TY - JOUR A1 - Westwood, S. A1 - Josephs, R. A1 - Choteau, T. A1 - Daireaux, A. A1 - Mesquida, C. A1 - Wielgosz, R. A1 - Rosso, A. A1 - de Arechavaleta, M.R. A1 - Davies, S. A1 - Wang, H. A1 - do Rego, E.C.P. A1 - Rodrigues, J.M. A1 - de Freitas Guimaraes, E. A1 - Sousa, M.V.B. A1 - Monteiro, T.M. A1 - das Neves Valente, L.A. A1 - Violante, F.G.M. A1 - Almeida, R. R. R. A1 - Quaresma, M.C.B. A1 - Nogueira, R. A1 - Windust, A. A1 - Dai, X. A1 - Li, X. A1 - Zhang, W. A1 - Li, M. A1 - Shao, M. A1 - Wei, C. A1 - Wong, S.-K. A1 - Cabillic, J. A1 - Gantois, F. A1 - Philipp, Rosemarie A1 - Pfeifer, Dietmar A1 - Hein, Sebastian A1 - Klyk-Seitz, Urszula-Anna A1 - Ishikawa, K. A1 - Castro, E. A1 - Gonzalez, N. A1 - Krylov, A. A1 - Lin, T.T. A1 - Kooi, L.T. A1 - Fernandes-Whaley, M. A1 - Prévoo, D. A1 - Archer, M. A1 - Visser, R. A1 - Nlhapo, N. A1 - de Vos, B. A1 - Ahn, S. A1 - Pookrod, P. A1 - Wiangnon, K. A1 - Sudsiri, N. A1 - Muaksang, K. A1 - Cherdchu, C. A1 - Gören, A.C. A1 - Bilsel, M. A1 - LeGoff, T. A1 - Bearden, D. A1 - Bedner, M. A1 - Duewer, D. A1 - Hancock, D. A1 - Lang, B. A1 - Lippa, K. A1 - Schantz, M. A1 - Sieber, j. T1 - Final report on key comparison CCQM-K55.b (aldrin): An international comparison of mass friction purity assignment of aldrin N2 - Under the auspices of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a key comparison, CCQM K55.b, was coordinated by the Bureau International des Poids et Mesures (BIPM) in 2010/2011. Nineteen national measurement institutes and the BIPM participated. Participants were required to assign the mass fraction of aldrin present as the main component in the comparison sample for CCQM-K55.b which consisted of technical grade aldrin obtained from the National Measurement Institute Australia that had been subject to serial recrystallization and drying prior to sub-division into the units supplied for the comparison. Aldrin was selected to be representative of the performance of a laboratory's measurement capability for the purity assignment of organic compounds of medium structural complexity [molar mass range 300 Da to 500 Da] and low polarity (pKOW < -2) for which related structure impurities can be quantified by capillary gas phase chromatography (GC). The key comparison reference value (KCRV) for the aldrin content of the material was 950.8 mg/g with a combined standard uncertainty of 0.85 mg/g. The KCRV was assigned by combination of KCRVs assigned by consensus from participant results for each orthogonal impurity class. The relative expanded uncertainties reported by laboratories having results consistent with the KCRV ranged from 0.3% to 0.6% using a mass balance approach and 0.5% to 1% using a qNMR method. The major analytical challenge posed by the material proved to be the detection and quantification of a significant amount of oligomeric organic material within the sample and most participants relying on a mass balance approach displayed a positive bias relative to the KCRV (overestimation of aldrin content) in excess of 10 mg/g due to not having adequate procedures in place to detect and quantify the non-volatile content–specifically the non-volatile organics content–of the comparison sample. There was in general excellent agreement between participants in the identification and the quantification of the total and individual related structure impurities, water content and the residual solvent content of the sample. The comparison demonstrated the utility of 1H NMR as an independent method for quantitative analysis of high purity compounds. In discussion of the participant results it was noted that while several had access to qNMR estimates for the aldrin content that were inconsistent with their mass balance determination they decided to accept the mass balance result and assumed a hidden bias in their NMR data. By contrast, laboratories that