Preparation method and application of boron affinity adsorbent for separating myricetin in weak acid environment
By combining HOF-101 with eutectic solvents DES1 and DES2, the problem of alkalinity adaptability for the separation of myricetin in a weakly acidic environment was solved, achieving efficient and green separation and selective enrichment of myricetin, which is suitable for separation and detection in fruit juice.
Patent Information
- Application Number
- CN202511424763.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-30
- Publication Date
- 2025-12-16
AI Technical Summary
Existing technologies face challenges in separating myricetin due to its alkaline environment compatibility, which leads to a decrease in the affinity of boron-affinity materials in weakly acidic environments. Furthermore, traditional methods use toxic solvents, making it difficult to meet the requirements of green chemistry.
Using HOF-101 as the matrix material, combined with the eutectic solvents DES1 and DES2, a boron affinity adsorbent in a weakly acidic environment was prepared by thermal polymerization. By utilizing the boric acid groups in DES1 and the BO coordination of DES2, an imprinted cavity with high recognition effect was constructed to achieve selective separation of myricetin.
The method achieves efficient separation and selective enrichment of myricetin under weakly acidic conditions, reduces the use of toxic solvents, is suitable for multiple cycles of complex samples, conforms to green chemistry strategies, and is applicable to the separation and detection of myricetin in fruit juice.
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Figure CN121135969A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of material preparation and separation technology, in particular to a preparation method and application of a boron affinity adsorbent for separating myricetin in a weak acid environment. BACKGROUND
[0002] As a typical representative of natural flavonoids, myricetin has attracted much attention due to its biological activities such as antioxidant, anti-inflammatory and anticancer, and is widely used in food, medicine and health care fields. However, its complex biological matrix background, low concentration and high similarity with structural analogues pose a serious challenge to high-sensitivity detection and selective separation.
[0003] The commonly used separation and purification methods at present include chromatography, liquid-liquid extraction and solid phase extraction method, etc. Among them, solid phase extraction method mainly relies on the different partition coefficients of each component in the mixture between the mobile phase and the stationary phase, so that the target component is separated by repeated adsorption, elution and re-adsorption, which is the most commonly used pretreatment technology for separating trace target products from complex sample matrix. Common adsorbent materials are C18, Al2O3, carbon-based materials, polyamide resin, macroporous resin, molecularly imprinted polymer, etc. Molecularly imprinted polymer has attracted widespread attention due to its excellent selective recognition ability and high adsorption capacity, and can quickly and efficiently separate target analytes from complex matrix. However, traditional molecularly imprinted polymer often uses a large amount of organic solvents such as acetonitrile and chloroform in the preparation process, and the embedding of imprinting sites is too deep due to bulk polymerization, which leads to difficulties in elution and low rebinding efficiency. Boron affinity technology mainly forms pH-responsive recognition sites through the dynamic covalent bond between boronic acid monomers and cis-diols. However, the insufficient deprotonation of commercial boronic acid monomers leads to alkaline environment, and myricetin is easily decomposed in alkaline environment. The pH adaptability of the two is in conflict, which significantly reduces the affinity. These problems seriously hinder the development of green chemistry and the application in the field of natural product separation in fruit juice. SUMMARY
[0004] The present application provides a preparation method and application of a boron affinity adsorbent for separating myricetin in a weak acid environment, which combines high specific surface area matrix material HOF-101 with low eutectic solvent DES to improve the synthesis of molecularly imprinted polymer MIP. The boron affinity adsorbent prepared by the present application can be effectively applied to the separation of myricetin in a weak acid environment, overcoming the limitations of traditional boron affinity adsorbent which relies on alkaline environment, and meeting the green chemistry strategy.
