This method (GB/T 10345- 2007) will also be implemented in June this year. In the new version of liquor
In the analysis method, the parallel errors of alcohol content determination, total ester determination and determination are all
Great changes have taken place. With the development of chromatography technology, the gas phase of monomer components in liquor
The chromatographic analysis method is also more perfect. In order to better cooperate with the implementation, a new version of liquor is now introduced.
The analysis method is discussed as follows.
Determination of 1 alcohol content
As a production enterprise, alcohol meter method is widely used, although density measurement is the first.
A method, but not suitable for the needs of mass production, is generally only supervised by functional departments.
Use. Although there is a certain error between the two methods (the maximum alcohol content is different)
0.2%Vol), but as long as the alcohol meter method is accurate, the alcohol content should be controlled at the nominal value as far as possible.
About (+/- 0.5%Vol), it will not be sentenced by the regulatory authorities because of its use.
Determine as unqualified.
The two most important points of the new method are: First, it is stipulated that alcohol content must be steamed.
Distillation can be measured; Second, the conversion table of alcohol content and temperature adopts the international standard conversion table, and
The alcohol value keeps two decimal places, which makes the result more accurate.
1. 1 alcohol content is the percentage of alcohol volume content in alcohol aqueous solution, because it is white.
Wine contains a certain amount of fusel, esters and solids, so it is directly measured.
The refined content is not the true value of the alcohol content of this degree. Distilled liquor can be avoided.
The interference of medium solids on alcohol measurement and the difference of solid content, white
The influence of alcohol content is also different (at present, there is no influence of solid content on alcohol content
Accurate literature report on the influence of order of magnitude relationship). If the influence of solids is not considered,
It must bring the alcohol content closer to the true value. Because it is difficult to separate fusel,
Esters are completely separated from ethanol, so these effects are not considered.
1.2 original alcohol content-temperature conversion table only keeps one decimal place.
Count. The new method adopts international standards and keeps two decimal places, which makes the results more accurate.
It also meets the requirement that the processing result is one decimal more than the report result. Classics and new standards
Compared with the alcohol content table, it is converted to 20℃ at the same temperature and alcohol content.
The maximum difference of alcohol content is 0. 1%Vol, so the new conversion table can be used for measurement.
The result is more accurate.
2 Determination of total esters
In the new analytical method, the determination of total esters is blank, which has two advantages:
2. 1 In the process of acid-base titration, the titration of strong acid and strong base is the same in use.
On the premise of acid-base concentration, due to the difference of titration direction and indicator color change point,
The titration results will not be completely consistent. This method uses the same titration solution to titrate the blank.
The error caused by back titration can be deducted.
2.2 in the saponification process of liquor determination, the role of condensation tube is good, but because of B.
The volatilization of alcohol and the entry of foreign gas during cooling will affect the sodium hydroxide standard.
Changes of quasi-solution in reaction solution. Experiments show that in the aqueous solution of ester-free alcohol
Add a certain amount of sodium hydroxide standard solution, and then titrate with sulfuric acid standard solution.
L, and boil in boiling water bath for 30min, and then titrate ml with sulfuric acid.
It is a match, and different alcohol contents are different. Therefore, the new method passed the blank calibration.
Volume 34, No.5
September 20th, 2007
make wine
make wine
Volume 34, page 5
September 2007
Date of receipt: July 6, 2007
About the author: Hu Shaowu (1966-), male, from Sheqi, Henan, engineer, laboratory director, Bi.
Shenyang Institute of Technology, majoring in chemical analysis, is now mainly engaged in alcohol analysis and has published many papers.
Articles.
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The system error is reduced to some extent, which makes the result more realistic.
3 chromatographic analysis
Because the original analysis method of liquor was formulated earlier, capillary technology is not available yet.
Cooked columns used for chromatographic analysis are packed columns, while new wines are more.
The content of alcohol and ester in traditional liquor is high, although some packed column methods are successful.
The separation is not good, but the main indexes (such as ethyl caproate) can also be reproduced and accurate.
Highly accurate results. Moreover, it is reasonable that this method does not make rigid regulations on chromatographic conditions.
Suitable. In the new analytical method, a lot of space is spent on the chromatography of two chromatographic methods.
There is no need to set conditions, because:
3. 1 chromatographic conditions should be determined by the instrument to achieve better separation effect and reproducibility.
It depends on gender.
3.2 chromatographic conditions should be determined according to the purpose, such as the routine of Luzhou-flavor liquor and Fen-flavor liquor.
