Multi-substance detection method for content of water wine sample

Abstract

The invention relates to the technical field of detection, and discloses a multi-substance detection method for the content of a water wine sample, which comprises the following steps: (1) preparing a standard solution; (2) preparing a test solution; (3) detecting; the multi-substance detection method for the content of the water wine sample, provided by the invention, has the characteristic of enriching the types of detection substances, and a standard solution system covers as many as 30 substances and comprehensively covers various components such as organic acids, alcohols, saccharides and the like. The traditional water and wine detection technology can only detect a small number of common components and is difficult to comprehensively analyze a complex component system in water and wine, however, the method greatly expands the detection range and can accurately measure multiple key components in the water and wine at the same time. Therefore, the components of the water wine can be comprehensively and deeply understood, and the quality, flavor and nutritional value of the water wine can be accurately evaluated.

Description

Technical Field

[0001] The present invention relates to the technical field of detection, and specifically to a multi-substance detection method for the content of water and alcohol samples. Background Art

[0002] Water and alcohol, as a beverage with a long history and rich cultural connotations, occupies an important position in people's daily life and social activities.

[0003] For the detection of water and alcohol samples, from the perspective of quality control, the quality of water and alcohol is affected by various factors, including the quality of raw materials, differences in brewing processes, and storage conditions. By detecting various components in water and alcohol, its quality can be accurately evaluated. For example, the content and proportion of organic acids, alcohols, sugars, etc. will directly affect the taste, aroma, and flavor of water and alcohol. Detecting these components can help brewing enterprises adjust the brewing process, ensure the consistency and stability of products, and produce high-quality water and alcohol that meet the taste requirements of consumers.

[0004] In terms of food safety, certain components in water and alcohol may pose potential hazards to human health. For example, some harmful microorganisms, heavy metals, and excessive additives, if not detected and controlled, may cause health problems for consumers. By comprehensively detecting water and alcohol, these safety hazards can be discovered and eliminated in a timely manner, ensuring the physical health of consumers. In addition, with the continuous improvement of people's pursuit of health and quality of life, detecting the nutritional components of water and alcohol has become increasingly important, which helps consumers understand the nutritional value of water and alcohol and make more healthy consumption choices.

[0005] Although the detection of water and alcohol is of great significance, the current detection technology still has some limitations. One of the main problems is that the existing detection technology can only detect a small number of substances.

[0006] Currently, most commonly used water and alcohol detection methods mainly focus on the detection of some common components, such as alcohol content, total acid, total ester, etc. Although these detection methods can provide some basic quality information, they are far from comprehensive for the complex component system in water and alcohol.

[0007] In summary, the existing water and alcohol detection technology can no longer meet the needs of the current development of the water and alcohol industry. Developing a method that can comprehensively and accurately detect various components in water and alcohol is of great significance, which can not only improve the quality control level and food safety guarantee ability of water and alcohol, but also provide strong support for the technological innovation and sustainable development of the water and alcohol industry. Summary of the Invention

[0008] In view of the problems in the prior art, the present invention provides a multi-substance detection method for the content of water and alcohol samples.

[0009] The technical solution adopted by the present invention to solve its technical problems is: a multi-substance detection method for the content of water and wine samples, including the following steps:

[0010] (1) Preparation of standard solutions:

[0011] 30 standard solutions cover various components such as organic acids, alcohols, sugars, etc.; appropriate amounts of 30 standard solutions are accurately pipetted respectively. For the remaining reference substances except acetic acid and caprylic acid, anhydrous ethanol is added to make a solution containing 50 mg per 1 ml; acetic acid is added to anhydrous ethanol to make a solution containing 400 mg per 1 mL; caprylic acid is added to anhydrous ethanol to make a solution containing 100 mg per 1 mL, thereby obtaining the stock solutions of each reference substance.

