Isotope ratio mass spectrometry: Analysis of wines from different european countries

Abstract

Natural stable isotope ratios for carbon, hydrogen and oxygen depend on the origin of the studied chemical compound. Such a precept is the basis of the control of the authenticity of food and especially alcoholic beverages. 13C/12C analysis of ethanol as well as 180/160 determination of water contained in wines from different European countries underline the importance of the photosynthetic pathway as well as of the environmental and climatological conditions of the vine. Interesting results in agreement with isotopic fractionation rules for the geographical origin of the samples were obtained. That encouraged us to propose the establishment of a database for isotopic parameters in wines. Stable aboutisotope ratio analysis can yield information the origin of a chemical compound. Natural stable isotope"abundances for elements such as H , C and 0 show small but measurable variations ( Fig. 1) due to isotopic fractionation which occurs during the chemical and physical processes of the natural cycles. '-4 The primary carbon pools in nature are HCO; in the hydrosphere and C 0 2 in the atmosphere. The use of isotope ratio mass spectrometry (IRMS) applied to the carbon bioelement has underlined the I3C discrimination of plants.In C3 plants, including the vine (Calvin photosynthetic cycle), the interstomatal diffusion of C 0 2 and also its dissolution cause negligible isotopic fractionation compared to the carboxylation of ribulose 1,5-biphosphate. Therefore C3 plants show a 6I3C range between -32%, and -25%0 PDB (Pee-Dee Belemnite, SC, USA).5*6 In the C4 plants (Hatch and Slack photosynthetic cycle) both the interstomatal diffusion of C 0 2 and the carboxylation of phosphoenolpyruvate limit the C 0 2 fixation and control the carbon isotopic content of those plant^.^,^ The so-called 'Crassulacean Acid Metabolism' (CAM) plants demonstrate an adaptation capacity in keeping with their environmental Such a difference in the stable carbon isotope content has often been used to detect adulteration of aromas and flavors, especially with gas chromat~graphy/'~C-I~C IRMS instruments,' (e.g. , sweetening of maple syrup) and also to establish the authenticity of wine products and spirit^.^. 3. I", Atmospheric O2 and C02, as well as H 2 0 , are the major sources of the oxygen element. Isotopic fractionation occurs during the various evapo-condensation processes. Clouds are lower in "0 than ocean water; meteoric waters are enriched in compared to clouds. The fermentation process causes no enrichment in the "0 content of the water. Due to the I*O enrichment of plant water compared to exogenous water (tap water), "0 measurements have also been used to ' detect the watering of wines as well as the redilution of fruit Water is the major pool of the hydrogen bioelement, too. As is observed for oxygen, an isotopic fractionation of hydrogen takes place during the evapocondensation process in the atmosphere, and during evaporation and biochemical reactions in plants. During the fermentation process an enrichment in 2H of wine water is obser...

Oxygen-18 measurement by continuous flow pyrolysis/isotope ratio mass spectrometry of vegetable oils

“…These results demonstrate a geographical dependence of these parameters, as already observed for wine. 7 A correlation between enrichment in heavy isotopes and latitude was observed. For instance, lower 18 O contents are observed for the oils coming from the northern regions (e.g.…”

“…Evapotranspiration is known to create an enrichment in heavy isotopes of oxygen and hydrogen in plant water. This is particularly observable for the 18 O/ 16 O ratio of the water of fruits from various areas of production, 6,7 and differences in 18 O values higher than 5% were found on comparing warmer and colder countries. This geographical dependence has also been reported by Koziet and Bricout 28 for the 18 O values of fruit juice sugar.…”

“…carbohydrates) gives interesting information about the environmental climatic conditions during their formation. [7][8][9] However, until recently, only a few studies have been published reporting the determination of the 18 O content of organic compounds. [10][11][12][13][14][15] The reasons for this are linked to the safety precautions involved and also to the difficult materials handling in the implementation of the method.…”

Laser-based measurements of 18O/16O stable isotope ratios (δ18O) in wine samples

“…3 Recently, measurements of the 18 O/ 16 O stable isotope ratio (expressed as δ 18 O) of water in wine have been used for wine authentication, and extensive databases of wine isotope ratios are now being developed. [4][5][6][7] These technologies have also been extended to fruit juice extracts, 8 concentrated spirits, 9 and other food authentication applications.…”

13C and 18O isotopic analysis to determine the origin of L‐tartaric acid

“…Stable isotope ratio methods exploit these differences of origin, which leave a recognisable trace in the end product. In the case of tartaric acid, we found that 13 Therefore, stable isotope ratio measurements of carbon cannot be used to differentiate natural tartaric acid from synthetic ones, but allow a preliminary, inexpensive screening of synthetic samples with d…”