System and method for detecting the ratio of single solvent in a dual solvent system for plant extraction

Abstract

The present invention discloses a system and method for detecting the proportion of a single solvent in a plant extraction dual-solvent system. The system comprises a recovery solvent storage tank and a raw material extraction tank; a measuring pipeline and an intermediate storage tank; the liquid outlet of the raw material extraction tank is connected to the intermediate storage tank via a pipeline and a control valve; the liquid inlet of the measuring pipeline is connected to the liquid outlet of the recovery solvent storage tank via a first liquid outlet pipeline and a first liquid outlet valve, and is connected to the liquid outlet of the intermediate storage tank via a second liquid outlet pipeline and a second liquid outlet valve; the liquid outlet of the measuring pipeline is connected to the liquid inlet of the recovery solvent storage tank via a first liquid return pipeline and a first liquid return valve, and is connected to the liquid inlet of the intermediate storage tank via a second liquid return pipeline and a second liquid return valve; the measuring pipeline is provided with an ultraviolet-visible spectrometer and a circulation pump; and the intermediate storage tank is provided with a liquid injection port connected to a H2O2 solution pipeline. The system is simple to operate, low in cost, and has high detection accuracy, meeting the needs of workshop production process control.

Description

Technical Field

[0001] The present invention relates to a solvent detection system and method, in particular to a system and method for detecting the proportion of a single solvent in a dual solvent system for plant extraction. Background Art

[0002] Plant extracts are products made from plants as raw materials. According to the needs of the final product, they undergo a physical and chemical extraction and separation process to specifically obtain and concentrate one or more active ingredients in the plant without changing the structure of the active ingredients.

[0003] Solvent extraction is one of the commonly used methods for extracting plant extracts. During the extraction process of the solvent extraction method, changes in solvent concentration, especially the ratio of a single solvent in the dual solvent system, will directly affect the extraction effect of the active ingredient. Common organic extraction solvents are hydrophilic solvents such as methanol, ethanol, and acetone, and lipophilic solvents such as petroleum ether, benzene, chloroform, ether, ethyl acetate, and dichloroethane. The above solvents are generally highly volatile, so the solvent ratio in the dual solvent system is prone to change during the extraction process, especially after distillation recovery, which will affect the extraction effect and product quality when reused.

[0004] Currently, methods for determining the ratio of a single solvent in a dual-solvent system primarily rely on gas chromatography and gas chromatography-mass spectrometry. These methods are expensive and time-consuming, making them inadequate for workplace production process control. Therefore, finding a method for real-time measurement of the ratio of a single solvent in a dual-solvent system is a pressing technical challenge. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a detection system for the ratio of a single solvent in a plant extraction dual solvent system which can detect the ratio in real time; the present invention also provides a method for determining the ratio of a single solvent in a plant extraction dual solvent system.

[0006] In order to solve the above technical problems, the technical solution adopted by the system of the present invention is: it includes a recovery solvent storage tank and a raw material extraction tank, and also includes a measuring pipeline and an intermediate storage tank; the liquid outlet of the raw material extraction tank is connected to the intermediate storage tank through a pipeline and a control valve; the liquid inlet end of the measuring pipeline is connected to the liquid outlet of the recovery solvent storage tank through a first liquid outlet pipeline and a first liquid outlet valve, and is connected to the liquid outlet of the intermediate storage tank through a second liquid outlet pipeline and a second liquid outlet valve; the liquid outlet end of the measuring pipeline is connected to the liquid inlet of the recovery solvent storage tank through a first return liquid pipeline and a first return liquid valve The measuring pipeline is provided with a UV-visible spectrometer and a circulation pump; the intermediate storage tank is provided with a liquid injection port connected to the H2O2 solution pipeline; the measuring pipeline at the liquid inlet front end of the UV-visible spectrometer is provided with a temperature control tube and a filter tube, and the filter tube is filled with spherical activated carbon with a pore size of ≤3nm; the measuring pipeline at the liquid outlet rear end of the filter tube is provided with a glass tube, and the glass tube is filled with anhydrous magnesium sulfate and / or anhydrous sodium sulfate, and sodium carbonate and / or sodium bicarbonate.

[0007] The method of the present invention uses the above-mentioned detection system, and its steps are: 1) determining the proportion of a single solvent in the recovered solvent: opening the liquid outlet and liquid inlet of the recovered solvent storage tank, and passing through a circulation pipeline formed by a first liquid outlet pipeline, a measuring pipeline and a first liquid return pipeline; starting a circulation pump, recording the absorbance value of the ultraviolet-visible spectrometer online, and calculating the proportion of the single solvent in the recovered solvent dual solvent system based on the absorbance standard curve;

[0008] 2) Determining the proportion of a single solvent in the raw material extract: injecting a certain amount of the raw material extract into the intermediate storage tank from the raw material extraction tank, and adding an H2O2 solution into the intermediate storage tank through the liquid injection port; opening the liquid outlet and liquid inlet of the intermediate storage tank, and passing through a circulation pipeline formed by a second liquid outlet pipeline, a measuring pipeline, and a second liquid return pipeline; starting a circulation pump, recording the absorbance value of the UV-visible spectrometer online, and calculating the proportion of the single solvent in the dual-solvent system of the raw material extract based on the absorbance standard curve.

[0009] The mass concentration of the H2O2 solution in step 2) of the method of the present invention is 0.3% to 1.0%. The amount of the H2O2 solution added is 2 to 5 times the volume of the raw material extract.

[0010] The dual solvent system in the method of the present invention is an acetone-vegetable oil extraction solvent, an acetone-cyclohexane or an acetone-n-hexane dual solvent system.

[0011] The absorbance standard curve of the method of the present invention is drawn with the absorbance value as the ordinate and the ratio of a certain solvent in the dual solvent system as the abscissa.

[0012] The raw material extract dual solvent system described in the method of the present invention is a mixed solution obtained by extracting the pigment as the target component and the dual solvent system as the extraction solvent under the conditions of a raw material: extraction solvent (m / v) ratio of 1:2 to 8, an extraction temperature of 30 to 50°C, and an extraction time of 20 to 60 minutes.

[0013] The recovery solvent dual solvent system described in the method of the present invention is a dual solvent system obtained by distilling the extract dual solvent system 2 to 5 times.

[0014] The beneficial effects of adopting the above technical solution are: the system of the present invention can conveniently detect the absorbance value of the dual solvent system in the recovery solvent storage tank and the raw material extraction tank through the setting of the measuring pipeline, the intermediate storage tank and the ultraviolet-visible spectrometer, and the absorbance value can be used to calculate the proportion of a single solvent in the dual solvent system; the present invention, especially after adopting the filter tube and the glass tube, adopts different technical means to purify impurities of different particle sizes, stabilizes the detection environment, and improves the precision and accuracy of the ultraviolet-visible spectrometer detection results; the present invention is simple to operate and low in cost, realizes the online detection of the proportion of a single solvent in the dual solvent system, has high detection accuracy, and can meet the needs of workshop production process control. The present invention optimizes the pretreatment method by adding a storage tank, expands the scope of application, realizes the detection of process liquids in two sections, greatly reduces the detection cost, and improves the accuracy of detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] Figure 1 It is a structural diagram of the system of the present invention;

[0017] Figure 2 This is the absorbance standard curve of the dual solvent system of vegetable oil extraction solvent and acetone described in the examples of the present invention.

