RU2484459C1 - Method for determination of tartaric acid origin in wines and juice-containing beverages - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: method for determination of tartaric acid origin is as follows: one performs settlement of tartaric acid barium salt from a wine or juice-containing beverage sample. The resultant residue is washed and dried. The dried residue is divided into three parts. The first part is subjected to isotopic mass-spectrometer analysis with ¹³C/¹²C stable isotopes relation establishment to identify the summary isotopic characteristic of tartaric acid barium salt carbon. One performs introduction of the second residue part into an ampoule sealed at one end, addition of cupric oxide, vacuumisation, sealing and maintenance in the muffle furnace. After cooling the ampoule is broken and isotopic characteristics of tartaric acid alkyl group carbon are measured. The third residue part is maintained in the muffle furnace for alkyl group removal. The remaining residue is analysed using the isotopic mass-spectrometer for determination of isotopic characteristics of tartaric acid barium salt carboxylic group carbon. The obtained quantitative characteristics of wine or juice-containing beverage being analysed are compared with the reference mixtures characteristics; one concludes on tartaric acid origin according to coincidence or deviation degree.

EFFECT: method allows to enhance accuracy and validity.

5 tbl, 9 ex

Description

The invention relates to the wine industry.

A known method for the determination of tartaric acid by precipitation in the form of calcium racemate and determination by gravimetric method (Collection of international methods for the analysis and evaluation of wines and wort. M: Food industry, 1993, p. 82-93).

The disadvantage of this method is the low accuracy of the analysis. A known method for the determination of tartaric acid in wine by the method of liquid ion-exclusion chromatography (Seliverstova I.V. Determination of organic acids in wine by the method of liquid ion-exclusion chromatography. Winemaking and viticulture. 2001, No. 4, pp. 9-11).

The disadvantage of this method is the low accuracy of the analysis.

Closest to the proposed method is a method for the determination of organic acids using liquid chromatography ("Methodology for measuring the mass concentration of organic acids in wine products using high-performance liquid chromatography", developed and approved by GNU VNIIPBiVP Russian Agricultural Academy, certification certificate No. 38-09 registration code MVI according to the Federal Register FR.1.31.2009.06524).

The disadvantage of this method is the low specificity, which does not allow to determine the sources of organic acids and establish the authenticity or falsification of the analyzed object. The technical result of the proposed method is to obtain previously unknown characteristics of tartaric acid, based on determining the difference in the content of ¹³ C isotope in the carboxyl and alkyl groups of tartaric acid with respect to their total characteristic, i.e. determination of intramolecular isotope heterogeneity, depending on the nature of its origin.

This is achieved by the fact that the method for determining the intramolecular isotope heterogeneity of tartaric acid in wines and juice drinks is characterized by the fact that tartaric acid salts are precipitated from a sample of wine or juice drink by cold treatment in the presence of 0.1 N HCl, the precipitate formed is collected, 1 M NaOH is added to pH values of 9, was added 10 cm ³ of 1 M BaCl ₂ was heated to a temperature of 60 ° C, cooled to 4 ° C, kept at this temperature for 24 hours, the precipitate formed tartaric acid salt of barium besiege centrifugation, washed with distilled water until pH = 7, dried, the dried precipitate is separated into three parts, the first part is subjected to isotope mass spectrometer analysis with establishing relationships stable isotope ¹³ C / ¹² C to obtain the total isotope carbon characteristics of tartaric acid, a second portion the precipitate is introduced into a vial of refractory glass sealed on one side, 0.5 g of copper oxide is added, and vacuumized to a pressure of 2 × 10 ^-2 mm RT. Art., sealed, kept in a muffle furnace at a temperature of 560 ° C for 24 hours, after cooling, the ampoule is cracked in a setup connected to an isotope mass spectrometer, and the carbon isotopic characteristics of the tartaric acid alkyl group are measured, a third of the precipitate is kept in a muffle furnace at a temperature of 560 ° C for 24 hours to remove the alkyl group, after which the remainder of the precipitate was analyzed on an isotopic mass spectrometer to establish the isotopic characteristics of the carbon of the carboxylic acid group of tartaric acid, compared quantitative isotopic characteristics of the three parts and the degree of coincidence or deviation judge the origin of tartaric acid.

The method is as follows.

150 cm ^{3 of} wine or juice-containing drink are placed in a conical flask with a capacity of 200 cm ³ , at a pH value above 3, 0.1 N HCl is added to reduce this indicator to the indicated value, kept at a temperature from 0 to minus 2 ° C for 24 hours. The precipitate of tartaric acid salts is collected, 1M NaOH is added to a pH of 9, 10 cm ^{3 of} 1M BaCl _{2 is} added, heated to a temperature of 60 ° C, cooled to a temperature of 4 ° C, maintained at this temperature for 24 hours, the precipitate formed salts of barium tartaric acid precipitated by centrifugation, washed with distilled water to a pH value of 7, dried, the dried precipitate was divided into three parts.

The first part is subjected to isotopic mass spectrometric analysis with the establishment of the ratio of stable isotopes ¹³ C / ¹² C to obtain the total isotopic characteristic of carbon salts of tartaric acid.

The second part of the precipitate is introduced into a vial of refractory glass sealed on one side, 0.5 g of copper oxide is added, and vacuumized to a pressure of 2 × 10 ^-2 mm Hg. Art., sealed, kept in a muffle furnace at a temperature of 560 ° C for 24 hours. After cooling, the ampoule is cracked in a vacuum system and the carbon dioxide obtained by burning the alkyl group of the barium salt of tartaric acid is quantitatively collected in a sealed container for subsequent isotopic analysis.

The carbon dioxide gas container is opened in the mass spectrometer inlet system and the analyzed carbon dioxide is dosed. In the process of isotope mass spectrometric analysis, currents are alternately recorded due to the number of ions with m / z 44 ( ¹² C ¹⁶ O ₂ ⁺ ), m / z 45 ( ¹³ C ¹⁶ O ₂ ⁺ ) and m / z 46 ( ¹² C ¹⁶ O ¹⁸ O) in the mass spectra of the carbon dioxide of the sample and laboratory standard. Carbon dioxide gas is used as the working gas.

The third part of the precipitate is kept in a muffle furnace at a temperature of 560 ° C for 24 hours to remove the alkyl group. The remainder of the precipitate is analyzed on an isotopic mass spectrometer to establish the carbon isotopic characteristics of the carboxyl group of the barium salt of tartaric acid.

Characteristics of the isotopic composition of the total carbon of carbon dioxide produced by burning sludge tartaric acid salt, an International Carbon Standard V-PDB defined in relative units of δ ¹³ C _^(0/00), using the formula (1) included in the software for the mass spectrometer Delta V Advantage, of the following form:

$${\delta }^{13}C=\left(R_{\mathrm{about}bR}/R_{\mathrm{from}t}-\mathrm{one}\right)•1000\left(\raisebox{1ex}{$0$}\!\left/ \!\raisebox{-1ex}{$00$}\right.\right),\left(\mathrm{one}\right)$$

Where

R _arr. = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _arr.

R _article = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _article

R _arr and R _st are the ratios of the prevalence of stable ¹³ C and ¹² C isotopes in the analyzed carbon dioxide obtained by burning a precipitate of tartaric acid salts and the international carbon standard V-PDB, respectively.

The characteristics of the carbon isotopic composition of carbon dioxide obtained by burning the carboxyl group of a barium salt of tartaric acid relative to the international carbon standard V-PDB are determined in relative units of δ ¹³ C (‰) using the formula (1):

$${\delta }^{13}C=\left(R_{\mathrm{about}bR}/R_{\mathrm{from}t}-\mathrm{one}\right)•1000\left(\raisebox{1ex}{$0$}\!\left/ \!\raisebox{-1ex}{$00$}\right.\right),\left(\mathrm{one}\right)$$

Where

R _arr. = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _arr.

R _article = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _article

R _arr and R _st are the ratios of the prevalence of stable isotopes ¹³ C and ¹² C in the analyzed carbon dioxide obtained by burning the carboxyl group of barium salt of tartaric acid, and the international carbon standard V-PDB, respectively.

For calibration, control aqueous solutions are prepared containing 6.8 g / dm ^{3 of} tartaric acid of various origin: tartaric acid from grapes, tartaric acid of non-grape origin, tartaric acid of non-plant origin (synthetic). The prepared mixtures are used to verify the entire sample preparation scheme and measure the isotopic characteristics of tartaric acid obtained from various types of raw materials. Moreover, the carbon isotopic characteristics (δ ¹³ C, ‰) of all control samples of tartaric acid of different origin should be previously determined.