[0012] Appropriate amounts of the stock solutions of each reference substance are accurately pipetted respectively and placed in the same volumetric flask, and diluted with anhydrous ethanol to prepare a standard series working solution. Among them, the concentrations of acetic acid are 40, 80, 160, 400, 800, 1600, 4000 mg / L respectively, the concentrations of caprylic acid are 10, 20, 40, 100, 200, 400, 1000 mg / L respectively, and the concentrations of the remaining reference substances are 5, 10, 20, 50, 100, 200, 500 mg / L respectively; the linear range of the standard curve is acetic acid 0.4 - 40 mg / L, caprylic acid 0.1 - 10 mg / L.

[0013] The standard series working solution is stored at -18°C for standby, and the concentration change rate of the standard solution within 3 months under the storage condition of -18°C ≤ 5%.

[0014] (2) Preparation of test solution:

[0015] For the turbid water and wine samples, first perform filtration treatment. Use a 0.45 μm nylon filter membrane to replace the conventional filter membrane to reduce the loss caused by the adsorption of organic solvents, and take 5.00 ml of the filtrate.

[0016] Anhydrous ethanol is added to the filtrate, and it is accurately diluted to 10.00 ml and stored at 0 - 10°C.

[0017] (3) Detection: The prepared standard series working solution and test solution are respectively injected into the liquid chromatograph for injection detection. According to the detection results of the standard series working solution, a standard curve is drawn, and then the components in the test solution are quantitatively analyzed according to the standard curve. Optimize the FID parameters to make the detection limit reach below 0.1 mg / L.

[0018] As a further technical solution, the chromatographic conditions of the liquid chromatograph are set as:

[0019] Use a chromatographic column of Zafex ZFQ2119 60 m * 0.32 mm * 1.0 μm;

[0020] Detection is carried out using a flame ionization detector (FID).

[0021] Programmed temperature rise: The initial temperature is set to 50 - 55 °C and held for 8 min. Then, it is raised to 160 - 165 °C at a rate of 5 - 6 °C / min and held for 1 min. Next, it is raised to 220 - 230 °C at a rate of 10 - 12 °C / min and held for 10 - 15 min. Finally, it is raised to 250 - 255 °C at a rate of 15 - 18 °C / min and held for 5 min. Through this segmented temperature control method, effective separation of compounds with different boiling points (such as low-boiling esters, medium-boiling alcohols, and high-boiling acids) is achieved.

[0022] The carrier gas is N 2 , and the carrier gas flow rate is 1.0 - 1.2 mL / min.

[0023] The injection method is split injection, and the split ratio is 20 - 22:1. Through this split ratio design, peak broadening is reduced and the resolution is improved. The injection volume is 1 μL, and the equilibration time before injection is 1 min.

[0024] The injection port temperature is set to 200 - 205 °C, and the detector temperature is set to 300 °C.

[0025] Gas flow rate setting: The hydrogen flow rate is 30 - 35 mL / min, the air flow rate is 400 - 420 mL / min, and the make-up gas flow rate is 25 - 30 mL / min. Through the make-up gas design, peak broadening is further reduced and the resolution is improved.

[0026] As a further technical solution, the operation of precisely sucking the standard solution is carried out under the precise weighing of a one-ten-thousandth balance to ensure the accuracy of the sucking amount, thereby guaranteeing the accuracy of the concentration of the reference stock solution.

[0027] As a further technical solution, when preparing the standard series working solutions, the volumetric flasks are strictly cleaned and calibrated to ensure the accuracy of their volumes. During the dilution process with absolute ethanol, the method of adding in multiple small amounts and shaking thoroughly is adopted to make the solution mix evenly.

[0028] As a further technical solution, when filtering the unclear sample, medium-speed qualitative filter paper is used for preliminary filtration to remove larger particulate impurities, and then a 0.45 μm nylon filter membrane is used for secondary filtration to further improve the clarity of the filtrate;

[0029] The pore size range of the medium-speed qualitative filter paper is 3 - 15 μm, and the basis weight is 80 - 120 g / m 2 , and the filtration speed is 10 - 30 mL per minute.

