Method for determining acetaldehyde content in white spirit

Abstract

The invention provides a method for determining the content of acetaldehyde in Baijiu, and relates to the field of food detection.The method comprises the steps that an acetaldehyde standard sample in water is mixed with an ethanol aqueous solution, and acetaldehyde-ethanol aqueous solutions with different concentrations are prepared and serve as acetaldehyde standard series working solutions; preparing a white spirit sample; respectively carrying out gas chromatography determination on the acetaldehyde standard series working solution and the white spirit sample by using a gas chromatograph; quantifying by adopting an external standard method, and calculating the acetaldehyde content in the white spirit sample; a chromatographic column in the gas chromatograph is a DB-WAX UI chromatographic column, and the detector is a hydrogen flame ionization detector. On the premise of meeting the analysis accuracy, the problem that no standard method for detecting the content of acetaldehyde in Baijiu exists in the industry is effectively solved, and the method is simple, convenient, low in detection cost, good in analysis method reproducibility and stability, free of retention time drift and stable in data.

Description

Technical Field

[0001] The present application relates to the field of food testing, and in particular to a method for determining the acetaldehyde content in liquor. Background Art

[0002] Liquor is an alcoholic beverage passed down from generation to generation in my country. It is one of the important industries in my country's food industry and has played an important role in my country's economic construction. Today, Chinese liquor has penetrated into all aspects of people's social and cultural life, and people's requirements for physical signs of drinking have gradually shifted to health and comfort. Acetaldehyde is the main source of spicy taste in liquor. The lower the content of acetaldehyde in liquor, the better. Too high a content will cause the liquor to have a strong spicy taste. Frequent drinking of liquor with high acetaldehyde content will cause it to accumulate in the body, forcing the surrounding blood vessels to dilate, leading to increased blood flow to the face, and causing the central nervous system to control muscle contraction, so the heartbeat speeds up and blood pressure rises. After drinking, people feel dry throat, dizziness, and pain, which is one of the main reasons for feeling drunk after drinking. Therefore, accurately measuring the acetaldehyde content in liquor and guiding enterprises to control the acetaldehyde content in liquor has important positive significance for human health and liquor quality control.

[0003] Acetaldehyde, also known as acetic acid aldehyde, is an organic compound with the chemical formula CH3CHO. It is a colorless and transparent liquid with a boiling point of 20.8°C. It is soluble in water and miscible in ethanol. Acetaldehyde has a low boiling point and is volatile. It can react with ethanol to form acetal. At present, the industry has not yet released a standard for the detection of acetaldehyde content in liquor. The detection method is mostly seen in scientific research papers, but there is little description of the specific detection process. It is difficult to accurately quantify the acetaldehyde content in liquor through reference methods. In the existing technology, the use of gas chromatographs to detect the acetaldehyde content in liquor has the following problems: (1) The boiling point of acetaldehyde is only 20.8°C. When weighing pure acetaldehyde, it is extremely volatile, resulting in inaccurate weighing results, which ultimately affects the accuracy of the test results. (2) The gas chromatograph heating program is set unreasonably, resulting in poor peak shape of acetaldehyde when directly detected by gas chromatograph.

[0004] Therefore, the existing technology for detecting the acetaldehyde content in liquor still has the objective problem of optimizing the quantitative analysis of the acetaldehyde content in liquor, and cannot meet the needs of improving accuracy and timeliness and reducing detection costs. Summary of the invention

[0005] The purpose of this application is to provide a method for determining the acetaldehyde content in liquor to solve the above-mentioned problem.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] The present application provides a method for determining the acetaldehyde content in liquor, comprising:

[0008] The acetaldehyde standard sample in water is mixed with the ethanol aqueous solution to prepare acetaldehyde-ethanol aqueous solutions of different concentrations as the acetaldehyde standard series working solutions;

[0009] Prepare liquor samples;

[0010] Using a gas chromatograph to perform gas chromatography determination on the acetaldehyde standard series working solution and the liquor sample respectively;

[0011] Calculating the acetaldehyde content in the liquor sample after quantitative analysis using an external standard method;

[0012] The chromatographic column in the gas chromatograph is a DB-WAX UI chromatographic column, and the detector is a hydrogen flame ionization detector.

[0013] Optionally, the concentration of the acetaldehyde standard is 10 mg / mL.

[0014] Optionally, the ethanol in the ethanol aqueous solution includes anhydrous ethanol, and the concentration is analytical grade.

[0015] Optionally, the ethanol aqueous solution is a 50% vol ethanol aqueous solution.

[0016] Optionally, the method for configuring the acetaldehyde standard series working solution includes:

[0017] Pipette 0.10mL, 0.20mL, 0.40mL, 0.60mL, 0.80mL, and 1.00mL of the acetaldehyde standard sample in water, dilute to volume with ethanol aqueous solution, mix well, and prepare the acetaldehyde standard series working solutions with concentrations of 10.0mg / 100mL, 20.0mg / 100mL, 40.0mg / 100mL, 60.0mg / 100mL, 80.0mg / 100mL, and 100mg / 100mL.

[0018] Optionally, the liquor samples include light-flavor liquor, strong-flavor liquor, and sauce-flavor liquor.

[0019] Optionally, the specification of the chromatographic column is 30m*0.250mm*0.25μm.

[0020] Optionally, the DB-WAX UI column should be balanced to a baseline noise of ≤10 before use. -12 A (about 20 minutes).

[0021] The operating conditions of the gas chromatography are:

[0022] Optionally, nitrogen is used as a carrier gas;

[0023] Optionally, the running time is 25.2 to 26.2 minutes, preferably 26 minutes.

[0024] Optionally, the detector temperature is 240-270°C, preferably 260°C.

[0025] Optionally, the injection port temperature is 230-250°C, preferably 240°C.

[0026] Optionally, the mode is a constant flow mode, and the carrier gas flow rate is 0.8 to 1.2 mL / min, preferably 1.0 mL / min.

[0027] Optionally, the hydrogen flow rate is 30-50 mL / min, preferably 40 mL / min.

[0028] Optionally, the air flow rate is 300-500 mL / min, preferably 400 mL / min.