The isotopic characteristics of the total carbon of salts of tartaric acid, carbon alkyl and carbon of the carboxyl group of barium salts of tartaric acid are indicators of the qualification of tartaric acid in wines and juice drinks. The obtained ratios of the prevalence of stable ¹³ C and ¹² C isotopes of control mixtures consisting of water and tartaric acid of various origins are compared with the results of the analyzed wine or juice-containing drink, and the origin of tartaric acid in them is judged by the degree of coincidence or deviation.

The obtained quantitative isotopic characteristics of the total carbon of tartaric acid salts are compared with δ ¹³ C values not exceeding (-21) ‰ for tartaric acid obtained from grapes, and δ ¹³ C values exceeding (-14) ‰ for non-grape tartaric acid, and the degree of coincidence or deviation is judged on the origin of tartaric acid. The quantitative isotopic characteristics of the carbon of the alkyl and carbon of the carboxyl groups of the barium salt of tartaric acid for each analyzed sample are compared and the difference in the nature of the origin of tartaric acid is judged.

Example 1. (Control)

1 g of tartaric acid obtained from grapes is placed in a conical flask with a capacity of 50 cm ³ , add 1 M NaOH to a pH value of 9, add 10 cm ³ 1 M BaCl ₂ , heated to a temperature of 60 ° C, cooled to a temperature of 4 ° C, maintained at this temperature for 24 hours, the precipitate of barium salt of tartaric acid precipitated by centrifugation, washed with distilled water to a pH value of 7, dried, the dried precipitate was divided into three parts.

The first part is subjected to isotopic mass spectrometric analysis with the establishment of the ratio of stable isotopes ¹³ C / ¹² C to obtain the total isotopic characteristic of carbon of barium salt of tartaric acid.

The second part of the precipitate is introduced into a vial of refractory glass sealed on one side, 0.5 g of copper oxide is added, and vacuumized to a pressure of 2 × 10 ^-2 mm Hg. Art., sealed, kept in a muffle furnace at a temperature of 560 ° C for 24 hours. After cooling, the ampoule is cracked in a vacuum system and the carbon dioxide obtained by burning the alkyl group of the barium salt of tartaric acid is quantitatively collected in a sealed container for subsequent isotopic analysis.

The carbon dioxide gas container is opened in the mass spectrometer inlet system and the analyzed carbon dioxide is dosed. In the process of isotope mass spectrometric analysis, currents are alternately recorded due to the number of ions with m / z 44 ( ¹² C ¹⁶ O ₂ ⁺ ), m / z 44 ( ¹² C ¹⁶ O ₂ ⁺ ) and m / z 46 ( ¹² C ¹⁶ O ¹⁸ O) in the mass spectra of the carbon dioxide of the sample and laboratory standard. Carbon dioxide gas is used as the working gas.

The third part of the precipitate is kept in a muffle furnace at a temperature of 560 ° C for 24 hours to remove the alkyl group. The remainder of the precipitate is analyzed on an isotopic mass spectrometer to establish the isotopic characteristics of the carbon of the carboxyl group of the barium salt of tartaric acid. The characteristics of the isotopic composition of the total carbon dioxide obtained by burning a precipitate of barium tartaric acid salt, relative to the international carbon standard V-PDB, is determined in relative units of δ ¹³ C (‰) using formula (1) included in the software for the Delta mass spectrometer V Advantage as follows:

$${\delta }^{13}C=\left(R_{\mathrm{about}bR}/R_{\mathrm{from}t}-\mathrm{one}\right)•1000\left(\raisebox{1ex}{$0$}\!\left/ \!\raisebox{-1ex}{$00$}\right.\right),\left(\mathrm{one}\right)$$

Where

R _arr. = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _arr.

R _article = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _article

R _arr and R _st are the ratios of the prevalence of stable isotopes ¹³ C and ¹² C in the analyzed carbon dioxide obtained by burning a precipitate of barium salt of tartaric acid, and the international carbon standard V-PDB, respectively.

