Method for detecting exogenous mineral oil in alcoholic products

Abstract

The application discloses a method for detecting exogenous mineral oil in wine products. The method comprises the following steps: mixing, oscillating, and separating a to-be-detected wine sample, water, and n-hexane according to a volume ratio of (5-15):(0-7.5):(2.5-7.5) to obtain an extraction liquid; eluting the extraction liquid through a solid-phase extraction column with a first eluent and a second eluent in sequence, collecting saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil eluent respectively, and concentrating to obtain a purified liquid; and detecting the purified liquid through gas chromatography-hydrogen flame ionization detector, and determining the content according to a standard curve. The method can realize accurate quantification of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil, has low detection cost, simple operation, small matrix interference, good separation effect, and is suitable for wine quality control and pollution screening.

Description

Technical Field

[0001] This application relates to the field of food testing technology, specifically to a method for detecting exogenous mineral oils in alcoholic beverages. Background Technology

[0002] Baijiu (Chinese liquor) has a long history and is mainly produced through fermentation, distillation, and blending. Its flavor and quality are composed of thousands of volatile and non-volatile components, among which hydrocarbons are an important part, covering terpenes, alkanes, and aromatic hydrocarbons. They not only contribute to flavor but also have safety research value. However, in the entire baijiu production chain, there may be a potential migration risk of exogenous hydrocarbon components—mineral oil. It mainly enters the liquor through three pathways: First, production equipment and packaging materials, such as non-food grade plastic pipes, gaskets, recycled paper packaging inks, and processing lubricants containing mineral oil, can migrate and contaminate under the action of ethanol solvents; second, during the distillation and storage stages, incomplete cleaning of distillation equipment may leave residual industrial oil stains, or ceramic jars and stainless steel tanks may adsorb small mineral oil molecules from the environment; third, raw materials and auxiliary materials may be introduced into the liquor through the environment, such as raw material storage in contact with transportation vehicles containing mineral oil, or the production environment being polluted by industrial waste gas and wastewater.

[0003] Mineral oils cover a wide range of carbon numbers and boiling ranges, containing tens of thousands of compounds with different structures. Their pollution levels are typically characterized by total amounts. Based on differences in chemical structure, mineral oils are mainly divided into two categories: saturated hydrocarbon mineral oils (MOSH) composed of alkanes and cycloalkanes, and highly alkylated aromatic hydrocarbon mineral oils (MOAH). Studies have shown that saturated hydrocarbon mineral oils are chemically stable and difficult to degrade, easily accumulating in the human body, producing microgranulomas, and inducing cellular dysfunction and other harmful effects; while some aromatic hydrocarbon mineral oils even possess genotoxic carcinogenicity and cytotoxicity, seriously threatening human health. Therefore, strengthening the monitoring of mineral oil contaminants in wine samples is of great significance.

[0004] Currently, methods for detecting mineral oil mainly include sensory analysis, fluorescence methods, saponification methods, secondary saponification methods, infrared spectroscopy, thin-layer chromatography, gas chromatography-flame ionization detector (GC-FID), high-performance liquid chromatography-gas chromatography (HPLC-GC-MS), and two-dimensional gas chromatography-time-of-flight mass spectrometry (GC-MS / MS). Sensory analysis, fluorescence methods, saponification methods, secondary saponification methods, infrared spectroscopy, and thin-layer chromatography are mostly used for qualitative detection, but they have low sensitivity and are easily affected by subjective factors, thus limiting their effectiveness in detecting mineral oil. HPLC-GC-MS and two-dimensional GC-MS / MS require highly skilled personnel and advanced equipment, and are relatively expensive, making them difficult to popularize. Patent document CN115078560A discloses a method for detecting mineral oil in wine or beverages using two-dimensional GC-MS / MS, but this method can only achieve qualitative detection of mineral oil in wine samples and cannot provide precise quantification. Furthermore, the instruments are expensive (each costing over three million yuan), making it difficult for ordinary laboratories to adopt. Although high performance liquid chromatography-gas chromatography is sensitive and accurate, the instruments are expensive (each unit costs more than 1.5 million yuan) and have limited applications, making it difficult to meet the needs of multi-functional research.

[0005] Therefore, developing rapid, low-cost, efficient, and accurate mineral oil detection methods is of great significance for liquor enterprises in terms of liquor tasting and quality control. Summary of the Invention

[0006] Therefore, it is necessary to provide a method for detecting exogenous mineral oils in alcoholic beverages.

[0007] The first aspect of this application provides a method for detecting exogenous mineral oil in alcoholic beverages, comprising the following steps:

[0008] The wine sample to be tested, water, and n-hexane were mixed in a volume ratio of (5~15):(0~7.5):(2.5~7.5), shaken, the organic phase was separated, concentrated, and the extract was prepared.

[0009] The extract was transferred to a solid-phase extraction column and eluted sequentially with a first eluent and a second eluent. Saturated hydrocarbon mineral oil eluent and aromatic hydrocarbon mineral oil eluent were collected and concentrated to prepare saturated hydrocarbon mineral oil purified solution and aromatic hydrocarbon mineral oil purified solution, respectively.

[0010] The saturated hydrocarbon mineral oil purification solution and the aromatic hydrocarbon mineral oil purification solution were detected by gas chromatography-flame ionization detector to obtain chromatograms;

[0011] The content of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil in the wine sample to be tested was determined based on the standard curves of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil.

[0012] In some embodiments, the wine sample to be tested includes at least one of finished wine, blended wine, and base wine; optionally, the alcohol content of the wine sample to be tested is 45 vol% to 55 vol.

[0013] In some embodiments, the oscillation conditions include an oscillation rate of 1500~2500 r / min and an oscillation time of 20~40 min.