[0029] Optionally, the injection volume is 0.8 to 1.2 μL, preferably 1 μL.

[0030] Optionally, the split ratio is 25 to 35:1, preferably 30:1.

[0031] Optionally, the operating conditions of the gas chromatography also include an initial temperature of 32-38°C, maintained for 1-3 min; then increased to 40-50°C at 1.5-2.5°C / min, and then increased to 225-235°C at 11-17°C / min, and maintained for 3-7 min.

[0032] Optionally, under the operating conditions of the gas chromatography, there should be no residue in the chromatographic column before sample analysis, and the baseline noise should be no greater than 10 -12 A.

[0033] Optionally, the calculation method of the mass concentration Xi of acetaldehyde in the liquor sample is Xi=Ci / 100; wherein Ci is the mass concentration of acetaldehyde in the liquor sample to be tested obtained from the standard curve, in units of mg / 100mL; and 100 is the unit conversion coefficient.

[0034] Compared with the prior art, the beneficial effects of this application include:

[0035] In this application, by using a DB-WAX UI chromatographic column, optimizing the experimental conditions, selecting reagents and preparing solvents, it is possible to accurately analyze the acetaldehyde content in liquor for the analysis of acetaldehyde indicators in liquor. The analytical method of this application has good reproducibility and stability, no retention time drift, and stable data. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0037] Figure 1 is the linear correlation diagram of acetaldehyde in Example 1;

[0038] Figure 2 is the gas chromatogram of the acetaldehyde standard sample in water in Example 1;

[0039] Figure 3 This is the gas chromatogram of the 50% vol ethanol blank sample in Example 1;

[0040] Figure 4 This is the gas chromatogram of the liquor sample in Example 1. DETAILED DESCRIPTION

[0041] As used herein:

[0042] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0043] The conjunction "consisting of excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed-ended so that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0044] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0045] In these examples, parts and percentages are by mass unless otherwise indicated.

[0046] "Parts by mass" refers to the basic unit of measurement for expressing the mass ratio of multiple components. 1 part can represent any unit mass, such as 1g or 2.689g. If we say that the mass of component A is a parts and the mass of component B is b parts, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass of all components is not limited to 100 parts.

[0047] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0048] In order to better explain the technical solution provided by this application, an overall statement of the technical solution is first made before the embodiments.

[0049] The present application provides a method for determining the acetaldehyde content in liquor, comprising:

[0050] The acetaldehyde standard sample in water is mixed with the ethanol aqueous solution to prepare acetaldehyde-ethanol aqueous solutions of different concentrations as the acetaldehyde standard series working solutions;

[0051] Prepare liquor samples;

[0052] Using a gas chromatograph to perform gas chromatography determination on the acetaldehyde standard series working solution and the liquor sample respectively;

[0053] Calculating the acetaldehyde content in the liquor sample after quantitative analysis using an external standard method;

[0054] The chromatographic column in the gas chromatograph is a DB-WAX UI chromatographic column, and the detector is a hydrogen flame ionization detector.

[0055] In an optional embodiment, the concentration of the acetaldehyde standard is 10 mg / mL.

[0056] In an optional embodiment, the ethanol in the ethanol aqueous solution includes anhydrous ethanol, and the concentration is analytical grade.

[0057] In an optional embodiment, the ethanol aqueous solution is a 50% vol ethanol aqueous solution.

[0058] In an optional embodiment, the method for preparing the acetaldehyde standard series working solution includes:

[0059] Pipette 0.10mL, 0.20mL, 0.40mL, 0.60mL, 0.80mL, and 1.00mL of the acetaldehyde standard sample in water, dilute to volume with ethanol aqueous solution, mix well, and prepare the acetaldehyde standard series working solutions with concentrations of 10.0mg / 100mL, 20.0mg / 100mL, 40.0mg / 100mL, 60.0mg / 100mL, 80.0mg / 100mL, and 100mg / 100mL.

[0060] In an optional embodiment, the liquor samples include light-flavor liquor, strong-flavor liquor, and sauce-flavor liquor.

[0061] Optionally, the specification of the chromatographic column is 30m*0.250mm*0.25μm.

[0062] In an optional embodiment, the DB-WAX UI chromatographic column should be balanced to a baseline noise of ≤10 before use. -12 A.

[0063] The operating conditions of the gas chromatography are:

[0064] In an optional embodiment, nitrogen is used as the carrier gas;

[0065] In an optional embodiment, the running time is 25.2 to 26.2 minutes.

[0066] Optionally, the running time can be 25.2 min, 25.3 min, 25.4 min, 25.5 min, 25.6 min, 25.7 min, 25.8 min, 25.9 min, 26 min, 26.1 min, 26.2 min, or any value between 25.2 and 26.2 min.

[0067] In an optional embodiment, the detector temperature is 240-270°C.

[0068] Optionally, the detector temperature can be 240℃, 241℃, 242℃, 243℃, 244℃, 245℃, 246℃, 247℃, 248℃, 249℃, 250℃, 251℃, 252℃, 253℃, 254℃, 255℃, 256℃, 257℃, 258℃, 259℃, 260℃, 261℃, 262℃, 263℃, 264℃, 265℃, 266℃, 267℃, 268℃, 269℃, 270℃, or any value between 240 and 270℃.

[0069] In an optional embodiment, the injection port temperature is 230-250°C.

[0070] Optionally, the temperature of the injection port can be 230° C., 231° C., 232° C., 233° C., 234° C., 235° C., 236° C., 237° C., 238° C., 239° C., 240° C., 241° C., 242° C., 243° C., 244° C., 245° C., 246° C., 247° C., 248° C., 249° C., 250° C., or any value between 230 and 250° C. In an optional embodiment, the mode is a constant flow mode, and the carrier gas flow rate is 0.8 to 1.2 mL / min.

[0071] Optionally, the flow rate may be 0.8 mL / min, 0.9 mL / min, 1 mL / min, 1.1 mL / min, 1.2 mL / min, or any value between 0.8 and 1.2 mL / min.

