Preparation method of high-capacity cation chromatographic stationary phase
By preparing polymer microspheres with high cross-linking degree and high carboxyl density, the problems of low exchange capacity and pore blockage of traditional cation exchange resins are solved, achieving a balance between high exchange capacity and mechanical strength, and improving the performance of the chromatographic column.
Patent Information
- Application Number
- CN202511862183.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-11
- Publication Date
- 2026-01-27
AI Technical Summary
Traditional cation exchange resins grafted with carboxylic acid groups on the surface of polystyrene microspheres have low exchange capacity and are prone to pore blockage, affecting column efficiency and mechanical strength.
Non-crosslinked PS seed microspheres were prepared by dispersion polymerization, and polymer microspheres with high crosslinking degree and high carboxyl density were prepared by swelling, mixed emulsion polymerization and hydrolysis to form a controllable pore structure, thereby improving exchange capacity and mechanical strength.
It achieves a balance between high exchange capacity and mechanical strength, solves the problems of low exchange capacity and pore blockage in traditional methods, and improves the performance of the chromatographic column.
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Abstract
Description
Technical Field
[0001] This invention relates to a technique for preparing chromatographic packing materials, and particularly to a method for preparing a high-capacity cation chromatographic stationary phase. Background Technology
[0002] Traditional cation exchange resins, which introduce carboxylic acid groups onto the surface of polystyrene microspheres, typically have an exchange capacity below 2.0 meq / g. The grafting process is inefficient and heavily influenced by the pore structure of the substrate microspheres. Excessive grafting can lead to microsphere surface densification, forming an ion diffusion barrier and rendering the underlying functional groups essentially ineffective. Furthermore, it can clog the pores of the microspheres, increasing column pressure and decreasing column efficiency. Summary of the Invention
[0003] To address the shortcomings of the prior art, the present invention aims to provide a method for preparing a high-capacity cation chromatography stationary phase. The chromatographic packing material prepared by this method has high cross-linking degree, high carboxyl density, and controllable pore structure, which not only ensures the exchange capacity but also improves its mechanical strength.
[0004] The technical solution adopted by this invention to solve its technical problem is: a method for preparing a high-capacity cation chromatography stationary phase, comprising the following steps:
[0005] S1. Non-crosslinked PS seed microspheres are prepared by dispersion polymerization, and then the non-crosslinked PS seed microspheres are dispersed in an aqueous solution containing an emulsifier to prepare a seed microsphere emulsion.
[0006] S2. Prepare the swelling solution and stir it using a homogenizer. After stirring, add it to the seed microsphere emulsion and stir to ensure that the swelling solution and the seed microsphere emulsion are fully swollen.
[0007] S3. Prepare a mixed emulsion of maleic anhydride, divinylbenzene, porogen, and initiator, and add the mixed emulsion to the solution obtained in step S2, and continue stirring;
[0008] S4. After purging nitrogen into the emulsion system obtained in step S3 to remove oxygen, the temperature is raised to the polymerization reaction temperature, and the reaction is carried out under mechanical stirring.
[0009] S5. After the reaction is complete, the product is washed by vacuum filtration to remove residual reagents and monomers, and polymer microspheres are obtained.
[0010] S6. Add the cleaned polymer microspheres to an isopropanol aqueous solution, heat and stir mechanically to fully hydrolyze the maleic anhydride inside the microspheres, at which point the microspheres can be functionalized.
[0011] S7. Wash, filter, and dry the hydrolyzed microspheres;
[0012] S8. The polymer microspheres obtained in step 7 are packed into a chromatographic column using a wet homogenization method, which can be used for cation separation testing.
[0013] Optionally, the particle size of the non-crosslinked PS seed microspheres prepared in step S1 is 1~2 μm.
[0014] Optionally, in step S2, the solvent in the swelling solution is dibutyl phthalate or dioctyl phthalate.
[0015] Optionally, in the mixed emulsion prepared in step S3, maleic anhydride is a monomer, divinylbenzene is a crosslinking agent, and the degree of crosslinking is at least 50%.