[0030] As a further technical solution, before sample injection, the chromatographic column is aged. The aging treatment steps are as follows: maintaining at an initial temperature of 42 - 45 °C for 2 h, then rising to 260 - 265 °C at a rate of 3 - 5 °C / min and maintaining for 4 h to remove impurities in the chromatographic column and improve the stability and accuracy of detection.

[0031] As a further technical solution, during the storage of the standard series working solutions and the test sample solutions, regularly check whether the storage temperature is stable to avoid affecting the stability and component content of the solutions due to temperature fluctuations.

[0032] As a further technical solution, when plotting the standard curve, the linear regression analysis method is used to process the peak area and concentration data of the standard series working solutions to ensure a good linear relationship of the standard curve, and the correlation coefficient R 2 is not less than 0.995.

[0033] As a further technical solution, the FID parameters are optimized to a hydrogen flow rate of 30 - 32 mL / min and an air flow rate of 400 - 420 mL / min.

[0034] Advantages of the present invention:

[0035] The multi - substance detection method for the content of water - wine samples proposed by the present invention has the characteristic of rich detected substance types. The standard solution system of the present invention covers up to 30 substances, comprehensively covering various components such as organic acids, alcohols, and sugars. Traditional water - wine detection techniques can often only detect a few common components and are difficult to comprehensively analyze the complex component system in water - wine. However, the present invention greatly expands the detection range and can accurately determine multiple key components in water - wine simultaneously. This enables us to have a more comprehensive and in - depth understanding of the components of water - wine, which helps to more accurately evaluate the quality, flavor, and nutritional value of water - wine.

[0036] The present invention adopts the designed programmed temperature rising method. This segmented temperature control design can effectively separate compounds such as low - boiling - point esters, medium - boiling - point alcohols, and high - boiling - point acids in appropriate temperature ranges according to the characteristics of compounds with different boiling points. Compared with traditional constant temperature or simple temperature rising methods, the programmed temperature rising of the present invention can better meet the separation requirements of complex components in water - wine, enabling various components to be fully separated in the chromatographic column, reducing peak overlap, and improving the separation degree and detection accuracy. For example, low - boiling - point esters are first separated at lower temperatures, avoiding interference with high - boiling - point components, so that each component can be accurately detected and quantified.

[0037] Split flow and make-up gas design improves separation effect; Split injection can effectively control the amount of sample entering the chromatographic column, avoiding peak broadening and deterioration of separation effect caused by the simultaneous entry of excessive samples. The role of make-up gas is to accelerate the transmission speed of the sample in the chromatographic column, reduce the diffusion of the sample in the column, further improve the peak shape, and increase the resolution. Through the synergistic effect of these two designs, the chromatographic peaks of various components in the water-alcohol can be sharper and more symmetrical, and the separation between adjacent peaks is clearer, thus improving the detection sensitivity and accuracy, and enabling more accurate detection of low-content components.

[0038] Optimize the carrier gas and gas flow rates, and reasonably set the flow rates of hydrogen, air, and make-up gas. Appropriate carrier gas flow rate can ensure the normal transmission and separation of the sample in the chromatographic column, while the optimized flow rates of hydrogen, air, and make-up gas can provide a stable detection environment for the flame ionization detector (FID), improving the sensitivity and stability of the detector. The optimized settings of these parameters enable the entire chromatographic detection system to operate more efficiently, ensuring the accuracy and reliability of the detection results.

[0039] For unclear samples, first filter them preliminarily with medium-speed qualitative filter paper, and then filter them secondary with a 0.45μm nylon filter membrane. Medium-speed qualitative filter paper can effectively remove larger particulate impurities, while the nylon filter membrane further filters out fine impurities, improving the clarity of the filtrate. Such a multi-stage filtration method can reduce the interference of impurities on the subsequent detection process, protect the chromatographic column and detector, and improve the accuracy and stability of the detection results.