[0072] In an optional embodiment, the hydrogen flow rate is 30 to 50 mL / min.

[0073] Optionally, the hydrogen flow rate can be 30mL / min, 31mL / min, 32mL / min, 33mL / min, 34mL / min, 5mL / min, 36mL / min, 37mL / min, 38mL / min, 39mL / min, 40mL / min, 41mL / min, 42mL / min, 43mL / min, 44mL / min, 45mL / min, 6mL / min, 47mL / min, 48mL / min, 49mL / min, 50mL / min, or any value between 30 and 50mL / min.

[0074] In an optional embodiment, the air flow rate is 300-500 mL / min.

[0075] Optionally, the air flow rate can be 300mL / min, 310mL / min, 320mL / min, 330mL / min, 340mL / min, 350mL / min, 360mL / min, 370mL / min, 380mL / min, 390mL / min, 400mL / min, 410mL / min, 420mL / min, 430mL / min, 440mL / min, 450mL / min, 460mL / min, 470mL / min, 480mL / min, 490mL / min, 500mL / min, or any value between 300 and 500mL / min.

[0076] In an optional embodiment, the injection volume is 0.8-1.2 μL.

[0077] Optionally, the injection volume can be 0.8 μL, 0.85 μL, 0.9 μL, 1 μL, 1.05 μL, 1.1 μL, 1.15 μL, 1.2 μL, or any value between 0.8 and 1.2 μL.

[0078] In an optional embodiment, the split ratio is 25-35:1.

[0079] Optionally, the split ratio can be 25:1, 26:1, 27:1, 28:1, 29:1, 30:1, 31:1, 32:1, 33:1, 34:1, 35:1, or any value between 25 and 35:1.

[0080] In an optional embodiment, the operating conditions of the gas chromatography also include an initial temperature of 32-38°C, maintained for 1-3 min; then increased to 40-50°C at 1.5-2.5°C / min, and then increased to 225-235°C at 11-17°C / min, and maintained for 3-7 min.

[0081] Optionally, the initial temperature can be 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, or any value between 32 and 38°C; the holding time of the initial temperature can be 1 min, 2 min, 3 min, or any value between 1 and 3°C. Optionally, the heating rate of the initial temperature can be 1.5℃ / min, 1.6℃ / min, 1.7℃ / min, 1.8℃ / min, 1.9℃ / min, 2℃ / min, 2.1℃ / min, 2.2℃ / min, 2.3℃ / min, 2.4℃ / min, 2.5℃ / min, or any value between 1.5 and 2.5℃ / min; the temperature after heating at this heating rate can be 40℃, 41℃, 42℃, 43℃, 44℃, 45℃, 46℃, 47℃, 48℃, 49℃, 50℃, or any value between 40 and 50℃; after reaching this temperature, the temperature is raised again The temperature may be maintained for 3 min, 4 min, 5 min, 6 min, 7 min, or any value between 3 and 7 min.

[0082] In an optional embodiment, under the operating conditions of the gas chromatography, there should be no residue in the chromatographic column before sample analysis, and the baseline noise should be no greater than 10 -12 A.

[0083] In an optional embodiment, the calculation method of the mass concentration Xi of acetaldehyde in the liquor sample is Xi=Ci / 100; wherein Ci is the mass concentration of acetaldehyde in the liquor sample to be tested obtained from the standard curve, in mg / 100mL; and 100 is the unit conversion coefficient.

[0084] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0085] In the following embodiments of the present application, the gas chromatograph used has a hydrogen flame ionization detector, and the gas chromatographic column is a DB-WAX UI chromatographic column, and the parameters are shown in Table 1 below:

[0086] Table 1 Column parameters

[0087]

[0088] In the following examples of the present application, the ethanol used is anhydrous ethanol with a chromatographic purity; the acetaldehyde standard substance in water used is 10 mg / ml.

[0089] Example 1

[0090] This embodiment provides a method for determining the acetaldehyde content in liquor, and the specific steps are as follows:

[0091] 1. Validation of the analytical method of this application

[0092] 1. Accuracy of analytical method - recovery rate determination

[0093] Different amounts of acetaldehyde standard solution in water were added to samples of liquor (Luzhou-flavor liquor) produced by Fenggu Liquor Co., Ltd. in Mianyang City, Sichuan Province, and the mixture was thoroughly mixed to prepare liquor sample solutions with different spiked concentrations.

[0094] Then, a gas chromatograph with a DB-WAX UI column and a hydrogen flame ionization detector was used to perform gas chromatographic separation and determination according to the following parameters. Before the standard series samples and sample analysis, the instrument must meet the requirements, and then the automatic sampler of the equipment should be used for sample injection and analysis and determination. The gas chromatographic conditions are:

[0095] Running time: 26 minutes;

[0096] Detector temperature: 260°C;

[0097] Inlet temperature: 240°C;

[0098] Constant flow mode, carrier gas flow rate: 1.0mL / min;

[0099] Hydrogen flow rate: 40mL / min;

[0100] Air flow rate: 400mL / min;

[0101] Injection volume: 1 μL;

[0102] Split ratio: 30:1

[0103] Heating program: initial temperature 35°C, hold for 2 min, increase to 45°C at 2°C / min, increase to 230°C at 14°C / min, hold for 5 min.

[0104] The measurement results are shown in Table 2:

[0105] Table 2 Acetaldehyde recovery experimental results

[0106]

[0107] The above results show that the average recoveries of the three different levels of spiked amounts are 94.80%, 96.46% and 96.11%, respectively, with good repeatability, proving that the analytical method of this application has high accuracy.

[0108] 2. Precision of analytical methods - Determination of deviations

[0109] Five samples of clarified liquor (Luzhou-flavor liquor) produced by Fenggu Liquor Co., Ltd. in Mianyang City, Sichuan Province were taken and analyzed by gas chromatography in the same way as in “Recovery Determination”. The deviation determination results are shown in Table 3.

[0110] Table 3 Results of acetaldehyde mass concentration analysis deviation determination

[0111]

[0112] The above results show that the standard deviation among the five sample treatments is 0.14, the relative standard deviation is 1.09, and the Horwitz formula result is 1.84%, which proves that the analytical method of the present application has high precision and small deviation.

