Enrichment and purification material for flavonoids and preparation method and application thereof

Abstract

The application discloses a purification and enrichment material for flavonoids and a preparation method and application thereof, wherein the purification and enrichment material is a magnetic covalent organic polymer material, comprising a magnetic core and a nanoshell, wherein the nanoshell is composed of repeated polybasic ring units and has a structure shown in formula (I). The magnetic covalent organic polymer material can be used for rapid and efficient purification and enrichment of flavonoids in food and traditional Chinese medicines, and has the advantages of high efficiency, small dosage, good stability, large adsorption capacity, easy separation and the like.

Description

Technical Field

[0001] This invention relates to the field of chemistry, and more specifically, to enrichment and purification materials, their preparation methods, and applications. Background Technology

[0002] Magnetic solid phase extraction (MSPE) is a dispersion-based solid phase extraction technique that uses magnetic or magnetizable materials as adsorbents. Compared to traditional solid phase extraction techniques, MSPE is simpler to operate. It eliminates the need to fill the solid phase extraction column with the adsorbent; instead, the adsorbent is directly dispersed in the sample solution for adsorption. Then, an external magnetic field is used to separate the magnetic solid phase extraction material from the sample. Finally, elution with an organic solvent achieves the separation and enrichment of the target analytes. MSPE features high extraction efficiency, simple operation, and wide applicability, making it a novel and effective sample pretreatment method.

[0003] Flavonoids are among the main bioactive components in many foods and traditional Chinese medicines, possessing a variety of pharmacological and biochemical effects, including antioxidant, antibacterial, anti-vascular disease, and anti-inflammatory properties. However, extracting and separating trace amounts of flavonoids from complex food or traditional Chinese medicine matrices still faces many technical challenges, making the development of efficient and selective enrichment and purification materials crucial.

[0004] Therefore, further research is needed on magnetic enrichment and purification materials for extracting flavonoids from different sample matrices. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, one objective of this invention is to propose an enrichment and purification material with advantages such as good stability, large adsorption capacity, and easy adsorption and separation. The inventors used covalent organic polymers (COPs) as raw materials to coat the surface of magnetic iron oxide (Fe3O4) to form a porous organic nanoshell. This enrichment and purification material is then used to efficiently enrich flavonoids present in complex samples, exhibiting strong and rapid adsorption capacity.

[0006] Covalent organic polymers (COPs) are a class of porous organic polymers based on light elements such as C, H, N, and O, and have wide applications in separation, catalysis, sensing, drug delivery, and energy harvesting. Furthermore, magnetic materials offer a simpler and more effective alternative to traditional solid-phase extraction adsorbents, enabling rapid separation of target analytes from complex samples and overcoming the drawbacks of COP materials in terms of separation and recovery. Therefore, according to one aspect of the present invention, an enrichment and purification material is provided. According to an embodiment of the present invention, the enrichment and purification material comprises: a magnetic core formed of Fe3O4; and a nanoshell covering at least a portion of the surface of the magnetic core, composed of repeating multi-ring units, with the structural formula (I) below.

[0007]

[0008] The enrichment and purification material of this invention uses iron oxide (Fe3O4) as a magnetic core, which is magnetic and easily adsorbed and separated, thus solving the problems of inconvenient operation and difficult recycling of covalent organic polymers. The nanoshell is a covalent organic polymer material with a large specific surface area and good stability, and has broad application prospects in the adsorption of flavonoids. Using this enrichment and purification material to adsorb flavonoids exhibits high specificity and short adsorption time; only a very small amount of organic reagent is needed to complete the adsorption and desorption of flavonoids within minutes. It has the advantages of simple operation, time-saving efficiency, and environmental friendliness, and is particularly suitable for the enrichment and adsorption of flavonoids in complex samples, such as food and traditional Chinese medicine.

[0009] In addition, the enrichment and purification material according to the above embodiments of the present invention may also have the following additional technical features:

[0010] According to an embodiment of the present invention, the average pore size of the nanoshell is 2-4 nm and the thickness is 30 nm.

[0011] According to an embodiment of the present invention, the specific surface area and pore volume of the enriched purification material are 60-100 m². 2 / g and 0.02-0.08cm 3 / g.