The characteristics of the carbon isotopic composition of carbon dioxide obtained by burning the carboxyl group of a barium salt of tartaric acid, relative to the international carbon standard V-PDB, are determined in relative units of δ ¹³ C (‰) using formula (I):

$${\delta }^{13}C=\left(R_{\mathrm{about}bR}/R_{\mathrm{from}t}-\mathrm{one}\right)•1000\left(\raisebox{1ex}{$0$}\!\left/ \!\raisebox{-1ex}{$00$}\right.\right),\left(\mathrm{one}\right)$$

Where

R _arr. = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _arr.

R _article = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _article

R _arr and R _st are the ratios of the prevalence of stable ¹³ C and ¹² C isotopes in the analyzed carbon dioxide obtained by burning the carboxyl group of barium salt of tartaric acid and the international carbon standard V-PDB, respectively. The measurement results are shown in table 1.

Table 1 Characterization of the carbon isotopic composition of tartaric acid obtained from grapes The value of δ ¹³ C (‰) Total carbon of barium salt of tartaric acid Carbon of the carboxy group of the barium salt of tartaric acid Carbon of the alkyl group of barium salt of tartaric acid -21.7 -21.2 -25.3 -21.6 -21.1 -25.1 -21.8 -21.2 -25.4

The isotopic characteristics of the total carbon of tartaric acid, the carbon of the alkyl group of the barium salt of tartaric acid, the carboxyl group of the barium salt of tartaric acid are indicators of the qualification of tartaric acid and the nature of its origin.

By the values of the quantitative isotopic characteristics of the total carbon of barium salt of tartaric acid, not exceeding (-21) ‰, the presence of tartaric acid of grape origin is judged. The obtained quantitative isotopic characteristics of the carbon of the alkyl and carbon of the carboxyl groups of the barium salt of tartaric acid are compared with each other and the difference is used to judge the plant nature of the origin of tartaric acid.

Example 2 (control)

The method is carried out analogously to example 1, only use as a control sample an aqueous solution of tartaric acid obtained from corn at a concentration of 6.8 g / DM. The results are presented in table 2.

table 2 Characterization of the carbon isotopic composition of tartaric acid obtained from corn The value of δ ¹³ C (‰) Total carbon of barium salt of tartaric acid Carbon of the carboxy group of the barium salt of tartaric acid Carbon of the alkyl group of barium salt of tartaric acid -13.8 -12.5 -15.1 -13.6 -12.1 -14.9 -13.8 -12.4 -15.0

The isotopic characteristics of the total carbon of barium salt of tartaric acid, carbon of the alkyl and carboxyl groups of barium salt of tartaric acid are indicators of the qualification of tartaric acid and the nature of its origin.

The values of the quantitative isotopic characteristics of the total carbon of barium salt of tartaric acid exceeding (-14) суд indicate the presence of tartaric acid of non-grape origin. The obtained quantitative isotopic characteristics of the carbon of the alkyl and carbon of the carboxyl groups of the barium salt of tartaric acid are compared with each other and the difference is used to judge the plant origin of tartaric acid. The obtained ratios of the prevalence of stable isotopes ¹³ C and ¹² C of the control sample of tartaric acid obtained from corn are compared with the results of the analyzed wine or juice-containing drink and the origin of tartaric acid in them is judged by the degree of coincidence or deviation.

Example 3 (control)

The method is carried out analogously to examples 1 and 2, only use as a control sample an aqueous solution of synthetic tartaric acid at a concentration of 6.8 g / DM.

The results are presented in table 3.

Table 3 Characterization of the carbon isotopic composition of tartaric acid of non-plant origin (synthetic) The value of δ ¹³ C (‰) Total carbon of barium salt of tartaric acid Carbon of the carboxy group of the barium salt of tartaric acid Carbon of the alkyl group of barium salt of tartaric acid -23.5 -25.9 -22.4 -23.6 -25.1 -22.1 -23.8 -25.4 -22.2

The isotopic characteristics of the total carbon of barium salt of tartaric acid, carbon of the alkyl and carboxyl groups of barium salt of tartaric acid are indicators of the qualification of tartaric acid and the nature of its origin. The obtained quantitative isotopic characteristics of the carbon of the alkyl and carbon of the carboxyl groups of the barium salt of tartaric acid are compared with each other and the difference is used to judge the non-vegetative nature of the origin of tartaric acid.

