Polyelectrolyte modified porous microspheres for amino acid separation and preparation method of polyelectrolyte modified porous microspheres

Abstract

The invention relates to the field of polymer synthesis and porous microsphere preparation, and particularly discloses a polyelectrolyte modified porous microsphere for amino acid separation and a preparation method of the polyelectrolyte modified porous microsphere. The polyelectrolyte modified porous microsphere is prepared by taking a porous microsphere as a substrate and modifying a layer of polymer of cationic electrolyte on the surface of the porous microsphere through interfacial polymerization. By regulating and controlling the pore diameter structure and the surface charge distribution of the microspheres, the porous microspheres can realize efficient separation of different amino acids, and show good selectivity and separation efficiency. The porous microsphere provided by the invention not only improves the separation performance, but also has relatively strong structural stability and applicability, and can meet the separation requirements under various complex conditions. The method has wide application prospects in amino acid separation and related fields, and is suitable for industrial application in the industries of food processing, biological medicine and the like.

Description

Technical Field

[0001] The present invention relates to the fields of polymer synthesis and porous microsphere preparation, and in particular to a polyelectrolyte-modified porous microsphere for amino acid separation and a preparation method thereof. Background Art

[0002] Amino acids, as a very important raw material, are widely used in food, medicine, industry, biotechnology and other fields. Currently, the main ways to obtain amino acids are biological fermentation and chemical synthesis. Whether it is biological fermentation or chemical synthesis, separation and purification are key factors affecting product quality.

[0003] The main methods for separating and purifying amino acids include ion exchange chromatography, gel filtration chromatography, affinity chromatography, reversed-phase high-performance liquid chromatography, electrophoresis, liquid membrane chromatography, crystallization, and distillation. These methods, based on the physicochemical properties of amino acids, such as charge, size, and hydrophobicity, achieve separation and purification through different mechanisms to meet the needs of biochemical research and industrial production. Currently, the fillers used in chromatography and other methods are generally micron-sized porous microspheres. The main methods for preparing porous microspheres include seed swelling, membrane emulsification, and microfluidics.

[0004] Currently, microsphere surface modification methods primarily rely on chemically modifying specific functional groups on the microsphere surface. However, polystyrene and polymethyl methacrylate microspheres, which lack relevant reactive groups, often require re-surface modification before the next step of modifying cationic groups can be performed. This process is not only complex but also often requires the use of concentrated sulfuric acid or other sulfates, which can corrode equipment and cause environmental pollution. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a polyelectrolyte-modified porous microsphere for amino acid separation and a preparation method thereof.

[0006] It should be noted that the present invention employs a membrane emulsification-suspension polymerization method to first prepare porous polymer microspheres, followed by surface modification of the microspheres with a layer of cationic electrolytes via interfacial polymerization. Compared to existing technologies, the porous microspheres of the present invention not only improve separation performance but also possess greater structural stability and applicability, meeting separation requirements under a variety of complex conditions. This invention has broad application prospects in amino acid separation and related fields, and is suitable for industrial applications in industries such as food processing and biopharmaceuticals.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The first technical purpose of the present invention is to provide a polyelectrolyte-modified porous microsphere, which is obtained by using micron-scale cross-linked porous polymer microspheres as a substrate and modifying a layer of phospholipid-aromatic acyl copolymer cationic polyelectrolyte on the surface of the substrate through interfacial polymerization.

[0009] Furthermore, the particle size of the micron-sized cross-linked porous polymer microspheres is 10-60 μm, and the cross-linking degree is 30%-60%; the thickness of the phospholipid-aromatic acyl copolymer cationic polyelectrolyte is 10-500 nm, preferably 50-200 nm.

[0010] The second technical purpose of the present invention is to provide a method for preparing the polyelectrolyte-modified porous microspheres as described above, which comprises the following steps:

[0011] S1. Using a pressure of 1 to 15 kPa, the dispersed phase precursor is forced through the membrane pores to form dispersed phase droplets in the continuous phase. The mixed liquid of the dispersed phase droplets and the continuous phase is subjected to a suspension polymerization method, i.e., the mixture is heated at a temperature of 70 to 80° C. and stirred at a rate of 200 to 500 rpm for 24 hours to obtain micron-sized cross-linked porous polymer microspheres.

[0012] S2. Modifying the surface of the porous polymer microspheres with a layer of phospholipid-aromatic acyl copolymer cationic polyelectrolyte by interfacial polymerization to obtain the polyelectrolyte-modified porous microspheres.