[0012] According to an embodiment of the present invention, the atomic composition ratio of C, N, O and Fe on the surface of the enriched purification material is 85-90:5-10:5-10:0-5.

[0013] According to an embodiment of the present invention, the particle size of the core is 50-100 nm.

[0014] According to an embodiment of the present invention, the saturated adsorption capacity of the enrichment and purification material for flavonoids is approximately 90–210 mgg.-1 .

[0015] According to an embodiment of the present invention, the adsorption equilibrium time of the enrichment and purification material for flavonoids is 10-20 minutes.

[0016] According to an embodiment of the present invention, the water contact angle of the enrichment and purification material is 55-65°.

[0017] According to an embodiment of the present invention, the surface of the enrichment and purification material includes two binding sites.

[0018] According to embodiments of the present invention, the flavonoid compound is at least one selected from hesperidin, naringenin, daidzein, glycyrrhizin, pinocembrin, and styracin.

[0019] According to another aspect of the present invention, the present invention provides a method for preparing the aforementioned enriched purification material. According to an embodiment of the present invention, the method includes: dissolving Fe3O4 nanoparticles and an aldehyde monomer in an organic solvent to obtain a solution; and dissolving an amino monomer in the solution to perform a polymerization reaction to obtain the enriched purification material.

[0020] According to the preparation method of this invention, magnetic iron oxide nanoparticles are coated with nanoshells synthesized from amino and aldehyde monomers to form a magnetic covalent organic polymer. The resulting enriched purification material is magnetic and easily adsorbed and separated. This enriched purification material is highly specific for adsorbing flavonoids, with a short adsorption time. Only a very small amount of organic reagent is needed to complete the adsorption and desorption of flavonoids within minutes. It has advantages such as simple operation, time-saving efficiency, and environmental friendliness, thus solving the problems of inconvenient operation and difficulty in recycling covalent organic polymers. Furthermore, this method requires simple experimental equipment and is easy to promote and apply.

[0021] According to an embodiment of the present invention, the aldehyde monomer is 4,4′,4″-(1,3,5-triazine ring-2,4,6-triyl)tribenzaldehyde (TFPB).

[0022] According to an embodiment of the present invention, the amino monomer is tetrakis(4-aminophenyl)methane (TAPM).

[0023] According to an embodiment of the present invention, the molar ratio of the amino monomer to the aldehyde monomer is 3:4-5.

[0024] According to an embodiment of the present invention, the polymerization reaction is carried out under catalytic conditions, wherein the catalyst is acetic acid.

[0025] According to an embodiment of the present invention, the dissolution process is performed under ultrasound for 15-25 minutes.

[0026] According to an embodiment of the present invention, the polymerization reaction is carried out at 60-70 degrees Celsius; the rotation speed is 400-1000 rpm, preferably 500-600 rpm, and the time is 2-4 hours.

[0027] According to an embodiment of the present invention, the organic solvent is tetrahydrofuran.

[0028] According to another aspect of the present invention, a method for adsorbing flavonoids is provided. According to an embodiment of the present invention, the method utilizes the aforementioned enrichment and purification material. Therefore, it has a large adsorption capacity, a fast adsorption rate, and is easy to adsorb and separate, enabling rapid and efficient extraction of flavonoids from complex samples. Using this enrichment and purification material for adsorbing flavonoids exhibits high specificity and a short adsorption time; only a very small amount of organic reagent is needed to complete the adsorption and desorption of flavonoids within minutes. It has advantages such as simple operation, time-saving efficiency, and environmental friendliness.

[0029] According to an embodiment of the present invention, the saturated adsorption capacity of the enrichment and purification material is approximately 90–210 mg·g. -1 .

[0030] According to an embodiment of the present invention, the adsorption equilibrium time of the enrichment and purification material for flavonoids is 10-20 minutes.

[0031] According to an embodiment of the present invention, the flavonoid compound is at least one selected from hesperidin, naringenin, daidzein, glycyrrhizin, pinocembrin, and styracin.

[0032] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0033] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0034] Figure 1 Characterization images of the enriched purification material according to an embodiment of the present invention are shown, wherein A and B are SEM images of Fe3O4 and Fe3O4@TAPM-TFPB, respectively; and C and D are TEM images of Fe3O4 and Fe3O4@TAPM-TFPB, respectively.

