Liquid chromatography silica gel microspheres, preparation method and application thereof

Abstract

The present application relates to a kind of liquid chromatography silica gel microspheres and its preparation method and application, the surface of the silica gel microspheres is fixed with proton, the proton is fixed on the surface of silica gel microspheres by the charge attraction of electron-rich group and oxygen atom in silicon hydroxyl group together.The present application introduces electron-rich group on the surface of microsphere, based on the charge attraction of electron-rich group to proton, and the charge attraction of oxygen atom in silicon hydroxyl group to proton forms double charge fixing force, utilize the attraction between charges and fix proton on the surface of silica gel, so as to eliminate the adverse effects due to proton in silicon hydroxyl group free, can fundamentally solve the problem of proton in silicon hydroxyl group free, compared with traditional space seal tail technology has significant superiority.

Description

Technical Field

[0001] This invention belongs to the field of liquid chromatography silica microsphere technology, specifically relating to a liquid chromatography silica microsphere, its preparation method, and its application. Background Technology

[0002] Due to their excellent mechanical strength and easily controllable pore and particle size, porous silica microspheres have been widely used in chromatographic analysis. Using porous silica microspheres as a matrix, a variety of chromatographic stationary phases can be obtained by chemically modifying the active silanol groups on their surface, especially reversed-phase stationary phases modified with C18, C8, phenyl, etc., which have wide applications in scientific research and production. However, during the modification of silica microspheres, a large number of unreacted silanol groups remain due to steric hindrance and other reasons. These silanol groups have acidity and certain ion exchange properties, which can interact with basic or ionic analytes, leading to poor separation. Traditional methods use small-molecule silanizing reagents to react with the residual silanol groups, but unreacted silanol groups always remain. The protons in the silanol groups are free, which has an adverse effect. Summary of the Invention

[0003] The purpose of this invention is to provide a liquid chromatography silica microsphere, its preparation method, and its application in order to solve the above-mentioned problems, aiming to address the issue of residual unreacted silanol groups and the adverse effects caused by protons ionizing in the silanol groups.

[0004] The present invention achieves the above objectives through the following technical solutions:

[0005] A type of silica microsphere for liquid chromatography, wherein protons are immobilized on the surface of the silica microsphere, and the protons are immobilized on the surface of the silica microsphere by the charge attraction generated by the electron-rich groups and the oxygen atoms in the silanol groups.

[0006] A method for preparing silica microspheres for liquid chromatography involves introducing electron-rich groups onto the surface of the silica microspheres. The electrostatic attraction between the electron-rich groups and the oxygen atoms in the silanol groups and protons fixes the protons onto the surface of the silica microspheres, thereby preparing silica microspheres with surface double charge and proton fixation.

[0007] As a further optimization of the present invention, the electron-rich groups are introduced by one of the following methods: chemical bonding, physical coating, or atomic lattice embedding.

[0008] As a further optimization of the present invention, the silica microspheres are all silica microspheres with silanol groups on their surface.

[0009] As a further optimization of the present invention, the silica microspheres are pure silica or hybrid silica porous microspheres used for reversed-phase liquid chromatography separation.

[0010] As a further optimization of the present invention, the microspheres are at least one of pure silica microspheres, organic-inorganic hybrid silica microspheres, silica-encapsulated polymer microspheres, titanium dioxide / silica composite microspheres, and zirconium dioxide / silica composite microspheres.

[0011] As a further optimization of the present invention, the electron-rich group is at least one of the groups, atoms, ions or molecules that can provide electrons to form charge attraction with protons.

[0012] As a further optimization of the present invention, the electron-rich group is a group containing lone pairs of electrons or a group containing large π bonds.

[0013] As a further optimization of the present invention, the group containing lone pair electrons is at least one of Lewis acid, amino or quaternary ammonium group.

[0014] As a further optimization of the present invention, the amino group is introduced by a silanizing agent containing an amino group.

[0015] As a further optimization of the present invention, the amino-containing silanizing agent is 3-aminopropyltriethoxysilane.

[0016] As a further optimization of the present invention, the quaternary ammonium group is introduced through the product obtained by reacting the epoxy group in 3-glycidyl etheroxypropyltrimethoxysilane with trimethylamine.

[0017] As a further optimization of the present invention, the group containing the large π bond is at least one of a benzene ring, a double bond, and a triple bond.

[0018] As a further optimization of the present invention, functional groups are introduced onto the surface of the silica microspheres before or after the introduction of electron-rich groups.

[0019] As a further optimization of the present invention, the functional groups include C18, C8 and phenyl.

[0020] Application of a method for preparing silica gel microspheres for liquid chromatography in the separation and analysis of alkaline substances.

