CN111707758B - Method for detecting oxygen stable isotope of flavor substance in Luzhou-flavor liquor - Google Patents
Method for detecting oxygen stable isotope of flavor substance in Luzhou-flavor liquor Download PDFInfo
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Abstract
The invention belongs to the technical field of stable isotope analysis, and particularly relates to a method for detecting an oxygen stable isotope of a flavor substance in strong aromatic Chinese spirits. Book (I)The invention solves the technical problem that a rapid and simple detection method for the stable oxygen isotope of the flavor substance in the Luzhou-flavor liquor is not available in the prior art. The method adopts a gas chromatograph to separate various flavor substances from other oxygen-containing substances in the Luzhou-flavor liquor sample, adopts a conversion device to convert various flavor substances into CO, and utilizes a stable isotope ratio mass spectrometer to detect the delta of the flavor substances in the Luzhou-flavor liquor 18 And O. The detection method is beneficial to the improvement of the detection technology of the strong aromatic Chinese spirits and is the flavor substance delta 18 The application of O in the field of strong aromatic Chinese spirits identification provides technical support, and is beneficial to inhibiting the execution of Chinese spirits counterfeiting behaviors to a certain extent.
Description
Technical Field
The invention belongs to the technical field of white spirit flavor substance analysis, and particularly relates to a detection method of an oxygen stable isotope of a flavor substance in strong aromatic white spirit.
Background
The white spirit is obtained by fermenting and distilling one or more grains, wherein more than 98% of the ingredients are water and ethanol, and the remaining trace ingredients less than 2% determine the flavor and quality of the white spirit. The trace components are collectively called as flavor substances, and the components and the content of the flavor substances in the white spirit are easily influenced by factors such as raw materials, climate, environment, process and the like, so the white spirit has different flavor types, and the strong flavor type white spirit has very important positions in the history of the Chinese white spirit due to the characteristics of strong fragrance, softness, sweetness, sweet taste, lingering taste, remaining length of tail cleaning and the like.
The IRMS technology is mainly used for authenticity identification and origin tracing of foods such as honey, wine, dairy products and the like in the field of foods, and is mainly used for detecting ethanol delta in the field of white spirit 13 C. Ethanol delta 18 O, organic acid delta 13 C. Ester delta 13 C, etc. to establish a liquor identification system for flavor substances delta 18 O is rarely mentioned. If no exogenous additive is added, the flavor substances in the Luzhou-flavor liquor are mainly generated by fermenting and metabolizing brewing raw materials through microorganisms, stable isotopes of the flavor substances have a metabolic homology relation, part of oxygen in oxygen-containing metabolites is from fermentation sugar, part of oxygen is from fermentation water, and the oxygen-containing flavor substances delta are detected 18 And O, providing a theoretical basis for the research of raw material and authenticity identification of the white wine. At present, a fake liquor event occurring in the market puts more strict requirements on the development of a strong aromatic white liquor identification system and an identification technology, so that the establishment of a detection method of the oxygen stable isotope of the flavor substance in the strong aromatic white liquor based on the IRMS technology is necessary, the development of the strong aromatic white liquor identification technology is facilitated, the detection index of the stable isotope of the strong aromatic white liquor is increased, the white liquor counterfeiting cost is increased, the counterfeiting behavior is restrained to a certain extent, and the improvement of the strong aromatic white liquor identification system is further facilitated.
Disclosure of Invention
The invention solves the technical problem that a rapid and simple detection method for the stable oxygen isotope of the flavor substance in the Luzhou-flavor liquor is not available in the prior art.
In order to solve the problems in the prior art, the invention provides a method for acquiring and analyzing special aroma in liquor, a strong aromatic liquor sample is directly injected, a gas chromatograph is adopted to separate flavor substances from other oxygen-containing substances, a conversion device is adopted to convert the flavor substances into CO, and a stable isotope ratio mass spectrometer is utilized to detect the delta of the flavor substances in the strong aromatic liquor 18 O。
Wherein the flavor substance comprises at least one of ethyl caproate, ethyl lactate, acetic acid and caproic acid.