[0113] 3. Determination of linear correlation of analytical methods

[0114] Acetaldehyde standard substance in water was prepared into a series of concentrations with 50% vol ethanol solution and analyzed by gas chromatography in the same way as the "recovery rate determination". The relevant linear determination data are shown in Table 4 below.

[0115] Table 4 Acetaldehyde linear correlation experimental data

[0116]

[0117] The standard mass was used as the horizontal axis and the corresponding peak area as the vertical axis. The linear regression equation of acetaldehyde obtained by fitting was: y = 0.361487x-0.392997, the correlation coefficient R = 0.99965, and the correlation linear equation was as follows: Figure 1 It can be seen that the data obtained by the analysis method of the present application has a good linear correlation.

[0118] From the above results, it can be seen that the recovery rate, precision and linear correlation of the analytical method of this application are good, meet the analytical requirements, and are suitable for the determination of acetaldehyde content in liquor.

[0119] 2. Determination of acetaldehyde content in a liquor sample

[0120] The liquor samples to be tested were produced by Fenggu Liquor Co., Ltd. in Mianyang City, Sichuan Province (Luzhou-flavor liquor).

[0121] (1) Preparation of acetaldehyde standard solution series

[0122] Accurately pipette 0.10mL, 0.20mL, 0.40mL, 0.60mL, 0.80mL, and 1.00mL of acetaldehyde standard solution in water into 6 10mL volumetric flasks respectively, make up to the scale with ethanol solution (50% vol, volume fraction), mix thoroughly, and set aside.

[0123] (2) Preparation of liquor samples

[0124] Remove impurities from the liquor sample and make sure the sample is clear and transparent for later use.

[0125] (3) Gas chromatography analysis

[0126] The DB-WAX UI column and hydrogen flame ionization detector were used to separate and determine the acetaldehyde standard series solutions and liquor samples.

[0127] The chromatographic conditions are:

[0128] Running time: 26 minutes;

[0129] Detector temperature: 260°C;

[0130] Inlet temperature: 240°C;

[0131] Constant flow mode, carrier gas flow rate: 1.0mL / min;

[0132] Hydrogen flow rate: 40mL / min;

[0133] Air flow rate: 400mL / min;

[0134] Injection volume: 1 μL;

[0135] Split ratio: 30:1

[0136] Heating program: initial temperature 35°C, hold for 2 min, increase to 45°C at 2°C / min, increase to 230°C at 14°C / min, hold for 5 min.

[0137] Under the gas chromatography conditions, there should be no residue in the column before sample analysis, and the baseline noise should be ≤10 -12 A (about 20 minutes); according to the standard solution concentration from low to high, the sample is automatically injected in sequence, and the standard solution test is completed, and then the sample analysis and determination are carried out. The chromatogram of the acetaldehyde standard sample is as follows Figure 2 As shown, the chromatogram of the 50% vol ethanol blank sample is as follows Figure 3 As shown, the chromatogram of the liquor sample is as follows Figure 4 shown.

[0138] For each sample, an external standard was used for quantification. The recovery and deviation of the sample determination results were calculated. The results are shown in Table 5 below.

[0139] Table 5 Determination results of acetaldehyde content in Luzhou-flavor liquor

[0140]

[0141] Example 2

[0142] This embodiment provides a method for determining the acetaldehyde content in liquor, and the specific steps are as follows:

[0143] The liquor sample to be tested is from Shanxi Xinghua Village Fenjiu Group Co., Ltd. (light-fragrance liquor).

[0144] (1) Preparation of acetaldehyde standard solution series

[0145] Accurately pipette 0.10mL, 0.20mL, 0.40mL, 0.60mL, 0.80mL, and 1.00mL of acetaldehyde standard solution in water into 6 10mL volumetric flasks respectively, make up to the scale with ethanol solution (50% vol, volume fraction), mix thoroughly, and set aside.

[0146] (2) Preparation of liquor samples

[0147] Remove impurities from the liquor sample and make sure the sample is clear and transparent for later use.

[0148] (3) Gas chromatography analysis

[0149] The DB-WAX UI column and hydrogen flame ionization detector were used to separate and determine the acetaldehyde standard series solutions and liquor samples.

[0150] The chromatographic conditions are:

[0151] Running time: 26 minutes;

[0152] Detector temperature: 260°C;

[0153] Inlet temperature: 240°C;

[0154] Constant flow mode, carrier gas flow rate: 1.0mL / min;

[0155] Hydrogen flow rate: 40mL / min;

[0156] Air flow rate: 400mL / min;

[0157] Injection volume: 1.0 μL;

[0158] Split ratio: 30:1

[0159] Heating program: initial temperature 35°C, hold for 2 min, increase to 45°C at 2°C / min, increase to 230°C at 14°C / min, hold for 5 min.

[0160] Under the gas chromatography conditions, there should be no residue in the column before sample analysis, and the baseline noise should be ≤10 -12 A (about 20min); automatically inject samples in order from low to high concentrations of standard solutions, and after the standard solution test is completed, perform sample analysis and determination.

[0161] For each sample, an external standard was used for quantification. The recovery and deviation of the sample determination results were calculated. The results are shown in Table 6 below.

[0162] Table 6 Determination results of acetaldehyde content in light-flavor liquor

[0163]

[0164] Example 3

[0165] This embodiment provides a method for determining the acetaldehyde content in liquor, and the specific steps are as follows:

[0166] The liquor sample to be tested is from Kweichow Moutai Co., Ltd. (sauce-flavor liquor).

[0167] (1) Preparation of acetaldehyde standard solution series

[0168] Accurately pipette 0.10mL, 0.20mL, 0.40mL, 0.60mL, 0.80mL, and 1.00mL of acetaldehyde standard solution in water into 6 10mL volumetric flasks respectively, make up to the scale with ethanol solution (50% vol, volume fraction), mix thoroughly, and set aside.

[0169] (2) Preparation of liquor samples

[0170] Remove impurities from the liquor sample and make sure the sample is clear and transparent for later use.