[0014] In some embodiments, the separation of the organic phase is carried out by centrifugation followed by static separation, wherein the centrifugation rate is 4000~6000 r / min and the centrifugation time is 4~6 min; the static separation time is 5~15 min.

[0015] In some embodiments, the concentration is achieved by nitrogen blowing.

[0016] In some embodiments, the solid-phase extraction column comprises a silver nitrate silica gel column.

[0017] In some embodiments, the first eluent comprises n-hexane; optionally, the volume ratio of the first eluent to the extract is (8~12):1.

[0018] In some embodiments, the second eluent is a mixed solution comprising n-hexane and dichloromethane; optionally, the volume ratio of n-hexane to dichloromethane in the second eluent is (0.8~1.2):(0.8~1.2); the volume ratio of the second eluent to the extract is (6~10):1.

[0019] In some embodiments, the gas chromatographic conditions in the gas chromatography-flame ionization detector include:

[0020] Chromatographic column: weakly polar capillary column; injection volume: 1~10 μL; splitless injection; column flow rate: 1~2 mL / min; injection port temperature: 250~300 ℃; temperature program: initial temperature 45~55 ℃, hold for 1~3 min, increase to 280~320 ℃ at 10~20 ℃ / min, hold for 6~10 min;

[0021] Optionally, the gas chromatography conditions may also include the use of an inert liner.

[0022] In some embodiments, the flame ionization detection conditions in the gas chromatography-flame ionization detector include:

[0023] Detector temperature: 340~360 ℃; Post-running temperature: 280~320 ℃; Post-running time: 2~4 min; Hydrogen flow rate: 20~40 mL / min, air flow rate: 300~500 mL / min, nitrogen flow rate: 20~40 mL / min.

[0024] In some embodiments, before mixing the wine sample to be tested, water, and n-hexane, a mixed standard is added, which includes n-undecane, n-tetrazane, pentylbenzene, 2-methylnaphthalene, bicyclohexane, 1-methylnaphthalene, 1,3,5-tri-tert-butylbenzene, cholesterane, and perylene.

[0025] In some embodiments, the saturated hydrocarbon mineral oil standard curve and the aromatic hydrocarbon mineral oil standard curve are obtained by detecting mineral oil standards and polycyclic aromatic hydrocarbon standards, respectively, wherein the polycyclic aromatic hydrocarbon standards include naphthalene, acenaphthene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, α, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indo[1,2,3-cd]pyrene, dibenzo[a,h]anthracene, and benzo[g,h,i]pyrene.

[0026] The aforementioned detection method only requires a conventional gas chromatography-flame ionization detector to accurately quantify saturated hydrocarbon mineral oils and aromatic hydrocarbon mineral oils. It has low detection cost and is easy to operate. By optimizing extraction and fractional elution, matrix interference is effectively reduced and the two types of mineral oils are well separated. The results are stable and accurate, and it is suitable for quality control of alcoholic beverages and screening for mineral oil contamination. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments and examples of this application, and to more completely understand this application and its beneficial effects, the accompanying drawings used in the description of the embodiments or examples will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of this application. Those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0028] Figure 1 This is a standard curve of saturated hydrocarbon mineral oil in one embodiment of this application;

[0029] Figure 2 This is a standard curve of aromatic hydrocarbon mineral oil in one embodiment of this application;

[0030] Figure 3 This is a comparison diagram of a blank sample and a spiked sample (40 mg / L) of saturated hydrocarbon mineral oil in one embodiment of this application;

[0031] Figure 4 This is a comparison diagram of a blank sample and a spiked sample (2 mg / L) of saturated hydrocarbon mineral oil in one embodiment of this application;

[0032] Figure 5 This is a comparison diagram of the separation effects of different types of liner tubes in one embodiment of this application;

[0033] Figure 6 The n-hexane elution curve is shown in one embodiment of this application;

[0034] Figure 7 This is an example of a hexane / dichloromethane elution curve in one embodiment of this application. Detailed Implementation

[0035] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0038] In this application, terms such as "preferred," "better," "more suitable," and "ideal" are merely used to describe implementation methods or embodiments that achieve better results, and should be understood not to limit the scope of protection of this application.

[0039] The terms “having,” “containing,” “comprising,” and “including” as used in this application are synonyms and are inclusive or open-ended, not excluding additional, uncited members or features. Members or features include, for example, materials or components, structures, elements, instruments, etc.; non-limiting examples of members or features include actions, conditions under which actions occur, timing, states, etc.

[0040] In this application, the technical features or solutions described in open-ended language include both closed-ended technical features or solutions consisting of the listed contents and open-ended technical features or solutions that include the listed contents.

[0041] In this application, if the unit of a data range is only followed by the right endpoint, it means that the units of the left and right endpoints are the same.

[0042] In this application, where the method flow involves multiple steps, unless otherwise explicitly stated herein, there is no strict order restriction on the execution of these steps; they can be executed in any order other than those described. Moreover, any step may include multiple sub-steps or multiple stages, which are not necessarily completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be performed alternately or simultaneously with other steps or parts of the sub-steps or stages of other steps.

[0043] In this application, the exemplary descriptions such as "in some implementations (or embodiments)" and "in one implementation (or embodiment)" may cover, but are not limited to, the following meanings: these solutions can be combined with other solutions in a suitable manner to form new technical solutions.

[0044] In this application, the terms "first aspect," "second aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first aspect," "second aspect," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0045] In this application, when numerical intervals (i.e., numerical ranges) are mentioned, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include numerical interval types such as percentage intervals, ratio intervals, and proportion intervals.