[0005] Technical solution: In a first aspect, the application provides a method for preparing a boron affinity adsorbent for separating myricetin in a weak acid environment, using HOF-101 as a matrix material, myricetin as a template molecule, a eutectic solvent DES1 as a functional monomer, ethylene glycol dimethacrylate as a crosslinking agent, and a eutectic solvent DES2 as a porogen. In the preparation of the eutectic solvent DES1, choline chloride, 3-acetylamino phenyl boronic acid and acrylic acid are mixed, and stirred at a certain temperature until a uniform and stable liquid is formed. In the preparation of the eutectic solvent DES2, choline chloride and ethylene glycol are mixed, and stirred at a certain temperature until a uniform and stable liquid is formed.
[0006] Further, the specific preparation method is as follows: S1. Prepare the matrix material HOF-101. S2. Add the matrix material HOF-101, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 5-hexene-1-ol in a mixed solution of tetrahydrofuran and deionized water, stir for a certain time, wash and centrifuge to obtain HOF-101-C=C. S3. Add the HOF-101-C=C in S2 to the eutectic solvent DES2, ultrasonic dispersion, then add myricetin, dissolve, and then add the eutectic solvent DES1, mix and stir to obtain a pre-polymer. Under nitrogen protection, add azobisisobutyronitrile and ethylene glycol dimethacrylate to the pre-polymer, and heat polymerize, then elute with an eluent and dry to obtain a boron affinity adsorbent for separating myricetin in a weak acid environment.
[0007] Further, in the preparation of the eutectic solvent DES1, the molar ratio of choline chloride, 3-acetylamino phenyl boronic acid and acrylic acid is 1:0.5:2, the stirring temperature is 70-90℃, and the stirring time is 1-2h. In the preparation of the eutectic solvent DES2, the molar ratio of choline chloride and ethylene glycol is 1:2, the stirring temperature is 70-90℃, and the stirring time is 1-2h.
[0008] Further, in S1, the specific preparation steps of the matrix material HOF-101 are as follows: disperse 4,4'4'4''-(1,9-dihydrogen pyrene-1,3,6,8-tetraacyl) tetrabenzoic acid in DMF, heat in an oil bath, then add anhydrous ethanol, stir for a certain time, centrifuge to remove the supernatant, dry the obtained precipitate to obtain HOF-101.
[0009] Further, the 4, 4' 4' 4''- (1, 9-dihydrogen pyrene-1, 3, 6, 8-tetraacyl) tetrabenzoic acid, DMF and anhydrous ethanol are used in the following amount relationship: 0.1-10.0g: 10-1000mL: 100-10000mL; the heating temperature of the oil bath heating is 70-90℃, and the heating time is 1-3h; the stirring time is 5-7h; and the drying temperature is 50-70℃.
[0010] Further, in S2, the substrate material HOF-101, 1- (3-dimethylamino propyl) -3-ethyl carbodiimide hydrochloride and 5-hexene-1-alcohol are used in the following amount relationship: 0.04-8.0g: 0.004-0.8g: 100-20000μL; the volume ratio of the tetrahydrofuran and deionized water is 20:6; the stirring temperature is room temperature, and the stirring time is 10-14h.
[0011] Further, in S3, the HOF-101-C=C, the eutectic solvent DES2, myricetin, the eutectic solvent DES1, azobis isobutyronitrile and ethylene glycol dimethyl acrylate are used in the following amount relationship: 0.01-10.0g: 5-5000mL: 0.0157-15.7g: 25-25000μL: 0.005-5.0g: 200-200000μL.
[0012] Preferably, in S3, the specific conditions of the mixing and stirring are as follows: the stirring time is 1-3h, and the stirring temperature is 20-30℃; In S3, the specific conditions of the thermal polymerization reaction are as follows: the reaction time is 3-5h, and the reaction temperature is 60-70℃; In S3, the eluent is a mixed solution of methanol and acetic acid in a volume ratio of 9:1; In S3, the specific conditions of the drying are as follows: the drying temperature is 50-70℃, and the drying time is 5-7h.
[0013] In the second aspect, the application provides a boron affinity adsorbent for separating myricetin in a weak acid environment, which is prepared by any one of the above methods.
[0014] In the third aspect, the application provides an application of the boron affinity adsorbent for separating myricetin in a weak acid environment, which is prepared by any one of the above methods, in separating and purifying myricetin in a weak acid environment.
