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18 O of Ethanol in Wine and Spirits forAuthentication PurposesMatteo Perini and Federica Camin

Abstract: Since 1986 the European Union has established ofcial isotopic analysis methods for detecting the illegaladdition of sugar and water to wine and to enable geographical traceability. In this paper we investigate the possibility of

using analysis of the 18

O/16

O stable isotope ratio (expressed as 18

O) of ethanol to improve detection of the wateringof wine and to determine the origin of ethanol. Sixty-nine authentic wine samples from all over Italy, 59 spirits fromfruit and cereals, 5 chemically synthesized ethanols, one concentrated and rectied must, one beet and one cane sugar,one fresh must, and 6 waters with increasing 18O values were considered. Ethanol was recovered by distillation, usinga Cadiot spinning band column, following the ofcial OIV methods. The residual water was trapped by storing thedistillate for at least 24 h on a molecular sieve. The 18O/ 16O ratio was measured using a pyrolyser interfaced with anisotope ratio mass spectrometer. The -18 O of ethanol is signicantly related to the 18O of the fermentation water andcan be considered as a reliable internal reference. The values ranged from + 24 to + 36 in wine (years 2008 to 2012),+ 10 to + 26 in fruit and cereal distillates, and from 2 to + 12 in synthetic ethanol. The method was shownto be effective in improving detection of the watering of wine and determining the origin of ethanol (from grapes, other fruit, or synthesis), but not in detecting the addition of cane or beet sugar to wine.

Keywords: dehydrated ethanol, ethanol origin, TC/EA-IRMS, wine watering

Practical Application: The method can be used to improve the detection of illegal watering of wine.

IntroductionIn the last 10 y thedemandforalcoholic products (wine andspir-

its) has increased by around 8.6% (source Statistical report on worldvitiviniculture 2012. International Organisation of Vine and Wine2012, http://www.uibm.gov.it/images/stories/Notizie/sintesi_

impatto_contraf_su_sistema-paese.pdf ). The rise in prices anddifcult access to raw materials have encouraged adulterationin the oenological eld (source: Ufcio italiano brevetti emarchi. Direzione generale lotta alla contraffazione. Report2012, http://www.uibm.gov.it/images/stories/Notizie/sintesi_ impatto_contraf_su_sistema-paese.pdf ). Since 1986, the EuropeanUnion and the Organisation Internationale de la Vigna et du Vin(OIV) have ofcially established isotopic analytical methods for detecting the illegal addition of sugar (OIV MA-AS-311-05, OIVMA-AS-312-06) and water (OIV MA-AS2-12) to wine and toenable geographical traceability.

With regard to the detection of water addition, this is deter-mined on the basis of analysis of the isotopic ratio 18O/ 16O (ex-pressed as 18O ) of wine water and the comparison of thisvalue with the reference data dened by the ofcial wine data-bank (EU Regulation 555/2008). The addition of water causes adecrease in the original 18O value of wine and is detectable if the value falls below the limit dened by the EU wine databank.This decrease is due to the fact that the vegetal water containedin wine has a 18O value that is much higher than tap water asa consequence of the evapotranspiration processes occurring in

MS 20130240 Submitted 2/20/2013, Accepted 3/25/2013. Authors are withIASMA Fondazione Edmund Mach, Via E. Mach 1, 38010 San Michele allAdige (TN), Italy. Direct inquiries to author Camin (E-mail: [email protected]).