[0040] Before injection, age the chromatographic column. The aging treatment can remove impurities and residual substances in the chromatographic column, making the chromatographic column reach a stable working state. The chromatographic column after aging treatment can provide more stable separation performance, reduce baseline drift and noise, and improve the repeatability and accuracy of the detection results.

[0041] In summary, the multi-substance detection method for the content of water-alcohol samples of the present invention has made remarkable progress in terms of the types of detected substances, detection accuracy, separation effect, stability, and sensitivity through the comprehensive optimization and improvement of the standard solution system, preparation of test solution, chromatographic conditions, and other related technical links, providing a more scientific, accurate, and efficient method for water-alcohol detection. Detailed implementation mode

[0042] In order to enable those skilled in the art of this technology to better understand the solution of this application, the technical solutions in the embodiments of this application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0043] Example 1

[0044] Example 1:

[0045] (I) Preparation of Standard Solutions

[0046] Preparation of stock solution of reference substances: There are 30 standard solutions, and their components cover various types such as organic acids, alcohols, and sugars. Under the precise weighing of a ten-thousandth balance, appropriate amounts of the 30 standard solutions were accurately pipetted respectively. For the remaining reference substances except acetic acid and octanoic acid, absolute ethanol was added to make a solution containing 50 mg per 1 ml; acetic acid was added to absolute ethanol to make a solution containing 400 mg per 1 mL; octanoic acid was added to absolute ethanol to make a solution containing 100 mg per 1 mL, so as to obtain the stock solutions of each reference substance and ensure the accuracy of the concentration of the stock solutions of reference substances.

[0047] Preparation of standard series working solutions: Appropriate amounts of the stock solutions of each reference substance were accurately pipetted into strictly cleaned and calibrated volumetric flasks respectively. Absolute ethanol was added for dilution, and the solution was mixed evenly by adding in small amounts several times and shaking well. Standard series working solutions were prepared. Among them, the concentrations of acetic acid were 40, 80, 160, 400, 800, 1600, 4000 mg / L respectively, the concentrations of octanoic acid were 10, 20, 40, 100, 200, 400, 1000 mg / L respectively, and the concentrations of the remaining reference substances were 5, 10, 20, 50, 100, 200, 500 mg / L respectively. The linear range of the standard curve was acetic acid 0.4 - 40 mg / L, octanoic acid 0.1 - 10 mg / L.

[0048] Storage of standard solutions: The standard series working solutions were stored at -18 °C for future use. The storage temperature was regularly checked for stability to avoid affecting the stability and component content of the solution due to temperature fluctuations, and the concentration change rate of the standard solution within 3 months of storage at -18 °C was ≤5%.

[0049] (II) Preparation of Test Sample Solutions

[0050] Filtration of samples: For unclear aqueous alcoholic samples, they were first preliminarily filtered with medium-speed qualitative filter paper. The pore size range of this medium-speed qualitative filter paper was 3 μm, and the quantification was 80 g / m 2 , and the filtration rate was 10 mL per minute to remove larger particulate impurities. Then, a 0.45 μm nylon filter membrane was used for secondary filtration to reduce the loss caused by the adsorption of organic solvents. 5.00 ml of the filtrate was taken to further improve the clarity of the filtrate.

[0051] Dilution and storage of samples: Absolute ethanol was added to the filtrate, and it was accurately diluted to 10.00 ml and stored at 0 °C.

[0052] (III) Detection

[0053] Chromatographic column aging treatment: Before injection, age the Zafex ZFQ2119 60m * 0.32mm * 1.0μm chromatographic column. The aging steps are to hold at an initial temperature of 42°C for 2h, then increase the temperature to 260°C at a rate of 3°C / min and hold for 4h to remove impurities in the chromatographic column and improve the stability and accuracy of detection.