[0021] The beneficial effects of this invention are as follows:

[0022] This invention introduces electron-rich groups on the surface of silica microspheres. By utilizing the combined charge attraction between the electron-rich groups and the oxygen atoms in the silanol groups on the protons, the protons are fixed on the silica surface, thereby eliminating the adverse effects caused by the free protons in the silanol groups. This completely shields the adverse effects of the silanol groups, making the separation and analysis of alkaline substances more efficient. Attached Figure Description

[0023] Figure 1 Separation chromatogram for C18-bonded modified porous silica microspheres;

[0024] Figure 2 Separation chromatogram for trimethylchlorosilane-capped C18-bonded microspheres;

[0025] Figure 3 Separation chromatogram for C18 bonded microspheres with surface amino double charge proton immobilization;

[0026] Figure 4 The separation chromatogram is for C18 bonded microspheres with surface trimethylamine double-charged protons. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and several optional embodiments. It should be noted that the present invention is not limited to the following embodiments. Any technical features and implementations in the following embodiments are one or more of a variety of optional technical features and implementations. For the sake of simplicity, this document cannot exhaustively list all alternative technical features and implementations included in this patent. Therefore, those skilled in the art should understand that any technical features and implementations within this embodiment do not limit the scope of protection of this patent, which includes all alternative technical features and implementations adopted by those skilled in the art without inventive effort.

[0028] 1. Explanation

[0029] Unless otherwise specified in the embodiments, the techniques and conditions described in the literature in this field or the product instructions shall be followed. If the manufacturers of the reagents or instruments used are not specified, they are all conventional products that can be purchased commercially.

[0030] 2. Method

[0031] 2.1 C18 Bonding Modification of Porous Silica Microspheres

[0032] 2.1.1 Preparation steps

[0033] S1: Take 200g of porous silica microspheres (particle size 5μm, pore size...) Specific surface area 350m² 2 / g);

[0034] S2: The porous silica microspheres in S1 were mixed with 10% hydrochloric acid solution and then refluxed for 24 hours. After washing with pure water until neutral, they were dried at 125 degrees Celsius.

[0035] S3: The porous silica microspheres treated with S2 were mixed with 2000 mL of toluene, heated to reflux, triethylamine catalyst was added, and octadecyl dimethyl chlorosilane toluene solution was added dropwise. The mixture was refluxed for 24 h, washed successively with toluene, acetone and methanol, and dried to obtain C18 modified porous silica microspheres.

[0036] 2.1.2 Test methods and results for C18-modified porous silica microspheres

[0037] The microspheres were subjected to column packing tests under the following conditions: methanol / 0.02M PSB, pH=7.0 (80:20, v / v), column temperature 30℃, flow rate 1mL / min, detection wavelength 254nm, and the target analytes were uracil, toluene, ethylbenzene, 1,4-dihydroxyanthraquinone, and amitriptyline hydrochloride.

[0038] Test results: Separation spectra as follows Figure 1 As shown, from Figure 1 As can be seen, the amitriptyline peak exhibits severe tailing, with a tailing factor of 4.53 (the tailing factor is a parameter used to evaluate peak shape by calculating the ratio of the peak width at 5% peak height to the distance from the peak apex to the leading edge, in order to ensure chromatographic separation effect and measurement accuracy).

[0039] 2.2 Trimethylchlorosilane-capped C18 bonded microspheres

[0040] 2.2.1 Preparation steps

[0041] S1: Take 50g of the C18 bonded modified porous silica microspheres prepared according to 2.1.1 and disperse them in 500mL of dry toluene;

[0042] S2: The porous silica microspheres treated by S1 were added to triethylamine catalyst and 50 mL of trimethylchlorosilane, heated under reflux for 24 h, washed successively with toluene, acetone and methanol, and dried to obtain C18 modified porous silica microspheres with trimethylchlorosilane tailing.

[0043] 2.2.2 Test methods and results for trimethylchlorosilane-capped C18 modified porous silica microspheres

[0044] The microspheres were subjected to column packing tests under the following conditions: methanol / 0.02M PSB, pH=7.0 (80:20, v / v), column temperature 30℃, flow rate 1mL / min, detection wavelength 254nm, and the target analytes were uracil, toluene, ethylbenzene, 1,4-dihydroxyanthraquinone, and amitriptyline hydrochloride.

[0045] Test results: Separation spectra as follows Figure 2 As shown, from Figure 2As can be seen, the amitriptyline peak exhibits significant tailing, with a tailing factor of 2.79 (the tailing factor is a parameter used to evaluate peak shape by calculating the ratio of the peak width at 5% peak height to the distance from the peak apex to the leading edge, in order to ensure chromatographic separation effect and measurement accuracy).

[0046] 2.3 C18 bonded microspheres with surface amino double-charge proton immobilization

[0047] 2.3.1 Preparation steps

[0048] S1: Take 50g of the C18 bonded modified porous silica microspheres prepared according to 2.1.1 and disperse them in 500mL of dry toluene;

[0049] S2: The porous silica microspheres treated with S1 were added to triethylamine catalyst and 50 mL of 3-aminopropyltriethoxysilane (but not limited to this amino-containing silanizing reagent), heated under reflux for 24 h, washed successively with toluene, acetone and methanol, and dried to obtain C18 modified porous silica microspheres with double-charged protons fixed by the introduction of the electron-rich amino group.