During analysis, both the sampler and the detection temperature are set above 200℃ (hereinafter referred to as high temperature chromatography).
On the contrary, some similar components are not well separated, which has a great influence on the repeatability and accuracy of measurement.
Have a certain impact.
Therefore, liquor enterprises should choose different columns according to their own actual situation.
And chromatographic conditions.
3.2. Accuracy and reproducibility of1packed column (DNP) chromatography in the determination of conventional main esters.
Good sex, only ethyl acetate tails in ethanol, and the error is large. For the formation of low boiling point
The detection limit is low, and the analysis time is generally over 30min. If the chromatographic conditions are controlled,
Poor preparation will reduce the separation degree between isoamyl alcohol and internal standard.
3.2.2 LZP930 column and AT liquor column have the same performance, and they are both large-caliber wool.
Thin-tube column, which has different application effects under different selection conditions. If you use
The temperature of detector and sampler is relatively low (about 65438 050℃) (hereinafter referred to as cryogenic chromatography).
The peak shape effect of packed column can be achieved, and the repeatability and accuracy are good, and the separation situation is good.
The conditions and detection limit are better than those of packed column, and the time is shorter than that of packed column (about 1.5 min).
It is the first choice for routine analysis of various fragrance types. If high temperature chromatography is used
In the analysis of liquor characteristics and scientific research, it is basically related to the role of small-caliber capillary method.
More than 30 components can be separated in the last 30 minutes, and the separation of each component is good.
More than 4 kinds of low-boiling acids can be detected, but the peak shape, reproducibility and parallelism are the same.
Sex is not as good as cryogenic chromatography.
3.2.3 PEG20M and FFAD columns commonly used in small-diameter capillaries, among which
Generally, high temperature chromatography is used for characteristic analysis and scientific research analysis with good separation.
It has the characteristics of many separated components and high detection limit. But it is generally not suitable for routine analysis.
In addition, PEG20M column can not separate ethyl acetate, acetal, methanol and ethyl acetate well.
Esters and acetals are often combined and are not suitable for the analysis of ethyl acetate. Analysis of high boiling point
It is effective for esters, alcohols, acids and other components, and can be used for flavor analysis of liquor.
Should be the first choice.
3.2.4 The split ratio specified in this standard is 37∶ 1, which should be used as reference data.
International work should be based on operating conditions. Theoretically, the segmentation ratio is greater than 100: 1.
Component distortion is minimal, but in practice, large-caliber capillary chromatography is used for
The smaller the shunt, the better.
3.2.5 In this standard, the preparation of standard solution is not applicable to production analysis. offer a price
Quasi-prescribed method, standard solution used several times, due to frequent opening, the concentration has been
Slight changes, especially low-boiling alcohols and esters, will directly affect the response factor value.
Correction. Conventional ingredients should be prepared to a certain concentration according to the needs of the product, and then mixed with 1mL.
Properly packed and sealed. Only in this way can we ensure the concentration of each use. Doing so not only
The reagent is saved, and the accuracy of calibration is also ensured.
3.2.6 Chromatography, especially capillary chromatography, is used to measure some components, such as ethyl lactate.
The accuracy of the results is directly related to the injection technology, injection speed and injection volume.
Relationship. Therefore, it is best to calibrate by the same person and analyze by the same person to ensure the consistency of injection, so that,
Only by correcting and measuring the approximate peak area of the internal standard can we get better analysis results. the same
Considering the great difference between solid liquor and liquid liquor, it is necessary to use it.
Calibrate the F value with standard solutions of different concentrations.
4 Determination of solid matter
The control temperature in the original standard is 100~ 105℃, which is different from this standard.
The cost is the same, which can prevent high solids and high temperature caused by low temperature.
(105℃) makes the solid content low, and also ensures the parallelism and constant weight of the results.
Requirements.
The description of parallel error in this method is different from the original analysis method.
5. The parallel errors of1chromatography are all less than 5% of the average value, and ethyl acetate is less than the average value.
It is difficult to reach this value, and it is also difficult to determine low-boiling components by high-temperature capillary method. be filled/suffused/brimming with
Generally, column packing method for routine analysis and low-temperature large-caliber capillary chromatography can be realized.
Here you are. It is suitable according to the boiling point and content of the components.
5.2 The contents of total acids, total esters, solids and alcohol are determined according to the results.
The size of line error is more applicable.
In a word, the implementation of the new method can improve the authenticity of alcohol content and total esters.
High, it can also make chromatographic analysis more choices, which is an improvement on the original analysis method.
The place is also worth learning and emulating.
The fifth phase of brewing 2007
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