[0046] In this application, the terms "room temperature" or "normal temperature" generally refer to 4°C to 35°C, for example, 20°C ± 5°C. In some embodiments of this application, "room temperature" or "normal temperature" refers to 10°C to 30°C. In some embodiments of this application, "room temperature" or "normal temperature" refers to 20°C to 30°C.

[0047] Currently, traditional mineral oil detection methods such as sensory analysis, fluorescence, saponification, secondary saponification, infrared spectroscopy, and thin-layer chromatography are mostly used for qualitative detection. They have low sensitivity and are easily affected by subjective factors, which limits their application in detecting mineral oil. High-performance liquid chromatography-gas chromatography and full two-dimensional gas chromatography-time-of-flight mass spectrometry require highly skilled personnel and advanced equipment, and are relatively expensive, making them difficult to popularize.

[0048] Based on this, the embodiments of this application at least provide a method for detecting exogenous mineral oils in alcoholic beverage products.

[0049] In a first aspect of this application, a method for detecting exogenous mineral oil in alcoholic beverages is provided, comprising the following steps:

[0050] S100: Mix the wine sample to be tested, water and n-hexane in a volume ratio of (5~15):(0~7.5):(2.5~7.5), shake, separate the organic phase, concentrate, and prepare the extract;

[0051] S200: The extract is transferred to a solid-phase extraction column and eluted sequentially with the first and second eluents. The saturated hydrocarbon mineral oil eluent and the aromatic hydrocarbon mineral oil eluent are collected and concentrated to prepare the saturated hydrocarbon mineral oil purified solution and the aromatic hydrocarbon mineral oil purified solution.

[0052] S300: The saturated hydrocarbon mineral oil purification solution and the aromatic hydrocarbon mineral oil purification solution were detected by gas chromatography-flame ionization detector to obtain chromatograms;

[0053] S400: Determine the content of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil in the wine sample to be tested based on the standard curves of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil.

[0054] In some embodiments, the wine sample to be tested includes at least one of finished wine, blended wine, and base wine. Further, the alcohol content of the wine sample to be tested is 45 vol% to 55 vol%.

[0055] In some embodiments, in step S100, the volume ratio of the wine sample to be tested, water, and n-hexane can be, but is not limited to, 5:0:2.5, 10:0:5, 15:0:7.5, 5:2.5:2.5, 10:5:5, 15:7.5:7.5, 5:7.5:2.5, 10:2.5:7.5, or any ratio or range between two of the above.

[0056] It should be noted that the wine sample already contains a certain amount of water, therefore the additional water volume added in step S100 can be zero. Since ethanol and water are miscible in wine, adjusting the amount of additional water added can change the polarity of the solvent system, thereby effectively controlling the partition coefficient of the target mineral oil between the hexane phase and the water-ethanol phase. If the proportion of water in the solvent system is too high, it may dilute the analyte and reduce extraction efficiency. As a non-polar extraction solvent, the amount of hexane used must balance extraction capacity and phase separation efficiency: too low a amount will not be sufficient to fully extract the mineral oil, resulting in a low recovery rate; too high a amount, while increasing extraction capacity, will increase the workload of subsequent concentration and may introduce more non-polar co-extractants, interfering with the purification effect.

[0057] In some embodiments, in step S100, the oscillation conditions include: an oscillation rate of 1500~2500 r / min and an oscillation time of 20~40 min. Non-limitingly, the oscillation rate can be, but is not limited to, 1500 r / min, 2000 r / min, or 2500 r / min; the oscillation time can be, but is not limited to, 20 min, 30 min, or 40 min.

[0058] It should be noted that the above-mentioned shaking conditions ensure sufficient contact between the wine sample and hexane, achieving efficient liquid-liquid extraction. Shaking too slowly or for too short a time will result in incomplete extraction, while shaking too slowly or for too long may cause emulsification, affecting subsequent phase separation.

[0059] In some embodiments, in step S100, the organic phase is separated by centrifugation followed by settling, wherein the centrifugation rate is 4000-6000 r / min, the centrifugation time is 4-6 min, and the settling time is 5-15 min. Non-limitingly, the centrifugation rate can be 4000 r / min, 5000 r / min, or 6000 r / min; the centrifugation time can be 4 min, 5 min, or 6 min; and the settling time can be 5 min, 10 min, or 15 min. It is understood that a clear organic phase can be obtained within the above-mentioned centrifugation and settling parameter range, which is beneficial to the stability of subsequent concentration and purification steps.

[0060] In some embodiments, in step S100, the concentration method is nitrogen blowing concentration.

[0061] In some embodiments, step S100, before mixing the wine sample, water, and n-hexane, further includes adding a mixed standard, which comprises 300 mg / L n-undecane, 150 mg / L n-tetrazane, 300 mg / L pentylbenzene, 300 mg / L 2-methylnaphthalene, 300 mg / L bicyclohexane, 300 mg / L 1-methylnaphthalene, 300 mg / L 1,3,5-tritert-butylbenzene, 600 mg / L cholesterane, and 600 mg / L perylene. It is understood that the mixed standard is primarily used for instrument performance and method evaluation.

[0062] In some embodiments, the solid-phase extraction column comprises a silver nitrate silica gel column. Further, the silver nitrate silica gel column is a 0.3% silver nitrate silica gel solid-phase extraction glass column.

[0063] In some embodiments, step S200 includes activation and equilibration with dichloromethane and n-hexane sequentially before elution.

[0064] In some embodiments, in step S200, the first eluent comprises n-hexane. Further, the volume ratio of the first eluent to the extract is (8~12):1. Non-limitingly, the volume ratio of the first eluent to the extract can be, but is not limited to, 8:1, 10:1, 12:1, or any ratio or range between two of the above.

