The application of SNIF-NMR and IRMS combined with C, H and O isotopes for detecting the geographical origin of Chinese wines

The regional origin of Chinese wines was investigated using two important complementary techniques, site-specific natural isotopic fractionation nuclear magnetic resonance (SNIF-NMR) and isotope ratio mass spectrometry (IRMS). Twenty samples from five different grape varieties were collected from north Xinjiang in 2009, along with 100 wine samples from five different regions during 2010-2013. The (D/H)(I) and (D/H)(II) in wine ethanol ranged from 95.10 to 102.86ppm and from 115.99 to 126.39ppm using SNIF-NMR, respectively. The C-13/C-12 of wine ethanol and O-18/O-16 of wine water were detected using IRMS. The C-13 value (-23.36 parts per thousand) in coastal regions was higher than that in continental regions (-27.75 parts per thousand). The temperature is the key for C-13 value. The O-18 ranged from -1.94 to 4.57 parts per thousand. The O-18 values were only positive in north Xinjiang which had the arid climate and strong sunshine. No difference was found for isotope ratios for wines made from five different grape varieties in north Xinjiang. All data evaluated by principal component analysis and linear discriminant analysis showed that the best method to distinguish the regional wine origin correctly is a combination of (D/H)(I), (D/H)(II), R, C-13 and O-18. Therefore, natural multi-elemental isotope ratios are effective in contributing to wine quality control in the Chinese market.