[0015] Beneficial effects: Compared with the prior art, the application has the following specific beneficial effects: The application provides a preparation method and application of a boron affinity adsorbent for separating myricetin in a weak acid environment, in which HOF-101 is used as a high specific surface area matrix material, myricetin is used as a template molecule, a deep eutectic solvent DES1 is used as a functional monomer, ethylene glycol dimethacrylate (EGDMA) is used as a crosslinking agent, and a deep eutectic solvent DES2 is used as a porogen. The boron affinity adsorbent (BA-DES / DMIP) for separating myricetin in a weak acid environment is prepared by combining HOF-101 and DES through a DES driving strategy. The boronic acid groups in DES1 play a dominant role and combine with hydrogen bonding to construct an imprinted cavity with high recognition effect; and the 'team boronic acid affinity' effect (B-O coordination) of DES2 solves the limitation of traditional boronic acid affinity materials in dependence on an alkaline environment. The boron affinity adsorbent prepared in the application has a remarkable effect on enrichment and selective analysis of complex samples and can be recycled multiple times. The preparation method of the boron affinity adsorbent is simple, low in cost, green and environmentally friendly, reduces the use of toxic chemical solvents, solves the limitation of traditional boronic acid affinity, is conducive to industrialized production and application, and has a wide application prospect in separating myricetin in fruit juice. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 Fig. 1 is a SEM image of HOF-101, BA-DES / DMIP and BA-DES / MMIP in the application; wherein a is HOF-101, b is BA-DES / DMIP, and c is BA-DES / MMIP; Figure 2 Fig. 2 is a FT-IR image of BA-DES / DMIP and BA-DES / MMIP in the application; Figure 3 Fig. 3 is an XRD image of BA-DES / DMIP and BA-DES / MMIP in the application Figure 4 Fig. 4 is an adsorption performance test image of BA-DES / DMIP and BA-DES / MMIP in the application; wherein a is adsorption capacity, and b is B-O coordination XPS spectrum; Figure 5 Fig. 5 is a selectivity test image of BA-DES / DMIP and BA-DES / DNIP in the application; it should be noted that, Figure 5 (a) in Fig. 5, BA-DES / M is taken as an example, BA-DES / M refers to an adsorbent prepared by using a traditional solvent methanol as a porogen, the column with a heart symbol is BA-DES / MMIP, and the column without a heart symbol is BA-DES / MNIP, and unified indications are adopted due to limited space and aesthetics; Figure 6 Fig. 6 is a regeneration performance test image of BA-DES / DMIP in the application. DETAILED DESCRIPTION
[0017] Unless otherwise specified, the reagents involved in the embodiments of the present application are all commercially available products, which can be purchased through commercial channels.
[0018] The adsorption experiments of the green-prepared BA-DES / DMIP and BA-DES / MMIP are all carried out in a weak acid environment with pH = 6.0.
[0019] The present application will be further described below in conjunction with examples: Example 1:
[0020] The present embodiment provides a preparation method of a boron affinity adsorbent for separating myricetin in a weak acid environment, which is specifically as follows: (1) Preparation of matrix material HOF-101: First, 0.2 g of 4,4'4'4''-(1,9-dihydro-pyrene-1,3,6,8-tetraacyl)tetraphthalic acid (H4TBAPy) is dissolved into 20 mL of DMF to obtain a first mixture by ultrasonic dispersion; Then, the first mixture is heated at 80°C in an oil bath for 2 h, transferred into 200 mL of ethanol, stirred for 6 h, and then centrifuged to remove the supernatant. The precipitate is washed with ethanol and dried in an oven at 60°C to obtain a bright yellow solid powder HOF-101.
[0021] (2) Preparation of HOF-101-C=C: 80 mg of HOF-101, 8 mg of 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride (EDC), and 200 μL of 5-hexen-1-ol prepared in step (1) are added to a mixed solution of tetrahydrofuran and water (20:6, v / v), stirred at room temperature for 12 h, washed with acetone, and then centrifuged to obtain HOF-101-C=C.