[0065] It should be noted that controlling the volume ratio of the first eluent to the extract within the above-mentioned range ensures that the saturated hydrocarbon mineral oil is fully eluted while avoiding premature interference with the subsequent elution of aromatic hydrocarbon mineral oil. If the amount of the first eluent is too small, the saturated hydrocarbon mineral oil may not be completely eluted, resulting in a low recovery rate; if the amount of the first eluent is too large, some weakly polar aromatic hydrocarbon mineral oil may be eluted prematurely, causing cross-contamination between the two components.

[0066] In some embodiments, in step S200, the second eluent is a mixed solution comprising n-hexane and dichloromethane; further, the volume ratio of n-hexane to dichloromethane in the second eluent is (0.8~1.2):(0.8~1.2); the volume ratio of the second eluent to the extract is (6~10):1. Non-limitingly, the volume ratio of the second eluent to the extract can be, but is not limited to, 6:1, 8:1, 10:1, or any ratio or range between two of the above.

[0067] It should be noted that the amount of the second eluent directly affects the elution efficiency and separation purity of aromatic mineral oils. If the amount is too small, the aromatic mineral oils may not be completely eluted and remain on the solid-phase extraction column, resulting in a low recovery rate. If the amount is too large, although it can ensure complete elution, it may introduce more weakly retained impurities, increase matrix interference in subsequent detection, and cause solvent waste.

[0068] In some embodiments, in step S200, the concentration method is nitrogen blowing concentration.

[0069] In some embodiments, in step S300, the gas chromatographic conditions in the gas chromatography-flame ionization detector include:

[0070] Chromatographic column: weakly polar capillary column; injection volume: 1~10 μL; splitless injection; column flow rate: 1~2 mL / min; injection port temperature: 250~300 ℃; temperature program: initial temperature 45~55 ℃, hold for 1~3 min, increase to 280~320 ℃ at 10~20 ℃ / min, hold for 6~10 min.

[0071] In some embodiments, the gas chromatography conditions also include the use of an inert liner. Further, the inert liner is an ultra-high inert liner.

[0072] It should be noted that, compared with the traditional gas chromatography-flame ionization detector method, the gas chromatography conditions used in this application have the following advantages: the use of an ultra-high inert liner can effectively reduce the number of impurity peaks; the injection volume is larger, which is conducive to lowering the detection limit; and the overall detection time is shorter, which improves the analytical efficiency.

[0073] In some embodiments, in step S300, the flame ionization detection conditions in the gas chromatography-flame ionization detector include:

[0074] Detector temperature: 340~360 ℃; Post-running temperature: 280~320 ℃; Post-running time: 2~4 min; Hydrogen flow rate: 20~40 mL / min, air flow rate: 300~500 mL / min, nitrogen flow rate: 20~40 mL / min.

[0075] In some embodiments, in step S400, the saturated hydrocarbon mineral oil standard curve and the aromatic hydrocarbon mineral oil standard curve are obtained by detecting mineral oil standards and polycyclic aromatic hydrocarbon standards, respectively. The polycyclic aromatic hydrocarbon standards include naphthalene, acenaphthene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, α, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indo[1,2,3-cd]pyrene, dibenzo[a,h]anthracene, and benzo[g,h,i]pyrene.

[0076] In some embodiments, in step S400, the hump areas obtained from the mineral oil and polycyclic aromatic hydrocarbon standards are used as the ordinates, and the mass concentrations of the mineral oil and polycyclic aromatic hydrocarbon standards are used as the abscissas, respectively, and linear regression is performed to obtain the standard curves for mineral oil and polycyclic aromatic hydrocarbons.

[0077] In some implementations, in step S400, the saturated hydrocarbon mineral oil content in the wine sample to be tested is calculated using a mineral oil standard curve, and the aromatic hydrocarbon mineral oil content is calculated using a polycyclic aromatic hydrocarbon standard curve. In both calculations, the peak area of ​​the blank sample needs to be deducted.

[0078] In some embodiments, a method for detecting exogenous hydrocarbon components in alcoholic beverage products is provided, comprising the following steps:

[0079] Step 1, Extraction: Add 10-30 μL of mixed standard to a 50 mL glass test tube, then add the wine sample to be tested and ultrapure water, extract with n-hexane, shake, centrifuge, and allow to stand for separation; take the upper n-hexane solution into a nitrogen blow-off tube, concentrate with nitrogen to 0.5 mL, and make up to 1 mL with n-hexane to obtain the extract.

[0080] Step 2, purification and elution: The extract obtained in Step 1 is transferred to a solid-phase extraction column for purification. Different eluents are used to elute in sequence, and saturated hydrocarbon mineral oil eluent and aromatic hydrocarbon mineral oil eluent are collected. The eluent is concentrated to less than 0.1 mL by nitrogen blowing, and then diluted to 1 mL with n-hexane to obtain the purified solution.

[0081] Step 3, Detection: The purified solution obtained in Step 2 is introduced into a gas chromatograph-flame ionization detector via liquid injection. After separation by the chromatographic column, chromatograms of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil are obtained.

[0082] Step 4, Quantitative Analysis: Substitute the peak areas of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil obtained in Step 3 into the standard curves of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil, respectively, and calculate the content of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil in the sample.

[0083] It should be noted that by adopting the above technical solution, quantitative analysis of saturated hydrocarbon mineral oils and aromatic hydrocarbon minerals in wine samples can be achieved, with advantages such as low detection cost, strong applicability, ease of operation, high efficiency and accuracy. Addressing the difficulties encountered in the quantitative detection of mineral oils in wine using GC-FID, such as complex matrix interference, irregular continuous broad peaks of the target analyte leading to difficult integral calculations, and the difficulty in effectively separating the two types of mineral oils, this application overcomes these difficulties through the following methods: 1. Improving the extraction efficiency of mineral oils by optimizing the solvent system ratio, followed by solid-phase extraction to remove impurities and reduce interference. 2. Since the mineral oil chromatographic peaks are continuous broad peaks, the total peak area is calculated by summing the peak areas; the final result is calculated by subtracting the peak area of ​​a blank sample under the same conditions and then substituting it into the standard curve. 3. Optimizing the volume of elution solutions of different polarities and performing segmented elution to achieve effective separation of saturated hydrocarbon mineral oils and aromatic hydrocarbon mineral oils.