[0013] The dispersed phase droplets are composed of monomers, cross-linking agents, auxiliary agents, initiators, and porogens. The volume of the monomers is 2 to 4 mL, the volume ratio of the monomers to the cross-linking agents is 1:(0.5-1), the volume percentage of the auxiliary agents to the monomers is 25 to 40%, the volume ratio of the monomers to the porogens is 1:(0.5-1), and the initiator accounts for 1 to 2.5 wt% of the weight of the monomers.

[0014] Furthermore, in the composition of the dispersed phase droplets, the monomer is a styrene monomer or a methyl methacrylate monomer; the crosslinking agent is p-vinylbenzene or diallyl phthalate; the auxiliary agent is dodecanol; the porogen is one of pentane, hexane, heptane, isooctane, and toluene; and the initiator is benzoyl peroxide;

[0015] The continuous phase is composed of a mobile phase dispersant, a mobile phase surfactant, an inorganic salt, and deionized water. The volume of the deionized water is 100 to 150 g, the mass fraction concentration of the mobile phase dispersant is 1 to 2 wt %, the mass fraction concentration of the mobile phase surfactant is 0.1 to 0.2 wt %, and the amount of the inorganic salt is 0.1 to 0.2 g.

[0016] Furthermore, the mobile phase dispersant is selected from one or more combinations of polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene glycol, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and ethyl hydroxyethyl cellulose; further, when the dispersant is polyvinyl alcohol, PVA-1788 can be specifically selected.

[0017] Furthermore, the continuous phase surfactant is selected from one of sodium lauryl sulfate, ammonium lauryl sulfate, and sodium dodecylbenzene sulfonate.

[0018] Furthermore, the inorganic salt is selected from at least one of sodium salt, potassium salt, and magnesium salt. When the inorganic salt is a sodium salt, it is specifically at least one of sodium chloride, sodium bromide, sodium sulfate, sodium sulfite, sodium carbonate, sodium bicarbonate, sodium nitrate, sodium phosphate, sodium hydrogen phosphate, and sodium silicate; when the inorganic salt is a potassium salt, it is specifically at least one of potassium chloride, potassium bromide, potassium sulfate, potassium sulfite, potassium carbonate, potassium bicarbonate, potassium nitrate, potassium phosphate, potassium hydrogen phosphate, and potassium silicate; when the inorganic salt is a magnesium salt, it is specifically at least one of magnesium chloride, magnesium bromide, magnesium sulfate, and magnesium nitrate.

[0019] Furthermore, in step S2, the method for modifying the surface of the porous polymer microspheres by interfacial polymerization is as follows:

[0020] The reactant A solution is added to the micron-sized cross-linked porous polymer microspheres prepared in step S1, stirred thoroughly, and then drained; the reactant B solution is added to the treated porous polymer microspheres, and the mixture is allowed to react thoroughly to obtain polyelectrolyte-modified porous microspheres for amino acid separation.

[0021] Furthermore, the volume ratio of the reactant A solution to the reactant B solution is 1:(1-2); the reactant A solution is a cyclohexane solution of 1,3,5-benzenetricarboxylic acid chloride, and the concentration of the 1,3,5-benzenetricarboxylic acid chloride is 0.01 mol / L to 0.1 mol / L;

[0022] The reactant B solution is an aqueous solution of tetrakis(hydroxymethyl)phosphonium chloride, and the concentration of the tetrakis(hydroxymethyl)phosphonium chloride is 0.1 mol / L to 2 mol / L;

[0023] The reaction temperature is 20-50°C, and the reaction time is 30-60 minutes.

[0024] The third technical purpose of the present invention is to provide an application of the polyelectrolyte-modified porous microspheres as described above in amino acid separation.

[0025] Specifically, the polyelectrolyte modified porous microspheres have a lysine retention rate of more than 90%, a glutamic acid retention rate of less than 20%, and a selectivity coefficient between glutamic acid and lysine greater than 10.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1) This invention specifically discloses polyelectrolyte-modified porous microspheres for amino acid separation and a method for preparing the same. The polyelectrolyte-modified porous microspheres are prepared by using porous microspheres as a substrate and modifying the surface with a cationic electrolyte polymer via interfacial polymerization. The resulting polyelectrolyte-modified porous microspheres have the advantages of a simple preparation process, strong operability, controllable pore size, low energy consumption, and cost-effective production.

