Method for simultaneously determining 13 terpene compounds in Maotai-flavor liquor

Abstract

The invention relates to the technical field, discloses a method for simultaneously determining 13 terpene compounds in Maotai-flavor baijiu, aims at exploration and optimization of pretreatment steps and chromatographic conditions, and aims to establish a stable and reliable detection method for the terpene compounds in the baijiu. And collection of terpene compound content data is carried out for representative Maotai-flavor white spirit samples, so that some technical support and data reference can be provided for research on white spirit quality improvement.

Description

Technical Field

[0001] The present invention relates to the technical field, and more particularly to a method for simultaneously determining 13 terpene compounds in sauce-flavor liquor. Background Art

[0002] Terpenes are a class of naturally occurring hydrocarbons found in plants or produced by microbial metabolism. Currently, over 50,000 terpenes have been discovered. Their molecular formula is an integer multiple of isoprene, and they are chain or cyclic olefin compounds conforming to the general formula (C₅H₃)n. Terpenes possess a distinctive aroma and are important flavor and aroma compounds. They also possess antifungal, antitumor, antioxidant, anti-inflammatory, analgesic, and drug absorption-enhancing properties, making them important active ingredients in traditional Chinese medicine. Existing studies have reported the presence of terpenes in Dongjiu (Dong-flavor liquor). The types and amounts of terpenes in liquor are also found to be related to the koji used in its production, with baijiu produced using the Daqu process containing more terpenes than those produced using the Xiaoqu process. Other studies have reported the presence of terpenes in sesame-flavored, Luzhou-flavored, Qingxiang-flavored, and Laobaigan-flavored liquors, as well as blended liquors and wines. However, research on the terpene content in Maotai-flavor liquors is rare.

[0003] In recent years, research on the aroma and flavor components of Maotai-flavor liquor has expanded beyond traditional base compounds like acids, esters, alcohols, aldehydes, and ketones to include pyrazines and volatile phenols. Research on Maotai-flavor liquor raw materials and auxiliary ingredients by Bi Rongyu, Pan Mu, and others has shown that terpenes in baijiu are derived from both the brewing grains sorghum and wheat, as well as auxiliary ingredients like koji (Chinese medicine), and from a series of biochemical reactions carried out by microorganisms during the brewing process. The presence of microorganisms like yeast significantly influences the types and content of terpenes. The characteristic aromas of terpenes, such as tea, magnolia, and flowers, contribute significantly to the sensory qualities of the finished Maotai-flavor liquor, including aromas of tea, magnolia, and flowers.

[0004] Regarding the detection of terpenes, relevant research reports mainly include methods such as "full two-dimensional-time of flight gas chromatography-mass spectrometry detector", "headspace solid phase microextraction-gas chromatography-mass spectrometry" and "headspace solid phase microextraction combined with full two-dimensional gas chromatography-time of flight mass spectrometry". Although full two-dimensional-time of flight mass spectrometry has high resolution and sensitivity, its complex operation and relatively insufficient stability in quantitative analysis have, to a certain extent, limited the promotion and application of this method in the quality analysis of liquor. Although the headspace solid phase microextraction-gas chromatography-mass spectrometry method eliminates the relatively complex pretreatment operation, it fails to effectively avoid the influence of the complex matrix of sauce-flavor liquor on the detection results, resulting in its low sensitivity. In addition, the defect of insufficient stability of headspace solid phase microextraction in the specific detection practice process means that this method fails to meet the technical requirements for the inspection and detection of terpenes in sauce-flavor liquor. Summary of the Invention

[0005] In order to overcome the above-mentioned defects in the prior art, the present invention provides a method for the simultaneous determination of 13 terpene compounds in Maotai-flavor liquor. This application is devoted to the exploration and optimization of the pretreatment steps and chromatographic conditions, and intends to establish a stable and reliable method for the inspection and detection of terpene compounds in liquor. It also collects data on the content of terpene compounds in representative Maotai-flavor liquor samples, in order to provide some technical support and data reference for the research on improving the quality of liquor.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions: A method for simultaneously determining 13 terpene compounds in Maotai-flavor liquor, comprising the following steps:

[0007] S1. Sample procurement: Purchase Maotai-flavor liquor from the market as standard samples;

[0008] S2. Prepare the standard solution, which specifically includes the following steps:

[0009] (1) Accurately weigh 10 mg of a Maotai-flavor liquor standard sample to the nearest 0.1 mg, dilute it with ethanol, and make up to 10 mL to obtain a 1000 mg / L single standard stock solution. Store at 2-8°C for later use.

[0010] (2) Accurately pipette 1.0 mL of each individual standard stock solution into a 10 mL volumetric flask, dilute to volume with ethanol, and obtain a 100 mg / L mixed standard stock solution of 13 terpenes. Store at 2-8°C for future use.

[0011] (3) Accurately pipette 1.0 mL of the 13 terpene mixed standard stock solutions into a 10 mL volumetric flask, dilute to volume with ethanol to obtain a 10 mg / L mixed standard intermediate solution, and store at 2-8 °C for future use;

[0012] (4) Accurately pipette 1.0 mL of the 10 mg / L mixed standard stock solution of 13 terpenes into a 10 mL volumetric flask and dilute to volume with ethanol to obtain a 1.0 mg / L mixed standard intermediate solution, which is prepared and used immediately.

[0013] (5) Accurately pipette 1.0 mL, 0.5 mL, and 0.2 mL of a 10 mg / L mixed standard stock solution of 13 terpenes into a 10 mL volumetric flask, respectively; Accurately pipette 1.0 mL, 0.5 mL, and 0.2 mL of a 10 mg / L mixed standard stock solution of 13 terpenes into a 10 mL volumetric flask, respectively; Add 0.2 mL of a 10 mg / L internal standard substance, cymene, and dilute to volume with ethanol to obtain a standard working curve with concentrations of 20 μg / L, 50 μg / L, 100 μg / L, 200 μg / L, 500 μg / L, and 1000 μg / L;

[0014] S3. Sample pretreatment. The specific steps are as follows:

[0015] 8 mL of ethyl acetate-methanol (with a ratio of ethyl acetate to methanol of 9:1) and 12 mL of cyclohexane-ethyl acetate (with a ratio of cyclohexane to ethyl acetate of 8:2) were used to wash and activate the C18 solid phase extraction column and the Florisil solid phase extraction column, respectively. After the activation, the C18 solid phase extraction column and the Florisil solid phase extraction column were connected in series, 10 mL of the liquor sample was transferred to the solid phase extraction column, 0.2 mL of the 10 mg / L internal standard substance cymene was added, and the sample was After the sample solution naturally passes through the packing layer, the serial solid-phase extraction cartridges are separated and then washed with 6 mL of ethyl acetate-methanol and 10 mL of cyclohexane-ethyl acetate to remove impurities, respectively. Then, the C18 solid-phase extraction cartridge and the Florisil solid-phase extraction cartridge are eluted with 10 mL of cyclohexane-ethyl acetate and 15 mL of ethyl acetate-methanol, respectively. The eluates are collected and combined, concentrated to near dryness with nitrogen blowdown at 40°C, and made up to volume with 1 mL of ethyl acetate. After vortex mixing, the eluate is passed through a 0.22 μm organic filter membrane and then analyzed by gas chromatography-mass spectrometry.

[0016] S4, performing gas chromatography detection;

[0017] S5. Perform mass spectrometry detection.

[0018] Furthermore, in step S4, the gas chromatography detection conditions are as follows:

[0019] Quartz capillary column DB-5MS, 30m×250μm×0.25μm; carrier gas: He, purity ≥99.999%, flow rate 1.00mL / min; heating program: initial temperature is 50℃, hold for 1min, then increase the temperature to 90℃ at 3℃ / min, hold for 2min, then increase the temperature to 120℃ at 5℃ / min, hold for 5min, and finally increase the temperature to 220℃ at 12℃ / min, hold for 6min; splitless injection; injection volume: 1μL; injection port temperature: 250℃.