Wherein, the strong aromatic Chinese spirits sample is directly injected.
Among them, the gas chromatograph is equipped with a capillary column.
Wherein, the conversion device is GC Isolink.
Wherein the conversion device is provided with a ceramic cracking tube.
Wherein the working temperature of the conversion device is 1278-1282 ℃.
Wherein the GC working condition is a waterproof polar gas chromatographic column TR-WAXMS capillary column (30-60 m multiplied by 0.25mm multiplied by 0.25 mu m); the carrier gas is high-purity helium, the flow rate is 0.8-1.2 mL/min in a constant-current mode; the sample introduction volume is 0.5-1 mu L, and the temperature of a sample introduction port is 210-220 ℃; the temperature rising procedure is as follows: the initial temperature is 50-60 ℃, the temperature is kept for 3-6 min, the temperature is raised to 78-82 ℃ at the speed of 3-5 ℃/min, then the temperature is kept for 3-5 min, the temperature is raised to 98-102 ℃ at the speed of 5-7 ℃/min, the temperature is kept for 6-8 min, then the temperature is raised to 118-122 ℃ at the speed of 14-16 ℃/min, the temperature is kept for 0-2 min, and finally the temperature is raised to 210-220 ℃ at the speed of 8-12 ℃/min, and then the temperature is kept for 2-5 min.
Wherein the stable isotope ratio mass spectrometer is provided with ion source vacuum of 1.2 × 10 -6 mBar, voltage of 2.996-3.06 KV and current of 1.50mA.
The invention has the beneficial effects that:
the invention establishes a method for detecting oxygen stable isotope of flavor substance in Luzhou-flavor liquor, and the previous IRMS technology is used for detecting ethanol delta in the liquor field 13 C. Ethanol delta 18 O, organic acid delta 13 C. Ester delta 13 C, etc. to establish a liquor identification system for flavor substances delta 18 O is mentioned little, and the method of the invention realizes the flavor substance delta in the Luzhou-flavor liquor by using GC-IRMS combined technology 18 Rapid and accurate determination of O;
the detection method provided by the invention has the advantages that the sample introduction is directly carried out, the sample pretreatment is not needed, the pretreatment time is saved, the cost is reduced, the operation is simplified, and the delta of important flavor substances in 4 kinds of strong aromatic white spirits can be simultaneously and accurately separated and detected 18 O, has the advantages of rapidness, simplicity, accuracy and the like;
the detection method is beneficial to the improvement of the detection technology of the Luzhou-flavor liquor, increases the stable isotope detection index of the Luzhou-flavor liquor, increases the liquor counterfeiting cost, is beneficial to inhibiting the counterfeiting behavior to a certain extent, and is a flavor substance delta 18 And the application of O in the field of strong aromatic Chinese spirits identification provides technical support.
Drawings
FIG. 1 flavor substance delta in Standard solution 18 A GC-IRMS spectrum of O;
FIG. 2 flavor substance delta in Luzhou-flavor liquor sample 18 GC-IRMS profile of O.
Detailed Description
The method aims at the flavor substance delta in the Luzhou-flavor liquor 18 The method has the advantages that the O detection is simple and accurate, GC equipped with a gas chromatographic column is used for separating different oxygen-containing organic matters in the strong aromatic Chinese spirits, then GC Isolink equipped with a cracking tube is used for converting various flavor substances into CO, and finally IRMS is used for measuring the flavor substance delta 18 O, promotes the progress of the detection technology of the Luzhou-flavor liquor, increases the stable isotope detection index of the Luzhou-flavor liquor, increases the liquor counterfeiting cost, is favorable for restraining the counterfeiting behavior to a certain extent, and is a flavor substance delta 18 And the application of O in the field of strong aromatic Chinese spirits identification provides technical support.
