| In recent years, along with the improvement of economy and living standards, wine industry development is very rapid. At the same time, the wine adulteration events often occur. As the traditional physical and chemical analysis method cannot meet the requirement of the authenticity identification, stable isotope method shows the unique advantages.In this study, a method of determination of δ18O in water from wine was established by Gasbench-IRMS. How the stable isotopes of grape berries were distributed in the nature and which factors influence it in the process of wine production were studied. The δ18Odatabase of wine has been gradually established, and applied to authenticity identification in wine. The summary as follows:(1) A method of determination of δ18O in water from wine samples by Gasbench Ⅱ-IRMS using on-line equilibration technique was reported, and the effects of sample volume, equilibration time and ethanol content on the determination of δ18O in water were discussed. Results demonstrated that the method above was stable with a standard deviation (1σ) lower than0.1‰。 This method had an advantage of easy and rapid operating with lowering sample consumption, and especially can be used continuously for loading a large number of samples.(2) The distribution of δ18O in grape berries in nature and the influence factors were explored. The results showed that the higher the annual average temperature, the more stronger plant transpiration, the value will more prejudiced. If the harvest time is rainy, it will make the value significantly reduced. If the grape juice was not fermented in time, or added exogenous water during fermentation process, the δ18O in water will also reduce.(3) Three kinds of grape juice were fermented in laboratory and winey, the δ18O in water was measured by GasBench-IRMS. It was shown that fermentation of grape juice into wine did not change the δ18O in water, and the variation was less than1%o. However, when exogenous water was added into grape juice before fermentation, the δ18O of water in wine would decrease and a significant linear relationship between the exogenous water addition and the δ18O was observed, the variation of the quantity of actual and calculated water was about1%. The method was shown to be effective in detection of the watering of wine.(4)15grape juices from10different origins were fermented and the δ18O of ethanol and fermentation water in wine was measured. It was shown that the δ18Oof ethanol is significantly related to the δ18O in the fermentation water, A mathematics modle,δ18Oethanol=δ18Owater×0.75+23.05was established. Compared with only use δ18O in water, this method was shown to be effective in improving detection of the watering of wine. The δ18O and δ13C in ethonal can determine the origin of ethanol C4plants or synthesis, but for C3plants need combined with D element.(5) A δ18O database of10domestic origin wine was preliminary established. Chinese wine region is divided into four parts. Xinjiang region is8‰-10‰, Hexi Corridor areas region is4%o-6%o, North areas region is0-3‰, Yunnan-Guangxi areas is-2‰-0. Foreign wine data can be used for import and export trade. |
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