[0084] The detection method provided above includes at least one of the following beneficial technical effects:

[0085] (1) Low detection cost: Through the above extraction, purification and concentration methods, the quantitative analysis of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil in wine samples can be completed without relying on expensive special equipment. Almost all analytical laboratories can carry out the analysis directly, which significantly reduces the detection cost.

[0086] (2) The results are stable and accurate. The wine samples to be tested and the standard curve working solution are purified, eluted, concentrated and reconstituted by solid phase extraction column, which ensures the consistency of the processing conditions, reduces the influence of matrix effect and improves the stability and accuracy of the detection results.

[0087] (3) It has strong applicability and high popularity. It is easy to operate and can complete the quantitative analysis of saturated hydrocarbons and aromatic hydrocarbon mineral oils in wine samples in ordinary laboratories. It has strong applicability and high popularity, and is suitable for wineries to carry out mineral oil screening work in wine samples, providing technical support for the quality control of baijiu.

[0088] In a second aspect of this application, a quality control method for alcoholic beverages is provided, comprising detecting mineral oil in alcoholic beverages using the aforementioned method.

[0089] In some embodiments, the quality control method includes using the above-mentioned detection method to detect the content of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil in the alcoholic beverage product to be tested, and judging whether the alcoholic beverage product is qualified based on the test results.

[0090] It should be noted that the matrix in the tested alcoholic beverages is extremely complex. In addition to the main components ethanol and water, alcoholic beverage samples usually contain a variety of natural fermentation products and flavor substances. These components may co-extract with the target mineral oil during the extraction and purification process, resulting in chromatographic interference. Therefore, the method provided in this application effectively reduces matrix interference and achieves accurate quantification of mineral oil by optimizing the extraction solvent ratio, using solid-phase extraction segmented elution and inert liner techniques.

[0091] The following are some examples.

[0092] The embodiments of this application will be described in detail below with reference to examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of this application. For experimental methods in the following embodiments where conditions are not specified, reference should be made to the guidelines given in this application, or to experimental manuals or conventional conditions in the art, or to the conditions recommended by the manufacturer, or to experimental methods known in the art.

[0093] In the following examples, the measurement parameters of the raw material components may have slight deviations within the weighing accuracy range unless otherwise specified. Temperature and time parameters are subject to acceptable deviations due to instrument testing accuracy or operational precision.

[0094] Example 1

[0095] The instruments, equipment, standard samples, reagents, and consumables used in this embodiment are as follows:

[0096] Instruments: 8890GC gas chromatograph with flame ionization detector, Agilent Technologies, USA; fully automated parallel concentrator, Beijing Ruike Company; multi-functional mixer, Heidolph, Germany; ultrapure water system, Aquaplore, USA; refrigerated centrifuge, Eppendorf, Germany; electronic balance, Ohaus, USA.

[0097] Standards: Polycyclic aromatic hydrocarbon standards (2000 μg / mL, product number 110061-02, O2SI, USA); mixed standards (150~600 mg / L, product number CDAA-M-690172, Shanghai Anpu Company); n-alkanes (C7~C40 mixed standard solution, 1000 mg / L, product number 110219-06, O2SI, USA); mineral oil (high purity standard, CAS8042-47-5, purity 99.8%, Shanghai Anpu Company).

[0098] Reagents and consumables: anhydrous sodium sulfate (analytical grade, Sinopharm Group); n-hexane (chromatographic grade, Shanghai Anpu); dichloromethane (chromatographic grade, Shanghai Anpu); 0.3% silver nitrate silica gel solid phase extraction glass column (3 g, 6 mL, Shanghai Anpu).

[0099] This embodiment provides a method for quantitatively analyzing saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil in baijiu (Chinese liquor), comprising the following steps:

[0100] Step 1, Extraction: Add 20 μL of mixed standard to each of the 50 mL glass test tubes, then add 10 mL of the wine sample to be tested, 5 mL of ultrapure water and 5 mL of n-hexane. Extract by shaking at 2000 r / min for 30 min, centrifuge at 5000 r / min for 5 min, and let stand for 10 min to allow the layers to separate. Take the upper n-hexane solution into a nitrogen blow-off tube and concentrate it with nitrogen until the liquid volume is less than 0.5 mL. Make up the volume to 1 mL with n-hexane to obtain the extract.

[0101] Step 2, Purification and Elution: Take a 0.3% silver nitrate silica gel solid-phase extraction glass column and activate and equilibrate it with 15 mL of dichloromethane and 15 mL of n-hexane, respectively. After completion, transfer 1 mL of the extract to the 0.3% silver nitrate silica gel solid-phase extraction glass column, elute with 10 mL of n-hexane, and collect the saturated hydrocarbon mineral oil eluent; continue eluting with 8 mL of a 1:1 (v / v) hexane / dichloromethane solution, and collect the aromatic hydrocarbon mineral oil eluent. Concentrate the eluent under nitrogen until the liquid volume is less than 0.1 mL, and then make up to 1 mL with n-hexane to obtain purified saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil solutions.