[0054] Liquid chromatograph condition setting

[0055] Chromatographic column: Use the Zafex ZFQ2119 60m * 0.32mm * 1.0μm chromatographic column.

[0056] Detector: Detect using a flame ionization detector (FID), optimize the FID parameters to make the detection limit reach below 0.1mg / L, and the optimized FID parameters are a hydrogen flow rate of 30mL / min and an air flow rate of 400mL / min.

[0057] Programmed temperature rise: Set the initial temperature to 50°C, hold for 8min, then increase the temperature to 160°C at a rate of 5°C / min and hold for 1min, then increase the temperature to 220°C at a rate of 10°C / min and hold for 10min, and finally increase the temperature to 250°C at a rate of 15°C / min and hold for 5min. Through this segmented temperature control method, effective separation of compounds with different boiling points (such as low-boiling esters, medium-boiling alcohols, and high-boiling acids) is achieved.

[0058] Carrier gas: Select N 2 , and the carrier gas flow rate is 1.0mL / min.

[0059] Injection method: Use split injection, with a split ratio of 20:1. Through this split ratio design, peak broadening is reduced and the resolution is improved; the injection volume is 1μL, and the equilibration time before injection is 1min.

[0060] Temperature setting: Set the injection port temperature to 200°C and the detector temperature to 300°C.

[0061] Gas flow rate setting: The hydrogen flow rate is 30mL / min, the air flow rate is 400mL / min, and the make-up gas flow rate is 25mL / min. Through the make-up gas design, peak broadening is further reduced and the resolution is improved.

[0062] Detection and quantitative analysis: Inject the prepared standard series working solutions and test sample solutions into the liquid chromatograph for injection detection respectively. Use the linear regression analysis method to process the peak area and concentration data of the standard series working solutions, draw a standard curve, ensure that the linear relationship of the standard curve is good, and the correlation coefficient R 2Not less than 0.995. Then, according to the standard curve, quantitative analysis is performed on the components in the test solution.

[0063] Example 2:

[0064] (I) Preparation of standard solution

[0065] Preparation of reference stock solution: The same as in Example 1.

[0066] Preparation of standard series working solutions: The same as in Example 1.

[0067] Storage of standard solution: The same as in Example 1.

[0068] (II) Preparation of test solution

[0069] Sample filtration: For turbid aqueous alcoholic samples, first perform preliminary filtration using a medium-speed qualitative filter paper with a pore size range of 8 μm and a basis weight of 100 g / m 2 , with a filtration rate of 20 mL per minute, to remove larger particulate impurities. Then use a 0.45 μm nylon membrane for secondary filtration to reduce losses caused by organic solvent adsorption. Take 5.00 ml of the filtrate to further improve the clarity of the filtrate.

[0070] Sample dilution and storage: Add absolute ethanol to the filtrate, accurately dilute it to 10.00 ml, and store it at 5°C.

[0071] (III) Detection

[0072] Chromatographic column aging treatment: Before injection, age the Zafex ZFQ2119 60 m * 0.32 mm * 1.0 μm chromatographic column. The aging procedure is to maintain at an initial temperature of 43°C for 2 h, then increase the temperature to 262°C at a rate of 4°C / min and maintain for 4 h to remove impurities in the chromatographic column and improve the stability and accuracy of detection.

[0073] Condition setting of liquid chromatograph

[0074] Chromatographic column: Use a Zafex ZFQ2119 60 m * 0.32 mm * 1.0 μm chromatographic column.

[0075] Detector: Detection is performed using a flame ionization detector (FID). Optimize the FID parameters to make the detection limit reach below 0.1 mg / L. The optimized FID parameters are a hydrogen flow rate of 31 mL / min and an air flow rate of 410 mL / min.