The obtained ratios of the prevalence of stable isotopes ¹³ C and ¹² C of the control sample of tartaric acid of non-plant origin are compared with the results of the analyzed wine or juice-containing drink and the origin of tartaric acid in them is judged by the degree of coincidence or deviation.

Example 4

In a conical flask with a capacity of 200 cm ^3, 150 cm ^{3 of} white table wine, obtained without the addition of tartaric acid, is added, at a pH above 3, 0.1 N HCl is added to reduce this indicator to the indicated value, kept at a temperature from 0 to minus 2 ° С in 24 hours. The precipitate of tartaric acid salts is collected, 1M NaOH is added to a pH of 9, 10 cm ^{3 of} 1M BaCl _{2 is} added, heated to a temperature of 60 ° C, cooled to a temperature of 4 ° C, maintained at this temperature for 24 hours, the precipitate formed salts of barium tartaric acid precipitated by centrifugation, washed with distilled water to a pH value of 7, dried, the dried precipitate was divided into three parts.

The first part is subjected to isotopic mass spectrometric analysis with the establishment of the ratio of stable isotopes ¹³ C / ¹² C to obtain the total isotopic characteristic of carbon salts of tartaric acid. The second part of the precipitate is introduced into a vial of refractory glass sealed on one side, 0.5 g of copper oxide is added, and vacuumized to a pressure of 2 × 10 ^-2 mm Hg. Art., sealed, kept in a muffle furnace at a temperature of 560 ° C for 24 hours. After cooling, the ampoule is cracked in a vacuum system and the carbon dioxide obtained by burning the alkyl group of the barium salt of tartaric acid is quantitatively collected in a sealed container for subsequent isotopic analysis.

The carbon dioxide gas container is opened in the mass spectrometer inlet system and the analyzed carbon dioxide is dosed. In the process of isotope mass spectrometric analysis, currents are alternately recorded due to the number of ions with m / z 44 ( ¹² C ¹⁶ O ₂ ⁺ ), m / z 45 ( ¹³ C ¹⁶ O ₂ ⁺ ) and m / z 46 ( ¹² C ¹⁶ O ¹⁸ O) in the mass spectra of the carbon dioxide of the sample and laboratory standard. Carbon dioxide gas is used as the working gas.

The third part of the precipitate is kept in a muffle furnace at a temperature of 560 ° C for 24 hours to remove the alkyl group. The remainder of the precipitate is analyzed on an isotopic mass spectrometer to establish the isotopic characteristics of the carbon of the carboxyl group of the barium salt of tartaric acid. The characteristics of the isotopic composition of the total carbon dioxide obtained by burning a precipitate of tartaric acid salts, relative to the international carbon standard V-PDB, is determined in relative units δ ¹³ C (‰) using formula (1) included in the software for the Delta V mass spectrometer Advantage, of the following form:

$${\delta }^{13}C=\left(R_{\mathrm{about}bR}/R_{\mathrm{from}t}-\mathrm{one}\right)•1000\left(\raisebox{1ex}{$0$}\!\left/ \!\raisebox{-1ex}{$00$}\right.\right),\left(\mathrm{one}\right)$$

Where

R _arr. = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _arr.

R _article = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _article

R _arr and R _st are the ratios of the prevalence of stable ¹³ C and ¹² C isotopes in the analyzed carbon dioxide obtained by burning a precipitate of tartaric acid salts and the international carbon standard V-PDB, respectively.

The characteristics of the carbon isotopic composition of carbon dioxide obtained by burning the carboxyl group of a barium salt of tartaric acid relative to the international carbon standard V-PDB are determined in relative units of δ ¹³ C (‰) using the formula (1):

$${\delta }^{13}C=\left(R_{\mathrm{about}bR}/R_{\mathrm{from}t}-\mathrm{one}\right)•1000\left(\raisebox{1ex}{$0$}\!\left/ \!\raisebox{-1ex}{$00$}\right.\right),\left(\mathrm{one}\right)$$

Where

R _arr. = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _arr.

R _article = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _article

R _arr and R _st are the ratios of the prevalence of stable isotopes ¹³ C and ¹² C in the analyzed carbon dioxide obtained by burning the carboxyl group of barium salt of tartaric acid, and the international carbon standard V-PDB, respectively.

The measurement results are presented in table 4.