[0102] Step 3, Detection: The purified solutions of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil were injected into a gas chromatograph-flame ionization detector via liquid injection for analysis and detection. The hump areas of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil were obtained by summing and integrating the areas of the chromatograms. The gas chromatography conditions were as follows: column: CD-5 HT capillary column (30m × 0.25 mm × 0.1 μm); injection volume: 5 μL; splitless injection; column flow rate: 2 mL / min; liner: Agilent 5190-2293 ultra-high inert liner; injection port temperature: 280 ℃; temperature program: initial temperature 50 ℃, hold for 2 min, increase to 300 ℃ at 15 ℃ / min, hold for 8 min; flame ionization detector temperature: 350 ℃; post-run temperature: 300 ℃; post-run time: 2 min; hydrogen flow rate: 30 mL / min, air flow rate: 400 mL / min, nitrogen flow rate: 30 mL / min.

[0103] Step 4, Quantitative Analysis: Using n-hexane, mineral oil standards were prepared into working solutions with mass concentrations of 1.85 mg / L, 3.70 mg / L, 9.25 mg / L, 18.50 mg / L, 37.00 mg / L, and 74.00 mg / L, respectively. Each solution was purified and eluted using a 0.3% silver nitrate silica gel solid-phase extraction glass column, concentrated to less than 0.1 mL by nitrogen blowing, and then brought to a final volume of 1 mL with n-hexane to obtain the processed saturated hydrocarbon mineral oil standard curve working solutions.

[0104] The polycyclic aromatic hydrocarbon standard solution was diluted with n-hexane to prepare 1 mL of each polycyclic aromatic hydrocarbon standard curve working solution with mass concentrations of 1.00 mg / L, 2.00 mg / L, 4.00 mg / L, 8.00 mg / L, 16.00 mg / L, and 20.00 mg / L. The solutions were purified and eluted using a glass column for solid-phase extraction with 0.3% silver nitrate silica gel, concentrated with nitrogen blowing to less than 0.1 mL, and then brought to a final volume of 1 mL with n-hexane to obtain the treated aromatic hydrocarbon mineral oil standard curve working solutions.

[0105] The processed standard curve working solutions of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil were injected into a gas chromatograph-flame ionization detector for analysis. Standard curves were plotted with the hump area of ​​the obtained standard substances as the ordinate and the mass concentration as the abscissa. The standard curve for saturated hydrocarbon mineral oil is shown below. Figure 1 As shown, the standard curve for aromatic hydrocarbon mineral oils is as follows: Figure 2 As shown in Table 1, the standard curve information is as follows.

[0106] Because the chromatogram of mineral oil on a gas chromatograph with a flame ionization detector (FIDD) consists of a peak composed of tens of thousands of compounds, this peak must be at a certain height above the baseline for accurate integration and to meet the uncertainty requirements of analytical detection. Therefore, the limit of quantitation (LOQ) for mineral oil analysis methods is usually calculated empirically. According to the guidelines of the Joint Research Centre of the European Commission (JCR), at least 50–100 ng of mineral oil is required to enter the FIDD for accurate quantification. Using 50 ng of mineral oil entering the detector, the LQ of the method in Example 1 is 1.0 mg / L. If a lower LQ is required, the sample size or concentration factor needs to be increased. Table 1 shows that the method has good linearity and a relatively low limit of detection.

[0107] Table 1. Information related to the mineral oil standard curve

[0108]

[0109] The hump areas of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil in the sample to be tested were subtracted from the hump area of ​​the blank control sample, and then substituted into the above standard curve to calculate the content of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil in the sample to be tested.

[0110] According to this embodiment, the saturated hydrocarbon mineral oil content in the liquor sample to be tested is calculated using the following formula:

[0111]

[0112] In the formula,

[0113] X b The value represents the saturated hydrocarbon mineral oil content in the liquor sample to be tested, in mg / L.

[0114] C b The content of saturated hydrocarbon mineral oil in the test solution is calculated based on the standard curve, and the unit is mg / L.

[0115] V b This is the final volume of the test solution, in mL;

[0116] V represents the sample volume of the liquor to be tested, in mL.

[0117] According to this embodiment, the aromatic hydrocarbon mineral oil content in the liquor sample to be tested is calculated using the following formula:

[0118]

[0119] In the formula,

[0120] X f The content of aromatic hydrocarbon mineral oil in the liquor sample to be tested is expressed in mg / L.

[0121] C f The content of aromatic hydrocarbon mineral oil in the test solution is calculated based on the standard curve, and the unit is mg / L;

[0122] V f This is the final volume of the test solution, in mL;

[0123] V represents the sample volume of the liquor to be tested, in mL.

[0124] According to Example 1, a spiked recovery test was conducted on saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil using a blank wine sample. The comparison diagram of the blank control sample and the spiked sample for saturated hydrocarbon mineral oil is shown below. Figure 3 As shown in the figure, the comparison between the blank control sample and the spiked sample of aromatic hydrocarbon mineral oil is as follows. Figure 4 As shown in Table 2, the recoveries at each spike level are as follows. The results indicate that the recoveries of saturated hydrocarbon mineral oil spikes range from 83.19% to 93.98%, and the recoveries of aromatic hydrocarbon mineral oil spikes range from 95.30% to 110.22%. This method is simple to operate and provides accurate results, and can be used for the quantitative detection of saturated hydrocarbon mineral oils and aromatic hydrocarbon mineral oils in wine samples.

[0125] Table 2 Spiking Recovery Rates of Saturated Hydrocarbon Mineral Oils and Aromatic Hydrocarbon Mineral Oils

[0126]

[0127] Comparative Example 1: Investigating the Influence of Different Types of Liners on Mineral Oil Separation

[0128] This comparative study investigated the effect of different types of liner on the separation of mineral oil. The difference from Example 1 was that an Agilent 5183-4647 ordinary liner was used, while the other experimental conditions were the same as in Example 1. The results showed that the ordinary liner produced more impurity peaks (such as...) in the separation chromatogram. Figure 5 As shown in the figure, the hump integral area and quantitative results are affected; while the ultra-inert liner separation chromatogram has fewer impurity peaks and better separation effect, which may be because the ultra-inert liner can reduce the adsorption and decomposition of the sample.

