TY - JOUR A1 - Zeleny, R. A1 - Voorspoels, S. A1 - Ricci, M. A1 - Becker, Roland A1 - Jung, Christian A1 - Bremser, Wolfram A1 - Sittidech, M. A1 - Panyawathanakit, N. A1 - Wong, W. F. A1 - Choi, S.M. A1 - Lo, K.C. A1 - Yeung, W. Y. A1 - Kim, D.H. A1 - Han, J. A1 - Ryu, J. A1 - Mingwu, S. A1 - Chao, W. A1 - Schantz, M.M. A1 - Lippa, K.A. A1 - Matsuyama, S. T1 - Evaluation of the state-of-the-art measurement capabilities for selected PBDEs and decaBB in plastic by the international intercomparison CCQM-P114 N2 - An international intercomparison involving eight national metrology institutes (NMIs) was conducted to establish their current measurement capabilities for determining five selected congeners from the brominated flame retardant classes polybrominated diphenyl ethers and polybrominated biphenyls. A candidate reference material consisting of polypropylene fortified with technical mixtures of penta-, octa- and decabromo diphenyl ether and decabromo biphenyl, which was thoroughly assessed for material homogeneity and stability, was used as study material. The analytical procedures applied by the participants differed with regard to sample pre-treatment, extraction, clean-up, employed calibrants and type of calibration procedure as well as regarding analytical methods used for separation, identification and quantification of the flame retardant congeners (gas chromatography coupled to an electron capture detector (GC-ECD), gas chromatography-mass spectrometry in the electron ionisation mode (GC-EI-MS), gas chromatography-mass spectrometry in the electron capture negative ionisation mode (GC-ECNI-MS), and liquid chromatography-inductive coupled plasma-mass spectrometry (LC-ICP-MS)). The laboratory means agreed well with relative standard deviations of the mean of means of 1.9%, 4.8%, 5.5% and 5.4% for brominated diphenyl ether (BDE) 47, 183 and 209 and for the brominated biphenyl (BB) congener 209, respectively. For BDE 206, a relative standard deviation of 28.5% was obtained. For all five congeners, within-laboratory relative standard deviations of six measurements obtained under intermediate precision conditions were between 1% and 10%, and reported expanded measurements uncertainties typically ranged from 4% to 10% (8% to 14% for BDE 206). Furthermore, the results are in good agreement with those obtained in the characterization exercise for determining certified values for the flame retardant congeners in the same material. The results demonstrate the state-of-the-art measurement capabilities of NMIs for quantifying representative BDE congeners and BB 209 in a polymer. The outcome of this intercomparison (pilot study) in conjunction with possible improvements for employing exclusively calibrants with thoroughly assessed purity suggests that a key comparison aiming at underpinning calibration and measurement capability (CMC) claims of NMIs can be conducted. KW - Flame retardants KW - Polymer KW - Polybrominated diphenyl ethers (PBDEs) KW - Polybrominated biphenyls (PBBs) KW - International intercomparison PY - 2010 DO - https://doi.org/10.1007/s00216-009-3314-7 SN - 1618-2642 SN - 1618-2650 VL - 396 IS - 4 SP - 1501 EP - 1511 PB - Springer CY - Berlin AN - OPUS4-22905 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brown, A. S. A1 - Milton, M. J. T. A1 - Cowper, C. J. A1 - Squire, G. D. A1 - Bremser, Wolfram A1 - Branch, R. W. T1 - Analysis of natural gas by gas chromatography Reduction of correlated uncertainties by normalisation N2 - The results of gas chromatographic analysis of natural gas mixtures reveal strong correlations (Pearson correlation coefficient of >0.96) between the uncertainty of each component and variations in the ambient pressure. Although correction for ambient pressure variations can reduce this variability, normalisation of the results of each analysis using the assumption that the sum of all component amount fractions is unity provides significantly greater reductions in the uncertainty of each measured component. We show that the uncertainty in normalised components can be estimated approximately using the correlation coefficient as a measure of the correlation present in the measurements, or exactly using a full calculation of the variance/covariance (V/C) structure of the data. KW - Uncertainty KW - Normalisation KW - Variance KW - Covariance KW - Natural gas KW - Gases KW - Alkanes PY - 2004 DO - https://doi.org/10.1016/j.chroma.2004.04.007 SN - 0021-9673 VL - 1040 IS - 2 SP - 215 EP - 225 PB - Elsevier CY - Amsterdam AN - OPUS4-3732 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Einax, J. W. A1 - Bremser, Wolfram A1 - Machelett, B. T1 - Inverse-variance weighted regression with uncertainty in both variables for the quantitative description of traffic-emitted lead transfer into plants PY - 1999 SN - 0937-0633 VL - 364 SP - 673 EP - 677 PB - Springer CY - Berlin AN - OPUS4-2560 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Viala, S. A1 - Tauer, K. A1 - Antonietti, M. A1 - Krüger, Ralph-Peter A1 - Bremser, W. T1 - Structural control in radical polymerization with 1,1-diphenylethylene. 1. Copolymerization of 1,1-diphenylethylene with methyl methacrylate N2 - The role of 1,1-diphenylethylene (DPE) in radical emulsion polymerization of methyl methacrylate is investigated. The presence of DPE causes a strong decrease in both the rate of polymerization and the molecular weight. According to the results of structure analysis by means of MALDI-TOF mass spectrometry, UV–vis spectroscopy, and 1H–NMR spectroscopy, DPE is incorporated in the copolymer chain exclusively as a reactive recombinant ?,p-dimer, underlining the peculiar role of DPE in radical polymerizations. KW - Emulsion polymerization KW - 1,1-Diphenylethylene KW - Copolymer structure PY - 2002 DO - https://doi.org/10.1016/S0032-3861(02)00676-6 SN - 0032-3861 SN - 1873-2291 VL - 43 IS - 26 SP - 7231 EP - 7241 PB - Springer CY - Berlin AN - OPUS4-1919 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Merchel, S. A1 - Bremser, Wolfram A1 - Akhmadaliev, S. A1 - Arnold, M. A1 - Aumaître, G. A1 - Bourlès, D.L. A1 - Braucher, R. A1 - Caffee, M. A1 - Christl, M. A1 - Fifield, L.K. A1 - Finkel, R.C. A1 - Freeman, S.P.H.T. A1 - Ruiz-Gómez, A. A1 - Kubik, P.W. A1 - Martschini, M. A1 - Rood, D.H. A1 - Tims, S.G. A1 - Wallner, A. A1 - Wilcken, K. M. A1 - Xu, S. T1 - Quality assurance in accelerator mass spectrometry: results from an international round-robin exercise for 10Be N2 - The first international round-robin exercise for the measurement of the long-lived radionuclide 10Be has been conducted. Ten participating accelerator mass spectrometry (AMS) facilities have each measured three samples at the 10-12 to 10-14 10Be/9Be level. All results have been made traceable to the NIST SRM 4325 standard to avoid additional discrepancies that arise when different facilities use different calibration materials. Hence, the data concentrates on pure measurement distinctions. Multivariate statistical investigations have been performed to reveal a bias between facilities, i.e. two distinguished groups could be identified. Maximum discrepancies between two single facilities are in the range of 6–31% depending on the absolute 10Be/9Be value. These findings should be considered when comparing 10Be data produced at one AMS facility with that produced at another facility, which is e.g. often the case for in situ 10Be dating studies. Round-robin exercises are a very helpful tool as part of an overall quality assurance scheme to improve the accuracy, and not only the precision, of AMS data. KW - Accelerator mass spectrometry KW - Terrestrial cosmogenic nuclides (TCN) KW - Cosmogenic nuclides (TCN) KW - Cosmogenic nuclide exposure dating KW - Calibration PY - 2012 DO - https://doi.org/10.1016/j.nimb.2012.07.038 SN - 0168-583X SN - 1872-9584 VL - 289 SP - 68 EP - 73 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-26772 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bremser, W T1 - Peculiarities of qualitative RM and accreditation of their producers N2 - Similarities and differences between accreditation strategies for producers of quantirative and qualitative reference materials are discussed, and possible approaches for the differeing parts in the process developed. T2 - DAkkS Informationsveranstaltung zur Akkreditierung von RMP CY - Berlin, Germany DA - 15.02.2018 KW - Qualitative analysis KW - Reference materials PY - 2018 AN - OPUS4-46777 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -