEL), Turkey (TUBITAK UME) and Netherlands (VSL). The comparison was organized as a round robin, started in December 2015 at PTB and finished in April 2018, also at PTB. As pilot laboratory, the national metrology institute of Germany (PTB) organised the comparison. A combined setup of a turbine meter and Coriolis meter was used as a transfer standard (TS), which was provided by the pilot laboratory. The nominal calibration conditions of the KC were defined within the flow range between 30 m3/h and 200 m3/h, 20 °C fluid temperature and 3 bar line pressure.A special focus of the comparison was to estimate the uncertainties of the transfer standard (u TS). Both transfer meters were subjected to extensive characterization measurements at pilot laboratory, with the following investigated parameters: fluid temperature, line pressure, repeatability, flow stability, meter sensitivity to varying inflow conditions and hysteresis effects.For turbine meter, all labs passed the E N criteria of ≤ 1.20. The calibrations of the turbine meter were strongly affected by the presence of the large values for u TS with > 0.12 % k =1) which were mainly caused by the meter sensitivity to disturbed inflow conditions. This effect led to inconclusive calibration results for all laboratories. The evaluation criteria u comp/u base exceeded the critical value of 2.00. Finally, the turbine meter was not suitable for a confirmation of all submitted CMC values.For Coriolis meter, all labs passed the E N criteria of ≤ 1.20. In contrast to turbine meter, the evaluation criteria u comp/u base exceeded the critical value of 2.00 for one laboratory, only. The maximum uncertainty u TS of Coriolis meter was estimated with 0.022 % (k =1).In summary, the comparison was successfully finished for a confirmation of the submitted CMC values, related to mass calibrations. For volume related CMCs this comparison was not suitable.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 CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

SIM.M.P-S8 final report

Main textThis report shows the final results of the bilateral comparison SIM.M.P-S8 between the Custodian Laboratory of National Pressure Standards of Chile, LCPN-P (with the National Aeronautics Company - ENAER) and the National Institute of Technology, Standardization and Metrology, INTN of Paraguay, in the field of hydraulic pressure up to 70 MPa. The comparison was carried out between December 2011 and May 2012. Each laboratory used a pressure balance as a reference standard covering the range from 7 MPa to 70 MPa for the comparison. The transfer standard for the comparison was a digital manometer OMEGA, PCL-3000-4 with an accuracy of 0.05 % of full scale and a resolution of 0.01 MPa.The pilot laboratory, LCPN-P, provided the transfer standard and made the analysis of the results, while the reference value was provided by INTN Paraguay.An analysis of compatibility between the results of the present bilateral comparison and the supplementary comparison SIM.M.P-S7 was made, obtaining satisfactory results, which enables a link between both comparisons.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 CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Final report on key comparison APMP.M.P-K7.3 in hydraulic gauge pressure from 10 MPa to 100 MPa

Main textThis report describes the results of a key comparison among hydraulic high pressure standards that have been maintained by seven National Metrology Institutes (NMIs: NIMT, NMIJ/AIST, NPLI, RCM-LIPI, NMIM, VMI and NMLPHIL). This comparison was carried out during the period March 2016 to October 2017 within the framework of the Asia-Pacific Metrology Programme (APMP) in order to determine their degrees of equivalence in the pressure range from 10 MPa to 100 MPa, gauge mode. The pilot institute was the National Institute of Metrology (Thailand) (NIMT). All participating institutes used hydraulic pressure balance as their pressure standards. In order to ensure reliability, two high precision pressure transducers were used as the transfer standard. The sensing element of the transducers was a precision quartz crystal resonator attached to a small Bourdon tube. During the comparison, the transfer standard was calibrated at the pilot institute two times, before and after circulating the transfer standard to participants. From the two NIMT calibration results, the transfer standard was sufficiently stable to meet the requirements of the comparison. The long-term instability obtained from the two calibration results was taken into account as the uncertainty of the transfer standard for all participants. As the matter of fact NPL India and NMIM participated in this comparison as one of the linkage institutes and participating institutes, respectively. However, it was found later that the systems of hydraulic pressure balance reference standards used in this comparison were not functioning. Therefore, the comparison results were withdrawn. The degrees of equivalence of each national measurement standard were expressed quantitatively by deviations from the key comparison reference value of the corresponding CCM key comparison, CCM.P-K7 through the linkage institute, NMIJ/AIST. In conclusion, the hydraulic pressure standards in the range 10 MPa to 100 MPa, gauge mode of the five participating NMIs were found to be equivalent within their claimed 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 CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