Specifically, the method for acquiring and analyzing the special aroma in the white spirit can be specifically carried out according to the following steps:
directly sampling a strong aromatic Chinese liquor sample, separating each flavor substance from other oxygen-containing substances (such as water, ethanol and the like) one by adopting a Gas Chromatograph (GC) provided with a capillary chromatographic column, converting each flavor substance into CO by adopting a conversion device (GC Isolink), and detecting the delta of the flavor substances in the strong aromatic Chinese liquor by utilizing a stable Isotope Ratio Mass Spectrometer (IRMS) 18 O。
The ethyl caproate, the ethyl lactate, the acetic acid and the caproic acid are very important flavor components in the strong aromatic Chinese spirits, the content of the flavor components is less than 0.5 percent, and the total content of the flavor components is not more than 2 percent. At present, the oxygen-containing organic substance delta 18 The O detection method is mainly a high-temperature cracking method, in which firstly oxygen-containing organic matter is cracked into CO, and then the delta of the CO is detected 18 O post-calculation of oxygen-containing organic matter delta 18 O, e.g. pyrolysis elemental analyzer-stable isotope ratio mass spectrometry (TC/EA-IRMS), which can detect the delta of solid, liquid oxygen-containing substances 18 O, but since there is no separation, the method is only applied to the total delta of the mixture 18 O determination or delta of pure substance 18 O determination, but cannot be used for complex componentsOxygen-containing flavor substance delta in Luzhou-flavor liquor 18 And (4) measuring O.
For white spirit delta 18 O is not much searched, mainly in terms of ethanol delta content of 30 to 60 vol 18 Detection of O, such as patent CN 102967661A, the final goal of researchers is only ethanol, and the main consideration in the establishment method is to separate ethanol in alcoholic beverages from water and other trace O-containing compounds and avoid the delta of O to ethanol of the latter two 18 The influence of O detection does not aim at the flavor substance delta of the strong aromatic Chinese spirits with more targets and small content 18 And (4) reporting of O detection.
Under the conditions of considering that the whole-process operation is simple, the artificial error is avoided, the authenticity stability of the sample is ensured, and the change of oxygen stable isotope caused by pretreatment is avoided, the method has no pretreatment and is used for directly feeding sample; considering that flavor substances are separated from a large amount of ethanol and water, trace flavor substances are separated respectively, and mutual influence is avoided, a large amount of experimental selections are carried out on separation means (gas phase conditions, chromatographic columns and the like) and the like, GC (gas chromatography) provided with a water-resistant polar gas chromatographic column (TR-WAXMS capillary column) is finally adopted to separate different oxygen-containing organic matters in the strong aromatic Chinese spirits, then GC Isolink provided with a cracking tube is adopted to convert each flavor substance into CO, and IRMS (infrared radiation spectrometry) is finally adopted to realize 4 important flavor substances delta in the strong aromatic Chinese spirits 18 The simple, pretreatment-free and rapid determination of O belongs to the first case.
The invention is further illustrated and explained below by way of examples, the substances delta 18 O is calculated based on the International Standard sample VSMOW.