[0028] 2) By regulating the pore structure and surface charge distribution of the microspheres, the present invention enables efficient separation of different amino acids, demonstrating good selectivity and separation efficiency. Compared with the prior art, the porous microspheres of the present invention not only improve separation performance but also have strong structural stability and applicability, which can meet the separation requirements under a variety of complex conditions. The present invention has broad application prospects in amino acid separation and related fields, and is suitable for industrial applications in industries such as food processing and biomedicine. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0030] Figure 1 This is a schematic diagram of the preparation of polyelectrolyte-modified micron-sized cross-linked porous polymer microspheres.

[0031] Figure 2 This is a scanning electron microscope image of the micron-sized cross-linked porous polymer microspheres in Example 1 at 300X.

[0032] Figure 3 This is a scanning electron microscope image of the micron-sized cross-linked porous polymer microspheres in Example 2 at 300X.

[0033] Figure 4 This is a scanning electron microscope image of the micron-sized cross-linked porous polymer microspheres in Example 2 at 50KX.

[0034] Figure 5 1 is a Fourier transform infrared spectrum of the unmodified, polyelectrolyte modified micron-sized cross-linked porous microspheres in Example 2 and Example 3.

[0035] Figure 6 This is a diagram showing the amino acid separation effect of the polyelectrolyte-modified micron-sized cross-linked porous microspheres in Example 2. DETAILED DESCRIPTION

[0036] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] The term "embodiment" is used herein specifically to describe any embodiment as "exemplary," and should not be construed as superior or preferable to other embodiments. Performance indicators in the embodiments of this application were tested using conventional testing methods in the art, unless otherwise specified. It should be understood that the terms used in this application are intended solely to describe specific implementations and are not intended to limit the disclosure herein.

[0038] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0039] In order to better illustrate the content of this application, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that this application can be implemented without certain specific details. In the examples, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of this application.

[0040] Under the premise of no conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the resulting technical solutions belong to the contents disclosed in the embodiments of this application.

[0041] The present invention discloses a polyelectrolyte-modified porous microsphere and a preparation method thereof. The preparation method uses a membrane emulsification + suspension polymerization method to prepare the porous polymer microspheres, and then modifies the surface of the porous polymer microspheres with a layer of cationic electrolyte by interfacial polymerization. This application is achieved by the following steps:

[0042] S1: First, prepare the continuous phase and dispersed phase precursors, and then prepare micron-sized cross-linked porous polymer microspheres through membrane emulsification + suspension polymerization;

[0043] S2: Infiltrating the surface of the porous polymer microspheres with reaction solution A, then adding the microspheres into reaction solution B, and modifying the surface of the microspheres with a layer of cationic polyelectrolyte by interfacial polymerization to obtain polyelectrolyte-modified porous microspheres.

[0044] In order to further understand the present invention, the porous microspheres and the preparation method thereof provided by the present invention are described in detail below with reference to examples. The protection scope of the present invention is not limited by the following examples.

[0045] Example 1

[0046] (1) Preparation of porous polymer microspheres by membrane emulsification + suspension polymerization

[0047] S1: 3 mL of styrene, 2 mL of divinylbenzene, 1 mL of dodecanol, and 2 mL of heptane were mixed and ultrasonicated at 40 kHz for 15 minutes. 0.159 g of benzoyl peroxide was then added and dissolved by stirring to obtain a dispersed phase precursor solution.

[0048] S2: 1 g of polyvinyl alcohol, 100 g of deionized water, 0.056 g of sodium lauryl sulfate, and 0.1 g of anhydrous sodium sulfate were mixed and heated to about 70° C. until the polyvinyl alcohol was completely dissolved, and then naturally cooled to room temperature to obtain a continuous phase.

[0049] S3: Nitrogen is used to supply pressure and maintain the pressure at 7KPa. The dispersed phase is uniformly and stably pressed through a porous membrane (the pore size of the membrane is 8μm) to form dispersed liquid droplets in the continuous phase. The continuous phase is continuously magnetically stirred, and the shear force generated by the stirring carries away the dispersed phase droplets.

[0050] S4: The mixture of the dispersed phase droplets and the continuous phase was collected and reacted at 75°C under nitrogen atmosphere and 300 rpm magnetic stirring for 24 hours. The mixture was then filtered, washed with ethanol and deionized water, and dried to obtain porous polymer microspheres.