[0076] Programmed temperature rise: The initial temperature is set at 52 °C and maintained for 8 min. Then it is heated to 162 °C at a rate of 5.5 °C / min and maintained for 1 min. Next, it is heated to 225 °C at a rate of 11 °C / min and maintained for 12 min. Finally, it is heated to 252 °C at a rate of 16 °C / min and maintained for 5 min. Through this segmented temperature control method, effective separation of compounds with different boiling points (such as low-boiling esters, medium-boiling alcohols, and high-boiling acids) is achieved.

[0077] Carrier gas: The carrier gas is N 2 , and the carrier gas flow rate is 1.1 mL / min.

[0078] Injection mode: Split injection is adopted, and the split ratio is 21:1. Through this split ratio design, peak broadening is reduced and the resolution is improved; the injection volume is 1 μL, and the equilibration time before injection is 1 min.

[0079] Temperature setting: The injection port temperature is set at 202 °C, and the detector temperature is set at 300 °C.

[0080] Gas flow rate setting: The hydrogen flow rate is 32 mL / min, the air flow rate is 410 mL / min, and the make-up gas flow rate is 27 mL / min. Through the make-up gas design, peak broadening is further reduced and the resolution is improved.

[0081] Detection and quantitative analysis: The same as in Example 1.

[0082] Example 3:

[0083] (I) Preparation of standard solution

[0084] Preparation of reference substance stock solution: The same as in Example 1.

[0085] Preparation of standard series working solutions: The same as in Example 1.

[0086] Storage of standard solution: The same as in Example 1.

[0087] (II) Preparation of test solution

[0088] Sample filtration: For unclear aqueous alcoholic samples, first perform preliminary filtration using medium-speed qualitative filter paper. The pore size range of this medium-speed qualitative filter paper is 15 μm, and the quantitative value is 120 g / m 2 , and the filtration rate is 30 mL per minute to remove larger particulate impurities. Then use a 0.45-μm nylon membrane for secondary filtration to reduce losses caused by organic solvent adsorption. Take 5.00 ml of the filtrate to further improve the clarity of the filtrate.

[0089] Sample dilution and storage: Add absolute ethanol to the filtrate, accurately dilute it to 10.00 ml, and store it at 10 °C.

[0090] (3) Detection

[0091] Chromatographic column aging treatment: Before injection, age the Zafex ZFQ2 1960m * 0.32mm * 1.0μm chromatographic column. The aging steps are to hold at an initial temperature of 45°C for 2 h, then increase the temperature to 265°C at a rate of 5°C / min and hold for 4 h to remove impurities in the chromatographic column and improve the stability and accuracy of detection.

[0092] Liquid chromatograph condition setting

[0093] Chromatographic column: Use the Zafex ZFQ2 1960m * 0.32mm * 1.0μm chromatographic column.

[0094] Detector: Use a flame ionization detector (FID) for detection. Optimize the FID parameters to make the detection limit reach below 0.1 mg / L. The optimized FID parameters are a hydrogen flow rate of 32 mL / min and an air flow rate of 420 mL / min.

[0095] Programmed temperature rise: Set the initial temperature to 55°C and hold for 8 min. Then increase the temperature to 165°C at a rate of 6°C / min and hold for 1 min. Next, increase the temperature to 230°C at a rate of 12°C / min and hold for 15 min. Finally, increase the temperature to 255°C at a rate of 18°C / min and hold for 5 min. Through this segmented temperature control method, effective separation of compounds with different boiling points (such as low-boiling esters, medium-boiling alcohols, and high-boiling acids) can be achieved.

[0096] Carrier gas: Select N 2 as the carrier gas, and the carrier gas flow rate is 1.2 mL / min.

[0097] Injection method: Use split injection with a split ratio of 22:1. Through this split ratio design, peak broadening can be reduced and resolution can be improved; the injection volume is 1 μL, and the equilibration time before injection is 1 min.

[0098] Temperature setting: Set the injection port temperature to 205°C and the detector temperature to 300°C.