[0016] Optionally, the monomer in the mixed emulsion configured in step S3 may also contain styrene.
[0017] Optionally, the porogen is any one of toluene, xylene, or long-chain alkanes, and the mass of the porogen is 0.2 to 2 times the mass of maleic anhydride.
[0018] Optionally, the initiator is an oil-soluble peroxide, and the mass of the initiator is 1% to 5% of the monomer mass.
[0019] Optionally, in step S2, the swelling temperature of the swelling solution and the seed microsphere emulsion is room temperature.
[0020] The chromatographic packing material prepared by the method of the present invention has high cross-linking degree, high carboxyl density and controllable pore structure, which not only ensures the exchange capacity but also improves its mechanical strength. Attached Figure Description
[0021] Figure 1 Here is an electron microscope image of the polymer microspheres prepared in Example 1;
[0022] Figure 2 This is a chromatogram of the column prepared in Example 1 for testing six cations;
[0023] Figure 3 This is a chromatogram of the column prepared in Example 2 for testing six cations.
[0024] Among them, Figure 2 and Figure 3 The ions represented by each number are: 1. Li + 2. Na + 3. NH4 + ; 4. K + 5. Mg 2+ 6.Ca 2+ . Detailed Implementation
[0025] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.
[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.
[0027] Example 1:
[0028] S1. Homemade PS seed microspheres:
[0029] 95g of anhydrous ethanol and 5g of deionized water were poured into a 500mL beaker, and 2g of polyvinylpyrrolidone (PVP) was added. The mixture was ultrasonically dispersed for 5 min, and then transferred to a 500mL three-necked flask. Next, 1g of azobisisobutyronitrile (AIBN) was weighed and dissolved in 20g of styrene (ST). The ST and AIBN solutions were slowly added dropwise to the three-necked flask over 30 min. The system was purged with nitrogen for 5 min, and the temperature was raised to 70 °C with mechanical stirring. The reaction was allowed to proceed for 24 h. After the reaction was completed, the reaction solution was transferred to a sintered glass funnel and washed with ethanol. The product (non-crosslinked PS seed microspheres) was then dried in a 50 °C oven for later use. The morphology of the product was observed using a scanning electron microscope to confirm the particle size. Particles with a size of 1-2 μm were considered acceptable.
[0030] S2. Preparation of polymer microspheres:
[0031] 1) Preparation of seed emulsion: Weigh 0.1g sodium dodecyl sulfate (SDS) and dissolve it in 50 mL of deionized water. Separately, take 5g of non-crosslinked PS seed microspheres and disperse them in the SDS aqueous solution. Sonicate the dispersion for 5 min to obtain the seed microsphere emulsion.
[0032] 2) First step of seed microsphere swelling: Weigh 0.04 g SDS and dissolve it in 20 mL deionized water. Add 5 mL dibutyl phthalate (DBP) dropwise to the SDS aqueous solution and homogenize at high speed (8000 rpm) for 5 min to obtain a swelling solution. Add this solution dropwise to the seed microsphere emulsion and mechanically stir at room temperature for 8 h.
[0033] 3) Seed swelling of mixed emulsion (maleic anhydride and styrene ratio 1:1): Weigh 1g SDS and 2g polyvinyl alcohol (PVA) and dissolve them in 200mL deionized water. Then add 2.5g maleic anhydride, 2.5g styrene (ST), 5g divinylbenzene (DVB), 20g toluene, and 0.5g benzoyl peroxide (BPO). Homogenize and disperse for 5 min (9000 rpm) to obtain a mixed emulsion. Add it to a flask with a swept-mouth design and mechanically stir at room temperature for 8 h.
[0034] 4) Purge with nitrogen for 3 minutes to remove oxygen, then heat to 70 °C with mechanical stirring (300 rpm) and react for 24 h. Clean the polymer microspheres using a sintered sand funnel and wash with ethanol to remove residual monomers.
[0035] 5) Prepare a 40% isopropanol aqueous solution and add it to a three-necked flask. Transfer the polymer microspheres that have completed the reaction to the three-necked flask, stir mechanically (200 rpm), heat to 70 degrees Celsius, and heat to hydrolyze maleic anhydride for 24 hours.