[0171] (3) Gas chromatography analysis

[0172] The DB-WAX UI column and hydrogen flame ionization detector were used to separate and determine the acetaldehyde standard series solutions and liquor samples.

[0173] The chromatographic conditions are:

[0174] Running time: 26 minutes;

[0175] Detector temperature: 260°C;

[0176] Inlet temperature: 240°C;

[0177] Constant flow mode, carrier gas flow rate: 1.0mL / min;

[0178] Hydrogen flow rate: 40mL / min;

[0179] Air flow rate: 400mL / min;

[0180] Injection volume: 1.0 μL;

[0181] Split ratio: 30:1

[0182] Heating program: initial temperature 35°C, hold for 2 min, increase to 45°C at 2°C / min, increase to 230°C at 14°C / min, hold for 5 min.

[0183] Under the gas chromatography conditions, there should be no residue in the column before sample analysis, and the baseline noise should be ≤10 -12 A (about 20min); automatically inject samples in order from low to high concentrations of standard solutions, and after the standard solution test is completed, perform sample analysis and determination.

[0184] For each sample, an external standard was used for quantification. The recovery and deviation of the sample determination results were calculated. The results are shown in Table 7 below.

[0185] Table 7 Determination results of acetaldehyde content in Maotai-flavor liquor

[0186]

[0187] Comparative Example 1

[0188] This comparative example provides a method for determining the acetaldehyde content in liquor, and the specific process is as follows:

[0189] The standard substance adopts pure acetaldehyde standard substance (Aladdin, purity 99.947%), and the liquor sample to be tested is the liquor (Luzhou-flavor liquor) produced by Fenggu Liquor Co., Ltd., Mianyang City, Sichuan Province as described in Example 1:

[0190] (1) Preparation of acetaldehyde standard solution

[0191] Accurately weigh 0.1000g of pure acetaldehyde standard substance into a 100mL volumetric flask filled with 30mL-50mL of 50% ethanol aqueous solution, dilute to the scale with 50% ethanol aqueous solution, shake well to prepare a 100mg / mL acetaldehyde standard solution, and then dilute 10 times to prepare a 10mg / mL acetaldehyde standard working solution.

[0192] (2) Preparation of acetaldehyde standard series solutions

[0193] Accurately pipette 0.10mL, 0.20mL, 0.40mL, 0.60mL, 0.80mL, and 1.00mL of 10mg / mL acetaldehyde standard solution into 6 10mL volumetric flasks respectively, make up to the mark with ethanol solution (50% vol, volume fraction), mix thoroughly, and set aside.

[0194] (2) Preparation of liquor samples

[0195] Remove impurities from the liquor sample and make sure the sample is clear and transparent for later use.

[0196] (3) Gas chromatography analysis

[0197] The DB-WAX UI column and hydrogen flame ionization detector were used to separate and determine the acetaldehyde standard series solutions and liquor samples.

[0198] The chromatographic conditions are:

[0199] Running time: 26 minutes;

[0200] Detector temperature: 260°C;

[0201] Inlet temperature: 240°C;

[0202] Constant flow mode, carrier gas flow rate: 1.0mL / min;

[0203] Hydrogen flow rate: 40mL / min;

[0204] Air flow rate: 400mL / min;

[0205] Injection volume: 1 μL;

[0206] Split ratio: 30:1

[0207] Heating program: initial temperature 35°C, hold for 2 min, increase to 45°C at 2°C / min, increase to 230°C at 14°C / min, hold for 5 min.

[0208] Under the gas chromatography conditions, there should be no residue in the column before sample analysis, and the baseline noise should be ≤10 -12 A (about 20 minutes); according to the standard solution concentration from low to high, the sample is automatically injected in sequence, and the standard solution test is completed, and then the sample analysis and determination are carried out. The chromatogram of the acetaldehyde standard sample is as follows Figure 2 As shown, the chromatogram of the 50% vol ethanol blank sample is as follows Figure 3 As shown, the chromatogram of the liquor sample is as follows Figure 4 shown.

[0209] For each sample, an external standard was used for quantification. The results of the calculated samples were compared with those of Example 1. The results are shown in Table 8 below.

[0210] Table 8 Comparison of acetaldehyde results of samples measured by acetaldehyde standard substance in water and acetaldehyde standard substance pure substance

[0211]

[0212] Comparative Example 2

[0213] This comparative example provides a method for determining the acetaldehyde content in liquor, and the specific process is as follows:

[0214] The sample to be tested is liquor (Luoxiang-flavor liquor) produced by Fenggu Liquor Co., Ltd. in Mianyang City, Sichuan Province. The chromatographic column used is Agilent DB-WAX UI chromatographic column and phenomenex (Fenome) chromatographic column ZB-WAXplus with equivalent performance for comparison. The parameters of ZB-WAX plus chromatographic column are shown in Table 9 below:

[0215] Table 9 Column parameters

[0216]

[0217] (1) Preparation of acetaldehyde standard solution series

[0218] Accurately pipette 0.10mL, 0.20mL, 0.40mL, 0.60mL, 0.80mL, and 1.00mL of acetaldehyde standard solution into 6 10mL volumetric flasks, respectively, make up to the mark with ethanol solution (50% vol, volume fraction), mix thoroughly, and set aside.

[0219] (2) Preparation of liquor samples

[0220] Remove impurities from the liquor sample and make sure the sample is clear and transparent for later use.

[0221] (3) Gas chromatography analysis

[0222] The liquor samples were separated and determined by gas chromatography using DB-WAX UI and ZB-WAX plus columns, respectively, and a hydrogen flame ionization detector.

[0223] The chromatographic conditions are:

[0224] Running time: 26 minutes;

[0225] Detector temperature: 260°C;

[0226] Inlet temperature: 240°C;

[0227] Constant flow mode, carrier gas flow rate: 1.0mL / min;

[0228] Hydrogen flow rate: 40mL / min;

[0229] Air flow rate: 400mL / min;

[0230] Injection volume: 1 μL;

[0231] Split ratio: 30:1

[0232] Heating program: initial temperature 35°C, hold for 2 min, increase to 45°C at 2°C / min, increase to 230°C at 14°C / min, hold for 5 min.