[0099] Gas flow rate setting: The hydrogen flow rate is 35 mL / min, the air flow rate is 420 mL / min, and the make-up gas flow rate is 30 mL / min. Through the make-up gas design, peak broadening can be further reduced and resolution can be improved.

[0100] Detection and quantitative analysis: The same as in Example 1.

[0101] Control group: Traditional gas chromatography - flame ionization detection method (GC - FID)

[0102] The traditional GC-FID detection method is a relatively classic method for analyzing volatile organic compounds. In the detection of the components of water and alcohol, it injects the sample into a gas chromatograph, separates the components by utilizing the differences in the distribution coefficients of different substances between the stationary phase and the mobile phase, and then detects them with a hydrogen flame ionization detector.

[0103] Specific operation process

[0104] Sample pretreatment: Take an appropriate amount of water and alcohol sample, dilute it by a certain multiple with anhydrous ethanol to reduce the viscosity and concentration of the sample, facilitating injection and separation. For unclear samples, use ordinary filter paper to filter out large particle impurities.

[0105] Chromatographic condition setting

[0106] Chromatographic column: Use a commonly used HP-5 capillary column (30m × 0.32mm × 0.25μm).

[0107] Column temperature: The initial temperature is 40°C, hold for 3 min, then increase the temperature to 180°C at a rate of 5°C / min, and hold for 5 min.

[0108] Injector temperature: 200°C.

[0109] Detector temperature: 250°C.

[0110] Carrier gas: Nitrogen, flow rate 1.0 mL / min.

[0111] Injection mode: Split injection, split ratio 10:1.

[0112] Detection and analysis: Inject the processed sample into the gas chromatograph, conduct qualitative analysis on the substances in the sample according to the retention time, and conduct quantitative analysis on the detected substances by the external standard method or the internal standard method.

[0113] Experiment

[0114] Take the water and alcohol sample to be tested for detection, and conduct detection respectively by the methods of the examples and the control group, and compare:

[0115] Table 1

[0116] Number of substance types Example 1 30 Example 2 28 Example 3 28 Comparative Example 1 22

[0117] It can be seen from Table 1 that the method of the present invention can detect more types of substances in the water and alcohol sample.

[0118] Conduct detection by the method of the example, and analyze and statistically analyze the specific situation of the detected substances:

[0119] Table 2

[0120]

[0121]

[0122] As can be seen from Table 2, the method of the present invention can detect up to 30 substances, and the detection method is relatively accurate.

[0123] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-substance detection method for the content of water and wine samples, characterized in that: The following steps are involved: (1) Preparation of standard solution: The 30 standard solutions cover various components such as organic acids, alcohols, and sugars; accurately pipette appropriate amounts of the 30 standard solutions respectively, and for the reference substances except acetic acid and octanoic acid, add anhydrous ethanol to make a solution containing 50 mg per 1 ml; add anhydrous ethanol to acetic acid to make a solution containing 400 mg per 1 mL; add anhydrous ethanol to octanoic acid to make a solution containing 100 mg per 1 mL, thereby obtaining the stock solutions of each reference substance; Accurately take an appropriate amount of each reference stock solution, place it in the same volumetric flask, add anhydrous ethanol to dilute it, and prepare a standard series of working solutions, wherein the concentrations of acetic acid are 40, 80, 160, 400, 800, 1600, and 4000 mg / L, the concentrations of octanoic acid are 10, 20, 40, 100, 200, 400, and 1000 mg / L, and the concentrations of the remaining reference substances are 5, 10, 20, 50, 100, 200, and 500 mg / L; the linear range of the standard curve is 0.4-40 mg / L for acetic acid and 0.1-10 mg / L for octanoic acid; The standard series working solutions are stored at -18°C for future use, and the concentration change rate of the standard solutions stored at -18°C within 3 months is ≤5%; (2) Preparation of test solution: For unclear water-wine samples, filter them first, use 0.45 μm nylon filter membrane instead of conventional filter membrane to reduce the loss caused by organic solvent adsorption, and take 5.00 ml of filtrate; Add anhydrous ethanol to the filtrate, dilute it accurately to 10.00 ml, and store at 0-10°C; (3) Detection: The prepared standard series working solutions and the test solution are respectively injected into the liquid chromatograph for sample injection detection. A standard curve is drawn based on the detection results of the standard series working solutions. The components in the test solution are then quantitatively analyzed based on the standard curve. The FID parameters are optimized to achieve a detection limit of less than 0.1 mg / L.