[0050] 2.3.2 Test methods and results for C18 bonded microspheres with surface amino double-charge proton immobilization

[0051] The microspheres were subjected to column packing tests under the following conditions: methanol / 0.02M PSB, pH=7.0 (80:20, v / v), column temperature 30℃, flow rate 1mL / min, detection wavelength 254nm, and the target analytes were uracil, toluene, ethylbenzene, 1,4-dihydroxyanthraquinone, and amitriptyline hydrochloride.

[0052] Test results: Separation spectra as follows Figure 3 As shown, from Figure 3 As can be seen, the peak shape of the basic substance amitriptyline was significantly improved, with a tailing factor of 1.22 (the tailing factor is a parameter used to evaluate peak shape by calculating the ratio of the peak width at 5% peak height to the distance from the peak apex to the leading edge, in order to ensure chromatographic separation effect and measurement accuracy).

[0053] 2.4 C18 bonded microspheres with surface-fixed trimethylamine double-charged protons

[0054] 2.4.1 Preparation steps

[0055] S1: Take 50g of the C18 bonded modified porous silica microspheres prepared according to 2.1.1 and disperse them in 500mL of dry toluene;

[0056] S2: The porous silica microspheres treated with S1 were added to triethylamine catalyst and 50 mL of 3-glycidyl etheroxypropyltrimethoxysilane, heated under reflux for 24 h, washed with toluene, acetone and methanol in sequence, and dried.

[0057] S3: The product obtained in S2 was dispersed in a methanol solution, and 50 mL of trimethylamine solution (30%) was added. The mixture was reacted at 50 °C for 6 h. After thorough filtration and washing with methanol, C18 modified porous silica microspheres with double-charged protons fixed by the electron-rich trimethylamine group were obtained.

[0058] 2.4.2 Test methods and results for C18 bonded microspheres with surface-fixed trimethylamine double-charged protons

[0059] The microspheres were subjected to column packing tests under the following conditions: methanol / 0.02M PSB, pH=7.0 (80:20, v / v), column temperature 30℃, flow rate 1mL / min, detection wavelength 254nm, and the target analytes were uracil, toluene, ethylbenzene, 1,4-dihydroxyanthraquinone, and amitriptyline hydrochloride.

[0060] Test results: Separation spectra as follows Figure 4 As shown, from Figure 4 As can be seen, the peak shape of the basic substance amitriptyline was significantly improved, with a tailing factor of 1.02 (the tailing factor is a parameter used to evaluate peak shape by calculating the ratio of the peak width at 5% peak height to the distance from the peak apex to the leading edge, in order to ensure chromatographic separation effect and measurement accuracy).

[0061] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A type of silica gel microspheres for liquid chromatography, characterized in that: Protons are fixed on the surface of the silica microspheres. The protons are fixed on the surface of the silica microspheres by the charge attraction generated by the electron-rich groups and the oxygen atoms in the silanol groups, thereby obtaining liquid chromatography silica microspheres with surface double charge proton fixation. The electron-rich group is a group containing lone pairs of electrons; The group containing lone pairs of electrons is at least one of amino or quaternary ammonium groups; The amino group is introduced by a silanizing agent containing an amino group, wherein the silanizing agent is 3-aminopropyltriethoxysilane; The quaternary ammonium group is introduced into the product obtained by reacting the epoxy group in 3-glycidyl etheroxypropyltrimethoxysilane with trimethylamine.

2. A method for preparing silica gel microspheres for liquid chromatography as described in claim 1, characterized in that: Electron-rich groups are introduced onto the surface of the silica microspheres. The electrostatic attraction between the electron-rich groups and the oxygen atoms in the silanol groups and the protons fixes the protons onto the surface of the silica microspheres, thereby preparing liquid chromatography silica microspheres with surface double charge and proton fixation.

3. The method for preparing silica gel microspheres for liquid chromatography according to claim 2, characterized in that: The silica microspheres are all silica microspheres with silanol groups on their surface.

4. The method for preparing silica gel microspheres for liquid chromatography according to claim 3, characterized in that: The silica microspheres are porous microspheres of pure silica or hybrid silica used for reversed-phase liquid chromatography separation.

5. The method for preparing silica gel microspheres for liquid chromatography according to claim 4, characterized in that: The microspheres are at least one of the following: pure silica microspheres, organic-inorganic hybrid silica microspheres, silica-encapsulated polymer microspheres, titanium dioxide / silica composite microspheres, and zirconium dioxide / silica composite microspheres.

6. A method for preparing silica gel microspheres for liquid chromatography according to any one of claims 2-5, characterized in that: Functional groups are introduced onto the surface of the silica microspheres before or after the introduction of electron-rich groups.

7. The method for preparing silica gel microspheres for liquid chromatography according to claim 6, characterized in that: The functional groups include C18, C8, and phenyl.

8. The application of the silica microspheres for liquid chromatography as described in claim 1 in the separation and analysis of alkaline substances.

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