[0051] (2) Cationic polyelectrolyte modified porous microspheres

[0052] 8 mL of 0.01 mol / L 1,3,5-benzenetricarboxylic acid chloride cyclohexane solution was added to 0.5 g of porous polymer microspheres and ultrasonically treated for 10 min. Then, excess 1,3,5-benzenetricarboxylic acid chloride cyclohexane solution on the surface of the porous polymer microspheres was removed by filtration. The treated porous polymer microspheres were then placed in 8 mL of 0.1 mol / L tetrakis(hydroxymethyl)phosphonium chloride aqueous solution and reacted under ultrasonic conditions at 40°C for 30 min. The product was collected, washed with cyclohexane / ethanol, respectively, and collected by centrifugation.

[0053] The porous polymer microspheres obtained in Example 1 were analyzed using a scanning electron microscope, and a scanning electron microscope image with a magnification of 300X was obtained. Figure 2 .

[0054] Example 2

[0055] Keeping step (2) in Example 1 unchanged, step (1) is changed to:

[0056] S1: First, prepare the dispersed phase by ultrasonically mixing 2 mL of methyl methacrylate, 1 mL of glycidyl methacrylate, 2 mL of divinylbenzene, 1 mL of dodecanol, and 2 mL of heptane. Then, add 0.159 g of benzoyl peroxide and stir evenly.

[0057] S2: 1 g of polyvinyl alcohol, 100 g of deionized water, 0.056 g of sodium lauryl sulfate, and 0.1 g of anhydrous sodium sulfate were mixed and heated to about 70° C. until the polyvinyl alcohol was completely dissolved, and then naturally cooled to room temperature to obtain a continuous phase.

[0058] S3: Nitrogen is used to supply pressure and maintain the pressure at 7 kPa. The dispersed phase is uniformly and stably pressed through a porous membrane (the pore size of the membrane is 8 μm) to form dispersed liquid droplets in the continuous phase. The continuous phase is continuously magnetically stirred, and the shear force generated by the stirring carries away the dispersed phase droplets.

[0059] S4: The mixture of the dispersed phase droplets and the continuous phase was collected and reacted at 75°C under nitrogen atmosphere and 250 rpm magnetic stirring for 24 hours. The mixture was then filtered, washed with ethanol and deionized water, and dried to obtain porous polymer microspheres.

[0060] The porous polymer microspheres obtained in Example 2 were analyzed using a scanning electron microscope, and a scanning electron microscope image with a magnification of 300X was obtained ( Figure 3 ) and scanning electron microscope images with a magnification of 50KX ( Figure 4 ).

[0061] Example 3

[0062] Keeping step (2) in Example 1 unchanged, step (1) is changed to:

[0063] S1: 3 mL of styrene, 2 mL of divinylbenzene, 1 mL of dodecanol, and 1 mL of heptane were mixed and ultrasonicated at 40 kHz for 15 minutes. Subsequently, 0.159 g of dibenzoyl peroxide was added and stirred to dissolve to obtain a dispersed phase precursor solution.

[0064] S2: 1 g of polyvinyl alcohol, 100 g of deionized water, 0.056 g of sodium lauryl sulfate, and 0.1 g of anhydrous sodium sulfate were mixed and heated to about 70° C. until the polyvinyl alcohol was completely dissolved, and then naturally cooled to room temperature to obtain a continuous phase.

[0065] S3: Nitrogen is used to supply pressure and maintain the pressure at 7 kPa. The dispersed phase is uniformly and stably pressed through a porous membrane (the pore size of the membrane is 8 μm) to form dispersed liquid droplets in the continuous phase. The continuous phase is continuously magnetically stirred, and the shear force generated by the stirring carries away the dispersed phase droplets.

[0066] S4: The mixture of the dispersed phase droplets and the continuous phase was collected and reacted at 75°C under nitrogen atmosphere and 300 rpm magnetic stirring for 24 hours. The mixture was then filtered, washed with ethanol and deionized water, and dried to obtain porous polymer microspheres.

[0067] Example 4

[0068] Keeping step (2) in Example 1 unchanged, step (1) is changed to:

[0069] S1: 3 mL of styrene, 2 mL of divinylbenzene, 1 mL of dodecanol, and 4 mL of heptane were mixed and ultrasonicated at 40 kHz for 15 minutes. 0.159 g of benzoyl peroxide was then added and dissolved by stirring to obtain a dispersed phase precursor solution.

[0070] S2: 1 g of polyvinyl alcohol, 100 g of deionized water, 0.056 g of sodium lauryl sulfate, and 0.1 g of anhydrous sodium sulfate were mixed and heated to about 70° C. until the polyvinyl alcohol was completely dissolved, and then naturally cooled to room temperature to obtain a continuous phase.

[0071] S3: Nitrogen is used to supply pressure and maintain the pressure at 7 kPa. The dispersed phase is uniformly and stably pressed through a porous membrane (the pore size of the membrane is 8 μm) to form dispersed liquid droplets in the continuous phase. The continuous phase is continuously magnetically stirred, and the shear force generated by the stirring carries away the dispersed phase droplets.

[0072] S4: The mixture of the dispersed phase droplets and the continuous phase was collected and reacted at 75°C under nitrogen atmosphere and 300 rpm magnetic stirring for 24 hours. The mixture was then filtered, washed with ethanol and deionized water, and dried to obtain porous polymer microspheres.

[0073] Example 5

[0074] Keep step (1) in Example 1 unchanged, and change step (2) to:

[0075] 8 mL of 0.01 mol / L 1,3,5-benzenetricarboxylic acid chloride cyclohexane solution was added to 0.5 g of porous polymer microspheres and ultrasonically treated for 10 min. Then, excess 1,3,5-benzenetricarboxylic acid chloride cyclohexane solution on the surface of the porous polymer microspheres was removed by filtration. The treated porous polymer microspheres were then placed in 8 mL of 0.2 mol / L tetrakis(hydroxymethyl)phosphonium chloride aqueous solution and reacted under ultrasonic conditions at 40°C for 30 min. The product was collected, washed with cyclohexane / ethanol, and collected by centrifugation.

[0076] Example 6

[0077] Keep step (1) in Example 1 unchanged, and change step (2) to:

[0078] 8 mL of 0.01 mol / L 1,3,5-benzenetricarboxylic acid chloride cyclohexane solution was added to 0.5 g of porous polymer microspheres and ultrasonically treated for 10 minutes. The excess 1,3,5-benzenetricarboxylic acid chloride cyclohexane solution on the surface of the porous polymer microspheres was then removed by filtration. The treated porous polymer microspheres were then placed in 8 mL of 0.4 mol / L tetrakis(hydroxyphosphonium) chloride aqueous solution and reacted under ultrasonic conditions at 40°C for 30 minutes. The product was collected, washed with cyclohexane / ethanol, and then collected by centrifugation.

[0079] The relevant data of the particle size and pore size of the porous polymer microspheres prepared in step S1 of Example 1, Example 4 and Example 5 are shown in Table 1. As shown in Table 1, when other conditions remain unchanged, when the content of the added porogen increases, the particle size of the microspheres does not change much, while the pore size range of the microsphere surface gradually increases. Among them, in Example 5, the pore size range of the microsphere surface can reach 50 to 200 nm. The infrared spectra of the porous polymer microspheres modified with porous polymers in Example 2 and Example 3 before and after modification are shown in Table 1. Figure 5 .

[0080] Table 1 Particle size and pore size of microspheres in different embodiments

[0081]

[0082]

[0083] The polyelectrolyte modified porous polymer microspheres obtained in Example 2 were subjected to amino acid separation test. The results are as follows: Figure 6 As shown in Figure 2, the modified microspheres exhibit excellent separation of glutamate and lysine, with a lysine retention rate exceeding 90% and a glutamate retention rate below 20%. Furthermore, the selectivity coefficient for these two amino acids remains above 10.

[0084] As demonstrated in the examples above, the present invention provides a method for preparing polyelectrolyte-modified microspheres capable of amino acid separation. By employing SPG membrane emulsification technology and interfacial modification methods, resin microspheres modified with a polyelectrolyte layer were rapidly and environmentally friendly prepared. These microspheres have been successfully applied in the field of amino acid separation, demonstrating excellent separation results.

[0085] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A polyelectrolyte modified porous microsphere, characterized in that: The polyelectrolyte modified porous microspheres are obtained by using micron-sized cross-linked porous polymer microspheres as substrates and modifying a layer of phospholipid-aromatic acyl copolymer cationic polyelectrolyte on the surface of the substrates through interfacial polymerization.

2. The polyelectrolyte-modified porous microspheres according to claim 1, characterized in that: The particle size of the micron-sized cross-linked porous polymer microspheres is 10 to 60 μm, and the cross-linking degree is 30% to 60%; The thickness of the phospholipid-aromatic acyl copolymer cationic polyelectrolyte is 10 to 500 nm.