[0233] Under the gas chromatography conditions, there should be no residue in the column before sample analysis, and the baseline noise should be ≤10 -12 A (about 20min); automatically inject samples in order from low to high concentrations of standard solutions, and after the standard solution test is completed, perform sample analysis and determination.

[0234] For each sample, an external standard was used for quantification. The comparison of the test results of two different chromatographic columns is shown in Table 10 below.

[0235] Table 10 Results of determination of acetaldehyde content in liquor by chromatographic columns with different performances

[0236]

[0237] Comparative Example 3

[0238] This comparative example provides a method for determining the acetaldehyde content in liquor. Compared with Example 1, changing the carrier gas flow rate is outside the scope of the present invention. The specific process is as follows:

[0239] The liquor samples to be tested are strong-flavor liquor produced by Fenggu Liquor Co., Ltd. in Mianyang City, Sichuan Province.

[0240] (1) Preparation of acetaldehyde standard solution series

[0241] Accurately pipette 0.10mL, 0.20mL, 0.40mL, 0.60mL, 0.80mL, and 1.00mL of acetaldehyde standard solution in water into 6 10mL volumetric flasks respectively, make up to the scale with ethanol solution (50% vol, volume fraction), mix thoroughly, and set aside.

[0242] (2) Preparation of liquor samples

[0243] Remove impurities from the liquor sample and make sure the sample is clear and transparent for later use.

[0244] (3) Gas chromatography analysis

[0245] The DB-WAX UI column and hydrogen flame ionization detector were used to separate and determine the acetaldehyde standard series solutions and liquor samples.

[0246] The chromatographic conditions are:

[0247] Running time: 26 minutes;

[0248] Detector temperature: 260°C;

[0249] Inlet temperature: 240°C;

[0250] Constant flow mode, carrier gas flow rate: 0.5mL / min;

[0251] Hydrogen flow rate: 40mL / min;

[0252] Air flow rate: 400mL / min;

[0253] Injection volume: 1 μL;

[0254] Split ratio: 30:1

[0255] Heating program: initial temperature 35°C, hold for 2 min, increase to 45°C at 2°C / min, increase to 230°C at 14°C / min, hold for 5 min.

[0256] Under the gas chromatography conditions, there should be no residue in the column before sample analysis, and the baseline noise should be ≤10 -12 A (about 20min); automatically inject samples in order from low to high concentrations of standard solutions, and after the standard solution test is completed, perform sample analysis and determination.

[0257] For each sample, an external standard was used for quantification. The carrier gas flow rate was changed to perform experiments outside the scope of the present patent, and the recovery rate and deviation of the sample determination results were calculated. The results compared with those of Example 1 are shown in Table 11 below.

[0258] Table 11 Comparison of the results of acetaldehyde in liquor measured by changing the carrier gas flow rate and Example 1

[0259]

[0260] Comparative Example 4

[0261] This comparative example provides a method for determining the acetaldehyde content in liquor. Compared with Example 1, the heating rate is changed outside the scope of the present invention. The specific process is as follows:

[0262] The liquor sample to be tested is a strong-flavor liquor produced by Fenggu Liquor Co., Ltd. in Mianyang City, Sichuan Province.

[0263] (1) Preparation of acetaldehyde standard solution series

[0264] Accurately pipette 0.10mL, 0.20mL, 0.40mL, 0.60mL, 0.80mL, and 1.00mL of acetaldehyde standard solution in water into 6 10mL volumetric flasks respectively, make up to the scale with ethanol solution (50% vol, volume fraction), mix thoroughly, and set aside.

[0265] (2) Preparation of liquor samples

[0266] Remove impurities from the liquor sample and make sure the sample is clear and transparent for later use.

[0267] (3) Gas chromatography analysis

[0268] The DB-WAX UI column and hydrogen flame ionization detector were used to separate and determine the acetaldehyde standard series solutions and liquor samples.

[0269] The chromatographic conditions are:

[0270] Running time: 18.25min;

[0271] Detector temperature: 260°C;

[0272] Inlet temperature: 240°C;

[0273] Constant flow mode, carrier gas flow rate: 1.0mL / min;

[0274] Hydrogen flow rate: 40mL / min;

[0275] Air flow rate: 400mL / min;

[0276] Injection volume: 1 μL;

[0277] Split ratio: 30:1

[0278] Heating program: initial temperature 35℃, hold for 2 min, increase to 45℃ at 5℃ / min, increase to 230℃ at 20℃ / min, hold for 5 min.

[0279] Under the gas chromatography conditions, there should be no residue in the column before sample analysis, and the baseline noise should be ≤10 -12 A (about 20min); automatically inject samples in order from low to high concentrations of standard solutions, and after the standard solution test is completed, perform sample analysis and determination.

[0280] For each sample, an external standard was used for quantification. The rate of change was outside the scope of the present invention, and the recovery and deviation of the sample determination results were calculated. The results compared with those of Example 1 are shown in Table 12 below.

[0281] Table 12 Comparison of the results of acetaldehyde in liquor measured by changing the heating rate and Example 1

[0282]

[0283] Comparative Example 5

[0284] This comparative example provides a method for determining the acetaldehyde content in liquor. Compared with Example 1, changing the injection port temperature is outside the scope of the present invention. The specific process is as follows:

[0285] The liquor sample to be tested is a strong-flavor liquor produced by Fenggu Liquor Co., Ltd. in Mianyang City, Sichuan Province.

[0286] (1) Preparation of acetaldehyde standard solution series

[0287] Accurately pipette 0.10mL, 0.20mL, 0.40mL, 0.60mL, 0.80mL, and 1.00mL of acetaldehyde standard solution in water into 6 10mL volumetric flasks respectively, make up to the scale with ethanol solution (50% vol, volume fraction), mix thoroughly, and set aside.

[0288] (2) Preparation of liquor samples

[0289] Remove impurities from the liquor sample and make sure the sample is clear and transparent for later use.