The isotopic characteristics of the total carbon of tartaric acid salts, the carbon of the alkyl group of tartaric acid salt of barium, the carboxylic acid group of tartaric acid salt are indicators of the qualification of tartaric acid and the nature of its origin.

By the difference in the values of the quantitative isotopic characteristics total carbon tartaric acid salt not exceeding 2 _^0/00 compared with the values of δ ¹³ C as specified in Table 1, judging the presence of tartaric acid, grape origin.

The obtained quantitative isotopic characteristics of the carbon of the alkyl and carbon of the carboxyl groups of the barium salt of tartaric acid are compared with each other and the difference is used to judge the plant nature of the origin of tartaric acid.

The obtained ratios of the prevalence of stable isotopes ¹³ C and ¹² C of control samples of tartaric acid are compared with the results of the analyzed wine, and the origin of tartaric acid in it is judged by the degree of coincidence or deviation.

Example 5

The method is carried out analogously to example 4, only they use white table wine with a quantity of tartaric acid of vegetable origin introduced in an amount of 2.0 g / dm ³ as an example.

The measurement results are presented in table 4.

The isotopic characteristics of the total carbon of tartaric acid salts, the carbon of the alkyl group of tartaric acid salt of barium, the carboxylic acid group of tartaric acid salt are indicators of the qualification of tartaric acid and the nature of its origin.

By the difference in the values of the quantitative isotopic characteristics of the total carbon of salts of tartaric acid in excess of 2 ‰ compared with the values of δ ¹³ C given in table 1, the presence of tartaric acid of non-grape origin is judged.

The obtained quantitative isotopic characteristics of the carbon of the alkyl and carbon of the carboxyl groups of the barium salt of tartaric acid are compared with each other and judged by the difference about the plant nature of the origin of tartaric acid.

The obtained ratios of the prevalence of stable isotopes ¹³ C and ¹² C of control samples of tartaric acid are compared with the results of the analyzed wine, and the origin of tartaric acid in it is judged by the degree of coincidence or deviation.

Example 6

The method is carried out analogously to example 4, only they use white table wine as a sample with 2.0 g / dm ³ tartaric acid of non-plant origin (synthetic) added.

The measurement results are presented in table 4.

Table 4 Characterization of the carbon isotopic composition of tartaric acid in white table wine The value of δ ¹³ C (‰) Example No. Total carbon of barium salt of tartaric acid Carbon of the carboxy group of the barium salt of tartaric acid Carbon of the alkyl group of barium salt of tartaric acid four -22.9 -21.1 -24.7 5 -16.5 -15.1 -18.3 6 -21.5 -24.3 -19.5

The obtained quantitative isotopic characteristics of the total carbon of tartaric acid salts are compared with δ ¹³ C values not exceeding (-21) ‰ for tartaric acid obtained from grapes, and δ ¹³ C values exceeding (-14) ‰ for non-grape tartaric acid, and the degree of coincidence or deviation is judged on the origin of tartaric acid. The quantitative isotopic characteristics of the carbon of the alkyl and carbon of the carboxyl groups of the barium salt of tartaric acid for each analyzed sample are compared and the difference in the nature of the origin of tartaric acid is judged.

Example 7

In a conical flask with a capacity of 200 cm ^3, 150 cm ^{3 of a} juice-containing drink obtained without the addition of tartaric acid is added, with a pH value above 3, 0.1 N HCl is added to reduce this indicator to the indicated value, kept at a temperature from 0 to minus 2 ° C in within 24 hours. The precipitate of tartaric acid salts is collected, 1M NaOH is added to a pH of 9, 10 cm ^{3 of} 1M BaCl _{2 is} added, heated to a temperature of 60 ° C, cooled to a temperature of 4 ° C, maintained at this temperature for 24 hours, the precipitate formed salts of barium tartaric acid precipitated by centrifugation, washed with distilled water to a pH value of 7, dried, the dried precipitate was divided into three parts.

The first part is subjected to isotopic mass spectrometric analysis with the establishment of the ratio of stable isotopes ¹³ C / ¹² C to obtain the total isotopic characteristic of carbon salts of tartaric acid.

