A kind of surface porous silica gel microspheres for chromatography, surface porous silica gel microspheres chromatography packing and preparation method thereof

Abstract

The application provides a kind of surface porous silica gel microspheres for chromatography, surface porous silica gel microspheres chromatography packing and a preparation method thereof.The method comprises the following steps: weighing solid silica gel microspheres and dispersing them in a mixed solvent formed by ethanol and water; adding aminopropyltrimethoxysilane as a solid support to the mixed solvent, stirring the whole system uniformly and heating; then adding a silica sol solution to the system in one go and reacting; centrifuging the solution after reaction, drying, and obtaining a surface porous silica gel microspheres powder; dispersing the powder in distilled water at room temperature by ultrasonic, centrifuging again, and drying; finally, calcining in a muffle furnace at 500 DEG C for 3 h, and finally obtaining sintered surface porous silica gel microspheres.The application has the characteristics of fast preparation speed and low production cost.

Description

Technical Field

[0001] This invention relates to the field of analytical chemistry, and in particular to a porous silica microsphere for chromatography, a porous silica microsphere chromatographic packing material, and a method for preparing the same. Background Technology

[0002] High-performance liquid chromatography (HPLC) uses porous silica microspheres as its core separation material. Among these, surface-porous silica microspheres offer advantages over fully porous silica microspheres, such as faster separation speed and reduced organic solvent consumption, and have received increasing attention and application in recent years. Preparation methods for surface-porous silica microspheres typically include layer-by-layer self-assembly, polymerization-induced colloidal aggregation, and template methods. Among them, the layer-by-layer self-assembly method utilizes the electrostatic interaction between surfactants and silica sol to coat silica sol layer by layer onto the surface of a solid silica core. This method is relatively cumbersome and has high production costs. The polymerization-induced colloidal aggregation method usually uses polymer gel reactions such as urea-formaldehyde resin to fix silica sol onto the surface of a solid silica core, forming porous silica microspheres. This method is difficult to avoid the silica sol itself agglomerating into spheres. The template method usually uses cationic surfactants as templates to generate silica sol through reactions such as hydrolysis and etching. Under the action of the template, it is deposited on the surface of a solid silica core to form a porous silica structure. This method does not use existing silica sol as the reaction material, and the resulting pore size is usually small, requiring pore expansion. In addition, the reaction time is also relatively long. Summary of the Invention

[0003] This invention provides porous silica microspheres for chromatography, a porous silica microsphere chromatographic packing material, and a method for preparing the same. The method uses aminopropyltrimethoxysilane as a carrier and existing silica sol as a reactant to rapidly prepare porous silica microspheres.

[0004] A method for preparing porous silica microspheres for chromatography, comprising:

[0005] Solid silica microspheres were weighed and dispersed in a mixed solvent of ethanol and water; aminopropyltrimethoxysilane was added to the mixed solvent as a carrier, the whole system was stirred evenly and heated to 60°C; then silica sol solution was added to the system in one go and the reaction was carried out for 1 hour.

[0006] After centrifugation, the solution was dried at 100°C to obtain porous silica microsphere powder.

[0007] The porous silica microsphere powder was ultrasonically dispersed with distilled water at room temperature, then centrifuged and dried. Finally, it was calcined in a muffle furnace at 500°C for 3 hours to remove organic matter, and finally sintered porous silica microspheres were obtained.

[0008] Furthermore, in the method for preparing porous silica microspheres for chromatography as described above, the particle size of the solid silica microspheres is 1.5–5 μm.

[0009] Furthermore, in the method for preparing surface porous silica microspheres for chromatography as described above, the mixed solvent has a volume ratio of ethanol to water of 3 / 2.

[0010] Furthermore, in the method for preparing surface porous silica microspheres for chromatography as described above, the silica sol solution has a mass percentage of 20%.

[0011] Furthermore, in the method for preparing surface porous silica microspheres for chromatography as described above, the stirring speed of the system is 300 r / min.

[0012] A porous silica microsphere prepared using the method described above.

[0013] A surface-porous silica microsphere chromatographic packing material is prepared using surface-porous silica microspheres as described above.

[0014] As described above, different functional groups such as carbon-18, phenyl, and amino are bonded to the surface of the porous silica microspheres to obtain different types of porous silica microsphere chromatographic packing materials.

[0015] The preparation method provided by this invention utilizes the hydrolytic polymerization reaction of aminopropyltrimethoxysilane under aqueous conditions and its easy adsorption onto the surface of silica gel. During the reaction, the aminopropyltrimethoxysilane adsorbed on the surface of the solid silica gel core undergoes a hydrolytic polymerization reaction under heating conditions. In this reaction, silica sol is polymerized onto the surface of the solid silica gel core, thereby forming a porous surface structure. Furthermore, during the hydrolytic polymerization reaction of aminopropyltrimethoxysilane, 2.5 mL to 5 mL of silica sol with a mass percentage of 20% can be polymerized onto the surface of 4 g of solid silica gel core microspheres within 1 hour. That is, one reaction can polymerize 1 / 8 to 1 / 4 of the mass of the solid silica gel core silica sol, which is far superior to methods such as layer-by-layer self-assembly that require repeated coating to obtain a certain quality of porous surface layer. The preparation method provided by this invention improves the preparation speed of porous silica gel microspheres and reduces production costs. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1This is a scanning electron microscope image of porous silica microspheres.

[0018] Figure 2 The image shows the XRD pattern of porous silica microspheres.