[0036] 6) Clean the polymer microspheres with ethanol, then dry them in an oven at 50°C for later use.
[0037] S3. Column packing:
[0038] Weigh 4g of dried polymer microspheres and pack them into a column using the homogenization method. The column tube size is 4.6*250mm. After packing, the column is washed with 30mM methanesulfonic acid at a flow rate of 1.0mL / min for 2h and tested. A conductivity suppression detector is provided.
[0039] Example 2:
[0040] In this embodiment, the ratio of maleic anhydride to styrene is adjusted to 4:1.
[0041] S1. The steps for making PS seed microspheres are the same as step S1 in Example 1.
[0042] S2. Preparation of polymer microspheres:
[0043] 1) Preparation of seed emulsion: Weigh 0.1g SDS and dissolve it in 50 mL of deionized water. Separately, take 5g of non-crosslinked PS seed microspheres and disperse them in the SDS aqueous solution. Sonicate the mixture for 5 min to obtain the seed microsphere emulsion.
[0044] 2) First step of seed microsphere swelling: Weigh 0.04 g SDS and dissolve it in 20 mL deionized water. Add 5 mL DBP dropwise to the SDS aqueous solution and homogenize at high speed (8000 rpm) for 5 min to obtain a swelling solution. Add this solution dropwise to the seed microsphere emulsion and mechanically stir at room temperature for 8 h.
[0045] 3) Seed swelling of mixed emulsion (maleic anhydride to styrene ratio 4:1): Weigh 1g SDS and 2g polyvinyl alcohol (PVA) and dissolve them in 200mL deionized water. Then add 4g maleic anhydride, 1g St, 5g DVB, 20g toluene, and 0.5g benzoyl peroxide (BPO). Homogenize and disperse for 5 min (9000 rpm) to obtain a mixed emulsion. Add it to a swept-mouth flask and mechanically stir at room temperature for 8 h.
[0046] 4) Purge with nitrogen for 3 minutes to remove oxygen, then heat to 70 °C with mechanical stirring (300 rpm) and react for 24 h. Clean the polymer microspheres using a sintered sand funnel and wash with ethanol to remove residual monomers.
[0047] 5) Prepare a 40% isopropanol aqueous solution and add it to a three-necked flask. Transfer the polymer microspheres that have completed the reaction to the three-necked flask, stir mechanically (200 rpm), heat to 70°C, and heat to hydrolyze maleic anhydride for 24 h.
[0048] 6) Clean the polymer microspheres with ethanol, then dry them in an oven at 50°C for later use.
[0049] S3. The column packing is the same as step S3 in Example 1.
[0050] Example 3:
[0051] In this embodiment, the ratio of maleic anhydride to styrene is adjusted to 1:4.
[0052] S1. The steps for making PS seed microspheres are the same as step S1 in Example 1.
[0053] S2. Preparation of polymer microspheres:
[0054] 1) Preparation of seed emulsion: Weigh 0.1g SDS and dissolve it in 50 mL of deionized water. Separately, take 5g PS seed microspheres and disperse them in the SDS aqueous solution. Sonicate the dispersion for 5 min to obtain seed microsphere emulsion.
[0055] 2) First step of seed microsphere swelling: Weigh 0.04 g SDS and dissolve it in 20 mL deionized water. Add 5 mL DBP dropwise to the SDS aqueous solution and homogenize at high speed (8000 rpm) for 5 min to obtain a swelling solution. Add this solution dropwise to the seed microsphere emulsion and mechanically stir at room temperature for 8 h.
[0056] 3) Seed swelling of mixed emulsion (maleic anhydride to styrene ratio 4:1): Weigh 1g SDS and 2g polyvinyl alcohol (PVA) and dissolve them in 200mL deionized water. Then add 4g maleic anhydride, 1g St, 5g DVB, 20g toluene, and 0.5g benzoyl peroxide (BPO). Homogenize and disperse for 5 min (9000 rpm) to obtain a mixed emulsion. Add it to a swept-mouth flask and mechanically stir at room temperature for 8 h.