[0035] Figure 2Characterization diagrams of an enriched purification material according to an embodiment of the present invention are shown, wherein A is an FT-IR spectrum; B is a nitrogen adsorption-desorption isotherm; C is a pore size distribution diagram; D is an energy dispersive spectrum; E is an X-ray photoelectron spectrum; F is an X-ray C1 spectrum; G is a thermogravimetric analysis diagram; and H is a magnetic hysteresis curve.

[0036] Figure 3 The diagram shows the adsorption of an enriched purification material according to an embodiment of the present invention, where A is a static adsorption curve and B is a dynamic adsorption curve. Detailed Implementation

[0037] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0038] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0039] According to one aspect of the present invention, an enrichment and purification material is provided. According to an embodiment of the present invention, the enrichment and purification material comprises: a magnetic core formed of iron(III) oxide; and a nanoshell covering at least a portion of the surface of the magnetic core, the nanoshell being composed of repeating multi-ring units as shown in Formula I.

[0040]

[0041] The enrichment and purification material of this invention uses iron(III) oxide as a magnetic core, which is magnetic and easily adsorbed and separated, thus solving the problems of inconvenient operation and difficulty in recycling of covalent organic polymer materials. The nanoshell, composed of multi-ring units as shown above, is a magnetic covalent organic polymer material with a large specific surface area and good stability, making it particularly suitable for the extraction of flavonoids. Using this enrichment and purification material to adsorb flavonoids exhibits high specificity and short adsorption time; only a very small amount of organic reagent is needed to complete the adsorption and desorption of flavonoids within minutes. It has advantages such as simple operation, time-saving efficiency, and environmental friendliness, and is particularly suitable for the enrichment and adsorption of flavonoids in complex samples, such as food and traditional Chinese medicine.

[0042] The nanoshells in this invention have a porous network structure. A thicker nanoshell indicates a greater number of repeating units and thus a higher adsorption capacity. According to embodiments of this invention, the average pore size of the nanoshell is 2–4 nm, and the thickness is 25–35 nm, preferably 30 nm. Therefore, it exhibits good adsorption performance for flavonoids.

[0043] According to an embodiment of the present invention, the specific surface area and pore volume of the enriched purification material are 60-100 m². 2 / g and 0.02-0.08cm 3 / g. Therefore, the enrichment and purification material has a large specific surface area and strong adsorption capacity, requiring less enrichment and purification material to adsorb the target compound, and the adsorption time is short.

[0044] According to an embodiment of the present invention, the atomic composition ratio of C, N, O, and Fe on the surface of the enriched purification material is 85-90:5-10:5-10:0-5. It should be noted that the "enriched purification material surface" is obtained based on the structure of the purification material detected by X-ray powder diffraction (XPS). XPS is a highly practical surface analysis method for qualitative and quantitative analysis and structural identification of solid surfaces. It measures the elemental composition of the material surface (the outermost part of the material), and the ratio of C, N, O, and Fe atoms is also obtained based on X-ray powder diffraction.

[0045] According to an embodiment of the present invention, the particle size of the core is 50-100 nm.

[0046] According to an embodiment of the present invention, the saturated adsorption capacity of the enrichment and purification material for flavonoids is approximately 90–210 mg / g. -1 Therefore, this enrichment and purification material has a strong adsorption capacity and can efficiently extract flavonoids from complex samples.

[0047] According to an embodiment of the present invention, the adsorption equilibrium time for flavonoids by the enrichment and purification material is 10-20 minutes, preferably 20 minutes. Therefore, the enrichment and purification material has a high adsorption rate and can rapidly extract flavonoids from complex samples.

[0048] According to an embodiment of the present invention, the water contact angle of the enrichment and purification material is 55-65°. Therefore, the enrichment and purification material can be well dispersed in the solution, easily contacting the sample, which is beneficial for more complete enrichment of flavonoids.

[0049] According to an embodiment of the present invention, the surface of the enrichment and purification material includes two types of binding sites. Therefore, the entire adsorption process is influenced not only by substance transport but also by chemisorption, increasing the material's adsorption capacity for the target analyte.

[0050] According to embodiments of the present invention, the flavonoid compound is at least one selected from hesperidin, naringenin, daidzein, glycyrrhizin, pinocembrin, and styracin.