plants (Rossmann and others 1999). If the starting wine is orig-inally characterized by a high 18O, detection of the addition of a small percentage of water is not easy. A new isotopic method,based on analysis of the 18O of ethanol after fermentation anddistillation, was shown to be very effective in improving the de-tection of added water in fruit juices (Jamin and others 2003;Monsallier-Bitea and others 2006). This is based on the relation-ship existing between the 18O value of fermentation water andethanol ( r = 0.96, Jamin and others 2003). 18O analysis of ethanolcan be done using 2 different techniques: isotope ratio mass spec-trometry (IRMS) combined with high temperature conversionelemental analyser (TC/EA-IRMS) (Calderone and others 2006)or gas chromatography-high-temperature conversion (GC-TC)IRMS in combination with the headspace SPME (solid-phasemicroextraction) technique (Aguilar-Cisneros and others 2002; Yamada and others 2007). Using the SPME procedure, the iso-topic fractionation varies according to the SPME conditions and ishard to control (Yamada and others 2007). For this reason, directdry-ethanol analysis using TC/EA-IRMS in pyrolysis conditionsappears to be more reliable. An international peer test, which tookplace in summer-autumn 2004, demonstrated that a critical aspectin this type of analysis is dehydration of the sample (Calderone andothers 2006). Indeed, due to the interference of water oxygen, thesample should be 100% ethanol. To achieve this, Jamin and others(2003 ) submitted the distillate obtained from fruit juice accordingto the procedure described in the AOAC 995.17 method (contentof ethanol higher than 95%v/v), to trap residual water using amolecular sieve.

With regard to the detection of added sugar, it is worth re-membering that according to EC Regulations 479/2008 (AnnexIV, sections 1 and 17) and 123/2007 (Annex XI ter, sections 1and 17), wine cannot contain ethanol from any sources other than

C 2013Institute of Food Technologists R

doi: 10.1111/1750-3841.12143 Vol. 78, Nr. 6,2013 Journal of Food Science C839Further reproductionwithout permissionis prohibited


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18 O of ethanol of wine and spirits . . .

grapes. On the basis of ofcial analysis of the D/H ratio using2H-SNIF-NMR ( 2H-Site-specic Natural Isotope Fractionation Nuclear Magnetic) and the 13 C/ 12C ratio (expressed as 13C )using IRMS, it is possible to determine whether ethanol derivesfrom grapes, cane and beet sugar, or chemical synthesis. On theother hand, the D/H and 13C/ 12C values of grapes are generallysimilar to those other fruits and cereals. It is therefore importantto nd other isotopic parameters making it possible to determinethe origin of ethanol contained in wine.

In this paper, we present and discuss the 18O results of ethanolfrom wine ( N = 69), cereal and fruit spirits ( N = 59), beet andcane sugar, and of synthetic origin ( N = 5), obtained for the 1sttime after suitable extraction and/or dehydration. The aim was tostudy the relationship between the 18O of ethanol from grapesand the 18O of fermentation water and postfermentation water in order to verify the ability of ethanol 18O analysis to improvedetection of the watering of wine (as compared to analysis of the18O of wine water). Moreover, we investigated the ability of thisanalysis to detect whether the ethanol originated from grapes,fruit, beet or cane sugar, or chemical synthesis and therefore todetermine the illegal addition of exogenous ethanol to wine (ascompared to ofcial OIV analyses of the D/H and 13 C/ 12C ratios

of ethanol).

Materials and Methods

SamplesA total of 133 fermented samples were considered: 69 authentic

wine samples from all over Italy (2 to 4 samples for each of the20 regions) belonging to the EU wine databank of years 2008to 2012, and 59 spirits from fruit and cereals obtained under controlled conditions in the distillery of our institute or other certied Italian producers. Moreover, 5 chemically synthesizedethanols with a purity of 99.9% were provided by Italian Customs.

One sample of concentrated and rectied must (65 Brix), one

of crystallized beet sugar, one of crystallized cane sugar, one of

fresh must (15 Brix), 2 of wine, and 6 of water with different 18Ovalues (9.8, 4.0 , 1.0 , + 2.7, + 4.9, + 7.2) wereconsidered, to study the effect of the 18O of fermentation andpostfermentation water and of the addition of beet and cane sugar,on ethanol 18O value of grape derivates.