[0018] In the figure: a recovered solvent storage tank 1; a first liquid outlet valve 2; a first liquid outlet pipeline 3; a filter tube 4; a glass tube 5; a measuring pipeline 6; a temperature control tube 7; a UV-visible spectrometer 8; a circulating pump 9; a first liquid return valve 10; a first liquid return pipeline 11; a second liquid outlet pipeline 12; a second liquid outlet valve 13; a drain valve 14; a drain pipe 15; an intermediate storage tank 16; a liquid injection port 17; a second liquid return pipeline 18; a second liquid return valve 19; a control valve 20; and a raw material extraction tank 21. DETAILED DESCRIPTION

[0019] Figure 1As shown, the detection system for the proportion of a single solvent in the plant extraction dual solvent system includes a recovery solvent storage tank 1, a raw material extraction tank 21, a measuring pipeline 6 and an intermediate storage tank 16; the raw material extraction tank 21 is used for extracting the raw material, and the recovery solvent storage tank 1 is used for storing the recovered solvent after extraction. The liquid outlet of the raw material extraction tank 21 is connected to the intermediate storage tank 16 through a pipeline and a control valve 20. A liquid injection port 17 is provided on the upper part of the intermediate storage tank 16, which is connected to the H2O2 solution pipeline for adding H2O2 solution to the intermediate storage tank 16; the second liquid outlet pipeline 12 between the intermediate storage tank 16 and the second liquid outlet valve 13 is connected to a drain pipe 15 and a drain valve 14 for discharging the solvent in the intermediate storage tank 16 after testing; the intermediate storage tank 16 is used to flow a certain amount of extract in the raw material extraction tank 21 for testing; the intermediate storage tank 16 is preferably a storage tank made of transparent organic glass with a height scale, with a volume of 20 to 50L, a bottom area of 1 to 2 square decimeters, and a minimum height scale precision of 1 cm. The liquid inlet of the measuring line 6 is connected to the liquid outlet of the recovery solvent storage tank 1 through the first liquid outlet line 3 and the first liquid outlet valve 2, and the liquid inlet of the measuring line 6 is connected to the liquid outlet of the intermediate storage tank 16 through the second liquid outlet line 12 and the second liquid outlet valve 13. The liquid outlet of the measuring line 6 is connected to the liquid inlet of the recovery solvent storage tank 1 through the first liquid return line 11 and the first liquid return valve 10, and the liquid outlet of the measuring line 6 is connected to the liquid inlet of the intermediate storage tank 16 through the second liquid return line 18 and the second liquid return valve 19.

[0020] Figure 1 As shown, the measuring line 6 of the present system for detecting the ratio of a single solvent in a dual-solvent system for plant extraction comprises a filter tube 4, a glass tube 5, a temperature control tube 7, a UV-visible spectrometer 8, and a circulation pump 9, arranged in sequence along the direction of liquid flow. The filter tube 4 is filled with spherical activated carbon, preferably with a pore size of ≤3 nm, to remove small molecules from the flowing liquid. The filter tubes 4 are made of transparent organic glass tubes, one or two in number, and are installed in series, connected via quick-connect connectors, with sieve plates installed at the outlet. The starting point for installation is preferably 0.5 to 2 meters from the rear end of the intersection of the first and second liquid outlet lines 3 and 12 with the measuring line 6. The filter tubes 4 are used to filter and adsorb impurities in the solvent being tested to improve detection accuracy. The glass tube 5 is filled with one or both of anhydrous magnesium sulfate and anhydrous sodium sulfate, and one or both of sodium carbonate and sodium bicarbonate, to remove water and stabilize the solution environment. One to two transparent organic glass tubes 5 are installed in series, connected via quick-connect connectors, and each is equipped with a sieve plate at the outlet. The outlet of the last glass tube 5 is preferably located 0.5 to 2 meters from the liquid inlet of the UV-visible spectrometer 8. The temperature control tube 7 is used to heat or cool the solvent entering the UV-visible spectrometer 8.

[0021] Figure 1 As shown, the dual solvent systems applicable to the detection method of the proportion of a single solvent in the plant extraction dual solvent system are: acetone-vegetable oil extraction solvent dual solvent system, acetone-cyclohexane dual solvent system, and acetone-n-hexane dual solvent system.

[0022] The raw material extract dual solvent system is a mixed solution obtained by extracting the pigment as the target component and the dual solvent system as the extraction solvent at a raw material: extraction solvent (m / v) ratio of 1:2 to 8, an extraction temperature of 30 to 50°C, and an extraction time of 20 to 60 minutes.

