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dc.contributor.authorZELENY REINHARDen_GB
dc.contributor.authorEMTEBORG HAKANen_GB
dc.contributor.authorULBERTH FRANZen_GB
dc.identifier.otherEUR 23243 ENen_GB
dc.identifier.otherOPOCE LA-NA-23243-EN-Cen_GB
dc.description.abstractThis report describes the production of a tetramethylurea reference material (STA-003k), certified for its deuterium-to-hydrogen (D/H) ratio. The material is to be used as an internal standard in site-specific natural isotope fractionation - nuclear magnetic resonance (SNIF-NMR) spectroscopy measurements for determining the D/H ratios of ethanol distilled from wines, an important measure in wine authenticity testing (Commission Regulation 2676/90, (1)). Commercially obtained TMU with a sufficiently high D/H ratio (>120 x 10-6) was purified by removing most of the residual water and filled into amber glass bottles in 500 mL portions. Homogeneity was tested and no heterogeneity observed. Stability studies indicated no material degradation for 4 weeks at 60 °C and a very minor degradation over a period of 5 years at 20 °C which is reflected in the corresponding uncertainty contribution. Batch characterisation was accomplished in an inter-laboratory comparison using the SNIF-NMR technique exclusively. The certified value was obtained as the unweighted mean of the laboratory means of the accepted sets of results. The expanded uncertainty associated (k = 2) includes contributions from (potential) heterogeneity, potential instability, characterisation, as well as the carried-over uncertainty from BCR-656 (96 % wine ethanol) that was used as the internal standard in the measurements. Due to its negligible contribution, the uncertainty associated with the purity of the material did not need to be included.en_GB
dc.description.sponsorshipJRC.D.2-Reference materialsen_GB
dc.titleCertifcation of the Deuterium-to-Hydrogen (D/H) in a 1,1,3,3-Tetramethylurea Batch, Certified Reference Material STA-003ken_GB
dc.typeEUR - Scientific and Technical Research Reportsen_GB
JRC Directorate:Health, Consumers and Reference Materials

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