2. The multi-substance detection method for the content of water and wine samples according to claim 1 is characterized in that: The chromatographic conditions of the liquid chromatograph are set as follows: Use Zafex ZFQ2119 60m*0.32mm*1.0μm column; The detection was carried out using a hydrogen flame ionization detector (FID); Program temperature rise: the initial temperature was set at 50-55°C, maintained for 8 min, then raised to 160-165°C at a rate of 5-6°C / min and maintained for 1 min, then raised to 220-230°C at a rate of 10-12°C / min, maintained for 10-15 min, and finally raised to 250-255°C at a rate of 15-18°C / min and maintained for 5 min; The carrier gas is N2, and the carrier gas flow rate is 1.0-1.2mL / min; The injection method adopted split injection, and the split ratio was 20-22:

1. The split ratio design reduced the peak broadening and improved the separation degree. The injection volume was 1 μL, and the equilibration time before injection was 1 min. The injection port temperature was set to 200-205°C, and the detector temperature was set to 300°C; Gas flow settings: hydrogen flow is 30-35 mL / min, air flow is 400-420 mL / min, and tail gas flow is 25-30 mL / min.

3. The multi-substance detection method for the content of water and wine samples according to claim 1 is characterized in that: The operation of precisely pipetting the standard solution is performed under precise weighing of a balance to one ten-thousandth of a scale to ensure the accuracy of the pipetting amount, thereby ensuring the accuracy of the concentration of the reference substance stock solution.

4. The multi-substance detection method for the content of water and wine samples according to claim 1 is characterized in that: When preparing the standard series working solutions, the volumetric flasks are strictly cleaned and calibrated to ensure that their volumes are accurate. During the dilution process of adding anhydrous ethanol, multiple small additions and sufficient oscillation are used to mix the solutions evenly.

5. The multi-substance detection method for the content of water and wine samples according to claim 1 is characterized in that: When filtering unclear samples, use medium-speed qualitative filter paper for preliminary filtration to remove larger particle impurities, and then use 0.45μm nylon filter membrane for secondary filtration to further improve the clarity of the filtrate; The pore size of the medium-speed qualitative filter paper is in the range of 3-15 μm, and the quantitative value is 80-120 g / m 2 , the filtration rate is 10-30mL per minute.

6. The multi-substance detection method for the content of water and wine samples according to claim 1 is characterized in that: Before injection, the chromatographic column was aged. The aging steps were as follows: maintain the initial temperature at 42-45°C for 2 hours, then increase the temperature to 260-265°C at a rate of 3-5°C / min and maintain for 4 hours to remove impurities in the chromatographic column and improve the stability and accuracy of detection.

7. The multi-substance detection method for the content of water and wine samples according to claim 1 is characterized in that: During the storage of the standard series working solutions and test sample solutions, regularly check whether the storage temperature is stable to avoid affecting the stability of the solution and the content of the components due to temperature fluctuations.

8. The multi-substance detection method for the content of water and wine samples according to claim 1 is characterized in that: When drawing the standard curve, the linear regression analysis method is used to process the peak area and concentration data of the standard series working solution to ensure that the linear relationship of the standard curve is good and the correlation coefficient R 2 Not less than 0.

995.

9. The multi-substance detection method for the content of water and wine samples according to claim 1 is characterized in that: The optimized FID parameters were hydrogen flow rate 30-32 mL / min and air flow rate 400-420 mL / min.

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