[0019] Figure 3 Chromatograms of compounds separated using C18-modified surface porous silica microsphere chromatographic packing material. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0021] Example 1

[0022] Preparation, modification and chromatographic separation of 2.5μm porous silica microspheres

[0023] ① Weigh 4g of solid silica microspheres with a particle size of 2.5μm and disperse them in 100mL of a 3 / 2 volume ratio ethanol / water mixed solvent; add 0.5mL of aminopropyltrimethoxysilane as a carrier; stir the entire system at 300r / min until homogeneous and heat to 60℃; add 2.5mL of silica sol solution with a mass percentage of 20% to the above system at once and react for 1h; after centrifugation, dry the system at 100℃ to obtain porous silica microspheres; weigh the product and the mass is 4.5g, which proves that the silica sol accounting for 1 / 8 of the mass of the solid silica core has been successfully immobilized on the surface of the silica core within 1h of reaction; disperse the product with distilled water ultrasonically at room temperature, then centrifuge and dry; finally, calcine in a muffle furnace at 500℃ for 3h to remove organic matter and sinter to form porous silica microspheres.

[0024] The morphology of the porous silica microspheres was characterized using scanning electron microscopy. Figure 1 XRD characterization of the phase composition of the porous silica microspheres confirmed that the porous silica microspheres prepared in this embodiment are amorphous silica. (See [link]). Figure 2 .

[0025] ② Based on this, weigh 3g of surface porous silica microspheres into a round-bottom flask, add 100mL of dry toluene, and then add 1mL of octadecyltrichlorosilane as a modifying reagent. Stir the system evenly and heat it to 105℃ for 6h. After centrifuging the system, wash the product with solvents such as n-hexane and ethanol in sequence, dry the solvent, and obtain C18 modified surface porous silica chromatographic packing material.

[0026] ③ A chromatographic column (50mm × 4.6mm) was packed with C18 modified surface porous silica gel chromatographic packing material and connected to a high-performance liquid chromatograph (HPLC). The separation performance of the chromatographic packing material was investigated. See [link to relevant documentation]. Figure 3 Chromatographic conditions: 60% acetonitrile / 40% water as mobile phase, 1 mL / min, UV detector at 254 nm. The chromatographic peaks from left to right correspond to uracil, nitrobenzene, naphthalene, and phenanthrene, respectively.

[0027] Example 2: Preparation of 5μm porous silica microspheres

[0028] ① Weigh 4g of solid silica microspheres with a particle size of 5μm and disperse them in 100mL of ethanol / water mixed solvent with a volume ratio of 3 / 2; add 0.5mL of aminopropyltrimethoxysilane as a carrier; stir the entire system at 300r / min until homogeneous and heat to 60℃; add 5mL of silica sol solution with a mass percentage of 20% to the above system at once and react for 1h; after centrifugation, dry the system at 100℃ to obtain porous silica microspheres; weigh the product and the mass is 5g, which proves that silica sol accounting for 1 / 4 of the mass of the solid silica core has been successfully immobilized on the surface of the silica core within 1h of reaction; disperse the product with distilled water ultrasonically at room temperature, then centrifuge and dry; finally, calcine in a muffle furnace at 500℃ for 3h to remove organic matter and sinter to form porous silica microspheres.

[0029] Example 3

[0030] Preparation, modification and chromatographic separation of 1.5 μm porous silica microspheres

[0031] ① Weigh 4g of solid silica microspheres with a particle size of 1.5μm and disperse them in 100mL of a 3 / 2 volume ratio of ethanol / water mixed solvent; add 0.5mL of aminopropyltrimethoxysilane as a carrier; stir the entire system at 300r / min until homogeneous and heat to 60℃; add 2.5mL of silica sol solution with a mass percentage of 20% to the above system at once and react for 1h; after centrifugation, dry the system at 100℃ to obtain porous silica microspheres; weigh the product and the mass is 4.5g, which proves that the silica sol accounting for 1 / 8 of the mass of the solid silica core has been successfully immobilized on the surface of the silica core within 1h of reaction; disperse the product with distilled water ultrasonically at room temperature, then centrifuge and dry; finally, calcine in a muffle furnace at 500℃ for 3h to remove organic matter and sinter to form porous silica microspheres.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for the preparation of a surface porous silica gel microsphere chromatography packing material, characterized in that, The preparation method includes the following steps: Solid silica microspheres were weighed and dispersed in a mixed solvent of ethanol and water; aminopropyltrimethoxysilane was added to the mixed solvent as a carrier, the whole system was stirred evenly and heated to 60°C; then silica sol solution was added to the system in one go and the reaction was carried out for 1 hour. After centrifugation, the solution was dried at 100°C to obtain porous silica microsphere powder. The porous silica microsphere powder was ultrasonically dispersed in distilled water at room temperature, then centrifuged and dried; finally, it was calcined in a muffle furnace at 500°C for 3 hours to remove organic matter, and finally sintered porous silica microspheres were obtained. The solid silica microspheres have a particle size of 1.5~5μm; The volume ratio of ethanol to water in the mixed solvent is 3:2; The silica sol solution has a mass percentage of 20%. By utilizing the hydrolytic polymerization reaction of aminopropyltrimethoxysilane under aqueous conditions and its easy adsorption onto the surface of silica gel, the aminopropyltrimethoxysilane adsorbed on the surface of the solid silica gel core undergoes a hydrolytic polymerization reaction under heating conditions during the reaction process. In this process, the silica sol is polymerized on the surface of the solid silica gel core, thereby forming a porous surface structure.

2. The method for preparing the porous silica microsphere chromatographic packing material according to claim 1, characterized in that, The stirring speed of the system is 300 r / min.

3. The porous silica microsphere chromatographic packing material prepared by the method according to claim 1.

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