Sample preparationEthanol was extracted from the samples of wine, spirit, and fer-

mented must and sugar by distillation, using a Cadiot spinningband column, following the ofcial methods for spirit and wine(OIV MA-AS-311-05, OIV-MA-BS-23). The residual water wastrapped by storing the distillate for at least 24 h on a molecular sieve (3.2 mm pellets, UOP type 3A, Sigma-Aldrich, St. Louis,Mo., U.S.A.) following the method described by Jamin and oth-ers (2003 ). By adding growing percentages of water to absoluteethanol and measuring the 18O of ethanol before and after dilu-tion, we found that the procedure guarantees the expected 18Ovalue and therefore is effective for samples containing less than15% of water. The method is therefore suitable for the distillatesproduced from the Cadiot spinning ban column, which guaranteesalcoholic degree higher than 95%. For samples containing morethan 15% of water, a higher amount of molecular sieve and/or a

longer period of storage are required.Water with a 18O of + 7.2 was obtained by evaporating

deionized water at 100 C for 9 h. Water samples with a 18Oof 4.0, 1.0 , + 2.7, + 4.9 were obtained by mixingwater with a 18O of + 7.2 with tap water (9.8 ).

The concentrated and rectied must (65 Brix) and beet sugar were diluted in the 6 water samples with a growing 18O value(from 9.8 to + 7.2) and then quantitatively fermented toethanol using Saccaromices cerevisie yeast (Lallemand Inc., Montreal,Canada), following the ofcial method for fruit juice (AOAC995.17) and for must (OIV MA-AS-311-05).

An increasing amount of beet and cane sugar (7 samples withgrowing concentration of sugar from 0gr/L to 180gr/L) was added

to a fresh must (15

Brix) and subjected to fermentation.

y = 0.34x + 31.35R2 = 1.00

y = 0.64x + 23.63R2 = 1.00

15

17

19

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23

25

27

29

31

33

35

-11 -9 -7 -5 -3 -1 1 3 5 7 9

18 O water ( vs V-SMOW)

1 8 O e t

h a n o

l ( v s

V - S

M O W )

BEET

CRM

Figure 1Correlation between 18 O values of ethanol and of fermentation water for concentrated and rectied must (CRM) and sugar (BEET).

C840 Journal of Food Science Vol. 78, Nr. 6, 2013


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An increasing amount of tap water was added to 2 samples of wine.

Stable isotope analysisThe D/H and 1 3C/ 12C isotope ratios of the alcohol from spirit

and wine were determined using the ofcial methods (OIV MA-AS-311-05, MA-AS-312-06, OIV-MA-BS-23, OIV-MA-BS-22)using SNIF-NMR (Site-specic Natural Isotope Fractionation-Nuclear Magnetic Resonance) (FT-NMR AVANCE III 400,Bruker BioSpin GmbH, Karlsruhe, Germany) and IRMS (SIRAII-VG ISOGAS, FISIONS, Rodano, Milano, Italy) interfaced withan Elemental Analyser (NA 1500, Carlo Erba, Milano, Italy). TheD/H values were measured site-specically in the methilic andmethilenic sites of ethanol [(D/H) I and (D/H) II ] and were cor-rected for the content of methanol and higher alcohols (Bauer-Christoph and others 1997). They are expressed in parts per mil-lion (ppm). The 13C/ 12C values are expressed in scale (seebelow) against the international V-PDB standard.

The 18O/ 16O ratio of wine water was analyzed in CO 2 ac-cording to the water equilibration method described in the OIVMA-AS2-12 method, using an IRMS (SIRA II VG ISOGAS,Rodano, Milano, Italy) interfaced with a CO 2 equilibration sys-

tem (Isoprep 18 VG ISOGAS) and the values are expressed in scale (see below) against the international V-SMOW standard.