placed greater confidence in their qNMR result were able to resolve the discrepancy through additional studies that provided evidence of the presence of non-volatile organic impurity at the requisite level to bring their mass balance and qNMR estimates into agreement. PY - 2012 U6 - https://doi.org/10.1088/0026-1394/49/1A/08014 SN - 0026-1394 SN - 1681-7575 VL - 49 IS - CCQM-K55.b Final Report October 2012 SP - 1 EP - 41 PB - Inst. of Physics Publ. CY - Bristol AN - OPUS4-26831 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Westwood, S. A1 - Josephs, R. A1 - Choteau, T. A1 - Daireaux, A. A1 - Stoppacher, N. A1 - Wielgosz, R. A1 - Davies, S. A1 - do Rego, E. A1 - Wollinger, W. A1 - Garrido, B. A1 - Fernandes, J. A1 - Lima, J. A1 - Oliveira, R. A1 - de Sena, R. A1 - Windust, A. A1 - Huang, T. A1 - Dai, X. A1 - Quan, C. A1 - He, H. A1 - Zhang, W. A1 - Wei, C. A1 - Li, N. A1 - Gao, D. A1 - Liu, Z. A1 - Lo, M. A1 - Wong, W. A1 - Pfeifer, Dietmar A1 - Koch, Matthias A1 - Dorgerloh, Ute A1 - Rothe, Robert A1 - Philipp, Rosemarie A1 - Hanari, N. A1 - Rezali, M. A1 - Arzate, C. A1 - Berenice, M. A1 - Caballero, V. A1 - Osuna, M. A1 - Krylov, A. A1 - Kharitonov, S. A1 - Lopushanskaya, E. A1 - Liu, Q. A1 - Lin, T. A1 - Fernandes-Whaley, M. A1 - Quinn, L. A1 - Nhlapo, N. A1 - Prevoo-Franzsen, D. A1 - Archer, M. A1 - Kim, B. A1 - Baek, S. A1 - Lee, S. A1 - Lee, J. A1 - Marbumrung, S. A1 - Kankaew, P. A1 - Chaorenpornpukdee, K. A1 - Chaipet, T. A1 - Shearman, K. A1 - Gören, A. A1 - Gündüz, S. A1 - Yilmaz, H. A1 - Un, I. A1 - Bilsel, G. A1 - Clarkson, C. A1 - Bedner, M. A1 - Camara, J. A1 - Lang, B. A1 - Lippa, K. A1 - Nelson, M. A1 - Toman, B. A1 - Yu, L. T1 - Mass fraction assignment of folic acid in a high purity material - CCQM-K55.d (Folic acid) Final Report N2 - The comparison required the assignment of the mass fraction of folic acid present as the main component in the comparison sample. Performance in the comparison is representative of a laboratory's measurement capability for the purity assignment of organic compounds of medium structural complexity [molecular weight range 300–500] and high polarity (pKOW < −2). Methods used by the eighteen participating NMIs or DIs were based on a mass balance (summation of impurities) or qNMR approach, or the combination of data obtained using both methods. The qNMR results tended to give slightly lower values for the content of folic acid, albeit with larger associated uncertainties, compared with the results obtained by mass balance procedures. Possible reasons for this divergence are discussed in the report, without reaching a definitive conclusion as to their origin. The comparison demonstrates that for a structurally complex polar organic compound containing a high water content and presenting a number of additional analytical challenges, the assignment of the mass fraction content property value of the main component can reasonably be achieved with an associated relative standard uncertainty in the assigned value of 0.5% KW - CCQM key comparison KW - Purity assessment KW - Folic acid PY - 2018 UR - https://www.bipm.org/utils/common/pdf/final_reports/QM/K55/CCQM-K55.d.pdf U6 - https://doi.org/10.1088/0026-1394/55/1A/08013 VL - 55 IS - Technical Supplement, 2018 SP - 08013, 1 EP - 38 PB - Institute of Physics Publishing (IOP) ; Bureau International des Poids et Mesures AN - OPUS4-44999 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Westwood, S. A1 - Josephs, R. A1 - Daireaux, A. A1 - Wielgosz, R. A1 - Davies, S. A1 - Wang, H. A1 - Rodrigues, J. A1 - Wollinger, W. A1 - Windust, A. A1 - Kang, M. A1 - Fuhai, S. A1 - Philipp, Rosemarie A1 - Kuhlich, Paul A1 - Wong, S.-K. A1 - Shimizu, Y. A1 - Pérez, M. A1 - Avila, M. A1 - Fernandes-Whaley, M. A1 - Prevoo, D. A1 - de Vos, J. A1 - Visser, R. A1 - Archer, M. A1 - LeGoff, T. A1 - Wood, S. A1 - Bearden, D. A1 - Bedner, M. A1 - Boroujerdi, A. A1 - Duewer, D. A1 - Hancock, D. A1 - Lang, B. A1 - Porter, B. A1 - Schantz, M. A1 - Sieber, J. A1 - White, E. A1 - Wise, S. A. T1 - Final report on key comparison CCQM-K55.a (estradiol): an international comparison of mass fraction purity assignment of estradiol N2 - Under the auspices of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a key comparison, CCQM K55.a, was coordinated by the Bureau International des Poids et Mesures (BIPM) in 2009/2010. Eleven national measurement institutes and the BIPM participated. Participants were required to assign the mass fraction of estradiol present as the main component in the comparison sample (CCQM-K55.a) which consisted of a bulk estradiol hemihydrate material obtained from a commercial supplier that had been extensively but not exhaustively dried prior to sub-division into the units supplied for the comparison. Estradiol was selected to be representative of the performance of a laboratory's measurement capability for the purity assignment of organic compounds of medium structural complexity [molar mass range 300–500 Da] and low polarity (pKOW < -2) for which related structure impurities can be quantified by capillary gas phase chromatography (GC) or by high performance liquid chromatography (LC). The majority of participants used a mass balance approach to determine the estradiol content. The key comparison reference value (KCRV) for estradiol in CCQM-K55.a was assigned by combination of KCRVs assigned by consensus from participant results for each orthogonal impurity class. This allowed participants to demonstrate the efficacy (or otherwise) of their implementation of the mass balance approach and to demonstrate that their assigned value for the main component agreed with the KCRV through use of internally consistent contributing methods. The KCRV for the estradiol content of the material was 984.3 mg/g with a combined standard uncertainty of 0.42 mg/g. The individual participant results showed that a relative expanded uncertainty for the purity assignment of 0.2% is a reasonable estimate of the best achievable result by an individual laboratory for a material of this complexity available in this amount at this level of purity. The relative expanded uncertainties reported by laboratories having results consistent with the KCRV ranged from 0.2% to 0.8%. The review of results that were biased from the KCRV showed that two major analytical challenges are posed by the material: the measurement of its water content and controlling for related substance artefact formation during the analysis process. The results displaying a positive bias relative to the KCRV (overestimation of estradiol content) were due to underestimation of the water content of the material, while those with a negative bias (underestimation of estradiol) overestimated the total related substance impurities through a failure to detect and control for artefact formation arising from in situ oxidative dimerization of estradiol in neutral solution prior to analysis. There was however good agreement between all participants in the identification and the quantification of the individual related structure impurities actually present in the sample. The comparison also demonstrated the utility of high-field 1H NMR for both quantitative and qualitative analysis of high purity compounds. It is noted that all the participants who used qNMR as a major or contributing technique and included it as part of, combined it or confirmed it with a conventional 'mass balance' data estimate, obtained results consistent with the KCRV. PY - 2012 U6 - https://doi.org/10.1088/0026-1394/49/1A/08009 SN - 0026-1394 SN - 1681-7575 VL - 49 IS - 1A Tech. Suppl. / 08009 SP - 1 EP - 33 PB - Inst. of Physics Publ. CY - Bristol AN - OPUS4-26411 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hein, Sebastian A1 - Philipp, Rosemarie A1 - Duewer, D.L. A1 - Gasca-Aragon, H. A1 - Lippa, K. A1 - Toman, B. A1 - Bremser, Wolfram A1 - Calderon, M.A.