[0129] Comparative Example 2: Investigating the effect of different extraction methods on the extraction efficiency of mineral oil in wine samples.

[0130] This comparative study investigated the effects of different extraction methods on the extraction efficiency of mineral oils in wine samples. The difference from Example 1 was that ultrasonic extraction was performed at 280 W for 30 min, while the other experimental conditions remained the same as in Example 1. Saturated hydrocarbon mineral oils were expressed as cholesteric peak areas, and saturated hydrocarbon mineral oils were expressed as perylene peak areas. The results are shown in Table 3. The results indicate that Example 1 achieved extraction efficiencies of 15.13% and 20.14% higher for saturated hydrocarbon mineral oils and aromatic hydrocarbon mineral oils in wine samples than ultrasonic extraction, respectively, demonstrating the superior extraction effect of Example 1.

[0131] Table 3. Extraction efficiency of mineral oil by different extraction methods

[0132]

[0133] Comparative Example 3: Investigating the effect of different extraction times on the extraction efficiency of mineral oil in wine samples.

[0134] This comparative study investigated the effect of different extraction times on the extraction efficiency of mineral oil in wine samples. The difference from Example 1 was that the shaking extraction times were set to 10 min, 20 min, 40 min, and 50 min, respectively, while the other experimental conditions remained the same as in Example 1. Saturated hydrocarbon mineral oil was expressed as the peak area of ​​cholesterane, and saturated hydrocarbon mineral oil was expressed as the peak area of ​​perylene. The results are shown in Table 4. The results showed that when the extraction times were 10 min, 20 min, 40 min, and 50 min, the extraction efficiency of saturated hydrocarbon mineral oil in the wine samples decreased by 26.25%, 8.59%, 6.51%, and 9.08% compared to Example 1, respectively, and the extraction efficiency of aromatic hydrocarbon mineral oil decreased by 28.94%, 9.00%, 13.65%, and 10.35% compared to Example 1, respectively. The extraction effects of the comparative study were all worse than those of the examples.

[0135] Table 4. Effects of different extraction times on the extraction efficiency of mineral oil

[0136]

[0137] Comparative Example 4: Investigating the effect of different solvent ratios on the extraction efficiency of mineral oil in wine samples.

[0138] To improve the extraction efficiency of mineral oil in liquor samples, the ratio of the water-ethanol-n-hexane solvent system needs to be optimized. The alcohol content of most Chinese baijiu is around 50% vol, so the volume ratio of ethanol to water can be approximated as 1:1, meaning 5 mL of water and 5 mL of ethanol per 10 mL of baijiu. This comparative example investigated the effect of different water-ethanol-n-hexane solvent ratios on the extraction efficiency of mineral oil in liquor samples. The difference from Example 1 is that the volume of water added during extraction was 0 mL, 10 mL, and 15 mL, resulting in water-ethanol-n-hexane solvent system ratios of 1:1:1, 3:1:1, and 4:1:1, respectively. Other experimental conditions were the same as in Example 1 (water-ethanol-n-hexane solvent system ratio of 2:1:1). Saturated hydrocarbon mineral oil is expressed as the cholesterane peak area, and saturated hydrocarbon mineral oil is expressed as the perylene peak area. The results are shown in Table 5. The results showed that when the water-ethanol-n-hexane solvent system ratios were 1:1:1, 3:1:1, and 4:1:1, the extraction efficiency of saturated hydrocarbon mineral oil in the wine samples decreased by 13.85%, 20.15%, and 16.53% respectively compared to Example 1, and the extraction efficiency of aromatic hydrocarbon mineral oil decreased by 6.36%, 13.06%, and 5.72% respectively compared to Example 1. The mineral oil extraction effect in the comparative examples was worse than that in the examples.

[0139] Table 5. Effects of different solvent system ratios on the extraction efficiency of mineral oil

[0140]

[0141] Comparative Example 5: Investigating the effect of n-hexane elution volume on the separation and purification effect of saturated hydrocarbon mineral oil.

[0142] Wine samples contain complex components such as acids, esters, alcohols, aldehydes, and ketones. Direct extraction with n-hexane introduces these complex components, affecting the accurate quantification of mineral oils. Solid-phase extraction (SPE) not only removes impurities but also separates saturated hydrocarbon mineral oils from aromatic hydrocarbon mineral oils, improving the accuracy of quantitative results. Based on the principle of "like dissolves like," using weakly polar n-hexane to elute non-polar saturated hydrocarbon mineral oils easily desorbs them from the stationary phase surface, achieving effective separation. The n-hexane elution volume needs to ensure complete elution of saturated hydrocarbon mineral oils while avoiding solvent waste. This comparative example uses mixed standards to investigate the effect of different n-hexane elution volumes on the separation and purification of saturated hydrocarbon mineral oils. Hexane elution volumes were 2 mL, 4 mL, 6 mL, 8 mL, 10 mL, and 12 mL. The eluent was continuously collected, with each 2 mL fraction representing a separate component. The separation and purification effect was evaluated after analysis (e.g., [missing information]). Figure 6(As shown in the figure). The results showed that as the hexane elution volume gradually increased, the four saturated hydrocarbon mineral oil standards were gradually eluted and their contents gradually decreased. When the hexane elution volume was 10 mL, the contents of the four saturated hydrocarbon mineral oils were reduced to a low level, and small amounts of aromatic hydrocarbon mineral oils pentylbenzene and 1,3,5-tri-tert-butylbenzene were eluted. At this point, the separation effect of saturated hydrocarbon mineral oils and aromatic hydrocarbon mineral oils was the best. When the hexane elution volume was further increased, saturated hydrocarbon mineral oils were not detected, but high contents of aromatic hydrocarbon mineral oils pentylbenzene and 1,3,5-tri-tert-butylbenzene were eluted. Therefore, when the hexane elution volume was 10 mL, the separation and purification effect of saturated hydrocarbon mineral oils was the best.