[0020] Furthermore, in step S5, the mass spectrometry detection conditions are as follows:

[0021] EI ion source temperature: 250 °C; ionization voltage: 70 eV, solvent delay: 5 min, transfer line temperature: 250 °C; full scan mode, mass scan range: m / z 30-450, reaction detection scan mode selected.

[0022] In summary, the present invention has the following beneficial effects:

[0023] 1. For the first time, a systematic methodological study was conducted on the pretreatment and chromatographic conditions for the detection of 13 terpenes, including myrcene, ocimene, linalool, menthol, terpen-4-ol, geraniol, anethole, geranyl acetate, trans-caryophyllene, geranylacetone, nerolidol, trans-trans-farnesol, and citral, in Maotai-flavor liquors. Verification experiments and data collection were also conducted on the contents of the corresponding terpenes in representative Maotai-flavor liquors.

[0024] 2. For the first time, the internal standard substance suitable for the detection of terpenes was determined through experimental comparison;

[0025] 3. For the first time, a pre-treatment method of activating, washing, and eluting solid-phase extraction columns of different polarities and loading the samples in series was used to achieve the simultaneous detection of terpenes of different polarities.

[0026] 4. For the first time, solid phase extraction columns were used to extract and purify terpene compounds in sauce-flavor liquor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the GC-MS total ion current diagram of 13 pyrazines in the liquor sample in Example 2 of the present invention. DETAILED DESCRIPTION

[0028] The following is combined with Figure 1 The present invention is described in further detail.

[0029] Example: A method for simultaneously determining 13 terpene compounds in Maotai-flavor liquor comprises the following steps:

[0030] S1. Sample procurement: Purchase Maotai-flavor liquor from the market as standard samples;

[0031] S2. Prepare the standard solution, which specifically includes the following steps:

[0032] (1) Accurately weigh 10 mg of a Maotai-flavor liquor standard sample to the nearest 0.1 mg, dilute it with ethanol, and make up to 10 mL to obtain a 1000 mg / L single standard stock solution. Store at 2-8°C for later use.

[0033] (2) Accurately pipette 1.0 mL of each individual standard stock solution into a 10 mL volumetric flask, dilute to volume with ethanol, and obtain a 100 mg / L mixed standard stock solution of 13 terpenes. Store at 2-8°C for future use.

[0034] (3) Accurately pipette 1.0 mL of the 13 terpene mixed standard stock solutions into a 10 mL volumetric flask, dilute to volume with ethanol to obtain a 10 mg / L mixed standard intermediate solution, and store at 2-8 °C for future use;

[0035] (4) Accurately pipette 1.0 mL of the 10 mg / L mixed standard stock solution of 13 terpenes into a 10 mL volumetric flask and dilute to volume with ethanol to obtain a 1.0 mg / L mixed standard intermediate solution, which is prepared and used immediately.

[0036] (5) Accurately pipette 1.0 mL, 0.5 mL, and 0.2 mL of a 10 mg / L mixed standard stock solution of 13 terpenes into a 10 mL volumetric flask, respectively; Accurately pipette 1.0 mL, 0.5 mL, and 0.2 mL of a 10 mg / L mixed standard stock solution of 13 terpenes into a 10 mL volumetric flask, respectively; Add 0.2 mL of a 10 mg / L internal standard substance, cymene, and dilute to volume with ethanol to obtain a standard working curve with concentrations of 20 μg / L, 50 μg / L, 100 μg / L, 200 μg / L, 500 μg / L, and 1000 μg / L;

[0037] S3. Sample pretreatment. The specific steps are as follows:

[0038] 8 mL of ethyl acetate-methanol (with a ratio of ethyl acetate to methanol of 9:1) and 12 mL of cyclohexane-ethyl acetate (with a ratio of cyclohexane to ethyl acetate of 8:2) were used to wash and activate the C18 solid phase extraction column and the Florisil solid phase extraction column, respectively. After the activation, the C18 solid phase extraction column and the Florisil solid phase extraction column were connected in series, 10 mL of the liquor sample was transferred to the solid phase extraction column, 0.2 mL of the 10 mg / L internal standard substance cymene was added, and the sample was After the sample solution naturally passes through the packing layer, the serial solid-phase extraction cartridges are separated and then washed with 6 mL of ethyl acetate-methanol and 10 mL of cyclohexane-ethyl acetate to remove impurities, respectively. Then, the C18 solid-phase extraction cartridge and the Florisil solid-phase extraction cartridge are eluted with 10 mL of cyclohexane-ethyl acetate and 15 mL of ethyl acetate-methanol, respectively. The eluates are collected and combined, concentrated to near dryness with nitrogen blowdown at 40°C, and made up to volume with 1 mL of ethyl acetate. After vortex mixing, the eluate is passed through a 0.22 μm organic filter membrane and then analyzed by gas chromatography-mass spectrometry.

[0039] S4. Perform gas chromatography detection. The detection conditions for gas chromatography detection are as follows:

[0040] Quartz capillary column DB-5MS, 30 m × 250 μm × 0.25 μm; carrier gas: He, purity ≥99.999%, flow rate 1.00 mL / min; temperature program: initial temperature 50°C, hold for 1 min, then increase to 90°C at 3°C / min, hold for 2 min, then increase to 120°C at 5°C / min, hold for 5 min, and finally increase to 220°C at 12°C / min, hold for 6 min; splitless injection; injection volume: 1 μL; injection port temperature: 250°C;

[0041] S5. Perform mass spectrometry detection. The detection conditions for mass spectrometry detection are as follows:

[0042] EI ion source temperature: 250 °C; ionization voltage: 70 eV, solvent delay: 5 min, transfer line temperature: 250 °C; full scan mode, mass scan range: m / z 30-450, reaction detection scan mode selected.

[0043] Example 2: Optimization of SIM conditions:

[0044] Under the determined gas chromatography conditions, a full mass spectrometry scan (30-300 m / z) was performed on the terpene compounds to obtain the peak times and representative quantitative and qualitative ions of the terpene compounds, as shown in Table 1 below; a SIM method was established based on the peak times and qualitative and quantitative ions to obtain TIC chromatograms of 13 terpene compounds under the selected gas chromatography and mass spectrometry conditions, as shown in Table 1. Figure 1 shown.

[0045] Table 1 Retention time, quantitative ion and qualitative ion of terpenes determined by GC-MS

[0046]

[0047]

[0048] Selection of solid phase extraction columns

[0049] This application examines five types of solid-phase extraction (SPE) cartridges: Based on the polarity differences of the terpene compounds being studied, SPE cartridges of varying polarity were selected for investigation. The results showed that the non-polar C18 SPE cartridge achieved a 90% recovery rate for non-polar compounds such as ocimene, myrcene, and anethole; however, the recovery rate for polar compounds such as menthol, linalool, and geraniol was less than 70%. Polar SPE cartridges such as the HLB Welchrom BRP SPE cartridge, the Florisil SPE cartridge (1000mg, 6mL), and the NH2 SPE cartridge achieved recoveries ranging from 80% to 110% for polar compounds such as menthol, linalool, and geraniol, while the recovery rate for non-polar compounds such as ocimene was less than 50%. In this study, two solid-phase extraction columns with different polarities, C18 and Florisil, were selected to purify the samples using a series connection and separate elution method, achieving good recovery and stability, as shown in Table 4 below.

[0050] Gas Chromatography Column Selection

[0051] This study compared the two gas chromatography columns DB-5 and HP-5. The results showed that the DB-5 column had more advantages than the HP-5 column. The response of myrcene, ocimene, citral, geraniol, etc. increased by more than 20%. At the same time, it could effectively separate menthol and terpene-4-ol (such as Figure 1 shown).