[0051] According to another aspect of the present invention, the present invention provides a method for preparing the aforementioned enrichment and purification material. According to an embodiment of the present invention, the method includes: placing an aldehyde monomer, an amino monomer, and iron(III) oxide nanoparticles in a reaction solvent, adding a catalyst, and mechanically stirring.

[0052] According to the preparation method of this invention, magnetic iron oxide nanoparticles are coated with nanoshells synthesized from amino and aldehyde monomers to form a magnetic covalent organic polymer. The resulting enriched purification material is magnetic and easily adsorbed and separated, thus solving the problems of inconvenient operation and difficult recycling of covalent organic polymers. Furthermore, this method requires simple experimental equipment and is easy to promote and apply.

[0053] According to embodiments of the present invention, the aldehyde monomer is 4,4′,4″-(1,3,5-triazinecyclo-2,4,6-triyl)tribenzaldehyde (TFPB), and the amino monomer is tetrakis(4-aminophenyl)methane (TAPM). The inventors compared multiple groups of aldehyde monomers and amino monomers, and found that the polymer formed by the above-mentioned aldehyde monomer and amino monomer exhibits good adsorption performance and high recovery rate for flavonoids.

[0054] According to an embodiment of the present invention, the molar ratio of the amino monomer to the aldehyde monomer is 3:4-5, preferably 3:4. Based on the number of amino groups (3) in the molecular formula of the amino monomer and the number of aldehyde groups (4-5) in the molecular formula of the aldehyde monomer, we selected a molar ratio of 3:4-5 for the two monomers, preferably 3:4. Therefore, at this ratio, the two monomers participating in the reaction can react to the maximum extent to achieve complete reaction.

[0055] According to an embodiment of the present invention, the organic solvent is tetrahydrofuran.

[0056] According to an embodiment of the present invention, the catalyst is acetic acid. Therefore, the polymerization reaction is highly efficient.

[0057] According to an embodiment of the present invention, the dissolution process is performed under ultrasound for 15-25 minutes. This ensures that the Fe3O4 nanoparticles and aldehyde monomers are fully dispersed in the organic solvent.

[0058] According to embodiments of the present invention, the polymerization reaction is carried out at 60-70 degrees Celsius; the rotation speed is 400-1000 rpm, preferably 500-600 rpm, and the time is 2-4 hours. This facilitates a fully efficient polymerization reaction and results in a high yield of the organic framework polymer.

[0059] According to another aspect of the present invention, a method for adsorbing flavonoids is provided. According to an embodiment of the present invention, the method utilizes the aforementioned enrichment and purification material. Therefore, it has a large adsorption capacity, a fast adsorption rate, and is easy to adsorb and separate, enabling rapid and efficient extraction of flavonoids from complex samples. In the pretreatment process, this enrichment and purification material significantly shortens the pretreatment time; only a very small amount of organic reagent is needed to complete the adsorption and desorption of flavonoids within minutes, offering advantages such as simple operation, time-saving efficiency, and environmental friendliness.

[0060] According to an embodiment of the present invention, the saturated adsorption capacity of the enrichment and purification material for flavonoids is approximately 90–210 mg / g. -1 Therefore, this enrichment and purification material has a strong adsorption capacity and can efficiently extract flavonoids from complex samples.

[0061] According to an embodiment of the present invention, the adsorption equilibrium time for flavonoids by the enrichment and purification material is 10-20 minutes, preferably 20 minutes. Therefore, the enrichment and purification material has a high adsorption rate and can rapidly extract flavonoids from complex samples.

[0062] According to embodiments of the present invention, the flavonoid compound is at least one selected from hesperidin, naringenin, daidzein, glycyrrhizin, pinocembrin, and styracin.

[0063] The present invention will now be described with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and should not be construed as limiting the present invention.

[0064] The present invention will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products, such as those purchased from Sigma.

[0065] Example 1

[0066] In this embodiment, tetrakis(4-aminophenyl)methane (TAPM) is used as the amino monomer, and 4,4′,4″-(1,3,5-triazinecyclo-2,4,6-triyl)tribenzaldehyde (TFPB) is used as the aldehyde monomer to prepare the enrichment and purification material. The specific method is as follows:

[0067] (1) Disperse or dissolve Fe3O4 (0.43 mmol, 100 mg) and 4,4′,4″-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde (0.2 mmol, 68.08 mg) in 20 mL of tetrahydrofuran in a double-necked round-bottom flask (100 mL) and sonicate for 20 minutes.

[0068] (2) The mixture was then transferred to a water bath at 65°C and mechanically stirred at 500 rpm for 30 min. TAPM (0.15 mmol, 119.8 mg) was dissolved in THF (10 mL) and slowly added to the above system.

[0069] (3) Acetic acid (1.5 mL) was added dropwise to the flask as a catalyst to accelerate the reaction. The mixture was mechanically stirred at 500 rpm for 2 h at room temperature.

[0070] (4) With the aid of an external magnet, the obtained magnetic dark green precipitate was washed alternately with MeOH and ACN until the supernatant was clear. Finally, the material was dried in an oven at 60°C for 12 hours (yield ≥87%) to obtain magnetic dark green powder particles Fe3O4@TAPM-TFPB. The reaction formula is as follows:

[0071]

[0072] Example 2

[0073] Detailed characterization experiments were conducted on the enriched purification material (Fe3O4@TAPM-TFPB) prepared in Example 1 to demonstrate its successful preparation and excellent physicochemical properties. The specific details are as follows:

[0074] 1. The morphology and internal structure of Fe3O4 nanoparticles and magnetic COPs were observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results are as follows: Figure 1 A and Figure 1 As shown in Figure B, the Fe3O4 nanoparticles and magnetic COPs exhibit regular structural patterns.

[0075] Furthermore, the diameter of Fe3O4 nanoparticles is approximately 50–100 nm, while the diameter of magnetic COPs increases by about 30 nm. From Figure 1 As shown in Figure D, Fe3O4@COPs exhibits a distinct core-shell structure, with the solid black core representing a magnetic core, indicating the adsorbent possesses good magnetic properties. The outer light gray coating is the COPs coating, which... Figure 1 Compared to Fe3O4, the core-shell thickness of magnetic COPs is about 30 nm, indicating that the COPs have been successfully modified on the surface of the magnetic core. This is also the key to ensuring that the adsorbent can adsorb the target analyte.

[0076] 2. The chemical structure and composition of Fe3O4 and the enrichment and purification material Fe3O4@TAPM-TFPB were analyzed by Fourier transform infrared spectroscopy. The results are as follows: Figure 2 As shown in Figure A, the transmittance of the particles is between 4000 and 500 cm⁻¹. -1 Measurements were performed within the specified range. The FT-IR results of the new material (curve 4) are shown at 591 cm⁻¹. -1 The characteristic adsorption band at this location is attributed to the Fe-O-Fe vibration of the Fe3O4 nanoparticles (curve 1). Meanwhile, at 1603 cm⁻¹... -1 A new absorption peak was observed at 2747 cm⁻¹, which can be attributed to the C=N stretching vibration, indicating that C=O (TFPB, curve 3) and NH (TAPM, curve 2) are converted into C=N groups. Furthermore, TFPB shows an absorption peak at 2747 cm⁻¹. -1 and 2827cm -1 The two characteristic peaks (curve 3) are attributed to the CH stretching vibration of the -CHO group, which are absent in the new material Fe3O4@TAPM-TFPB, indicating that the material was successfully synthesized.

[0077] 3. The gas adsorption isotherm was studied using nitrogen adsorption-desorption experiments. For example... Figure 2 As shown in Figure B, bare Fe3O4 exhibits a Type IUPACII isotherm, displaying a distinctly non-porous structure; Fe3O4@TAPM-TFPB exhibits a typical Type IV isotherm, displaying mesoporous characteristics. The calculated BET specific surface area and pore volume of Fe3O4@TAPM-TFPB are 78.34 m². 2 / g and 0.055cm 3 / g. Furthermore, due to the three-dimensional structure of the synthesized materials, the average pore sizes of M-COPs differ, being 2.8 nm and 3.8 nm, respectively. Figure 2 C).

[0078] 4. For example Figure 2 As shown in D and E, the chemical composition of the generated M-COPs was evaluated by EDS and XPS analysis, and the data obtained by the two methods were compared (Table 1). The results show that the Fe atomic content is less than 1%, further confirming that the Fe3O4 surface coating is a novel material. XPS (C1s) spectrum ( Figure 2 F) The presence of a peak related to the C=C bond at 284.8 eV, the C=C bond at 285.8 eV, and the C=N bond at 290.8 eV confirms the successful synthesis of Fe3O4@TAPM-TFPB.

[0079] Table 1 Elemental analysis results of M-COPs

[0080]

[0081] 5. In addition, the thermal stability of M-COPs in the range of 50–800 °C was studied using thermogravimetric analysis and differential thermal analysis. Figure 2 (G) A weight loss of 5.3% was observed between 50 and 495 °C, corresponding to two consecutive upward peaks on the DTA curve, which is likely due to the pyrogenic decomposition of the anomalous structure. When the temperature was between 495 and 579.3 °C, the TGA curve showed a significant weight loss (15.7%), consistent with the upward exothermic peak of the DTA curve. This is presumably due to the destruction and carbonization of the bulk material.

[0082] 6. The magnetic properties of the prepared Fe3O4 nanoparticles and M-COPs were characterized using a vibrating sample magnetometer. The saturation magnetization values ​​of Fe3O4 and Fe3O4@TAPM-TFPB were 82.5 and 38.2 emu / g, respectively. Figure 2 H); With the help of an external magnet, the phase separation of M-COPs from the solution can be completed within 20 seconds, meeting the requirements of rapid sample preparation.

[0083] 7. The hydrophobicity of the M-COPs surface was studied using a video optical contact angle meter. The water contact angle was 57.55°, indicating that the material can be well dispersed in the sample solution.

[0084] Example 3

[0085] The feasibility of enriching and purifying flavonoids using the enrichment and purification material (Fe3O4@TAPM-TFPB) prepared in Example 1 was investigated, as detailed below:

[0086] Experiments confirmed that Fe3O4@TAPM-TFPB can be used as an adsorbent for extracting flavonoids. The adsorption performance of this material for different concentrations of flavonoids at different times was investigated. The high adsorption capacity of these compounds can be attributed to van der Waals forces and the strong interaction between COPs and the target analytes. This example studies the adsorption of flavonoids on the Fe3O4@TAPM-TFPB adsorbent.

[0087] For the adsorption isotherm experiment, 1.0 mg of Fe3O4@TAPM-TFPB was added to 5 mL of 6 flavonoid compounds (0–80 μg·mL). -1 The sample was placed in a container and shaken. The maximum adsorption capacity of Fe3O4@TAPM-TFPB for six flavonoids was calculated.

[0088] Experimental results are as follows Figure 3 As shown in Figure A, when the amount of adsorbent is 1.0 mg, the adsorption capacity of the magnetic adsorbent for flavonoids ranges from 0 to 80 μg / mL. -1Within the concentration range, the adsorption capacity increases with increasing concentration. Experiments showed that the material achieved saturated adsorption capacities of 134, 147, 141, 195, 212, and 90 mg·g for hesperidin, naringenin, daidzein, pinocembrin, gentiopicrin, and glycyrrhizin, respectively. -1 The adsorption isotherms were determined using three models: Freundlich, Langmuir, and Temkin. The parameters of the obtained model adsorption isotherms are shown in Table 2. The results show that the Freundlich model (R... 2 (0.929-0.988) compared to Langmuir (R 2 (0.349-0.979) and the Temkin model (R 2 A value of 0.836-0.941 is more suitable. The results show that the adsorption sites on the adsorbent surface are non-uniform, and the adsorption process involves a multilayer adsorption mechanism.

[0089] Table 2 Adsorption isotherm parameters

[0090]

[0091]

[0092] Example 4

[0093] Kinetics studies the relationship between the concentration of adsorbate molecules and the adsorption rate in an adsorption process. A kinetic model, on the other hand, is an equation derived from kinetics and practical applications to describe the adsorption process. In solid-liquid adsorption, pseudo-first-order kinetic equations and pseudo-second-order kinetic equations are commonly used to describe the adsorption rate.

[0094] The adsorption kinetics of hesperidin, naringenin, daidzein, pinocembrin, gentiopicrin, and glycyrrhizin on the material were analyzed. The adsorption of the targets on the material gradually increased in the first 20 minutes, then reached an adsorption equilibrium. The results are as follows: Figure 3 As shown in B. Based on the pseudo-first-order and pseudo-second-order kinetic models of flavonoid adsorption by Fe3O4@TAPM-TFPB in Table 3, R... 2 By comparison, the linear correlation coefficient (R0) of the pseudo-second-order adsorption kinetic model can be obtained. 2 The linear correlation coefficient (R) of the pseudo-first-order adsorption kinetic model was ≥0.992. 2 (≤0.990) is closer to 1. Therefore, the adsorption process of flavonoids by magnetic COPs adsorbents can be described by a pseudo-second-order kinetic model, which indicates that there are two binding sites on the adsorbent surface and emphasizes that the adsorption process is affected not only by mass transport but also by chemisorption.

[0095] Table 3. Relevant parameters of the pseudo-first-order dynamic model and the pseudo-second-order dynamic model.

[0096]

[0097] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0098] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A material for enriching and purifying flavonoids, characterized in that, include: A magnetic core, wherein the magnetic core is formed of iron(III) oxide; A nanoshell, covering at least a portion of the surface of the magnetic core, is composed of repeating multi-ring units, with the structural formula shown in formula (I). Furthermore, the nanoshell is a porous structure with an average pore size of 2–4 nm and a thickness of 25–35 nm. The flavonoid is selected from at least one of hesperidin, naringin, daidzein, glycyrrhizin, pinocembrin and styracin; 。 2. The enrichment and purification material according to claim 1, characterized in that, The specific surface area and pore volume of the enrichment and purification material are 60-100 m². 2 / g and 0.02-0.08 cm 3 / g.

3. The enrichment and purification material according to claim 1, characterized in that, The magnetic core has a particle size of 50~100 nm.

4. The enrichment and purification material according to claim 1, characterized in that, The saturated adsorption capacity of the enrichment and purification material for flavonoids is 90–210 mg·g. -1 .

5. The enrichment and purification material according to claim 1, characterized in that, The adsorption equilibrium time for flavonoids by the enrichment and purification material is 10-20 minutes.

6. The enrichment and purification material according to claim 1, characterized in that, The water contact angle of the enriched purification material is 55-65°.

7. The enrichment and purification material according to claim 1, characterized in that, The surface of the enriched purification material includes two types of binding sites.

8. A method for preparing the enrichment and purification material according to any one of claims 1-7, characterized in that, include: Fe3O4 nanoparticles and aldehyde monomers were dissolved in an organic solvent to obtain a solution. as well as The amino monomer is dissolved in the solution and polymerized to obtain the enriched and purified material.

9. The method according to claim 8, characterized in that, The aldehyde monomer is 4,4',4''-(1,3,5-triazine-2,4,6-trimethyl)tribenzaldehyde (TFPB).

10. The method according to claim 8, characterized in that, The amino monomer is tetra(4-aminophenyl)methane (TAPM).

11. The method according to claim 8, characterized in that, The molar ratio of the amino monomer to the aldehyde monomer is 3:4-5.

12. The method according to claim 8, characterized in that, The polymerization reaction is carried out under catalytic conditions, wherein the catalyst is acetic acid.

13. The method according to claim 8, characterized in that, The dissolution process is performed under ultrasound for 15-25 minutes.

14. The method according to claim 8, characterized in that, The polymerization reaction is carried out at 60-70 degrees Celsius, at a rotation speed of 400-1000 rpm, for 2-4 hours.

15. The method according to claim 14, characterized in that, The polymerization reaction speed is 500-600 rpm.

16. The method according to claim 8, wherein the organic solvent is tetrahydrofuran.

17. A method for adsorbing flavonoids, characterized in that, The method is carried out using the enrichment and purification material according to any one of claims 1-7.

18. The method according to claim 17, characterized in that, The saturated adsorption capacity of the enrichment and purification material is 90–210 mg·g⁻¹. -1 .

19. The method according to claim 17, characterized in that, The adsorption equilibrium time for flavonoids by the enrichment and purification material is 10-20 minutes.

20. The method according to claim 17, characterized in that, The flavonoid compound is selected from at least one of hesperidin, naringenin, daidzein, glycyrrhizin, pinocembrin, and styracin.

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