[0057] 4) Purge with nitrogen for 3 minutes to remove oxygen, then heat to 70 °C with mechanical stirring (300 rpm) and react for 24 h. Clean the polymer microspheres using a sintered sand funnel and wash with ethanol to remove residual monomers.
[0058] 5) Prepare a 40% isopropanol aqueous solution and add it to a three-necked flask. Transfer the polymer microspheres that have completed the reaction to the three-necked flask, stir mechanically (200 rpm), heat to 70°C, and heat to hydrolyze maleic anhydride for 24 h.
[0059] 6) Clean the polymer microspheres with ethanol, then dry them in an oven at 50°C for later use.
[0060] S3. The column packing is the same as step S3 in Example 1.
[0061] Example 4:
[0062] In this embodiment, only maleic anhydride is used as the monomer, and no styrene is used.
[0063] S1. The steps for making PS seed microspheres are the same as step S1 in Example 1.
[0064] S2. Preparation of polymer microspheres:
[0065] 1) Preparation of seed emulsion: Weigh 0.1g SDS and dissolve it in 50 mL of deionized water. Separately, take 5g PS seed microspheres and disperse them in the SDS aqueous solution. Sonicate the dispersion for 5 min to obtain seed microsphere emulsion.
[0066] 2) First step of seed microsphere swelling: Weigh 0.04 g SDS and dissolve it in 20 mL deionized water. Add 5 mL DBP dropwise to the SDS aqueous solution and homogenize at high speed (8000 rpm) for 5 min to obtain a swelling solution. Add this solution dropwise to the seed microsphere emulsion and mechanically stir at room temperature for 8 h.
[0067] 3) Seed swelling of mixed emulsion: Weigh 1g SDS and 2g polyvinyl alcohol (PVA) and dissolve them in 200mL deionized water. Then add 5g maleic anhydride, 5g DVB, 20g toluene, and 0.5g benzoyl peroxide (BPO), and homogenize for 5 min (9000rpm) to obtain a mixed emulsion. Add it to a swept-mouth flask and mechanically stir at room temperature for 8 h.
[0068] 4) Purge with nitrogen for 3 minutes to remove oxygen, then heat to 70 °C with mechanical stirring (300 rpm) and react for 24 h. Clean the polymer microspheres using a sintered sand funnel and wash with ethanol to remove residual monomers.
[0069] 5) Prepare a 40% isopropanol aqueous solution and add it to a three-necked flask. Transfer the polymer microspheres that have completed the reaction to the three-necked flask, stir mechanically (200 rpm), and heat to 70 °C to hydrolyze maleic anhydride. React for 24 h.
[0070] 6) Clean the polymer microspheres with ethanol, then dry them in an oven at 50°C for later use.
[0071] S3. The column packing is the same as step S3 in Example 1.
[0072] Example 5:
[0073] In this embodiment, maleic anhydride is replaced with itaconic anhydride.
[0074] S1. The steps for making PS seed microspheres are the same as step S1 in Example 1.
[0075] S2. Preparation of polymer microspheres:
[0076] 1) Preparation of seed emulsion: Weigh 0.1g SDS and dissolve it in 50 mL of deionized water. Separately, take 5g PS seed microspheres and disperse them in the SDS aqueous solution. Sonicate the dispersion for 5 min to obtain seed microsphere emulsion.
[0077] 2) First step of seed microsphere swelling: Weigh 0.04 g SDS and dissolve it in 20 mL deionized water. Add 5 mL DBP dropwise to the SDS aqueous solution and homogenize at high speed (8000 rpm) for 5 min to obtain a swelling solution. Add this solution dropwise to the seed microsphere emulsion and mechanically stir at room temperature for 8 h.
[0078] 3) Seed swelling of mixed emulsion (itaconic anhydride and styrene ratio 1:1): Weigh 1g SDS and 2g polyvinyl alcohol (PVA) and dissolve them in 200mL deionized water. Then add 2.5g itaconic anhydride, 2.5g St, 5g DVB, 20g toluene, and 0.5g benzoyl peroxide (BPO), and homogenize for 5 min (9000 rpm) to obtain a mixed emulsion. Add it to a swept-mouth flask and mechanically stir at room temperature for 8 h.
[0079] 4) Purge with nitrogen for 3 minutes to remove oxygen, then heat to 70 °C with mechanical stirring (300 rpm) and react for 24 h. Clean the polymer microspheres using a sintered sand funnel and wash with ethanol to remove residual monomers.
[0080] 5) Prepare a 40% isopropanol aqueous solution and add it to a three-necked flask. Transfer the polymer microspheres that have completed the reaction to the three-necked flask, stir mechanically (200 rpm), heat to 70°C, and heat to hydrolyze maleic anhydride for 24 h.
[0081] 6) Clean the polymer microspheres with ethanol, then dry them in an oven at 50°C for later use.
[0082] S3. The column packing is the same as step S3 in Example 1.
[0083] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.
[0084] Apart from the technical features described in the specification, the other technical features are known to those skilled in the art. To highlight the innovative features of this invention, the other technical features will not be described in detail here.
Claims
1. A method for preparing a high-capacity cation chromatography stationary phase, characterized in that, Includes the following steps, S1. Non-crosslinked PS seed microspheres are prepared by dispersion polymerization, and then the non-crosslinked PS seed microspheres are dispersed in an aqueous solution containing an emulsifier to prepare a seed microsphere emulsion. S2. Prepare the swelling solution and stir it using a homogenizer. After stirring, add it to the seed microsphere emulsion and stir to ensure that the swelling solution and the seed microsphere emulsion are fully swollen. S3. Prepare a mixed emulsion of maleic anhydride, divinylbenzene, porogen, and initiator, and add the mixed emulsion to the solution obtained in step S2, and continue stirring; S4. After purging nitrogen into the emulsion system obtained in step S3 to remove oxygen, the temperature is raised to the polymerization reaction temperature, and the reaction is carried out under mechanical stirring. S5. After the reaction is complete, the product is washed by vacuum filtration to remove residual reagents and monomers, and polymer microspheres are obtained. S6. Add the cleaned polymer microspheres to an isopropanol aqueous solution, heat and stir mechanically to fully hydrolyze the maleic anhydride inside the microspheres, at which point the microspheres can be functionalized. S7. Wash, filter, and dry the hydrolyzed microspheres; S8. The polymer microspheres obtained in step 7 are packed into a chromatographic column using a wet homogenization method, which can be used for cation separation testing.
2. The method for preparing a high-capacity cation chromatography stationary phase according to claim 1, characterized in that, The non-crosslinked PS seed microspheres prepared in step S1 have a particle size of 1~2 μm.
3. The method for preparing a high-capacity cation chromatography stationary phase according to claim 1, characterized in that, In step S2, the solvent in the swelling solution is dibutyl phthalate or dioctyl phthalate.
4. The method for preparing a high-capacity cation chromatography stationary phase according to claim 1, characterized in that, In the mixed emulsion prepared in step S3, maleic anhydride is a monomer, divinylbenzene is a crosslinking agent, and the degree of crosslinking is at least 50%.
5. The method for preparing a high-capacity cation chromatography stationary phase according to claim 4, characterized in that, The monomer in the mixed emulsion prepared in step S3 also includes styrene.
6. The method for preparing a high-capacity cation chromatography stationary phase according to claim 1, characterized in that, The porogen is any one of toluene, xylene, or long-chain alkanes, and the mass of the porogen is 0.2 to 2 times the mass of maleic anhydride.
7. The method for preparing a high-capacity cation chromatography stationary phase according to claim 5, characterized in that, The initiator is an oil-soluble peroxide, and the mass of the initiator is 1% to 5% of the monomer mass.
8. The method for preparing a high-capacity cation chromatography stationary phase according to claim 1, characterized in that, In step S2, the swelling temperature of the swelling solution and the seed microsphere emulsion is room temperature.