[0052] Optimization of pretreatment conditions (activation, washing, elution)

[0053] In the process of optimizing the pre-treatment methods such as activation, washing and elution, this application successively used "methanol", "ethanol" and "ether-methanol (9:1)" instead of "ethyl acetate-methanol (9:1)", and used "cyclohexane", "n-hexane", "chloroform-acetone (9:1)" and "chloroform-ether (9:1)" instead of "cyclohexane-ethyl acetate (8:2)". The detection recovery rates of the obtained terpene compounds were all lower than those of the treatment method of 1.4; among them, the detection recovery rate of using "chloroform-methanol (8:2)" instead of "ethyl acetate-methanol (9:1)" was not significantly different, but considering that chloroform is more toxic than ethyl acetate, it is more reasonable to choose "ethyl acetate-methanol (9:1)".

[0054] Investigation of matrix effects

[0055] Matrix effect (ME) refers to the phenomenon in mass spectrometry analysis whereby the ionization of a target analyte is competed with other matrix components, resulting in either signal enhancement or suppression. This study used the relative response method to evaluate the matrix effect of samples based on the response of the target analyte measured in pure solvent (A) and the response of the same analyte measured in sample matrix (B), using the formula: matrix effect (%) = B / A × 100%. The results (Table 2) showed that the matrix ME (%) of 13 terpenes ranged from 60.22% to 124.93%. Only geraniol and trans-trans-farnesol exhibited an inhibitory effect, with ME (%) values ​​of 60.22% and 73.90%, respectively. The remaining eleven compounds exhibited strong enhancement effects, with ME (%) values ​​ranging from 109.25% to 124.93%.

[0056] Selection of internal standard substances

[0057] In order to reduce the influence of matrix effect on quantitative accuracy, this application compares the use of three substances, "cymene", "menthyl acetate" and "linalool-D3", as internal standards. The results show that "cymene", "menthyl acetate" and "linalool-D3" were not detected in 154 batches of sauce-flavor liquor samples. "Cymene" and "menthyl acetate" both had strong inhibitory effects in liquor samples. "Cymene" had an inhibitory effect similar to that of the 13 terpenes studied, with an ME / % of 115.43%, both of which showed an enhancement effect. However, "menthyl acetate" was different, showing a strong inhibitory effect of 44.01% ME / % (as shown in Table 2 below); "linalool-D3" had a poor response under the chromatographic conditions of 1.5, and its peak was not effectively separated from the target substance "myrcene", resulting in mutual interference; therefore, "cymene" as an internal standard has obvious advantages over "menthyl acetate" and "linalool-D3".

[0058] Table 2 Responses and matrix effects of 13 terpenes in pure solvents and matrices (concentration 100 μg / L)

[0059]

[0060]

[0061] Standard curve, detection limit and quantification limit

[0062] Accurately pipette 7 portions of 10.00 mL of blank simulated wine sample in parallel, add 100 μL and 200 μL of 0.1 mg / L mixed standard solution to two of them respectively, add 50 μL, 100 μL and 200 μL of 1 mg / L mixed standard solution to three of them respectively, add 100 μL and 200 μL of 10 mg / L mixed standard solution to two of them respectively, and then add 200 μL of 1 mg / L cymene standard solution to each portion and mix well. According to the pretreatment in 1.4, a series of accompanying matrix-matched standard working solutions with mass concentrations of 10 μg / L, 20 μg / L, 50 μg / L, 100 μg / L, 200 μg / L, 1000 μg / L and 2000 μg / L can be prepared. Determine under the chromatographic conditions in 1.5 and draw a standard curve using the internal standard method. As shown in Table 3 below, the results demonstrate good linear relationships between the 13 terpenoid compounds and their corresponding injected mass concentrations, with coefficients of determination (R²) all greater than 0.99 (see Table 3). At a standard solution concentration of 10 μg / L, the method limits of detection (LOD), determined by quantifying the ion pairs of the tested compounds at a signal-to-noise ratio (S / N) of 3 times, ranged from 0.05 to 7.14 μg / L, and the method limits of quantification (LOQ), determined by a signal-to-noise ratio (S / N) of 10 times, ranged from 0.16 to 23.81 μg / L.