CCAUV.W-K2 final report - key comparison CCAUV.W-K2: calibration of hydrophones in the frequency range from 250 Hz to 500 kHz

Main textThis report is the final report for key comparison CCAUV.W-K2. This key comparison covers primary free-field standards for sound in water at frequencies between 250 Hz and 500 kHz. This project is one of the key comparisons organised under the auspices of the Consultative Committee on Acoustics, Ultrasound and Vibration (CCAUV) of the CIPM.This report has the status of a Final Report and has been submitted to the Key Comparison Database (KCDB). In the report, the results of participants are presented with the Key Comparison Reference Values and Degrees of Equivalence. The results are calculated according to the procedures agreed after consideration of the Draft A1 and A2 reports, and the Draft B report has been approved by the CCAUV. All participants have had the opportunity to give final agreement on the contents and amendments have been made to account for their comments.In many respects, the comparison has been a success with good agreement achieved over an extended lower frequency range compared to the previous CCAUV.W-K1 comparison, the lower frequency limit for CCAUV.W-K2 being extended down by two octaves to 250 Hz. The generally more difficult frequency range from 100 kHz to 500 kHz has also shown very good agreement between the participants. However, in the range 60 kHz to 100 kHz the agreement was not as good, with three participants exhibiting some discrepant 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 CCAUV, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The CCL-K11 on-going key comparison. Final report for the period 2018 to 2020

Main textTo 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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

International comparison CCQM-K10.2018: BTEX in nitrogen at 5 nmol mol−1

Main textThe CCQM-K10.2018 comparison aimed to evaluate the capabilities of national metrology institutes (NMIs) to prepare and/or value assign primary reference mixtures containing benzene, toluene, ethylbenzene, p-xylene, m-xylene and o-xylene (subsequently referred to as BTEX) in nitrogen. This key comparison was separated into two parallel studies. The first study, deemed the "gravimetric study", evaluated the level of compatibility of BTEX standards provided by NMIs. Seven participating laboratories each submitted one standard at nominal 5 nmol mol-1 BTEX in nitrogen. Comparison measurements were performed by the National Institute of Standards and Technology (NIST) from July to October 2018. The second study, deemed the "comparative study", compared the capabilities of NMIs to measure the amount fractions of BTEX in a mixture provided by NIST. NIST prepared one standard at nominal 5 nmol mol-1 BTEX in nitrogen, which was measured consecutively by three participating laboratories. The participants' measurements took place from August 2018 to March 2019. The comparison protocol adopted for CCQM-K10.2018 was more challenging than for the original comparison, CCQM-K10 in 2001, and the results provide an extended evaluation of the level of compatibility of BTEX in nitrogen standards.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).

AFRIMETS.EM-S1 supplementary comparison of resistance standards

Main textAFRIMETS.EM-S1 supplementary comparison on resistance standards at 1 Ω, 10 Ω, 100 Ω, 1 kΩ and 10 kΩ commenced November 2015 and ended June 2018. The comparison approved by AFRIMETS technical committee for Electricity and Magnetism (TC-EM) and Consultative Committee for Electricity and Magnetism (CCEM). Seven National Metrology Institutes participated including National Metrology Institute of South Africa (NMISA)the pilot laboratory. The primary objective of the comparison is aimed to underpin and strengthen the capabilities of the National Metrology Institutes and establish the degree of equivalence and comparability. The results of the participants are found to be equivalent, comparable and in agreement with the comparison reference values within stated uncertainties of measurements.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).

Bilateral key comparison EURAMET.EM-K11.1 "AC-DC Voltage Transfer Difference at Low Voltages"

Main textTo 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).

Final report on CCQM-K167: carbon isotope delta measurements of vanillin

Main textThe CCQM Isotope Ratio Working Group (IRWG) determined that an additional key comparison of carbon isotope delta measurements was required to capture the progress of this field. Vials containing 0.25 mg of vanillin were prepared at NRC, and evaluated for bottle-to-bottle homogeneity prior to distribution to the eight participating institutes. Participants were able to choose any suitable method and reference materials for carbon isotope delta measurements, and report a carbon isotope delta value and the associated uncertainty, and analysis details. To determine the key comparison reference value (KCRV) and its associated uncertainty, the NRC in collaboration with the NIST, developed a multivariate Bayesian random laboratory effects model, which also incorporates the uncertainty due to bottle-to-bottle homogeneity and any correlations between the reported results that arise due to the use of common reference materials. The KCRV for this study was determined to be -25.833 ‰ relative to the VPDB, with associated uncertainty of 0.028 ‰, and expanded uncertainty of 0.056 ‰ (k=2). All the results reported by the participants in this study were considered equivalent to the KCRV.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).