Á. A1 - Castorena, A.P. A1 - Caixeiro, J.M.R. A1 - Do Rego, E.C.P. A1 - Rosso, A. A1 - De Arechavaleta, R. A1 - O'Connor, G. A1 - Holcombe, G. A1 - Ellison, S.L.R. A1 - Splett, J.D. A1 - Schantz, M.M. A1 - Sharpless, K.E. A1 - Croft, M. A1 - Archer, M. A1 - De Vos, J. A1 - Konopelko, L.A. A1 - Kustikov, Y. T1 - Final report on CCQM-K79: Comparison of value-assigned CRMs and PT materials: Ethanol in aqueous matrix N2 - The 2010 CCQM-K79 'Comparison of value-assigned CRMs and PT materials: Ethanol in aqueous media' is the second key comparison directly testing the chemical measurement services provided to customers by National Metrology Institutes (NMIs) and Designated Institutes (DIs). CCQM-K79 compared the assigned ethanol values of proficiency test (PT) and certified reference materials (CRMs) using measurements made on these materials under repeatability conditions. Nine NMIs submitted 27 CRM or value-assigned PT materials for evaluation. These materials represent many of the higher-order reference materials then available for this commercially and forensically important measurand. The assigned ethanol mass fraction in the materials ranged from 0.1 mg/kg to 334 mg/kg. All materials were stored and prepared according the specifications provided by each NMI. Samples were processed and analyzed under repeatability conditions by one analytical team using a gas chromatography with flame ionization detection (GC-FID) method of demonstrated trueness and precision. Given the number of materials and the time required for each analysis, the majority of the measurements were made in two measurement campaigns ('runs'). Due to a shipping delay from one NMI, an unanticipated third campaign was required. In all three campaigns, replicate analyses (three injections of one preparation separated in time) were made for one randomly selected unit of each of the 27 materials. Nine of the 27 materials were gravimetrically diluted before measurement to provide solutions with ethanol mass fraction in the established linear range of the GC-FID method. The repeatability measurement value for each analyzed solution was estimated as the mean of all replicate values. The within- and between-campaign variance components were estimated using one-way ANOVA. Markov Chain Monte Carlo Bayesian analysis was used to estimate 95% level-of-confidence coverage intervals for the mean values. Uncertainty-weighted generalized distance regression was used to establish the key comparison reference function (KCRF) relating the assigned values to the repeatability measurements. On the basis of leave-one-out cross-validation, all of the assigned values for all 27 materials were deemed equivalent at the 95% level of confidence. These materials were used to define the KCRF. Parametric bootstrap Monte Carlo was used to estimate 95% level-of-confidence coverage intervals for the degrees of equivalence of materials, d ± U95(d), and of the participating NMIs, D ± U95(D). Because of the very wide range of ethanol mass fraction in the materials, these degrees of equivalence are expressed in percent relative form: %d ± U95(%d) and %D ± U95(%D). The median of the absolute values of the %D for the participating NMIs is less than 0.05% with a median U95(%D) of less than 1%. These results demonstrate that the participating NMIs have the ability to correctly value-assign CRMs and proficiency test materials for ethanol in aqueous media and similar measurands. PY - 2013 U6 - https://doi.org/10.1088/0026-1394/50/1A/08005 SN - 0026-1394 SN - 1681-7575 VL - 50 IS - 1A / Technical Suppl. 2013 / 08005 SP - 1 EP - 49 PB - Inst. of Physics Publ. CY - Bristol AN - OPUS4-27730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -