A method for purifying hemoglobin

Abstract

The application provides a hematin purification method, comprising the following steps: S1, centrifuging anticoagulant pig blood, collecting blood corpuscles after solid-liquid separation; S2, adding water in a proportion of 1g:2-4ml, mixing and adjusting pH to 8.5-8.8, adding 0.04-0.06% ascorbic acid, and heating to 55-65 DEG C, and adding 0.8-2.5% compound enzyme for enzymolysis for 6.5-8.0h; S3, adjusting the pH of the enzymolysis solution to 3.6, standing for 20-60min, centrifuging and collecting the precipitate; S4, using a magnetic resin column for column adsorption; S5, filtering after vacuum extraction and recovery of ethanol, adjusting pH to 5.0, centrifuging and collecting the precipitate; and S6, drying to obtain the product. Compared with the acid acetone method, the hematin purification method provided by the application greatly reduces the use of organic solvents and the product purity reaches 99%, which preliminarily meets the quality requirements of pharmaceutical raw materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hematin, in particular to a hematin purification method. BACKGROUND

[0002] Hematin, also known as iron porphyrin, is formed by the complexation of protoporphyrin IX and an iron ion, and is widely present in the blood, muscle and certain plant tissues of animals, and is the prosthetic group of hemoglobin, myoglobin, cytochrome C, catalase and peroxidase, etc., and has been widely used in food, cosmetics and biochemical analysis research. With the deepening of research, hematin or its raw materials are gradually used in the field of medicine, for example, hematin can be used as an iron supplement or as a raw material for producing protoporphyrin disodium salt (liver function improver), hematin (cancer diagnosis and treatment drug).

[0003] At present, the commonly used and mature hematin extraction methods at home and abroad include the glacial acetic acid method, the acidic acetone method, the blood powder method, the methyl cellulose method, the enzymatic hydrolysis method, and the surfactant method, etc. However, the purity of hematin extracted from animal blood by the above methods is limited; therefore, the Chinese patent with the application number 201710948474.2 discloses a hematin extraction method, which adjusts the pH to 3-3.5 after enzymatic hydrolysis, and collects the first precipitate by standing; the first precipitate is dissolved in a sodium hydroxide solution to adjust the pH value to 7-9, and then centrifuged, and the supernatant is taken and precipitated by adding anhydrous calcium chloride, and the second precipitate is collected by centrifugation and washed to neutral, and then dried to obtain the hematin; the above scheme can further improve the purity of hematin, but it is still difficult to reach the pharmaceutical grade.

[0004] In view of this, the technical scheme is proposed as follows. SUMMARY

[0005] The problem solved by the present application is how to further improve the purity of hematin to meet the pharmaceutical requirements.

[0006] To solve the above problems, the present application provides a hematin purification method, which comprises the following steps:

[0007] S1, centrifuging the anticoagulated pig blood, collecting the blood cells after solid-liquid separation, and collecting the precipitate after centrifugation and washing with 0.9% NaCl;

[0008] S2, adding water in an amount of 2-4 ml per 1 g of the blood cells, mixing and adjusting the pH to 8.5-8.8, adding 0.04-0.06% ascorbic acid, and heating to 55-65℃, and adding 0.8-2.5% complex enzyme for enzymatic hydrolysis for 3.5-5.0 h;

[0009] S3, adjusting the pH of the enzymatic hydrolysate to 3.6, standing for 20-60 min, centrifuging and collecting the precipitate;

[0010] S4, dissolve the precipitate in sodium hydroxide solution with pH 9.8-10.5, filter the impurities with 0.5 μm filter membrane; load the magnetic resin into the resin column which is vertically placed and is in the adjustable magnetic field, control the magnetic induction intensity to be 0.8-1.2 T, and the filtrate is loaded into the magnetic resin column at the flow rate of 1.8-2.5 BV / h; after the adsorption is completed, adjust the magnetic induction intensity to be 1.4-1.6 T, and wash the impurities with the organic aqueous solution at 1.0-2.0 BV / h; then adjust the magnetic induction intensity to be 0.8-1.2 T, and elute with the pH 10.2, 60-80% ethanol solution, and collect the eluate;

[0011] S5, filter after the ethanol is recovered by vacuum pumping, adjust the pH to 5.0, and collect the precipitate by centrifugation;

[0012] S6, dry to obtain.

[0013] The application collects the blood cells, performs enzymolysis, adjusts the pH to 3.5, collects the crude hematin by centrifugation, dissolves the hematin in the alkaline aqueous solution, adsorbs with the magnetic resin, washes with the ethanol aqueous solution to remove the cell membrane fragments and other impurities, desorbs with the high-concentration ethanol alkaline solution, removes the ethanol, reduces the solution volume and the ethanol content, and precipitates part of the organic impurities, which is filtered through the 0.5 μm filter to remove part of the impurities, and is beneficial to the improvement of the purity of the final product.

[0014] Preferably, the step S2 comprises: S21, homogenate according to 1g:1.5ml of deionized water, freeze at-20℃ to-25℃ for 120-150min, and melt according to 8-10℃ / min to 30-35℃; S22, mix according to 1g:0.5ml of deionized water, adjust the pH to 8.5-8.8, add 0.04-0.06% ascorbic acid, and heat to 55-65℃, and enzymolysis for 6.5-8.0h.

[0015] Generally, the water is added to the blood cells to cause the red blood cells to absorb water and cause the cell membrane to rupture, and the mechanical external force such as stirring is used to improve the rupture speed, but the high stirring speed can increase the oxygen content in the solution and cause the hematin to be easily oxidized; the ice crystals are formed in the frozen state to promote the cell membrane rupture and release the hemoglobin, which is helpful to shorten the heating enzymolysis time to reduce the risk of oxidation, and is beneficial to improve the purity and yield of the final hematin product.

[0016] Preferably, the complex enzyme is composed of alkaline protease and flavor protease in a ratio of 1:1-3. Preferably, the ratio of the alkaline protease and the flavor protease is 1:3. The alkaline protease and the flavor protease act as endopeptidases and exopeptidases, respectively, to gradually undergo enzymatic reaction, and the degree of hydrolysis is improved; the hemoglobin catalyzed by the enzymes is hydrolyzed to form low-molecular-weight polypeptides and amino acids, which are finally removed in the pH 3.5 aqueous solution.

[0017] Preferably, the organic aqueous solution in step S4 is a 30% ethanol solution with a pH of 9.0. By increasing the magnetic field intensity during water washing, the adsorption strength of the resin to hematin can be further improved, and by using higher 30% ethanol, the broken cell membranes and other impurities can be eluted and removed, thereby improving the purity of the final product.

[0018] Preferably, the sodium hydroxide aqueous solution in step S4 is treated as follows: S11, the stirred tank is filled with nitrogen in advance, the pH 10.0 sodium hydroxide solution is added, and then heated to 50°C, vacuumed to 0.015 Mpa, and stirred at reduced pressure for 30 min; S12, slowly reduced to 4°C at a speed of 10°C / h, nitrogen is introduced into the stirred tank to 0.15 Mpa, and stirred at increased pressure for 30 min; S13, slowly increased to 50°C at a speed of 15°C / h, while slowly reduced the pressure to 0.015 Mpa at a speed of 0.04 Mpa / h, and stirred for 30 min; S14, slowly reduced to 4°C at a speed of 10°C / h, while slowly introducing nitrogen into the stirred tank to increase the pressure to 0.35 Mpa at a speed of 0.04 Mpa / h, and stirred at increased pressure for 30 min, and placed at room temperature and normal pressure for standby. The sodium hydroxide aqueous solution can effectively remove the residual oxygen content in the solution by controlling the temperature and pressure, and can improve the stability of hematin by physical methods without using chemical antioxidants, avoid oxidation during the dissolution and resin adsorption process, and is beneficial to improve the purity of the final product.

[0019] Preferably, the preparation method of the magnetic resin is as follows:

[0020] S401, weigh 6.2g FeCl3.6H2O and 2.2g FeCl2.4H2O, dissolve them in 180ml deionized water, introduce N2 protection, stir under 80°C water bath, and add NH3.H2O to adjust the pH to 10.0, react for 25 min, wash with deionized water, and then vacuum dry at 55°C to obtain magnetic particles; mix methanol, magnetic particles, and tetraethyl orthosilicate in a ratio of 5:1:0.2, react at 45°C for 3.5h, and obtain modified magnetic particles;

[0021] S402: Mix 10 parts acrylonitrile, 15 parts styrene, 70 parts divinylbenzene, 20 parts triallyl isocyanurate, 12 parts methyl acrylate, 36 parts gasoline, 1.2 parts diphenyl peroxide, and 5 parts modified magnetic particles evenly to form the oil phase; mix 600 parts deionized water, 55 parts calcium oxide, 24 parts sodium chloride, and 0.9 parts polyvinyl alcohol evenly to form the aqueous phase.

[0022] S403. Add the oil phase to the aqueous phase and stir to disperse the oil phase into beads; heat to 82℃ and after the beads have solidified, continue to heat to 90℃ and react for 2.5 hours; raise the reaction temperature to 102℃ and react for 1.5 hours.

[0023] S404 was cooled to room temperature and filtered. It was washed twice with 2 times (v / m) of anhydrous ethanol and dried under vacuum at 48°C to obtain a magnetic macroporous resin.

[0024] Preferably, step S6 includes: cooling to -25 to -20°C and holding for 2 to 5 hours, evacuating to a vacuum level <100 Pa, slowly heating to -5 to 0°C while adjusting the vacuum level to 0.8 to 1.0 kPa and holding for 1.0 to 1.5 hours; turning on a 2450 MHz microwave for 1 to 2 seconds every 5 to 10 minutes until the water content in the sample reaches 15 to 20%; maintaining a vacuum level of 1.4 to 1.6 kPa, turning on a 2450 MHz microwave for 2 to 4 seconds every 3 to 5 minutes until completely dry.

[0025] Typically, the high temperature of the drying process can easily lead to product oxidation; while freeze-dried samples have stable quality, the drying time is long and the sample has low bulk density and is loose, which increases the difficulty and cost of packaging. This invention uses intermittent microwave treatment during freeze-drying to improve the freeze-drying speed. At the same time, the low temperature required for freeze-drying can prevent microwaves from raising the internal temperature of the material, thus maintaining the stability of the material. Using microwave drying in the final stage can overcome the problem of low efficiency in the later stage of freeze-drying, which not only ensures product quality but also effectively shortens the drying time and obtains products with suitable bulk density.

[0026] Preferably, step S6 includes: cooling to -25℃ and holding for 4 hours, evacuating to a vacuum degree <100 Pa, slowly heating to -5℃ while adjusting the vacuum degree to 1.0 kPa and holding for 1.0 hours; turning on the 2450 MHz microwave for 1 second every 5 to 10 minutes until the water content in the sample reaches 15%; maintaining a vacuum degree of 1.4 kPa, turning on the 2450 MHz microwave for 4 seconds every 5 minutes until the moisture content is less than 5%.

[0027] Preferably, the step S1 comprises: adding 0.8% of trisodium citrate into fresh pig blood to obtain anti-coagulation pig blood; collecting the lower blood corpuscles after centrifugation at 3500-4500 rpm for 20-30 min; and adding 0.9% NaCl at 1.2-1.5 ml / ml to wash the blood corpuscles, and collecting after centrifugation at 3500-4500 rpm for 20-30 min, ready for use.

[0028] Compared with the prior art, the heme purification method has the following beneficial effects: 1) on the basis of the conventional extraction process, the magnetic resin is used to further remove impurities, and the freeze-drying and microwave drying are used, so that the purity of the final product can reach 99%, which preliminarily meets the quality requirements of medicinal raw materials; 2) the use of organic solvents is less and can be recycled, the cost is low, and the production process is simple and controllable. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below. It should be noted that the technical features in each embodiment of the present application can be combined with each other. The detection method of heme in the present application is the prior art, which will not be described here.

[0030] Heme is the active center of hemoglobin in the human body, and its core part is a divalent iron ion embedded in the center of a porphyrin ring, which has the ability to carry oxygen and has important physiological functions and high practical value. It can be used for the preparation of anti-anemia and anti-tumor drugs in clinical practice, and the purity of heme is required to be higher at this time. The existing extraction method has limited purity of heme prepared, which can be used in the food industry but usually needs to be further refined before being used in the pharmaceutical industry, and the cost is high.

[0031] On the other hand, the magnetic macroporous resin is composed of inorganic magnetic nanoparticles and high molecular polymer. Due to its unique pore structure, large specific surface area, small particle size, good magnetic and thermal stability, strong adsorption active site and other special physical and chemical properties, it has great application potential in many fields. The prior art finds that the magnetic macroporous resin has good adsorption effect on heme standard product. How to improve the heme purification process by using magnetic resin to further improve the purity, for which the applicant proposes the following technical scheme:

[0032] Embodiment 1

[0033] A heme purification process, comprising the following steps:

[0034] S1, taking 1500ml of anti-coagulation pig blood, centrifuging at 4000rpm for 25min, and collecting 600ml of lower blood corpuscles; washing once with 1000ml of 0.9% NaCl, and centrifuging at 4000r / min for 25min;

[0035] S2, after mixing with 1200ml water, adjust pH to 8.5, after adding 0.05% ascorbic acid, heat to 55℃, add 0.8% compound enzyme for enzymolysis for 8h, the compound enzyme is composed of alkaline protease and flavor protease in a ratio of 1:2;

[0036] S3, adjust the pH of the enzymolysis solution to 3.5, stand for 30min, then centrifuge at 3000rpm for 40min and collect the precipitate;

[0037] S4, dissolve the precipitate in sodium hydroxide solution with pH 10.2, filter out impurities with a ceramic membrane with a pore size of 0.5μm under a membrane pressure of 2MPa and a temperature of 20℃; load the magnetic resin into a resin column placed vertically and in an adjustable magnetic field, control the magnetic induction intensity to be 0.8T, and pass the filtrate through the magnetic resin column (height-diameter ratio 4:1, resin dosage 100ml) at a flow rate of 1.5BV / h; after adsorption, adjust the magnetic induction intensity to 1.2T, and wash the impurities with 3BV deionized water (pH 9.0) at a flow rate of 0.5-1.0BV / h;

[0038] The magnetic resin is prepared by the following method:

[0039] S401, weigh 6.2g FeCl3.6H2O and 2.2g FeCl2.4H2O, dissolve in 180ml deionized water, protect with N2, stir under 80℃ water bath, add NH3.H2O, adjust pH to 10.0, react for 25min, wash with deionized water, and vacuum dry at 55℃ to obtain magnetic particles; mix methanol, magnetic particles and tetraethyl orthosilicate in a ratio of 5:1:0.2, react at 45℃ for 3.5h to obtain modified magnetic particles;

[0040] S402, mix acrylonitrile 10 parts, styrene 15 parts, divinylbenzene 70 parts, triallyl isocyanurate 20 parts, methyl acrylate 12 parts, gasoline 36 parts, diphenyl peroxide 1.2 parts, and modified magnetic particles 5 parts uniformly as oil phase; mix deionized water 600 parts, calcium oxide 55 parts, sodium chloride 24 parts, and polyvinyl alcohol 0.9 parts uniformly as water phase;

[0041] S403, add the oil phase to the water phase and stir to disperse the oil phase into beads; heat to 82℃ until the beads are shaped, then continue to heat to 90℃, react for 2.5h; increase the reaction temperature to 102℃, react for 1.5h;

[0042] S404, cool to room temperature and filter, repeat washing twice with 2 times (v / m) of anhydrous ethanol, and vacuum dry at 48℃ to obtain the magnetic macroporous resin.

[0043] S5, elute with 70% ethanol solution of pH 10.2 at a flow rate of 0.7 BV / h and collect the eluate, concentrate to 1 / 3 of the original volume at 50°C under vacuum pressure -0.09 MPa, filter the concentrate through a 0.5 μm filter membrane, adjust the pH to 5.0, centrifuge at 3500 rpm for 20 min to collect the precipitate;

[0044] S6, hot air dry at 60°C to constant weight, and obtain the product; the purity of the hematin obtained in this example is 97.9%, and the yield is 89.4%.

[0045] Example 2

[0046] A hematin purification process, comprising the following steps:

[0047] S1, take 1500 ml of anticoagulated pig blood, centrifuge at 3500 rpm for 30 min, collect 600 ml of the lower layer of blood cells, wash once with 1000 ml of 0.9% NaCl, centrifuge at 3500 r / min for 35 min, add 600 ml of deionized water, freeze at -25°C for 120 min, and melt at 10°C / min to 30°C;

[0048] S2, add 600 ml of water, mix, adjust the pH to 8.8, add 0.04% ascorbic acid, heat to 60°C, add 1.0% of a composite enzyme, and hydrolyze for 6.5 h, wherein the composite enzyme is composed of alkaline protease and flavor protease at a ratio of 1:1;

[0049] S3, adjust the pH of the hydrolyzate to 3.6, stand for 40 min, then centrifuge at 3500 rpm for 35 min to collect the precipitate;

[0050] S4, dissolve the precipitate in a sodium hydroxide solution of pH 9.8, filter out impurities using a ceramic membrane with a pore size of 0.5 μm at a membrane pressure of 1.8 MPa and a temperature of 25°C; load the magnetic resin into a resin column placed vertically in an adjustable magnetic field, control the magnetic induction intensity to be 0.7 T, and pass the filtrate through the magnetic resin column (height-diameter ratio 5:1, resin dosage 120 ml) at a flow rate of 1.5 BV / h; after adsorption, adjust the magnetic induction intensity to 1.4 T, wash with 3 BV of 10% ethanol solution (pH 9) at a flow rate of 0.8 BV / h to remove impurities; the preparation method of the magnetic resin is the same as that of Example 1.

[0051] S5, adjust the magnetic induction intensity to 0.5-0.8 T, then elute with 60% ethanol solution of pH 9.5 at a flow rate of 0.6 BV / h, collect the eluate, then water wash until there is no alcohol smell and collect the water eluate; concentrate to 1 / 2 of the original volume at 55°C under vacuum pressure -0.08 MPa, filter through a 0.5 μm filter membrane; take the filtrate, adjust the pH to 5.0, centrifuge at 3500 rpm for 20 min to collect the precipitate;

[0052] S7, hot air drying at 60℃ to constant weight, to obtain; the purity of the hematin obtained in this example is 98.4%, and the yield is 89.1%.

[0053] Example 3

[0054] A hematin purification process, comprising the following steps:

[0055] S1, 1500ml of anticoagulant pig blood was centrifuged at 4500rpm for 20min, and the lower layer of blood cells 580ml was collected; washed once with 900ml of 0.9% NaCl, and centrifuged at 3500r / min for 30min; add 800ml of deionized water homogenate, freeze at-30℃ for 150min, and melt according to 12℃ / min to 32℃; homogenate again-28℃ freeze for 130min, and melt according to 10℃ / min to 30℃;

[0056] S2, add 400ml of water and mix to adjust pH to 8.7, add 0.05% ascorbic acid, heat to 55℃, add 0.8% complex enzyme, and hydrolyze for 8h, the complex enzyme is composed of alkaline protease and flavor protease according to 1:3;

[0057] S3, adjust the pH of the enzyme solution to 3.7, stand for 35min, then centrifuge at 4000rpm for 15min to collect the precipitate;

[0058] S4, dissolve the precipitate in a sodium hydroxide solution with pH 10.0, filter out impurities with a ceramic membrane with a pore size of 0.5μm at a membrane pressure of 1.8MPa and a temperature of 22℃; load the magnetic resin into a resin column placed vertically and in an adjustable magnetic field, control the magnetic induction intensity to be 0.8T, and pass the filtrate through the magnetic resin column (height-diameter ratio 6:1, resin dosage 90ml) at a flow rate of 1.8BV / h; after adsorption, adjust the magnetic induction intensity to 1.4T, and wash the impurities with 3BV of 30% ethanol solution (pH9.0) at a flow rate of 1.0BV / h; the preparation method of the magnetic resin is the same as that of Example 1.

[0059] The sodium hydroxide solution is treated as follows: S11, pre-fill the stirred tank with nitrogen, add a sodium hydroxide solution with pH 10.0, heat to 50℃, vacuum to 0.015Mpa, and reduce pressure stirring for 30min;

[0060] S12, slowly reduce to 4℃ at a speed of 10℃ / h, introduce nitrogen into the stirred tank to 0.15Mpa, pressurize and stir for 30min; S13, slowly increase to 50℃ at a speed of 15℃ / h, while slowly reduce the pressure to 0.015Mpa at a speed of 0.04Mpa / h, stir for 30min; S14, slowly reduce to 4℃ at a speed of 10℃ / h, while slowly introduce nitrogen into the stirred tank to pressurize to 0.35Mpa at a speed of 0.04Mpa / h, pressurize and stir for 30min, stand at room temperature and normal pressure for standby use.

[0061] S5, adjust the magnetic induction intensity to 0.7T, then elute and collect the eluent with 50% ethanol solution at pH 10.2 at a flow rate of 0.5BV / h; concentrate to 1 / 3 of the original volume at 48℃ under vacuum pressure-0.09MPa, filter with 0.5μm filter membrane; stir at a speed of 50rpm, add 4mol / l HCl dropwise to the filtrate to adjust pH to 5.2, then reduce to-2℃ at a speed of 10℃ / h, keep for 5h, then centrifuge at 3500rpm for 20min to collect the precipitate;

[0062] S6, take the precipitate and cool to-25℃, keep for 4h, vacuumize to a vacuum degree of <100pa, slowly warm to-5℃, while adjust the vacuum degree to 1.0kpa and keep for 1h; meanwhile, use microwave at 2450MHZ for 1s every 10min, until the water content in the sample is 15%; keep the vacuum degree at 1.4kPa, microwave dry at 2450MHZ for 4s every 5min until completely dry; the hematin obtained in this example is detected to have a purity of 99.3%, and the extraction yield is 90.4%.

[0063] Comparative Example 1

[0064] Take anticoagulant pig blood after centrifugation, prepare hematin according to the method of Example 1 in the publication CN111471013A, and the hematin is detected to have a purity of 97.2%, and the extraction yield is 87.4%.

[0065] Comparative Example 2

[0066] Prepare hematin by the method of Example 1, the only difference is that the resin type in step S4 is AB-8, the hematin obtained in this example is detected to have a purity of 91.1%, and the extraction yield is 90.9%.

[0067] Comparative Example 3

[0068] Prepare hematin by the method of Example 3, the only difference is that in step S5, heat 50% ethanol solution at pH 10.2 to 35℃ for desorption, the hematin is detected to have a purity of 95.2%, and the extraction yield is 84.7%.

[0069] Although the present application has been disclosed with reference to the above embodiments, the application is not limited to the above embodiments. It will be apparent to those skilled in the art that various modifications and changes can be made thereto without departing from the spirit and scope of the application. The scope of the application should be limited only by the appended claims.

Claims

1. A method for purifying heme, characterized in that, include: S1. Take 1500ml of anticoagulated pig blood and centrifuge at 4500rpm for 20min. Collect 580ml of the lower layer of blood cells. Wash once with 900ml of 0.9% NaCl and centrifuge at 3500r / min for 30min. Add 800ml of deionized water to homogenize. Freeze at -30℃ for 150min and thaw at 32℃ by increasing the temperature at 12℃ / min. After homogenization, freeze again at -28℃ for 130min and thaw at 30℃ by increasing the temperature at 10℃ / min. S2. Add 400ml of water and mix to adjust the pH to 8.

7. Add 0.05% ascorbic acid and heat to 55℃. Add 0.8% compound enzyme and hydrolyze for 8 hours. The compound enzyme is composed of alkaline protease and flavor protease in a 1:3 ratio. S3. Adjust the pH of the enzyme hydrolysate to 3.7, let it stand for 35 min, then centrifuge at 4000 rpm for 15 min to collect the precipitate. S4. Dissolve the precipitate in a sodium hydroxide solution with a pH of 10.0, and filter it through a ceramic membrane with a pore size of 0.5 μm at a membrane pressure of 1.8 MPa and a temperature of 22°C to remove impurities. Magnetic resin is packed into a vertically placed resin column and placed in an adjustable magnetic field, with the magnetic induction intensity controlled at 0.8 T. The filtrate is fed onto the magnetic resin column at a flow rate of 1.8 BV / h. The height-to-diameter ratio of the magnetic resin column is 6:1, and the resin volume is 90 ml. After adsorption, adjust the magnetic induction intensity to 1.4 T, and wash with 3 BV of 30% ethanol solution with a pH of 9.0 at a flow rate of 1.0 BV / h to remove impurities. The magnetic resin is prepared using the following method: S401: Weigh 6.2g FeCl3·6H2O and 2.2g FeCl2·4H2O and dissolve them in 180ml deionized water. Probe with N2 for protection, stir in an 80℃ water bath, add NH3·H2O, adjust the pH to 10.0, and react for 25min. After washing with deionized water, dry under vacuum at 55℃ to obtain magnetic particles. Mix methanol, magnetic particles, and tetraethyl orthosilicate in a ratio of 5:1:0.2 and react at 45℃ for 3.5h to obtain modified magnetic particles. S402: Mix 10 parts acrylonitrile, 15 parts styrene, 70 parts divinylbenzene, 20 parts triallyl isocyanurate, 12 parts methyl acrylate, 36 parts gasoline, 1.2 parts diphenyl peroxide, and 5 parts modified magnetic particles evenly to form the oil phase; mix 600 parts deionized water, 55 parts calcium oxide, 24 parts sodium chloride, and 0.9 parts polyvinyl alcohol evenly to form the aqueous phase. S403. Add the oil phase to the aqueous phase and stir to disperse the oil phase into beads; heat to 82℃ and after the beads have solidified, continue to heat to 90℃ and react for 2.5 hours; raise the reaction temperature to 102℃ and react for 1.5 hours. S404, cooled to room temperature and filtered, washed twice with 2 v / m of anhydrous ethanol, and dried under vacuum at 48°C to obtain magnetic macroporous resin; In step S4, the sodium hydroxide aqueous solution is treated as follows: S11. The stirred tank is pre-filled with nitrogen, and a sodium hydroxide solution with pH 10.0 is added. The mixture is then heated to 50°C, evacuated to 0.015 MPa, and stirred under reduced pressure for 30 minutes. S12. Slowly reduce the temperature to 4℃ at a rate of 10℃ / h, introduce nitrogen gas into the stirred tank to 0.15Mpa, and stir under pressure for 30min; S13. Slowly increase the temperature to 50℃ at a rate of 15℃ / h, while simultaneously slowly decreasing the pressure to 0.015Mpa at a rate of 0.04Mpa / h, and stir for 30min; S14. Slowly reduce the temperature to 4℃ at a rate of 10℃ / h, while simultaneously slowly introducing nitrogen gas into the stirred tank at a rate of 0.04Mpa / h to pressurize it to 0.35Mpa. Stir under pressure for 30 minutes, then let it stand at room temperature and pressure for later use. S5. After adjusting the magnetic induction intensity to 0.7T, elute with 50% ethanol solution at pH 10.2 at a flow rate of 0.5 BV / h and collect the eluent; concentrate to 1 / 3 of the original volume at 48℃ and vacuum pressure -0.09MPa, filter through a 0.5μm filter membrane; stir at 50rpm, add 4mol / L HCl dropwise to adjust the pH to 5.2, and simultaneously cool to -2℃ at 10℃ / h, keep warm for 5h, and then centrifuge at 3500rpm for 20min to collect the precipitate; S6. After cooling the precipitate to -25℃, keep it at that temperature for 4 hours. Evacuate the vacuum to <100 Pa, slowly raise the temperature to -5℃, and simultaneously adjust the vacuum to 1.0 kPa and keep it at that temperature for 1 hour. At the same time, microwave the sample at 2450 MHz for 1 second every 10 minutes until the water content in the sample reaches 15%. Keep the vacuum at 1.4 kPa and microwave dry the sample at 2450 MHz for 4 seconds every 5 minutes until it is completely dry.