[0022] (3) Preparation of the eutectic solvent DES: Choline chloride, 3-acetylamino phenylboronic acid (AAPBA), and acrylic acid are mixed in a molar ratio of 1:0.5:2 and stirred magnetically at 80°C to form a homogeneous and stable liquid DES1. Choline chloride and ethylene glycol are mixed in a molar ratio of 1:2 and stirred at 80°C for 1 h to obtain a functional monomer DES2.
[0023] (4) Preparation of BA-DES / DMIP First, 20 mg of HOF-101-C=C is ultrasonically dispersed in 10 mL of DES2 solvent, 50 μL of DES1 and 31.4 mg of myricetin are added, and the mixture is stirred at 25°C for 2 h to obtain a pre-polymerization solution; Then, 400 μL ethylene glycol dimethacrylate (EGDMA) and 10 mg azobisisobutyronitrile (AIBN) were added into the pre-polymerization solution, dissolved in the reaction system and deoxidized by nitrogen, polymerized at 65 °C for 4 h, washed with a mixed eluent of methanol and acetic acid (9:1, v / v) until no ultraviolet light adsorption at 375 nm wavelength was visible in the eluent, and dried at 60 °C for 8 h to obtain the boron affinity adsorbent for separating myricetin in a weak acid environment, denoted as 0.5BA-DES / DMIP.
[0024] The boron affinity adsorbent BA-DES / DMIP prepared in this example can be used for separating and purifying myricetin in fruit juice in a weak acid environment. Example 2:
[0025] In this example, the preparation of the eutectic solvent DES is substantially the same as in Example 1, except that in this example, choline chloride, 3-acetylamino phenylboronic acid (AAPBA) and acrylic acid are mixed at a molar ratio of 1:0.3:2 under magnetic stirring at 80 °C to form a homogeneous and stable liquid DES1.
[0026] The boron affinity adsorbent for separating myricetin in a weak acid environment prepared in this example is denoted as 0.3BA-DES / DMIP.
[0027] In addition, this embodiment is completely the same as Example 1, and thus will not be described here. Example 3:
[0028] In this example, the preparation of the eutectic solvent DES is substantially the same as in Example 1, except that in this example, choline chloride, 3-acetylamino phenylboronic acid (AAPBA) and acrylic acid are mixed at a molar ratio of 1:1.0:2 under magnetic stirring at 80 °C to form a homogeneous and stable liquid DES1.
[0029] The boron affinity adsorbent for separating myricetin in a weak acid environment prepared in this example is denoted as 1.0BA-DES / DMIP.
[0030] In addition, this embodiment is completely the same as Example 1, and thus will not be described here. Comparative Example 1:
[0031] This comparative example provides a method for preparing a surface molecularly imprinted polymer using methanol as a porogen, which is as follows: First, 20 mg of HOF-101-C=C was ultrasonically dispersed in 10 mL of methanol solvent, 50 μL of DES1 was added, and stirred at 25°C for 2 h to obtain a prepolymerization solution; then, 400 μL of EGDMA and 10 mg of AIBN were dissolved in the reaction system and deoxygenated with nitrogen, and after polymerization at 65°C for 4 h, dried at 60°C for 8 h to obtain a surface molecularly imprinted polymer using methanol as a pore-forming agent, denoted as 0.5BA-DES / MMIP.
[0032] The preparation of the above-mentioned matrix materials HOF-101, HOF-101-C=C, and eutectic solvent DES1 is the same as that of Example 1. Comparative Example 2:
[0033] This comparative example provides a preparation method of a non-surface molecularly imprinted polymer without myricetin, as follows: First, 20 mg of HOF-101-C=C was ultrasonically dispersed in 10 mL of DES2 solvent, 50 μL of DES1 was added, and stirred at 25°C for 2 h to obtain a prepolymerization solution; then, 400 μL of EGDMA and 10 mg of AIBN were dissolved in the reaction system and deoxygenated with nitrogen, and after polymerization at 65°C for 4 h, dried at 60°C for 8 h to obtain a non-surface molecularly imprinted polymer without myricetin, denoted as 0.5BA-DES / DNIP.