[0290] (3) Gas chromatography analysis

[0291] The DB-WAX UI column and hydrogen flame ionization detector were used to separate and determine the acetaldehyde standard series solutions and liquor samples.

[0292] The chromatographic conditions are:

[0293] Running time: 26 minutes;

[0294] Detector temperature: 260°C;

[0295] Inlet temperature: 150°C;

[0296] Constant flow mode, carrier gas flow rate: 1.0mL / min;

[0297] Hydrogen flow rate: 40mL / min;

[0298] Air flow rate: 400mL / min;

[0299] Injection volume: 1 μL;

[0300] Split ratio: 30:1

[0301] Heating program: initial temperature 35°C, hold for 2 min, increase to 45°C at 2°C / min, increase to 230°C at 14°C / min, hold for 5 min.

[0302] Under the gas chromatography conditions, there should be no residue in the column before sample analysis, and the baseline noise should be ≤10 -12 A (about 20min); automatically inject samples in order from low to high concentrations of standard solutions, and after the standard solution test is completed, perform sample analysis and determination.

[0303] For each sample, an external standard was used for quantification. The injection port temperature was changed to perform experiments outside the scope of the present invention, and the recovery and deviation of the sample determination results were calculated. The results compared with those of Example 1 are shown in Table 13 below.

[0304] Table 13 Comparison of the results of acetaldehyde in liquor measured by changing the injection port temperature and Example 1

[0305]

[0306] Comparative Example 6

[0307] This comparative example provides a method for determining the acetaldehyde content in liquor. Compared with Example 1, changing the detector temperature is outside the scope of the present invention. The specific process is as follows:

[0308] The liquor sample to be tested is a strong-flavor liquor produced by Fenggu Liquor Co., Ltd. in Mianyang City, Sichuan Province.

[0309] (1) Preparation of acetaldehyde standard solution series

[0310] Accurately pipette 0.10mL, 0.20mL, 0.40mL, 0.60mL, 0.80mL, and 1.00mL of acetaldehyde standard solution in water into 6 10mL volumetric flasks respectively, make up to the scale with ethanol solution (50% vol, volume fraction), mix thoroughly, and set aside.

[0311] (2) Preparation of liquor samples

[0312] Remove impurities from the liquor sample and make sure the sample is clear and transparent for later use.

[0313] (3) Gas chromatography analysis

[0314] The DB-WAX UI column and hydrogen flame ionization detector were used to separate and determine the acetaldehyde standard series solutions and liquor samples.

[0315] The chromatographic conditions are:

[0316] Running time: 26 minutes;

[0317] Detector temperature: 150°C;

[0318] Inlet temperature: 240°C;

[0319] Constant flow mode, carrier gas flow rate: 1.0mL / min;

[0320] Hydrogen flow rate: 40mL / min;

[0321] Air flow rate: 400mL / min;

[0322] Injection volume: 1 μL;

[0323] Split ratio: 30:1

[0324] Heating program: initial temperature 35°C, hold for 2 min, increase to 45°C at 2°C / min, increase to 230°C at 14°C / min, hold for 5 min.

[0325] Under the gas chromatography conditions, there should be no residue in the column before sample analysis, and the baseline noise should be ≤10 -12 A (about 20min); automatically inject samples in order from low to high concentrations of standard solutions, and after the standard solution test is completed, perform sample analysis and determination.

[0326] For each sample, an external standard was used for quantification. The detector temperature was changed to perform experiments outside the scope of the present invention, and the recovery and deviation of the sample determination results were calculated. The results compared with those of Example 1 are shown in Table 14 below.

[0327] Table 14 Comparison of the results of acetaldehyde in liquor measured by changing the detector temperature and Example 1

[0328]

[0329] Comparative Example 7

[0330] This comparative example provides a method for determining the acetaldehyde content in liquor. Compared with Example 1, changing the hydrogen flow rate is outside the scope of the present invention. The specific process is as follows:

[0331] The liquor samples to be tested are strong-flavor liquor produced by Fenggu Liquor Co., Ltd. in Mianyang City, Sichuan Province.

[0332] (1) Preparation of acetaldehyde standard solution series

[0333] Accurately pipette 0.10mL, 0.20mL, 0.40mL, 0.60mL, 0.80mL, and 1.00mL of acetaldehyde standard solution in water into 6 10mL volumetric flasks respectively, make up to the scale with ethanol solution (50% vol, volume fraction), mix thoroughly, and set aside.

[0334] (2) Preparation of liquor samples

[0335] Remove impurities from the liquor sample and make sure the sample is clear and transparent for later use.

[0336] (3) Gas chromatography analysis

[0337] The DB-WAX UI column and hydrogen flame ionization detector were used to separate and determine the acetaldehyde standard series solutions and liquor samples.

[0338] The chromatographic conditions are:

[0339] Running time: 26 minutes;

[0340] Detector temperature: 260°C;

[0341] Inlet temperature: 240°C;

[0342] Constant flow mode, carrier gas flow rate: 1.0mL / min;

[0343] Hydrogen flow rate: 20mL / min;

[0344] Air flow rate: 400mL / min;

[0345] Injection volume: 1 μL;

[0346] Split ratio: 30:1

[0347] Heating program: initial temperature 35°C, hold for 2 min, increase to 45°C at 2°C / min, increase to 230°C at 14°C / min, hold for 5 min.

[0348] Under the gas chromatography conditions, there should be no residue in the column before sample analysis, and the baseline noise should be ≤10 -12 A (about 20min); automatically inject samples in order from low to high concentrations of standard solutions, and after the standard solution test is completed, perform sample analysis and determination.

[0349] For each sample, an external standard was used for quantification. The hydrogen flow rate was changed outside the scope of the present invention to perform experiments, and the recovery rate and deviation of the sample measurement results were calculated. The results compared with those of Example 1 are shown in Table 15 below.

[0350] Table 15 Comparison of the results of acetaldehyde in liquor measured by changing the hydrogen flow rate and Example 1

[0351]

[0352] Comparative Example 8

[0353] This comparative example provides a method for determining the acetaldehyde content in liquor. Compared with Example 1, changing the air flow rate is outside the scope of the present invention. The specific process is as follows:

[0354] The liquor sample to be tested is a strong-flavor liquor produced by Fenggu Liquor Co., Ltd. in Mianyang City, Sichuan Province.