The second part of the precipitate is introduced into a vial of refractory glass sealed on one side, 0.5 g of copper oxide is added, and vacuumized to a pressure of 2 × 10 ^-2 mm Hg. Art., sealed, kept in a muffle furnace at a temperature of 560 ° C for 24 hours. After cooling, the ampoule is cracked in a vacuum system and the carbon dioxide obtained by burning the alkyl group of the barium salt of tartaric acid is quantitatively collected in a sealed container for subsequent isotopic analysis. The carbon dioxide gas container is opened in the mass spectrometer inlet system and the analyzed carbon dioxide is dosed. In the process of isotope mass spectrometric analysis, currents are alternately recorded due to the number of ions with m / z 44 ( ¹² C ¹⁶ O ₂ ⁺ ), m / z 45 ( ¹³ C ¹⁶ O ₂ ⁺ ) and m / z 46 ( ¹² C ¹⁶ O ¹⁸ O) in the mass spectra of the carbon dioxide of the sample and laboratory standard. Carbon dioxide gas is used as the working gas.

The third part of the precipitate is kept in a muffle furnace at a temperature of 560 ° C for 24 hours to remove the alkyl group. The remainder of the precipitate is analyzed on an isotopic mass spectrometer to establish the isotopic characteristics of the carbon of the carboxyl group of the barium salt of tartaric acid. The characteristics of the isotopic composition of the total carbon dioxide obtained by burning a precipitate of barium tartaric acid salt, relative to the international carbon standard V-PDB, is determined in relative units of δ ¹³ C (‰) using formula (1) included in the software for the Delta mass spectrometer V Advantage, of the following form:

$${\delta }^{13}C=\left(R_{\mathrm{about}bR}/R_{\mathrm{from}t}-\mathrm{one}\right)•1000\left(\raisebox{1ex}{$0$}\!\left/ \!\raisebox{-1ex}{$00$}\right.\right),\left(\mathrm{one}\right)$$

Where

R _arr. = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _arr.

R _article = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _article

R _arr and R _st are the ratios of the prevalence of stable ¹³ C and ¹² C isotopes in the analyzed carbon dioxide obtained by burning a precipitate of tartaric acid salts and the international carbon standard V-PDB, respectively.

The characteristics of the carbon isotopic composition of carbon dioxide obtained by burning the carboxyl group of a barium salt of tartaric acid, relative to the international carbon standard V-PDB, are determined in relative units of δ ¹³ C (‰) using formula (I):

$${\delta }^{13}C=\left(R_{\mathrm{about}bR}/R_{\mathrm{from}t}-\mathrm{one}\right)•1000\left(\raisebox{1ex}{$0$}\!\left/ \!\raisebox{-1ex}{$00$}\right.\right),\left(\mathrm{one}\right)$$

Where

R _arr. = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _arr.

R _article = ([ ¹³ C ¹⁶ O ₂ ] / [ ¹² C ¹⁶ O ₂ ]) _article

R _arr and R _st are the ratios of the prevalence of stable isotopes ¹³ C and ¹² C in the analyzed carbon dioxide obtained by burning the carboxyl group of barium salt of tartaric acid, and the international carbon standard V-PDB, respectively.

The measurement results are presented in table 5.

The isotopic characteristics of the total carbon of tartaric acid salts, the carbon of the alkyl group of tartaric acid salt of barium, and the carboxyl group of tartaric acid salt of barium are indicators of the qualification of tartaric acid and the nature of its origin.

By the difference in the values of the quantitative isotopic characteristics of the total carbon of tartaric acid salts, not exceeding 2 ‰ in comparison with the values of δ ¹³ C given in table 1, the presence of tartaric acid of grape origin is judged.

The obtained quantitative isotopic characteristics of the carbon of the alkyl and carbon of the carboxyl groups of the barium salt of tartaric acid are compared with each other and judged by the difference about the plant nature of the origin of tartaric acid.

The obtained ratios of the prevalence of stable isotopes ¹³ C and ¹² C of control samples of tartaric acid are compared with the results of the analyzed juice-containing drink and the origin of tartaric acid in it is judged by the degree of coincidence or deviation.

Example 8

The method is carried out analogously to example 7, only use as a sample a drink with introduced in an amount of 2.0 g / DM ³ tartaric acid of non-grape origin.

The measurement results are presented in table 5.

The isotopic characteristics of the total carbon of tartaric acid salts, the carbon of the alkyl group of tartaric acid salt of barium, and the carboxyl group of tartaric acid salt of barium are indicators of the qualification of tartaric acid and the nature of its origin.