[0063] Table 3 Linear range, correlation coefficient, signal-to-noise ratio, detection limit and quantification limit of 13 terpenes

[0064]

[0065]

[0066] Method precision and recovery

[0067] Spiked recoveries and relative standard deviations (RSDs) were measured in blank simulated liquor samples at spiking levels of 0.02 mg / L, 0.1 mg / L, and 1.0 mg / L, respectively. As shown in Table 4 below, the results show that the average recoveries of the 13 terpenes in liquor ranged from 81.0% to 104.8%, with relative standard deviations ranging from 4.28% to 9.26%. This demonstrates that the established method has excellent accuracy, precision, and reproducibility.

[0068] Table 4 Recovery rates and relative standard deviations of 13 terpenes at three spike levels in liquor (n=6)

[0069]

[0070]

[0071] 106 batches of representative Maotai-flavor liquor were purchased from home and on the market, as shown in Samples 105 and 106 in Table 5 below. Two batches of medicinal-flavor liquor were also selected for comparison. Following the sample pretreatment method and instrument chromatographic conditions proposed in this application, the test results are shown in Table 5. The test results indicate that, of the 13 terpenes studied, only myrcene was not detected in all samples, based on the detection rate. Five terpenes, including linalool, citral, geranyl acetate, geranylacetone, and trans-farnesol, had a detection rate of 100% in the Maotai-flavor liquor samples, followed by geraniol, trans-caryophyllene, and nerolidol, with detection rates exceeding 90%. The detection rate of anethole was relatively low, reaching only approximately 49%. While menthol and terpen-4-ol were detected, the detection rates were less than 10%. Among the terpenes examined, linalool was found to be the most abundant, followed by geranylacetone, trans-farnesol, geranyl acetate, geraniol, citral, and ocimene. Among samples containing anethole, over 95% of the samples tested contained less than 0.1 g / L, a level 10 times lower than that found in the medicinal-flavor liquor samples examined. This parameter is believed to be a key characteristic distinguishing Dong-flavor liquor from Maotai-flavor liquor. Furthermore, Dong-flavor liquors contained higher levels of geraniol, geranyl acetate, and trans-farnesol than Maotai-flavor liquors, while citral and nerolidol were lower. Significant differences in terpene content were observed between Maotai-flavor and Dong-flavor liquors. Within Maotai-flavor liquors, terpene content also varied between finished liquors produced using different processing methods, such as Kunsha, Fansha, and Suisha.

[0072] Table 5 Determination results of 13 terpenes in Maotai-flavor liquor samples

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079] In summary, this application uses SPE technology combined with gas chromatography-mass spectrometry to establish an analytical method that can simultaneously determine 13 terpene compounds with significantly different chemical properties in sauce-flavor liquor. This method screens the pretreatment methods and examines the matrix effect, thereby achieving the extraction, purification, concentration, rapid screening and confirmation of 13 terpene compounds in sauce-flavor liquor. The pretreatment operation of this method is simple, rapid, sensitive, accurate and stable, and can meet the needs of rapid qualitative and quantitative detection of 13 terpene compounds in liquor, and has achieved good results in the inspection and detection practice of terpene compounds in sauce-flavor liquor.

[0080] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as such modifications are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A method for simultaneously determining 13 terpene compounds in Maotai-flavor liquor, characterized in that: The following steps are involved: S1. Sample procurement: Purchase Maotai-flavor liquor from the market as standard samples; S2. Prepare the standard solution, which specifically includes the following steps: (1) Accurately weigh 10 mg of a Maotai-flavor liquor standard sample to the nearest 0.1 mg, dilute it with ethanol, and make up to 10 mL to obtain a 1000 mg / L single standard stock solution. Store at 2-8°C for later use. (2) Accurately pipette 1.0 mL of each individual standard stock solution into a 10 mL volumetric flask, dilute to volume with ethanol, and obtain a 100 mg / L mixed standard stock solution of 13 terpenes. Store at 2-8°C for future use. (3) Accurately pipette 1.0 mL of the 13 terpene mixed standard stock solutions into a 10 mL volumetric flask, dilute to volume with ethanol to obtain a 10 mg / L mixed standard intermediate solution, and store at 2-8 °C for future use; (4) Accurately pipette 1.0 mL of the 10 mg / L mixed standard stock solution of 13 terpenes into a 10 mL volumetric flask and dilute to volume with ethanol to obtain a 1.0 mg / L mixed standard intermediate solution, which is prepared and used immediately. (5) Accurately pipette 1.0 mL, 0.5 mL, and 0.2 mL of a 10 mg / L mixed standard stock solution of 13 terpenes into a 10 mL volumetric flask, respectively; Accurately pipette 1.0 mL, 0.5 mL, and 0.2 mL of a 10 mg / L mixed standard stock solution of 13 terpenes into a 10 mL volumetric flask, respectively; Add 0.2 mL of a 10 mg / L internal standard substance, cymene, and dilute to volume with ethanol to obtain a standard working curve with concentrations of 20 μg / L, 50 μg / L, 100 μg / L, 200 μg / L, 500 μg / L, and 1000 μg / L; S3. Sample pretreatment. The specific steps are as follows: 8 mL of ethyl acetate-methanol (with a ratio of ethyl acetate to methanol of 9:1) and 12 mL of cyclohexane-ethyl acetate (with a ratio of cyclohexane to ethyl acetate of 8:2) were used to wash and activate the C18 solid phase extraction column and the Florisil solid phase extraction column, respectively. After the activation, the C18 solid phase extraction column and the Florisil solid phase extraction column were connected in series, 10 mL of the liquor sample was transferred to the solid phase extraction column, 0.2 mL of the 10 mg / L internal standard substance cymene was added, and the sample was After the sample solution naturally passes through the packing layer, the serial solid-phase extraction cartridges are separated and then washed with 6 mL of ethyl acetate-methanol and 10 mL of cyclohexane-ethyl acetate to remove impurities, respectively. Then, the C18 solid-phase extraction cartridge and the Florisil solid-phase extraction cartridge are eluted with 10 mL of cyclohexane-ethyl acetate and 15 mL of ethyl acetate-methanol, respectively. The eluates are collected and combined, concentrated to near dryness with nitrogen blowdown at 40°C, and made up to volume with 1 mL of ethyl acetate. After vortex mixing, the eluate is passed through a 0.22 μm organic filter membrane and then analyzed by gas chromatography-mass spectrometry. S4, performing gas chromatography detection; S5. Perform mass spectrometry detection.

2. The method for simultaneously determining 13 terpene compounds in Maotai-flavor liquor according to claim 1, characterized in that: In step S4, the gas chromatography detection conditions are as follows: Quartz capillary column DB-5MS, 30m×250μm×0.25μm; carrier gas: He, purity ≥99.999%, flow rate 1.00mL / min; heating program: initial temperature is 50℃, hold for 1min, then increase the temperature to 90℃ at 3℃ / min, hold for 2min, then increase the temperature to 120℃ at 5℃ / min, hold for 5min, and finally increase the temperature to 220℃ at 12℃ / min, hold for 6min; splitless injection; injection volume: 1μL; injection port temperature: 250℃.

3. The method for simultaneously determining 13 terpene compounds in Maotai-flavor liquor according to claim 1, characterized in that: In step S5, the detection conditions for mass spectrometry detection are as follows: EI ion source temperature: 250 °C; ionization voltage: 70 eV, solvent delay: 5 min, transfer line temperature: 250 °C; full scan mode, mass scan range: m / z 30-450, reaction detection scan mode selected.

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