[0034] The preparation of the above-mentioned matrix materials HOF-101, HOF-101-C=C, eutectic solvents DES1, and DES2 is the same as that of Example 1. Comparative Example 3:
[0035] This comparative example is substantially the same as Example 1, except that in the preparation of the eutectic solvent DES of this comparative example, choline chloride and acrylic acid are subjected to magnetic stirring at a molar ratio of 1:2 at 80°C to form a uniform and stable liquid DES1.
[0036] The adsorbent prepared in this comparative example is denoted as DES / DMIP.
[0037] In addition, this comparative example is completely the same as Example 1, and will not be described here.
[0038] Performance and analysis: 1. Verification of the formation of "team-type boron affinity": The structures of 0.5BA-DES / DMIP prepared in Example 1 and 0.5BA-DES / MMIP prepared in Comparative Example 1 were comprehensively characterized, and the adsorption mechanism was explored, and the results are as follows: Figure 1SEM images of 0.5BA-DES / DMIP and 0.5BA-DES / MMIP, pristine HOF-101 matrix Figure 1 a) exhibited cubic rod-like morphology with smooth surface, which provided an ideal growth platform for polymer growth; using DES2 as solvent ( Figure 1 b), the imprinted layer formed uniform dispersed nanoparticles (50-80 nm) anchored on the HOF surface; when using methanol as solvent ( Figure 1 c), due to the weak hydrogen bonding interactions and fast solvent evaporation in methanol, the controlled nucleation and growth of the imprinted layer were hindered, and some larger irregular spherical aggregates (600-800 nm) were sparsely dispersed on the HOF surface. Figure 2 and Figure 3 Further evidence that the dual DES-driven imprinted polymerization process successfully integrated the functional monomer into the MIP structure while preserving the structural backbone of HOF-101, ensuring that the final imprinted material has sufficient molecular recognition ability.
[0039] Figure 4 Adsorption performance test of BA-DES / DMIP, BA-DES / MMIP. The adsorption capacity of DES / DMIP and BA-DES / MMIP increased with the change of pH value (5.0-7.0) ( Figure 4 a), which is consistent with the traditional borate affinity behavior. However, BA-DES / DMIP containing AAPBA showed a peak adsorption at pH 6.0, followed by a decrease at pH 6.5-7.0, which indicates that the DES2 solvent may have adjusted the acidity of the AAPBA borate molecule through B-O coordination between the ethylene glycol hydroxyl group and the AAPBA borate molecule. This coordination may have produced a "team borate affinity" phenomenon, thereby reducing the effective pKa value of the boronic acid, allowing cis-diol to bind at weakly acidic pH. 0.5BA-DES / MMIP showed a weak B-O signal at 191.2 eV ( Figure 4 b), and the B-O peak of 0.5BA-DES / DMIP at 192.2 eV was significantly enhanced, accompanied by a binding energy shift of 1.0 eV. This change reflects the improvement of B-O coordination in DES2, which enhances the positive electronegativity of boron atoms, confirming the formation of a "team borate affinity" configuration. 2. Selectivity test:
[0040] Take 2 mg of BA-DES / DMIP or BA-DES / DNIP prepared by the application respectively into 8 mL of Myrice, Naringenin, Lutin, Caffeic acid, Bisphenol A and Genistein solution (MeOH:PBS 1:4, v / v) with pH=6.0, and shake for 30 min. After standing and precipitation, take the supernatant to measure the absorbance of the solution by UV-vis, and calculate the imprint factor.