COOMET.PR-S1 Comparison of whiteness and brightness. Final report

Main textTo 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).

Supplementary comparison of the measurement of the alpha and beta particle surface emission rates from large area sources (CCRI(II)-S10 LASCE)

Main textIn 2009, the Consultative Committee for Ionizing Radiation (CCRI) approved its first supplementary comparison, to be organized by the ENEA (as the pilot laboratory), for the measurement of the alpha and beta particle surface (i.e. 2 solid angle) emission rate from large area sources of the type used for calibrating surface contamination monitors. Five sources were disseminated to the twenty-three participating laboratories consisting of one each of 241Am, 14C, 147Pm and 90Sr for emission rate measurements, with one additional 90Sr source for the evaluation of source uniformity. Measurements of the radionuclide activity and radionuclidic purity were also made although not strictly required. This report describes the organization of this comparison and the material and measurement methods used. The proposed supplementary comparison reference values (SCRV) for each of the comparison measurands are given, together with the Degrees of Equivalence and their associated uncertainties for each participating laboratory. The results of this supplementary comparison may be used as evidence by participating National Metrology Institutes (NMIs) and Designated Institutes (DIs) when submitting calibration and measurement capabilities (CMCs) for the given radionuclides for similar types of large area sources; this is an important aspect of this comparison, given that only one other international supplementary comparison for surface emission rates had been organized before.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).

SIM key comparison in pneumatic gauge pressure for high accuracy pressure balances up to 120 kPa (SIM.M.P-K6)

Main textThis report describes the results of a pneumatic pressure standards key comparison among eleven SIM National Metrology Institutes to determine their degree of equivalence in the pressure range from 10 kPa to 120 kPa in gauge mode. The pilot laboratory was the Centro Nacional de Metrología (CENAM, Mexico). All participating institutes used pneumatic pressure balances as their pressure standard. The transfer standard was a complete system including a pressure balance with a free-deformation piston-cylinder assembly and a set of masses. Eleven participants completed their measurements and reported the pressure-dependent effective areas of the transfer standard at specified pressures with the associated uncertainties. NRC/Canada and BSJ/Jamaica withdrew the comparison by not sending their measurements. To link the results of the nine laboratories that sent their results to the CCM.P- NIST, the USA provided the reference values. To evaluate the compatibility of the results of the participants their relative deviations from those obtained by NIST results were analyzed. The results of six participating NMIs agree with the NIST reference values within their expanded uncertainties (k = 2) in the entire pressure range from 10 kPa to 120 kPa according to the normalized error equation method.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 CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

High precision roundness measurement by error separation techniques (EURAMET.L-S30)

Main textThe results of the supplementary comparison EURAMET.L-S30 on roundness measurement on two spheres by using error separation techniques are reported. Five National Metrology Institutes from EURAMET participated in this comparison, which lasted nine months from March 2020 to November 2020.Two alumina spheres with diameters of 20 mm and 25 mm, respectively, were circulated. The sphere standards were permanently glued to base supports made of steel and they had to be clamped by each laboratory's own usual methods. The measurand was the roundness defect, measured on the equator. Peak-to-valley roundness deviation (RONt) had to be evaluated with reference to the least squares reference circle (LSCI) and, if possible, to the minimum zone reference circles (MZCI), in accordance with the ISO/TS 12181-1:2011.Each laboratory had to use an error separation technique to remove the contribution of the spindle error. In case of using a multistep technique it was advisable to inform on the number of steps used.All participants successfully demonstrated the validity of the claimed measurement capability. Three of them submitted their approved CMCs and two others smaller values which were shown to be valid when compared to the reference value. One participant did not use an error separation technique, showing, as expected, a higher uncertainty with respect to the rest of the participants but according to its declared CMC.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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

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 between INTI-PTB of scattering coefficients in PC-3.5 connector (SIM.EM.RF-S17)

Main textThis document presents the final report of the supplementary comparison identified as SIM.EM.RF-S17 and carried out by the NMI (National Metrology Institute) from Argentina (INTI) and Germany (PTB).The measurands were S-parameters up to 32 GHz in 3.5 mm coaxial connector. In addition, this comparison shows how digitalization during the measurement process and data analysis can improve a comparison outcome, this comparison being one of the first comparisons under BIPM scope in which exchanged data between participants consisted of digital uncertainty objects based on an XML structure.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).

