The reliable testing of the authenticity of wines requires the accurate calibration of specific isotope ratio measurements. Therefore, tetramethylurea (TMU) has been certified for its deuterium-to-hydrogen (D/H) amount-of-substance ratio. The D/H (i.e. 2H/1H) ratio is one of several parameters (among other isotope ratios such as 13C/12C (carbon), 18O/16O (oxygen), or 15N/14N (nitrogen)) which help to determine whether the analysed sample can be considered authentic or whether it has been adulterated. Hence, the material is important for laboratories authorised to perform those measurements, aiming to fight fraud by verifying the authenticity of wines.
In official wine controls the measured values are compared with those from the respective authentic wines listed in the European Union (EU) Wine Databank, operated by the European Office for Wine, Alcohol and Spirit Drinks (BEVABS) at the Joint Research Centre (JRC).
STA-003m will be the successor of STA-003k. It shall be used in site-specific natural isotope fractionation – nuclear magnetic resonance (SNIF-NMR) spectroscopy measurements as internal standard for determining D/H ratios of ethanol distilled from wines, which constitutes an important measure in wine authenticity testing (according to OIV-MA-AS311-05).
Homogeneity and stability of the material were assessed, and stability is guaranteed within the declared shelf life. The certified value was established by comparing the mean value of 18 samples of the STA-003m, tested together with 18 master batch samples of the CRM IRMM-425 under repeatability conditions. Moreover, these measurements were performed in one laboratory on 3 different NMR appliances by strictly adhering to the SNIF-NMR protocol prescribed in the standard OIV-MA-AS311-05. The project details are described in a comprehensive certification report, which will be available on-line once the material is released.