A DeltaPlus-XP isotope ratio mass spectrometer coupledto a Thermal Conversion/Elemental Analyser (TC/EA) (bothThermo Scientic, Bremen, Germany) was used for 18O/ 16Oanalysis of ethanol samples. The reactor tube of TC/EA was set to1450 C (with CG temperature at 80 C) and carrier gas pressurewas at 1.45 bar. One L of alcohol sample was injected 3 timesdirectly into the pyrolysis furnace using an autosampler (AS 2000Thermo Scientic) with a micro syringe for liquid. In the pyrolysis tube the oxygen atom of ethanol is quantitatively convertedto carbon monoxide, which is analyzed using IRMS. The ratiobetween m/z 30 ( 12C 18O) and 28 ( 12C 16O) gives the 18O/ 16O

ratio in the sample.

The values are expressed on the scale against the in-ternational V-SMOW standard according to the equation: =R sample R standard

R standard 1000 where R is the ratio of the heavy to light

stable isotope in the sample (Rsample) and in the internationalreference material (Rstandard).

The 18O data (the mean values of the 3 injections) were cor-rected against 2 different ethanol standards, by constructing a lin-ear equation. The 18O values of the 2 standards were 17.3and 36.9 and are currently being validated, through an in-ternational collaborative study supervised by Eurons Scientic(Thomas and others 2013). A 3rd ethanol sample named QualityControl ethanol was used to validate the whole analysis (mea-surement + correction). The nal value was reported in a controlchart and if it was within the tolerance range the whole sessionwas validated.

The analytical uncertainty (2s) of the measurements was 0.6for the 18O in ethanol, 0.3 for the 18O in wine water, and0.3 and 0.8 ppm, respectively, for the 13C and D/H in ethanol.

The standard deviation of intralaboratory reproducibility for the18O of ethanol, obtained by distilling, dehydrating and measuringthe same sample 10 times on different days and using differentoperators, was 0.4 .

Results and Discussion 18 O of wine ethanol and water

We rst studied the relationship between the 18O values of ethanol and fermentation water, fermenting a concentrated andrectied must diluted with 6 water samples with an increasing18O (Figure 1). We found a signicant correlation ( r 2 = 1.00)between the 18O values of ethanol and the 18O values of water.The reason for this is that the oxygen atoms of ethanol also de-rive from the fermentation water, which is incorporated into sugar (and then into ethanol) when sucrose is converted to monosaccha-ride (glucose and fructose) through enzyme-catalyzed hydrolysis

(Monsallier-Bitea and others 2006) and is added to the precursor

y = 0.88x - 22.65R2 = 0.57

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0

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4

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10

12

23 25 27 29 31 33 35 37 39 18 O ethanol (, vs V-SMOW)

1 8 O w a t e r

( , v

s V - S

M O W )

Wine data bank

Min (95% c.i.)

Regression Line

Figure 2Correlation between 18 O values of ethanol and of water of authentic Italian wine samples.

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Table 1Variation of 18 O values of water and ethanol of 2 winesamples (A and B) with increasing percentage of tap water.

18 O water 18 O ethanol% water vs vs

Sample addition V-SMOW V-MOW

A 0 7.1 31.0A 20 3.7 31.2A 30 1.6 30.9A 40 0.0 31.1

B 0 2.8 29.8B 20 0.3 29.8B 30 1.3 29.7B 40 2.5 29.8

of ethanol (acetaldehyde) to form the intermediate acetaldehydehydrate.

To investigate this relationship in real wine samples, we thenconsidered 69 authentic wines from all over Italy. The 18O valuesof wine ethanol varied between + 24 and 36 : they werehigher than the values found in the literature (Aguilar-Cisnerosand others 2002; Calderone and Guillou 2008), probably becausethe wines were produced in different areas and years and becauseprevious analysis had been performed using different analyticaltechniques (SPME and TC/EA respectively, without dehydrationor referring to other standards).