Instrumented Charpy tests on low- and high-energy specimens

Main textThis report describes a CIPM Key Comparison through the SIM/MWG-7 organization, concerning instrumented impact testing of low-energy (20 J) and high-energy (100 J) Charpy V-notch specimens.In this Comparison, various instrumented and non-instrumented data were obtained from instrumented Charpy tests performed at the pilot (NIST) and participant (INMETRO) laboratories using the same instrumented Charpy striker and acquisition system.The use of instrumented absorbed energy (Wt), rather than absorbed energy yielded by the impact machine encoder or dial gage (KV), guarantees traceability to the International System and offers the promise of reducing bias between NMIs and simplifying comparisons between certification systems.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 CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Elements in lipstick material

Main textCosmetics and personal care products are widely used globally. Although toxic elements are banned as intentional ingredients, they may exist as impurities either as contaminants in the raw ingredients, or as by-products of the manufacturing process. These toxic elements can accumulate in the body over time and cause adverse health effects. Different regions around the world have established relevant guidelines and regulations to safeguard the safety of consumers. Therefore, there is a need for metrology institutes to strengthen their measurement capabilities in this area.The supplementary comparison APMP.QM-S17: Elements in Lipstick Material was coordinated by the Health Sciences Authority, Singapore. Four measurands (arsenic, cadmium, mercury and lead) with maximum limits stated under the Association of Southeast Asian Nations (ASEAN) Guidelines on Limits of Contaminants for Cosmetics were chosen. Only one key comparison in the area of cosmetics (CCQM-K106: Lead, Arsenic and Mercury in Cosmetic Cream) was organised by the National Institute of Metrology (NIM) China in 2013. Hence, it was timely to organise another comparison in this area that covered cosmetics but in a different matrix. The study sample (lipstick) offered different analytical challenges as compared to the cream material used in the previous comparison. Moreover, it enabled National Metrology Institutes/Designated Institutes (NMIs/DIs) that did not participate in CCQM-K106 to demonstrate their measurement competencies.Seven institutes participated in the comparison for arsenic, nine for cadmium and lead, and eight for mercury. All participating NMIs/DIs employed microwave-assisted acid digestion for sample dissolution. Inductively coupled plasma mass spectrometry (ICP-MS) and sector field ICP-MS (SF-ICP-MS) were the two most commonly used instrumental techniques. Results of all participating NMIs/DIs were evaluated against the supplementary comparison reference value (SCRV). The SCRV and associated uncertainty were determined from results of NMIs/DIs that participated in the supplementary comparison using methods with demonstrated metrological traceability. For cadmium, mercury and lead, the median was used as estimator of the SCRVs. For arsenic, the arithmetic mean was used as estimator of the SCRV. The SCRVs (± expanded uncertainty) for arsenic, cadmium, mercury and lead (in mg/kg) were 4.188 (± 0.237), 2.0670 (± 0.0171), 2.732 (± 0.147) and 10.406 (± 0.080), respectively. The degree of equivalence and its associated uncertainty were calculated for each submitted result. Most participating institutes were able to demonstrate their capabilities in the determination of elements in lipstick material.Participating NMIs/DIs that have successfully participated in APMP.QM-S17 have demonstrated measurement capabilities in determining mass fraction of transition elements and metalloids/semi-metals, in mass fraction range from 0.1 mg/kg to 25 mg/kg in cosmetic matrices with high organic contents, such as lipstick.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).

Calibration of gauge blocks by optical interferometry comparison - final report

Main textGauge blocks are one of the main artifacts used to calibrate length measuring instruments. The highest grade gauge blocks are calibrated by interferometry making them traceable to the length unit, the metre. The transfer of the wavelength of light to these artifacts is a challenging calibration that requires state-of-the-art equipment, good control of ambient conditions and knowledgeable personnel. It is one of the main calibration services offered by National Metrology Institutes. The Consultative Committee for Length (CCL) has established key comparisons as a means for assuring world-wide traceability and equivalence of length measurements at the highest levels of accuracy. In the key comparison reported here, there were twelve participants from EURAMET, COOMET, AFRIMET, APMP, and SIM regions. This comparison was based on the circulation of seven short steel gauge blocks, six short ceramic gauge blocks, and three steel long gauge blocks. The exercise was successful, and the results of the participants are reported here.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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).