3. A method for preparing polyelectrolyte-modified porous microspheres according to claim 1, characterized in that: The specific steps are: S1, using a pressure of 1 to 15 kPa to force the dispersed phase precursor to pass through the membrane pores to form dispersed phase droplets in the continuous phase, and then performing a suspension polymerization method on the mixture of the dispersed phase droplets and the continuous phase to obtain micron-sized cross-linked porous polymer microspheres; S2. Modifying the surface of the porous polymer microspheres with a layer of phospholipid-aromatic acyl copolymer cationic polyelectrolyte by interfacial polymerization to obtain the polyelectrolyte-modified porous microspheres.

4. The preparation method according to claim 3, characterized in that The dispersed phase precursor solution is composed of a monomer, a cross-linking agent, an auxiliary agent, an initiator, and a porogen, wherein the volume of the monomer is 2 to 4 mL, the volume ratio of the monomer to the cross-linking agent is 1:(0.5-1), the volume percentage of the auxiliary agent to the monomer is 25 to 40%, the volume ratio of the monomer to the porogen is 1:(0.5-1), and the initiator accounts for 1 to 2.5 wt% of the weight of the monomer; The monomer is a styrene monomer or a methyl methacrylate monomer; the crosslinking agent is divinylbenzene or diallyl phthalate; the auxiliary agent is dodecanol; the porogen is one of pentane, hexane, heptane, isooctane and toluene; and the initiator is benzoyl peroxide.

5. The preparation method according to claim 3, characterized in that The continuous phase is composed of a mobile phase dispersant, a mobile phase surfactant, an inorganic salt, and deionized water, wherein the volume of the deionized water is 100 to 150 g, the mass fraction concentration of the mobile phase dispersant is 1 to 2 wt %, the mass fraction concentration of the mobile phase surfactant is 0.1 to 0.2 wt %, and the amount of the inorganic salt is 0.1 to 0.2 g; The mobile phase dispersant is one or more combinations of polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene glycol, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and ethyl hydroxyethyl cellulose; The mobile phase surfactant is selected from one of sodium lauryl sulfate, ammonium lauryl sulfate, and sodium dodecylbenzene sulfonate; The inorganic salt is selected from at least one of sodium salt, potassium salt, and magnesium salt. When the inorganic salt is a sodium salt, it is specifically at least one of sodium chloride, sodium bromide, sodium sulfate, sodium sulfite, sodium carbonate, sodium bicarbonate, sodium nitrate, sodium phosphate, sodium hydrogen phosphate, and sodium silicate; when the inorganic salt is a potassium salt, it is specifically at least one of potassium chloride, potassium bromide, potassium sulfate, potassium sulfite, potassium carbonate, potassium bicarbonate, potassium nitrate, potassium phosphate, potassium hydrogen phosphate, and potassium silicate; when the inorganic salt is a magnesium salt, it is specifically at least one of magnesium chloride, magnesium bromide, magnesium sulfate, and magnesium nitrate.

6. The preparation method according to claim 3, wherein in step S2, the method for modifying the surface of the porous polymer microspheres by interfacial polymerization is as follows: The reactant A solution is added to the micron-sized cross-linked porous polymer microspheres prepared in step S1, stirred thoroughly, and then drained; the reactant B solution is added to the treated porous polymer microspheres, and the mixture is allowed to react thoroughly to obtain polyelectrolyte-modified porous microspheres for amino acid separation.

7. The preparation method according to claim 6, characterized in that: The volume ratio of reactant A solution to reactant B solution is 1:(1-2); The reactant A solution is a cyclohexane solution of 1,3,5-benzenetricarboxylic acid chloride, and the concentration of the 1,3,5-benzenetricarboxylic acid chloride is 0.01 mol / L to 0.1 mol / L; The reactant B solution is an aqueous solution of tetrakis(hydroxymethyl)phosphonium chloride, and the concentration of the tetrakis(hydroxymethyl)phosphonium chloride is 0.1 mol / L to 2 mol / L; The reaction temperature is 20-50°C, and the reaction time is 30-60 minutes.

8. Use of the polyelectrolyte-modified porous microspheres according to claim 1 or the polyelectrolyte-modified porous microspheres prepared by the method according to claim 3 in amino acid separation.

9. The use according to claim 8, characterized in that The polyelectrolyte modified porous microspheres have a retention rate of more than 90% for lysine, a retention rate of less than 20% for glutamic acid, and a selectivity coefficient of more than 10 for glutamic acid and lysine.

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