[0023] The recovery solvent dual solvent system is a dual solvent system obtained by distilling the extract dual solvent system 2 to 5 times.

[0024] The process of the detection method is:

[0025] 1) Prepare a series of mixed solvents of a binary solvent system and measure their absorbance values; draw an absorbance standard curve with the absorbance value as the ordinate and the ratio of a certain solvent in the binary solvent system as the abscissa, such as Figure 2 The absorbance standard curve of the vegetable oil extraction solvent and acetone dual solvent system is shown; the calculation formula (1) is obtained:

[0026] Y=A*X+B (1)

[0027] In formula (1):

[0028] Y: absorbance value detected by the UV-visible spectrometer 8;

[0029] A: slope of the absorbance standard curve;

[0030] X: the ratio of a solvent in the recovery solvent of the dual solvent system, %;

[0031] B: The intercept of the ordinate in the absorbance standard curve, that is, the absorbance value when the proportion of a certain solvent in the mixed solvent is 0.

[0032] 2) Determine the proportion of a single solvent in the recovered solvent: Open the first liquid outlet valve 2 and the first liquid return valve 10, close the second liquid outlet valve 13 and the second liquid return valve 19, and simultaneously close the drain valve 14 and the control valve 20, thereby opening the recovered solvent circulation pipeline formed by the liquid outlet of the recovered solvent storage tank 1, the first liquid outlet pipeline 3, the measuring pipeline 6, the first liquid return pipeline 11, and the liquid inlet of the recovered solvent storage tank 1; start the circulation pump 9, and during the recycling solvent circulation process, adjust the temperature of the recovered solvent to be stable within ±1°C when entering the UV-visible spectrometer 8 by the temperature control tube 7, and record the absorbance value Y of the UV-visible spectrometer 8 online. Substitute the absorbance value Y detected by the UV-visible spectrometer 8 into the above calculation formula (1) to obtain the proportion X of a single solvent in the recovered solvent of the dual solvent system.

[0033] 3) Determining the proportion of a single solvent in the raw material extract: Open the control valve 20, close the second liquid outlet valve 13 and the drain valve 14; inject a certain amount of raw material extract into the intermediate storage tank 16 from the raw material extraction tank 21, and record the liquid level H1; inject H2O2 solution into the intermediate storage tank 16 through the liquid injection port 17, wherein the H2O2 solution has a mass concentration of 0.3% to 1.0% and the amount added is 2 to 5 times the volume of the raw material extract, and stir and mix for 10 to 30 minutes to remove color and other easily oxidized substances in the extract solution.

[0034] Open the second liquid outlet valve 13 and the second liquid return valve 19, close the first liquid outlet valve 2, the first liquid return valve 10, the drain valve 14 and the control valve 20, thereby opening the raw material extract circulation pipeline formed by the liquid outlet of the intermediate storage tank 16, the second liquid outlet pipeline 12, the measuring pipeline 6, the second liquid return pipeline 18 and the liquid inlet of the intermediate storage tank 15; start the circulation pump 9, and during the circulation of the raw material extract, the temperature control tube 7 adjusts the temperature of the raw material extract to be stable within ±1°C when entering the UV-visible spectrometer 8, and records the absorbance value Y of the UV-visible spectrometer 8 online. Substitute the absorbance value Y detected by the UV-visible spectrometer 8 into the above calculation formula (1) to obtain the single solvent ratio X in the raw material extract dual solvent system. After the measurement is completed, open the drain valve 14 and discharge the lower layer of liquid through the drain pipe 15.

[0035] Example 1: Taking a dual solvent system of a plant oil extraction solvent and an acetone mixed solvent as an example, the method for detecting the proportion of a single solvent in the plant extraction dual solvent system is specifically described as follows.