By comparing the 18O values of ethanol with the 18O of winewater, we obtained a signicant ( P < 0.001) linear relationship(18O water = 0.88 18O ethanol 22.65; Figure 2). The linear equation is similar to that found in the literature for fruit juices(y = 0.82x 22.08) (Jamin and others 2003). This means thatthe correlation is reliable and independent of the matrix and the18O values of water, therefore generally effective, regardless of the origin and the production year of wine. This is very importantbecause it makes it possible to use this relationship for authenticity

control, avoiding analysis of the 18O of ethanol for all the samplesin the ofcial wine databank (Reg. CE 555/2008).

We can indeed dene a threshold value for the relationship,calculating 95% of the condence interval of the regression linefrom the following equation:

y = 0.88x 22 .65 2s

where y = 00.88x 22.65 is the linear regression model ob-tained from the 69 data points, 2 is the Student t and s is thestandard deviation of the residues (difference between calculatedand observed value), which in this case is 1.9.

As the addition of water to wine changes only the 18O of water and not that of ethanol, as here demonstrated (Table 1), thewatering of wine changes this relationship, which could go outsidethe threshold value, even if the water 18O is not outside the limitdened by the wine databank.

To demonstrate the possibility of improving detection of thewatering of wine, we simulated adulteration of the 69 wines byadding a growing %(from 10% to 50%) of tap water ( 18O = 9 ) and calculated the number of samples identied as wateredon the basis of the 18O lower value of wine water and that of the

relationship between the 2 18Os (Figure 3). In all experimentalcases (from 10% to 50%) the 18O of ethanol improved detectionof the watering of wine. With an addition of 10% water this newmethod made it possible to increase the detection of adulteratedsamples from 3 to 10 out of 69. The best results were obtainedwith addition of 30% water.

18O analysis of ethanol can therefore be considered as a reliableinternal reference for improving detection of the watering of wine.

18 O of ethanol from different sourcesTable 2 shows the D/H, 13C, and 18O values of ethanol from

fruit spirits, vodka, rum, whisky, and of synthetic origin. The D/Hand 13C values are compatible with the botanical origin of the

0

10

20

30

40

50

60

70

80

10% 20% 30% 40% 50%

% of added water

N u m

b e r o f a d u l

t e r e

d s a m p l e s

Only 18O of water

18O of water + ethanol

Figure 3Improvement in wine watering detection by comparing 18 O of water with that of ethanol.



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Table 2D/H, 13 C, and 18 O values of ethanol from fruit spirits, vodka, rum, whisky, and of synthesis.

(D/H) I ppm (D/H) II ppm R 13 C vs V-PDB 18 O vs V-SMOW

Apricot (10) Mean 98.9 126.8 2.56 26.5 21.7Std dev 2.2 3.0 0.03 0.6 1.5

Min 95.1 122.8 2.53 27.3 19.0Max 102.7 130.2 2.60 25.5 23.9

Grain (1) 98.6 126.9 2.58 26.8 23.6Cherry (5) Mean 100.0 128.3 2.6 27.0 25.5

Std dev 0.8 1.4 0.0 0.8 1.7

Min 99.2 126.3 2.5 27.8 23.8Max 101.3 129.7 2.6 25.9 28.1Arbustus (3) Min 101.8 129.5 2.5 25.0 19.4

Max 103.8 132.4 2.6 24.5 23.4Raspberry (1) 93.2 127.8 2.74 28.3 21.7Quince (2) Min 102.5 125.3 2.45 25.1 23.6

Max 102.3 127.3 2.49 26.7 10.3Pear (20) Mean 100.4 125.4 2.5 27.7 21.1

Std dev 0.8 1.1 0.0 0.6 2.0Min 98.4 123.6 2.4 28.8 15.9Max 101.9 127.8 2.6 26.3 24.7