The method for detecting the oxygen stable isotope of the flavor substance in the Luzhou-flavor liquor provided by the embodiment of the invention comprises the following steps: directly sampling a Luzhou-flavor liquor sample, separating each flavor substance from other oxygen-containing substances (such as water, ethanol and the like) one by adopting a Gas Chromatograph (GC) provided with a capillary chromatographic column, converting each flavor substance into CO by adopting a conversion device (GC Isolink), and detecting delta of the flavor substances in the Luzhou-flavor liquor by utilizing a stable Isotope Ratio Mass Spectrometer (IRMS) 18 O。
The GC working conditions are as follows: a water-resistant polar gas chromatography column TR-WAXMS capillary column (60 m.times.0.25 mm.times.0.25 μm); the carrier gas is high-purity helium, the constant current mode is adopted, and the flow rate is 1.2mL/min; the sample injection volume is 0.5 mu L, the temperature of a sample injection port is 220 ℃, and no shunt is performed; the temperature rising procedure is as follows: the initial temperature is 55 ℃, the temperature is kept for 5min, the temperature is raised to 80 ℃ at the speed of 4 ℃/min and then kept for 4min, the temperature is raised to 100 ℃ at the speed of 6 ℃/min and kept for 7min, then the temperature is raised to 120 ℃ at the speed of 15 ℃/min and then kept for 0min, and finally the temperature is raised to 220 ℃ at the speed of 10 ℃/min and then kept for 3min;
the GC Isolink working conditions are as follows: a ceramic cracking tube is arranged, and the working temperature is 1280 ℃;
the IRMS conditions are as follows: ion source vacuum 1.2X 10 -6 mBar, voltage 3.06KV and current 1.50mA.
Example 1 flavor substance delta in Standard solution 18 And (3) detection of O:
the main apparatus is as follows: thermo fisher, trade GC Ultra gas chromatograph, gas conversion device (GC Isolink), delta V Advantage stable Isotope Ratio Mass Spectrometer (IRMS), usa.
Reagent: acetone (chromatographically pure); ethyl caproate, ethyl lactate, acetic acid and caproic acid, all of which are chromatographically pure and are all calibrated to delta 18 The true value of O is used as a standard substance.
Standard solution: diluting each standard substance (ethyl caproate, ethyl lactate, acetic acid and caproic acid) by using acetone, wherein the content of each standard substance is equivalent to that of the corresponding substance in the strong aromatic Chinese spirits.
And (3) putting the standard solution into a brown sample introduction bottle, directly injecting GC-IRMS for determination, wherein specific parameters of an instrument are shown as above, and obtaining 28, 29 and 30 ion graphs of ethyl caproate, ethyl lactate, acetic acid and caproic acid, wherein the specific parameters are shown in figure 1. FIG. 1 shows that under the detection conditions of the method, the separation degree of ethyl hexanoate, ethyl lactate, acetic acid and hexanoic acid in the standard solution is good, the interference is less, and the detection requirements are met.
Repeated determination of delta of ethyl hexanoate, ethyl lactate, acetic acid and hexanoic acid in standard solution 18 O, the results are shown in Table 1. As can be seen from Table 1, the delta values of ethyl hexanoate, ethyl lactate, acetic acid and hexanoic acid in the standard solution were repeatedly measured by the method of the present invention 18 O value and standard deviation STDEV are less than 0.3 ‰, and are stableGood qualitative performance and meets the measurement requirements.
TABLE 1 flavor substances delta in standard solutions 18 Results of repeated measurement of O
Example 2 flavor substance delta in Luzhou-flavor liquor sample 18 And (3) detection of O:
the main apparatus is as follows: thermo fisher corporation, trace GC Ultra gas chromatograph, gas conversion device (GC Isolink), delta V advanced stable Isotope Ratio Mass Spectrometer (IRMS), usa.
Wine sampling: a certain brand of Luzhou-flavor liquor sample, 52% vol.
Standard solution: the same as the first embodiment.
The assay sequence was arranged according to a two-point standard drift correction pattern: 2 standard solutions, 6-8 samples, \ 8230; \ 8230;, 2 standard solutions.
The delta of flavor substances in the standard solution and the wine sample were measured respectively according to the above method 18 O measuring value, and passing through each flavor standard substance delta according to two-point standard drift correction mode 18 Calculating the delta of each flavor substance in the Luzhou-flavor liquor sample according to the true value and the measured value of O 18 O, results are shown in Table 2.
