This report describes the production of a tetramethylurea (TMU) reference material (STA-003m), certified for its deuterium-to-hydrogen (D/H) amount-of-substance ratio. The material is to be used as an internal standard in site-specific natural isotope fractionation – nuclear magnetic resonance (SNIF-NMR) spectrometry measurements for determining the D/H amount-of-substance ratios of ethanol distilled from wines, an important measure in wine authenticity testing (Commission Regulation 2676/90).
Commercially obtained TMU with a sufficiently high D/H amount-of-substance ratio (>120 x 10-6) was first purified by removing most of the residual water and then filled into amber glass bottles of 500 mL. Between-unit homogeneity was quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2006. Batch characterisation was accomplished by comparing STA-003m samples with samples of the TMU master batch (IRMM-425) under repeatability conditions and by adhering to the SNIF-NMR technique.
The certified value was calculated as the unweighted mean of 18 individual results obtained on 3 different NMR appliances. The uncertainty of the certified value was estimated in compliance with ISO Guide 98-3, Guide to the Expression of Uncertainty in Measurement (GUM); it includes contributions from possible inhomogeneity, instability, and characterisation.
ZELENY Reinhard;
2013-06-06
Publications Office of the European Union
JRC80892
978-92-79-29507-2,
1831-9424,
EUR 25938,
OP LA-NA-25938-EN-N,
https://publications.jrc.ec.europa.eu/repository/handle/JRC80892,
10.2787/54498,
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