[0143] Comparative Example 6: Investigating the effect of hexane / dichloromethane elution volume on the separation and purification of aromatic hydrocarbon mineral oils.

[0144] Utilizing the principle of "like dissolves like," a moderately polar hexane / dichloromethane solution was used to elute weakly polar aromatic mineral oils. This comparative study investigated the effect of different volumes of hexane / dichloromethane eluent on the separation and purification of aromatic mineral oils. After saturated aromatic mineral oils were eluted with 10 mL of hexane, the hexane / dichloromethane eluent volume was gradually increased from 2 mL to 12 mL, with each 2 mL interval used to collect an aromatic mineral oil eluent fraction. The separation and purification effect of each fraction was evaluated after analysis (e.g., [missing information]). Figure 7 (As shown in the figure). The results showed that as the hexane / dichloromethane elution volume increased, the aromatic hydrocarbon mineral oil standards were eluted sequentially and their contents gradually decreased. When the hexane / dichloromethane elution volume was 8 mL, the contents of each aromatic hydrocarbon mineral oil standard in the fraction were already low. When the hexane / dichloromethane elution volume was further increased to 10 mL, the contents of each aromatic hydrocarbon mineral oil standard were not detected in the fraction. Therefore, the separation and purification effect of aromatic hydrocarbon mineral oil was best when the hexane / dichloromethane elution volume was 8 mL.

[0145] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0146] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for detecting exogenous mineral oil in alcoholic beverages, characterized in that, It includes the following steps: The wine sample to be tested, water, and n-hexane were mixed in a volume ratio of (5~15):(0~7.5):(2.5~7.5), shaken, the organic phase was separated, concentrated, and the extract was prepared. The extract was transferred to a solid-phase extraction column and eluted sequentially with a first eluent and a second eluent. Saturated hydrocarbon mineral oil eluent and aromatic hydrocarbon mineral oil eluent were collected and concentrated to prepare saturated hydrocarbon mineral oil purified solution and aromatic hydrocarbon mineral oil purified solution, respectively. The purified solutions of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil were detected by gas chromatography-flame ionization detector to obtain chromatograms. The content of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil in the wine sample to be tested was determined based on the standard curves of saturated hydrocarbon mineral oil and aromatic hydrocarbon mineral oil.

2. The detection method as described in claim 1, characterized in that, The wine sample to be tested includes at least one of finished wine, blended wine, and base wine; optionally, the alcohol content of the wine sample to be tested is 45 vol% to 55 vol.

3. The detection method as described in claim 2, characterized in that, One or more of the following conditions must be met: The conditions for the oscillation include: an oscillation rate of 1500~2500 r / min and an oscillation time of 20~40 min; The method for separating the organic phase is centrifugation followed by static stratification, wherein the centrifugation rate is 4000~6000 r / min, the centrifugation time is 4~6 min, and the static stratification time is 5~15 min; The concentration method is nitrogen blowing concentration.

4. The detection method as described in claim 1, characterized in that, The solid-phase extraction column includes a silver nitrate silica gel column.

5. The detection method as described in claim 1, characterized in that, The first eluent includes n-hexane; optionally, the volume ratio of the first eluent to the extract is (8~12):

1.

6. The detection method as described in claim 1, characterized in that, The second eluent is a mixed solution comprising n-hexane and dichloromethane; optionally, the volume ratio of n-hexane to dichloromethane in the second eluent is (0.8~1.2):(0.8~1.2); the volume ratio of the second eluent to the extract is (6~10):

1.

7. The detection method according to any one of claims 1 to 6, characterized in that, The gas chromatographic conditions in the gas chromatography-flame ionization detector include: Chromatographic column: weakly polar capillary column; injection volume: 1~10 μL; splitless injection; column flow rate: 1~2 mL / min; injection port temperature: 250~300 ℃; temperature program: initial temperature 45~55 ℃, hold for 1~3 min, increase to 280~320 ℃ at 10~20 ℃ / min, hold for 6~10 min; Optionally, the gas chromatography conditions may also include the use of an inert liner.

8. The detection method as described in claim 7, characterized in that, The flame ionization detection conditions in the gas chromatography-flame ionization detector include: Detector temperature: 340~360 ℃; Post-running temperature: 280~320 ℃; Post-running time: 2~4 min; Hydrogen flow rate: 20~40 mL / min, air flow rate: 300~500 mL / min, nitrogen flow rate: 20~40 mL / min.

9. The detection method according to any one of claims 1 to 6, characterized in that, Before mixing the wine sample to be tested, water, and n-hexane, a mixed standard is added, which includes n-undecane, n-tetrazane, pentylbenzene, 2-methylnaphthalene, bicyclohexane, 1-methylnaphthalene, 1,3,5-tri-tert-butylbenzene, cholesterane, and perylene.

10. The detection method according to any one of claims 1 to 6, characterized in that, The saturated hydrocarbon mineral oil standard curve and the aromatic hydrocarbon mineral oil standard curve were obtained by detecting mineral oil standards and polycyclic aromatic hydrocarbon standards, respectively. The polycyclic aromatic hydrocarbon standards included naphthalene, acenaphthene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, α, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indo[1,2,3-cd]pyrene, dibenzo[a,h]anthracene, and benzo[g,h,i]pyrene.

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