Plum (5) Mean 100.7 124.8 2.5 26.7 19.5Std dev 1.1 1.6 0.1 0.5 3.1

Min 99.5 122.2 2.4 27.2 13.9Max 102.3 126.3 2.5 26.0 21.2

Sorb (2) Min 108.5 128.2 2.36 17.7 26.4Max 112.7 130.2 2.31 16.5 28.8

Rum (5) Mean 110.8 124.2 2.2 12.1 22.1Std dev 1.1 0.6 0.0 1.3 1.6

Min 109.9 123.6 2.2 13.0 19.6Max 112.4 125.0 2.3 10.3 23.8

Whisky, oat (1) 98.6 124.2 2.52 26.6 26.7Vodka (4) Mean 94.8 122.0 2.6 26.0 24.9

Std dev 0.5 0.7 0.0 0.2 2.6Min 94.3 121.4 2.5 26.2 22.5Max 95.3 123.0 2.6 25.8 28.5

Synthesis (5) Mean 120.1 139.2 2.3 30.0 1.2Std dev 3.2 2.7 0.1 1.1 6.3

Min 116.5 137.1 2.3 31.1 2.6Max 125.1 142.9 2.5 28.4 12.4

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95

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105

110

115

120

125

130

-5 0 5 10 15 20 25 30 35 40

18O ethanol (, vs V-SMOW)

( D H ) I e t h a n o l

( p p m

)

Wine

Spirit

Synthesis

Figure 4Plot of distribution of 18 O and (DH)I values of ethanol samples of different origin.

Vol. 78, Nr. 6,2013 Journal of Food Science C843


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Table 3Variation of D/H, 13 C, and 18 O of ethanol of one wine sample with increasing percentage of beet and cane sugar.

gr/L sugar addition (D/H) II ppm (D/H) II ppm R 13 C vs V-PDB 18 O vs V-SMOW

Beet sugar 0 99.5 127.2 2.56 26.8 27.430 98.8 129.3 2.62 26.8 27.460 97.4 128.3 2.63 26.9 27.590 96.7 128.5 2.66 27.1 27.5

120 96.5 128.6 2.67 26.9 27.3150 95.9 129.2 2.69 27.2 27.4180 95.3 130.3 2.73 27.0 27.3

Cane sugar 0 100.7 129.4 2.57 28.1 29.130 101.9 129.3 2.54 25.8 28.260 103.1 129.6 2.51 24.1 27.090 103.9 131.2 2.52 22.9 28.4

120 104.8 131.2 2.50 21.8 28.3150 104.7 131.8 2.52 21.1 28.3180 105.4 131.4 2.49 20.1 28.4

sugar (for example, the sorb and cane sugar in rum have the char-acteristically higher values of C4 plants; Martin and others 1996)and with the values in the literature (Bauer-Christoph and oth-ers 1997; Ishida-Fujii and others 2005). While the ethanol 18Ovalues of cereals overlap with those of wine, the ethanol 18Ovalues of most fruit spirits (except cherries) are lower. A possibleexplanation is the different 18O of vegetal water characterizingthese products. All the fruits considered (for example, apples, apri-cots, or cherries) indeed showed 18O water values lower than for grapes (Dunbar and Wilson 1983) and therefore a lower 18 O of ethanol.

Considering the fruit spirits with (D/H) I and 13C values par-tially overlapping with those of wine, it is evident that the 18O of ethanol is able to improve discrimination between wine ethanoland ethanol from other fruits (Figure 4).

Moreover, the 18O of ethanol clearly distinguishes naturalethanol from synthetic ethanol (Figure 4). The low 18O valueof synthetic ethanol results from the addition of tap water to ethy-lene (Schmidt and others 2001).

Due to the possibility of distinguishing the botanical origin for some species, we investigated the ability of ethanol 18O analysisto determine the fraudulent addition of sugar to wine. First wechecked the relationship between the 18O values of ethanol andfermentation water, fermenting a sample of beet sugar diluted withthe 6 water samples with an increasing 18O (Figure 1). In thiscase we again found a signicant linear relationship, but the slopesof the 2 correlation lines were different. The same trend was alsoobserved for fruit juice (Monsallier-Bitea and others 2006) andwas justied on the basis of the much lower amount of sucrose inmust as compared to beet sugar (which is 100% sucrose). Water is indeed incorporated into sugar (and then into ethanol) whensucrose is converted to monosaccharide (Monsallier-Bitea and

others 2006).Then we added an increasing amount of beet and cane sugar to

a must sample in 7 experiments. In this case, there was no traceof exogenous water because the sugar was dissolved directly in thegrape must. In both cases, the 18O of ethanol did not changewith the addition of beet or cane sugar (Table 3).