[0041] Figure 5 is a selective test of the molecularly imprinted polymer MIP and the non-molecularly imprinted polymer, wherein Figure 5 a is the adsorption amount of different adsorbents on Myrice and the imprint factor figure, 0.5BA-DES / MMIP, the imprint factor only has a slight change, at the same time, BA-DES / DMIP has higher adsorption capacity on Myrice; BA-DES / DMIP has the highest adsorption capacity on Myrice among the six flavonoids (b), which indicates that it has a strong molecular recognition effect on Myrice, and BA-DES / DNIP has poor adsorption effect on all Myrice analogues, which indicates that the specific imprinting cavity has a great influence on the selective adsorption performance. Figure 5 b), which indicates that it has a strong molecular recognition effect on Myrice, and BA-DES / DNIP has poor adsorption effect on all Myrice analogues, which indicates that the specific imprinting cavity has a great influence on the selective adsorption performance. 3、BA-DES / DMIP regeneration performance test:
[0042] Add 4 mg of 0.5BA-DES / DMIP prepared in Example 1 to 16 mL of 20 mg / L Myrice solution and adsorb for 30 min, then centrifuge to collect the Myrice-loaded adsorbent, elute with MeOH / HAc solution (9:1, v / v) for 1 h to regenerate, and use it again for the cycle experiment. Repeat this process for 10 times, record the adsorption capacity each time, and calculate the rebinding rate.
[0043] Figure 6 is the regeneration performance test of 0.5BA-DES / DMIP. After 10 cycles of 0.5BA-DES / DMIP, the rebinding rate decreased to 84.8% of the initial value, but the adsorption capacity still reached 31.58 mg / g. The results show that the imprinting sites are firmly constructed on the adsorbent and can be easily recovered by a simple elution process of 1 h, indicating that BA-DES / DMIP is expected to become an adsorbent material with strong affinity, which is suitable for the practical application of Myrice separation. 4、Test with grape juice as real fruit juice sample:
[0044] The grape juice is diluted 100 times with MeOH-PBS (1:4, v / v) solution. After filtration, the extract is stored in a refrigerator at 4 DEG C, and the actual sample is analyzed by a standard addition method, and 5 mg of BA-DES / DMIP is added to the prepared solution, and oscillated at 25 DEG C for 30 min. The glassy carbon electrode is modified with BA-DES / DMIP to form a modified electrode with selective recognition effect, and the concentration of different sample extracts is detected by electrochemical method.
[0045] In the present application, the recovery rate of BA-DES / DMIP for myricetin in grape juice is 99.80% to 101.67%, indicating that the technology has been successfully used for enrichment and selective analysis of complex samples.
[0046] In summary, the present application uses HOF-101-C=C as a matrix material, myricetin as a template molecule, DES1 as a functional monomer, EGDMA as a crosslinking agent, and DES2 as a pore-forming agent to greenly prepare a boron affinity adsorbent for separating and purifying myricetin in fruit juice in a weak acid environment. The structure of BA-DES / DMIP is comprehensively characterized, the adsorption mechanism is explored, and it is used as a solid phase extraction adsorbent to separate and detect myricetin in fruit juice. The results show that BA-DES / DMIP is an effective adsorbent for separating and purifying myricetin in fruit juice in a weak acid environment.
[0047] The above embodiments only serve to illustrate the technical concepts and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent transformation or modification made according to the spirit and essence of the present application should be covered within the protection scope of the present application.
Claims
1. A method for preparing a boron affinity adsorbent for separating myricetin under a weakly acidic environment, characterized in that: Using HOF-101 as the matrix material, myricetin as the template molecule, DES1 as the eutectic solvent as the functional monomer, ethylene glycol dimethacrylate as the crosslinking agent, and DES2 as the eutectic solvent as the porogen, a boron affinity adsorbent for separating myricetin under a weakly acidic environment was obtained through thermal polymerization. The specific preparation of the eutectic solvent DES1 is as follows: choline chloride, 3-acetaminophenboronic acid and acrylic acid are mixed and stirred at a certain temperature until a uniform and stable liquid is formed; The specific preparation of the eutectic solvent DES2 is as follows: choline chloride and ethylene glycol are mixed and stirred at a certain temperature until a uniform and stable liquid is formed.