[0036] (1) Prepare a series of vegetable oil extraction solvents and acetone systems with different acetone ratios, detect the absorbance, and draw a standard curve with the absorbance value as the vertical axis and the acetone ratio value in the dual solvent system as the horizontal axis, such as Figure 2 As shown; the calculation formula is: y=1.8314*X+1.0901.

[0037] (2) Determining the proportion of a single solvent in the recovered solvent dual-solvent system: Using the detection system described in step 1), open the liquid inlet and outlet of the recovered solvent storage tank 1, connect them through the first liquid outlet line 3, the measuring line 6, and the first liquid return line 11 to form a circulation line. Start the circulation pump 9, and record the absorbance value X = 1.786 on the UV-visible spectrometer 8 online. Using the formula y = 1.8314 * x + 1.0901, calculate the proportion of acetone solvent in the mixed solvent to be 38%.

[0038] (3) Determine the proportion of a single solvent in the dual-solvent system of the raw material extract: 1 L of the extract was injected from the raw material extraction tank 21 into the intermediate storage tank 16. Two volumes of a 1.0% H2O2 solution were added through the injection port 17 and stirred for 10 minutes. The inlet and outlet of the intermediate storage tank 16 were opened, and the second outlet pipe 12, the measuring pipe 6, and the second return pipe 18 were connected to form a circulation pipe. The circulation pump 9 was turned on, and the absorbance value X = 1.640 was recorded online on the UV-visible spectrometer 8. Using the formula y = 1.8314 * x + 1.0901, the proportion of acetone solvent in the mixed solvent was calculated to be 30.0%. The drain valve 14 was opened, and the lower layer of liquid was discharged through the drain pipe 15.

[0039] Example 2: Taking a dual solvent system of a plant oil extraction solvent and an acetone mixed solvent as an example, the method for detecting the proportion of a single solvent in the plant extraction dual solvent system is specifically described as follows.

[0040] Steps (1) and (2) are the same as in Example 1.

[0041] (3) Determine the proportion of a single solvent in the dual-solvent system of the raw material extract: 2 L of the extract was injected from the raw material extraction tank 21 into the intermediate storage tank 16. Three times the volume of a 0.4% H2O2 solution was added through the injection port 17 and stirred for 15 minutes. The inlet and outlet of the intermediate storage tank 16 were opened, and the second outlet pipe 12, the measuring pipe 6, and the second return pipe 18 were connected to form a circulation pipe. The circulation pump 9 was turned on, and the absorbance value X = 1.645 was recorded online on the UV-visible spectrometer 8. Using the formula y = 1.8314 * x + 1.0901, the proportion of acetone solvent in the mixed solvent was calculated to be 30.3%. The drain valve 14 was opened, and the lower layer of liquid was discharged through the drain pipe 15.

[0042] Example 3: Taking a dual solvent system of a plant oil extraction solvent and an acetone mixed solvent as an example, the method for detecting the proportion of a single solvent in the plant extraction dual solvent system is specifically described as follows.

[0043] Steps (1) and (2) are the same as in Example 1.

[0044] (3) Determine the proportion of a single solvent in the dual-solvent system of the raw material extract: 4 L of the extract was injected from the raw material extraction tank 21 into the intermediate storage tank 16. Four times the volume of a 0.6% H2O2 solution was added through the injection port 17 and stirred for 20 minutes. The inlet and outlet of the intermediate storage tank 16 were opened, and the second outlet pipe 12, the measuring pipe 6, and the second return pipe 18 were connected to form a circulation pipe. The circulation pump 9 was turned on, and the absorbance value X = 1.672 was recorded online on the UV-visible spectrometer 8. The proportion of acetone solvent in the mixed solvent was calculated to be 31.8% using the formula y = 1.8314*x + 1.0901. The drain valve 14 was opened, and the lower layer of liquid was discharged through the drain pipe 15.

[0045] Example 4: Taking a dual solvent system of a plant oil extraction solvent and an acetone mixed solvent as an example, the method for detecting the proportion of a single solvent in the plant extraction dual solvent system is specifically described as follows.