FIG. 2 shows 28, 29 and 30 ion graphs of ethyl hexanoate, ethyl lactate, acetic acid and hexanoic acid in Luzhou-flavor liquor under the detection conditions of the method. Although the oxygen-containing substances in the Luzhou-flavor liquor are complex, the separation degree of each substance to be detected in the graph 2 is good, and the substances delta to be detected caused by other oxygen-containing substances are excluded 18 The interference of O detection meets the requirements of ethyl caproate, ethyl lactate, acetic acid and delta caproate in the strong aromatic white spirit 18 And (4) measuring the O.
As can be seen from Table 2, the delta of ethyl hexanoate, ethyl lactate, acetic acid and hexanoic acid in the Luzhou-flavor liquor is repeatedly measured by adopting the method 18 O, standard deviation STDEV is less than 0.3 per mill, stability is good, and the precision of the method meets the requirement of strong aromatic whiteFlavor substance delta in wine 18 And (4) detection requirements of O.
TABLE 2 flavor substances delta in Luzhou-flavor liquor 18 Duplicate results of O measurement
Claims (5)
1. The method for detecting the oxygen stable isotope of the flavor substance in the Luzhou-flavor liquor is characterized by comprising the following steps of: directly injecting a Luzhou-flavor liquor sample, separating each flavor substance from other oxygen-containing substances in the Luzhou-flavor liquor sample by using a gas chromatograph, converting each flavor substance into CO by using a conversion device, and detecting delta of the flavor substance in the Luzhou-flavor liquor by using a stable isotope ratio mass spectrometer 18 O, the flavor substances comprise ethyl caproate, ethyl lactate, acetic acid and caproic acid; the working condition of the conversion device is a waterproof polar gas chromatographic column TR-WAXMS capillary column with the specification of 30-60 m multiplied by 0.25mm multiplied by 0.25 mu m; the carrier gas is high-purity helium, the flow rate is 0.8-1.2 mL/min in a constant-current mode; the sample introduction volume is 0.5-1 mu L, and the temperature of a sample introduction port is 210-220 ℃; the temperature rising procedure is as follows: the initial temperature is 50-60 ℃, the temperature is kept for 3-6 min, the temperature is raised to 78-82 ℃ at 3-5 ℃/min, then the temperature is kept for 3-5 min, the temperature is raised to 98-102 ℃ at 5-7 ℃/min, the temperature is kept for 6-8 min, then the temperature is raised to 118-122 ℃ at 14-16 ℃/min, the temperature is kept for 0-2 min, finally the temperature is raised to 210-220 ℃ at 8-12 ℃/min, and then the temperature is kept for 2-5 min.
2. The method for detecting the oxygen stable isotope of the flavor substance in the Luzhou-flavor liquor according to claim 1, wherein the method comprises the following steps: the conversion device is GC Isolink.
3. The method for detecting the oxygen stable isotope of the flavor substance in the Luzhou-flavor liquor as claimed in claim 1, wherein the method comprises the following steps: the conversion device is equipped with a ceramic cracking tube.
4. The method for detecting the oxygen stable isotope of the flavor substance in the Luzhou-flavor liquor as claimed in claim 1, wherein the method comprises the following steps: the working temperature of the conversion device is 1278-1282 ℃.
5. The method for detecting the oxygen stable isotope of the flavor substance in the Luzhou-flavor liquor according to claim 1, wherein the method comprises the following steps: the stable isotope ratio mass spectrometer is provided with the ion source vacuum of 1.2 multiplied by 10 -6 mBar, voltage of 2.996-3.06 KV and current of 1.50mA.
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| JP2011043329A (en) * | 2007-12-14 | 2011-03-03 | Kirin Holdings Co Ltd | Method of analyzing isotope ratio of low-concentration ethanol sample |
| CN102967661B (en) * | 2012-10-28 | 2014-09-10 | 中国食品发酵工业研究院 | Rapid determination method for oxygen stable isotope of ethanol in alcoholic beverage |
| CN103792300B (en) * | 2013-11-22 | 2015-07-08 | 江苏出入境检验检疫局动植物与食品检测中心 | Detection method for determining whether liquor is adulterated |
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