2. The method for preparing the boron affinity adsorbent for separating myricetin under a weakly acidic environment according to claim 1, characterized in that, The specific preparation method is as follows: S1. Preparation of matrix material HOF-101; S2. The matrix material HOF-101, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 5-hexen-1-ol described in S1 are added to a mixed solution of tetrahydrofuran and deionized water and stirred for a certain period of time. After washing and centrifugation, HOF-101-C=C is obtained. S3. Add the HOF-101-C=C from S2 to the eutectic solvent DES2, disperse by ultrasonication, add myricetin, dissolve, then add the eutectic solvent DES1, mix and stir to obtain a prepolymer; under nitrogen protection, add azobisisobutyronitrile and ethylene glycol dimethacrylate to the prepolymer, carry out thermal polymerization reaction, then elute with eluent and dry to obtain a boron affinity adsorbent for separating myricetin under weak acid environment.
3. The method for preparing the boron affinity adsorbent for separating myricetin under a weakly acidic environment according to claim 1, characterized in that: In the preparation of the eutectic solvent DES1, the molar ratio of choline chloride, 3-acetaminophenboronic acid and acrylic acid is 1:0.5:2, the stirring temperature is 70-90℃, and the stirring time is 1-2h. In the preparation of the eutectic solvent DES2, the molar ratio of choline chloride to ethylene glycol is 1:2, the stirring temperature is 70-90℃, and the stirring time is 1-2h.
4. The method for preparing the boron affinity adsorbent for separating myricetin under a weakly acidic environment according to claim 2, characterized in that: In S1, the specific preparation steps of the matrix material HOF-101 are as follows: 4,4'4'4''-(1,9-dihydropyrene-1,3,6,8-tetraacyl)tetrabenzoic acid is dispersed in DMF and heated in an oil bath. Then anhydrous ethanol is added, and after stirring for a certain period of time, the supernatant is removed by centrifugation. The resulting precipitate is dried to obtain HOF-101.
5. The method for preparing the boron affinity adsorbent for separating myricetin under a weakly acidic environment according to claim 4, characterized in that: The dosage relationship of 4,4'4'4''-(1,9-dihydropyrene-1,3,6,8-tetraacyl)tetrabenzoic acid, DMF and anhydrous ethanol is: 0.1-10.0g : 10-1000mL : 100-10000mL; the heating temperature of the oil bath is 70-90℃ and the heating time is 1-3h; the stirring time is 5-7h; the drying temperature is 50-70℃.
6. The method for preparing the boron affinity adsorbent for separating myricetin under a weakly acidic environment according to claim 2, characterized in that: In S2, the amounts of the matrix material HOF-101, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 5-hexen-1-ol are in the following ratio: 0.04-8.0 g : 0.004-0.8 g : 100-20000 μL; the volume ratio of tetrahydrofuran to deionized water is 20 : 6; the stirring temperature is room temperature, and the stirring time is 10-14 h.
7. The method for preparing the boron affinity adsorbent for separating myricetin under a weakly acidic environment according to claim 2, characterized in that: In S3, the dosage relationship of HOF-101-C=C, eutectic solvent DES2, myricetin, eutectic solvent DES1, azobisisobutyronitrile, and ethylene glycol dimethacrylate is as follows: 0.01-10.0g∶5-5000mL∶0.0157-15.7g∶25-25000μL∶0.005-5.0g∶200-200000μL.
8. The method for preparing the boron affinity adsorbent for separating myricetin under a weakly acidic environment according to claim 2, characterized in that: In S3, the specific conditions for mixing and stirring are: stirring time of 1-3 hours and stirring temperature of 20-30℃. In S3, the specific conditions for the thermal polymerization reaction are: reaction time of 3-5 hours and reaction temperature of 60-70°C. In S3, the eluent is a mixture of methanol and acetic acid in a volume ratio of 9:1; In S3, the specific drying conditions are: drying temperature of 50-70℃ and drying time of 5-7h.
9. A boron affinity adsorbent for separating myricetin under a weakly acidic environment, prepared by the method according to any one of claims 1-8.
10. The application of a boron affinity adsorbent for separating myricetin under a weakly acidic environment, prepared by any one of claims 1-8, in the separation and purification of myricetin under a weakly acidic environment.