[0046] Steps (1) and (2) are the same as in Example 1.

[0047] (3) Determine the proportion of a single solvent in the dual-solvent system of the raw material extract: 6 L of the extract was injected from the raw material extraction tank 21 into the intermediate storage tank 16. Five volumes of 0.8% H2O2 solution were added through the injection port 17 and stirred for 25 minutes. The inlet and outlet of the intermediate storage tank 16 were opened, and the second outlet pipe 12, the measuring pipe 6, and the second return pipe 18 were connected to form a circulation pipe. The circulation pump 9 was turned on, and the absorbance value X = 1.621 was recorded online on the UV-visible spectrometer 8. The proportion of acetone solvent in the mixed solvent was calculated to be 29.0% using the formula y = 1.8314*x + 1.0901. The drain valve 14 was opened, and the lower layer of liquid was discharged through the drain pipe 15.

[0048] Example 5: Taking a dual solvent system of a plant oil extraction solvent and an acetone mixed solvent as an example, the method for detecting the proportion of a single solvent in the plant extraction dual solvent system is specifically described as follows.

[0049] Steps (1) and (2) are the same as in Example 1.

[0050] (3) Determine the proportion of a single solvent in the dual-solvent system of the raw material extract: 8 L of the extract was injected from the raw material extraction tank 21 into the intermediate storage tank 16. Five times the volume of a 0.3% H2O2 solution was added through the injection port 17 and stirred for 30 minutes. The inlet and outlet of the intermediate storage tank 16 were opened, and the second outlet pipe 12, the measuring pipe 6, and the second return pipe 18 were connected to form a circulation pipe. The circulation pump 9 was turned on, and the absorbance value X = 1.657 was recorded online on the UV-visible spectrometer 8. Using the formula y = 1.8314 * x + 1.0901, the proportion of acetone solvent in the mixed solvent was calculated to be 31.0%. The drain valve 14 was opened, and the lower layer of liquid was discharged through the drain pipe 15.

Claims

1. A system for detecting the ratio of a single solvent in a dual solvent system for plant extraction, comprising a recovery solvent storage tank (1) and a raw material extraction tank (21), characterized in that: It also includes a measuring pipeline (6) and an intermediate storage tank (16); the liquid outlet of the raw material extraction tank (21) is connected to the intermediate storage tank (16) through a pipeline and a control valve (20); the liquid inlet end of the measuring pipeline (6) is connected to the liquid outlet of the recovery solvent storage tank (1) through a first liquid outlet pipeline (3) and a first liquid outlet valve (2), and is connected to the liquid outlet of the intermediate storage tank (16) through a second liquid outlet pipeline (12) and a second liquid outlet valve (13); the liquid outlet end of the measuring pipeline (6) is connected to the liquid inlet of the recovery solvent storage tank (1) through a first liquid return pipeline (11) and a first liquid return valve (10), and is connected to the liquid inlet of the intermediate storage tank (16) through a second liquid return pipeline (18) and a second liquid return valve (19); The measuring pipeline (6) is provided with an ultraviolet-visible spectrometer (8) and a circulation pump (9); the intermediate storage tank (16) is provided with a liquid injection port (17) connected to the H2O2 solution pipeline; the measuring pipeline (6) at the liquid inlet front end of the ultraviolet-visible spectrometer (8) is provided with a temperature control tube (7) and a filter tube (4), and the filter tube (4) is filled with spherical activated carbon, and the pore size of the spherical activated carbon is ≤3nm; the measuring pipeline (6) at the liquid outlet rear end of the filter tube (4) is provided with a glass tube (5), and the glass tube (5) is filled with anhydrous magnesium sulfate and / or anhydrous sodium sulfate, and sodium carbonate and / or sodium bicarbonate; the volume of the intermediate storage tank 16 is 20 to 50L, the bottom area is 1 to 2 square decimeters, and the minimum precision of the height scale is 1cm; The detection method is as follows: 1) determining the proportion of a single solvent in the recovered solvent: opening the liquid outlet and liquid inlet of the recovered solvent storage tank (1), and passing through the circulation pipeline formed by the first liquid outlet pipeline (3), the measuring pipeline (6) and the first liquid return pipeline (11); starting the circulation pump (9), recording the absorbance value of the UV-visible spectrometer (8) online, and calculating the proportion of a single solvent in the recovered solvent dual solvent system according to the absorbance standard curve; 2) Determining the proportion of a single solvent in the raw material extract: the raw material extract tank (21) injects a certain amount of raw material extract into the intermediate storage tank (16), and adds H2O2 solution into the intermediate storage tank (16) through the liquid injection port (17); opens the liquid outlet and liquid inlet of the intermediate storage tank (16), and forms a circulation pipeline through the second liquid outlet pipeline (12), the measuring pipeline (6) and the second liquid return pipeline (18); starts the circulation pump (9), records the absorbance value of the ultraviolet-visible spectrometer (8) online, and calculates the proportion of a single solvent in the dual solvent system of the raw material extract according to the absorbance standard curve; the mass concentration of the H2O2 solution is 0.3% to 1.0%, and the amount of the H2O2 solution added is 2 to 5 times the volume of the raw material extract; The dual solvent system is an acetone-vegetable oil extraction solvent, an acetone-cyclohexane or an acetone-n-hexane dual solvent system; the raw material extract dual solvent system is a mixed solution obtained by extracting the target component, the dual solvent system as the extraction solvent, at a raw material:extraction solvent (m / v) ratio of 1:2 to 8, an extraction temperature of 30 to 50°C, and an extraction time of 20 to 60 minutes.