Ethanol 18O analysis cannot therefore be used to improve de-tection of the illegal addition of cane and beet sugar to wine.

ConclusionsThe 18O value of ethanol was shown to be related to the

18O of the fermentation water and can be considered as a reliableinternal reference.

18O analysis of ethanol is able to improve detection of the

watering of wine and in some cases of the origin of the ethanol(for example, from grapes, other fruit, or a synthesis), but not todetect the addition of cane or beet sugar to wine.

AcknowledgmentsWe kindly thank dott.sa Filippi and dott. Usseglio Tommaset for

having provided the samples of synthetic ethanol and MIPAAF-ICQRF for having provided the wine samples.

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assessment by headspace SPME-HRGC-IRMS analysis of 13C/ 12 C and 18O/ 16 O ratios of ethanol. J Agric Food Chem 50(26):75203.

Bauer-Christoph C, Wachter H, Christoph N, Rossmann A, Adam L. 1997. Assignment of rawmaterial and authentication of spirits by gas Chromatography, hydrogen- and carbon-isotoperatio measurement. Z Lebensm Unters Forsch A 204:44552.

Calderone G, Guillou C. 2008. Analysis of isotopic ratios for the detection of illegal watering of beverages. Food Chem 106(4):13991405.

Calderone G, Reniero F, Guillou C. 2006. Isotopic analysis of ethanol: study on 18O/ 16 Omeasurement using a high-temperature pyrolysis system coupled to an isotope ratio massspectrometer. Rapid Comm Mass Spectrom 20(5):93740.

Dunbar J, Wilson AT. 1983. Oxygen and hydrogen isotopes in fruit and vegetable juices. PlantPhysiol 72:7257.

Ishida-Fujii K, Goto S, Uemura R, Yamada K, Sato M, Yoshida N. 2005. Botanical and geo-graphical origin identication of industrial ethanol by stable isotope analyses of C, H, and O.Biosci Biotechnol Biochem 69(11):21939.

Jamin E, Gu erin R, R etif M, Lees M, Martin GJ. 2003. Improved detection of added water inorange juice by simultaneous determination of the oxygen-18/oxygen-16 isotope ratios of water and ethanol derived from sugars. J Agric Food Chem 51(18):52026.

Martin GG, Hanote V, Lees M, Martin YL. 1996. Interpretation of combined 2 H SNIF/NMRand 13 C SIRA/MS analyses of fruit juices to detect added sugar. J AOAC Int 79(1):6272.

Monsallier-Bitea C, Jamin E, Lees M, Zhang BL, Martin GJ. 2006. Study of the inuence of alcoholic fermentation and distillation on the oxygen-18/oxygen-16 isotope ratio of ethanol. J Ag ric Food Chem 54(2):27984.

Rossmann A, Reniero F, Moussa I, Schmidt HL, Versini G, Merle MH. 1999. Stable oxygenisotope content of water of EU data-bank wines from Italy, France and Germany. Z LebensmUnters Forsch A 208:4007.

Schmidt HL, Werner RA, Rossmann A. 2001. 18O pattern and biosynthesis of natural plantproducts. Phytochemistry 58:932.

Thomas F, Jamin E, Hammond D. 2013. 18 internal referencing method to detect water additionin wines and fruit juices: collaborative study. J AOAC Int. doi: 10.5740/jaoacint.12-339.

Yamada K, Yoshida N, Calderone G, Guillou C. Determination of hydrogen, carbon andoxygen isotope ratios of ethanol in aqueous solution at millimole levels. Rapid CommunMass Spectrom 21(8):14317.


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