By the difference in the values of the quantitative isotopic characteristics of the total carbon of salts of tartaric acid in excess of 2 ‰ compared with the values of δ ¹³ C given in table 1, the presence of tartaric acid of non-grape origin is judged.

The obtained quantitative isotopic characteristics of the carbon of the alkyl and carbon of the carboxyl groups of the barium salt of tartaric acid are compared with each other and judged by the difference about the plant nature of the origin of tartaric acid.

The obtained ratios of the prevalence of stable isotopes ¹³ C and ¹² C of control samples of tartaric acid are compared with the results of the analyzed juice-containing drink and the origin of tartaric acid in it is judged by the degree of coincidence or deviation.

Example 9

The method is carried out analogously to example 7, only use as a sample a drink with tartaric acid of non-plant origin (synthetic) introduced in an amount of 2.0 g / dm ³ .

The measurement results are shown in table 5.

Table 5 Characterization of the carbon isotopic composition of tartaric acid in a drink The value of δ ¹³ C (‰) Example No. Total carbon of barium salt of tartaric acid Carbon of the carboxy group of the barium salt of tartaric acid Carbon of the alkyl group of barium salt of tartaric acid 7 -23.7 -22.2 -26.0 8 -15.3 -13.3 -17.1 9 -21.3 -24.1 -19.7

The obtained quantitative isotopic characteristics of the total carbon of tartaric acid salts are compared with δ ¹³ C values not exceeding (-21) ‰ for tartaric acid obtained from grapes, and δ ¹³ C values exceeding (-14) ‰ for non-grape tartaric acid, and the degree of coincidence or deviation is judged on the origin of tartaric acid. The quantitative isotopic characteristics of the carbon of the alkyl and carbon of the carboxyl groups of the barium salt of tartaric acid for each analyzed sample are compared and the difference in the nature of the origin of tartaric acid is judged.

Comparison of the carbon isotopic characteristics showed that the difference in the value of the isotopic characteristics of δ ¹³ C (‰) of the total carbon of tartaric acid, carbon of the alkyl and carboxyl groups between the control and the analyzed sample should not exceed 2 ‰, and the difference of these values for each analyzed sample should not exceed 0.5 ‰. The proposed method allows to increase the accuracy and reliability of the analysis by 90%.

Claims (1)

A method for determining the origin of tartaric acid in wines and juice drinks, characterized in that tartaric acid salts are precipitated from a sample of wine or juice drink by cold treatment in the presence of 0.1 N HC1, the precipitate formed is collected, 1 M NaOH is added to a pH value of 9, add 10 cm 1M BaCl ₂ , heated to a temperature of 60 ° C, cooled to a temperature of 4 ° C, maintained at this temperature for 24 hours, the precipitate of barium tartaric acid salt precipitated by centrifugation, washed with distilled water until a pH of 7 is dried, the dried precipitate is divided into three parts, the first part is subjected to isotopic mass spectrometric analysis to establish the ratio of stable isotopes ¹³ C / ¹² C to obtain the isotopic characteristics of the total carbon of tartaric acid, the second part of the precipitate is introduced into sealed with on one side is an ampoule of refractory glass, copper oxide is added, vacuum to a pressure of 2 · 10 ^-2 mm RT. Art., sealed, kept in a muffle furnace at a temperature of 560 ° C for 24 hours, after cooling, the ampoule is cracked in a setup connected to an isotopic mass spectrometer and the carbon isotopic characteristics of the tartaric acid alkyl group are measured, a third of the precipitate is kept in a muffle furnace at at a temperature of 560 ° C for 24 hours to remove the alkyl group, after which the remainder of the precipitate was analyzed on an isotope mass spectrometer to establish the carbon isotopic characteristics of the carboxylic acid group of tartaric acid, compared Acquiring quantitative characteristics with values of δ ¹³ C of not more than (-21) ‰ for tartaric acid obtained from grapes, and the values δ ¹³ C greater than (-14) ‰ for tartaric acid nevinogradnogo origin, and the degree of coincidence or rejection is judged the origin of tartaric acid, the difference in the isotopic characteristics of the carbon of the alkyl and carboxyl groups is judged on the plant or non-plant origin of tartaric acid.