2. A method for detecting the proportion of a single solvent in a dual solvent system for plant extraction, using the detection system of claim 1, characterized in that: 1) Determine the proportion of a single solvent in the recovered solvent: open the liquid outlet and liquid inlet of the recovered solvent storage tank (1), and connect the circulating pipeline formed by the first liquid outlet pipeline (3), the measuring pipeline (6) and the first liquid return pipeline (11); start the circulating pump (9), record the absorbance value of the UV-visible spectrometer (8) online, and calculate the proportion of a single solvent in the recovered solvent dual solvent system according to the absorbance standard curve; 2) Determining the proportion of a single solvent in the raw material extract: the raw material extract tank (21) injects a certain amount of raw material extract into the intermediate storage tank (16), and adds H2O2 solution into the intermediate storage tank (16) through the liquid injection port (17); opens the liquid outlet and liquid inlet of the intermediate storage tank (16), and forms a circulation pipeline through the second liquid outlet pipeline (12), the measuring pipeline (6) and the second liquid return pipeline (18); starts the circulation pump (9), records the absorbance value of the ultraviolet-visible spectrometer (8) online, and calculates the proportion of a single solvent in the dual solvent system of the raw material extract according to the absorbance standard curve; the mass concentration of the H2O2 solution is 0.3% to 1.0%, and the amount of the H2O2 solution added is 2 to 5 times the volume of the raw material extract; The dual solvent system is an acetone-vegetable oil extraction solvent, an acetone-cyclohexane or an acetone-n-hexane dual solvent system; the raw material extract dual solvent system is a mixed solution obtained by extracting the target component, the dual solvent system as the extraction solvent, at a raw material:extraction solvent (m / v) ratio of 1:2 to 8, an extraction temperature of 30 to 50°C, and an extraction time of 20 to 60 minutes.

3. The method for detecting the proportion of a single solvent in a dual solvent system for plant extraction according to claim 2, wherein: The absorbance standard curve is drawn with the absorbance value as the ordinate and the ratio of a certain solvent in the dual solvent system as the abscissa.

4. The method for detecting the proportion of a single solvent in a dual solvent system for plant extraction according to claim 2 or 3, wherein: The recovery solvent dual solvent system is a dual solvent system obtained by distilling the extract dual solvent system 2 to 5 times.

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