[0355] (1) Preparation of acetaldehyde standard solution series

[0356] Accurately pipette 0.10mL, 0.20mL, 0.40mL, 0.60mL, 0.80mL, and 1.00mL of acetaldehyde standard solution in water into 6 10mL volumetric flasks respectively, make up to the scale with ethanol solution (50% vol, volume fraction), mix thoroughly, and set aside.

[0357] (2) Preparation of liquor samples

[0358] Remove impurities from the liquor sample and make sure the sample is clear and transparent for later use.

[0359] (3) Gas chromatography analysis

[0360] The DB-WAX UI column and hydrogen flame ionization detector were used to separate and determine the acetaldehyde standard series solutions and liquor samples.

[0361] The chromatographic conditions are:

[0362] Running time: 26 minutes;

[0363] Detector temperature: 260°C;

[0364] Inlet temperature: 240°C;

[0365] Constant flow mode, carrier gas flow rate: 1.0mL / min;

[0366] Hydrogen flow rate: 40mL / min;

[0367] Air flow rate: 200mL / min;

[0368] Injection volume: 1 μL;

[0369] Split ratio: 30:1

[0370] Heating program: initial temperature 35°C, hold for 2 min, increase to 45°C at 2°C / min, increase to 230°C at 14°C / min, hold for 5 min.

[0371] Under the gas chromatography conditions, there should be no residue in the column before sample analysis, and the baseline noise should be ≤10 -12 A (about 20min); automatically inject samples in order from low to high concentrations of standard solutions, and after the standard solution test is completed, perform sample analysis and determination.

[0372] For each sample, an external standard was used for quantification. The hydrogen flow rate was changed to conduct experiments outside the scope of the present invention, and the recovery rate and deviation of the sample measurement results were calculated. The results compared with those of Example 1 are shown in Table 16 below.

[0373] Table 16 Comparison of the results of acetaldehyde in liquor measured by changing the detector temperature and Example 1

[0374]

[0375] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0376] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the above claims, any one of the claimed embodiments may be used in any combination. The information disclosed in this background technology section is intended only to deepen the understanding of the overall background technology of the present application and should not be regarded as an admission or in any form of implication that the information constitutes prior art known to those skilled in the art.

Claims

1. A method for determining the acetaldehyde content in liquor, characterized in that: include: The acetaldehyde standard sample in water is mixed with the ethanol aqueous solution to prepare acetaldehyde-ethanol aqueous solutions of different concentrations as the acetaldehyde standard series working solutions; Prepare liquor samples; Using a gas chromatograph to perform gas chromatography determination on the acetaldehyde standard series working solution and the liquor sample respectively; Calculating the acetaldehyde content in the liquor sample after quantitative analysis using an external standard method; The chromatographic column in the gas chromatograph is a DB-WAX UI chromatographic column, and the detector is a hydrogen flame ionization detector.

2. The method for determining the acetaldehyde content in liquor according to claim 1, characterized in that: At least one of the following conditions is met: a. The concentration of the acetaldehyde standard is 10 mg / mL; b. The ethanol in the ethanol aqueous solution includes anhydrous ethanol, and the concentration is analytically pure; c. The ethanol aqueous solution is a 50% vol ethanol aqueous solution.

3. The method for determining the acetaldehyde content in liquor according to claim 2, characterized in that: The method for configuring the acetaldehyde standard series working solution comprises: Pipette 0.10mL, 0.20mL, 0.40mL, 0.60mL, 0.80mL, and 1.00mL of the acetaldehyde standard sample in water, dilute to volume with ethanol aqueous solution, mix well, and prepare the acetaldehyde standard series working solutions with concentrations of 10.0mg / 100mL, 20.0mg / 100mL, 40.0mg / 100mL, 60.0mg / 100mL, 80.0mg / 100mL, and 100mg / 100mL.

4. The method for determining the acetaldehyde content in liquor according to claim 1, characterized in that: The liquor samples include light-flavor liquor, strong-flavor liquor, and sauce-flavor liquor.

5. The method for determining the acetaldehyde content in liquor according to claim 1, characterized in that: The specification of the chromatographic column is 30m*0.250mm*0.25μm.

6. The method for determining the acetaldehyde content in liquor according to claim 1, characterized in that: The DB-WAX UI column should be balanced to a baseline noise of ≤10 before use. -12 A (about 20 minutes).

7. The method for determining the acetaldehyde content in liquor according to claim 1, characterized in that: The operating conditions of the gas chromatography meet at least one of the following conditions: d. Using nitrogen as carrier gas; e. The running time is 25.2 to 26.2 minutes; f. The detector temperature is 240-270°C; g. The injection port temperature is 230-250°C; h. The mode is constant flow mode, and the carrier gas flow rate is 0.8~1.2mL / min; i. Hydrogen flow rate is 30-50 mL / min; j. Air flow rate is 300~500mL / min; k. The injection volume is 0.8-1.2 μL; 1. The split ratio is 25 to 35:

1.

8. The method for determining the acetaldehyde content in liquor according to claim 1, characterized in that: The operating conditions of the gas chromatography also include an initial temperature of 32-38°C, maintained for 1-3 minutes; then raised to 40-50°C at 1.5-2.5°C / min, and then raised to 225-235°C at 11-17°C / min, and maintained for 3-7 minutes.

9. The method for determining the acetaldehyde content in liquor according to claim 7, characterized in that: Under the operating conditions of the gas chromatography, there should be no residue in the chromatographic column before sample analysis, and the baseline noise should not be greater than 10 -12 A.

10. The method for determining the acetaldehyde content in liquor according to any one of claims 1 to 9, characterized in that: The calculation method of the mass concentration Xi of acetaldehyde in the liquor sample is Xi=Ci / 100; wherein Ci is the mass concentration of acetaldehyde in the liquor sample to be tested obtained from the standard curve, in units of mg / 100mL; and 100 is the unit conversion coefficient.

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