Capillary electrochromatography open tubular column of nano material synthesized based on chiral metal organic framework and chiral molecularly imprinted polymer as well as preparation method and application of capillary electrochromatography open tubular column

Abstract

The invention discloses a nano material synthesized based on a chiral metal organic framework material and a chiral molecularly imprinted polymer, which is characterized in that L-glutamic acid is used as a chiral organic ligand, terephthalic acid is used as an achiral organic ligand, and tetrabutyl titanate is used as a metal salt to prepare the chiral metal organic framework material; the preparation method comprises the following steps: uniformly mixing a dispersion liquid of a chiral metal organic framework material with template molecules, a functional monomer, a cross-linking agent and an initiator, reacting at room temperature, filtering after the reaction is finished, washing an eluent to remove the template molecules, and drying to obtain the nano material. The invention discloses a capillary electrochromatography open tubular column. The capillary electrochromatography open tubular column takes a nano material as a stationary phase. The invention discloses an application of the capillary electrochromatography open tubular column in chiral resolution of DL-histidine. Compared with a CEC open tubular column taking L-Glu / MIL-125 (Ti) or CMIPs as a stationary phase, the chiral separation capability of the CEC open tubular column to the histidine enantiomers is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical synthesis and analysis, and particularly relates to a novel nanomaterial synthesized based on a chiral metal-organic framework material and a chiral molecularly imprinted polymer, a capillary electrochromatography open tubular column of the novel nanomaterial synthesized based on the chiral metal-organic framework material and the chiral molecularly imprinted polymer, and a preparation method thereof. Background Art

[0002] Chirality is a fundamental property of nature, and a large part of the currently used drugs are chiral. The two chiral molecules of a chiral drug may have different biological activities. Often, only one isomer is effective, while the other isomer is ineffective or even harmful. The problems of drug quality control and safe drug use brought by chiral drugs have attracted great attention from drug regulatory authorities in various countries. Establishing accurate, efficient, and sensitive chiral drug separation and analysis methods can provide effective methods for the research and development of single enantiomer new drugs and their pharmacodynamics and pharmacokinetics in vivo, and has very important application value and market prospects. At present, the commonly used chromatographic chiral separation methods mainly include high performance liquid chromatography, gas chromatography, capillary electrochromatography, etc. Among them, capillary electrochromatography (CEC) is widely used in the field of chiral separation because it combines the advantages of capillary electrophoresis (CE) and high performance liquid chromatography (HPLC). CEC capillary columns can be divided into packed columns, monolithic columns, and open tubular columns (also called coated columns). Open tubular columns have the advantages of simple preparation, not easily blocked, and easy to modify, and are widely used in the research of chiral separation. However, open tubular capillary electrochromatography has disadvantages such as low phase ratio, small column capacity, and weak chiral separation ability. If suitable materials can be introduced into the stationary phase to increase its specific surface area and improve the loading capacity, the above problems can be solved to a certain extent. Some researchers have increased the specific surface area by modifying nanoparticles such as titanium dioxide nanoparticles, silica nanoparticles, and metal-organic framework materials on the stationary phase.

[0003] Metal-organic framework materials (MOFs) are porous materials formed by the assembly of metal ions or metal clusters and organic ligands through metal-ligand coordination bonds. MOFs have the characteristics of large specific surface area, easy surface modification, and adjustable pore size. Chiral metal-organic framework materials (CMOFs) not only have the characteristics of traditional MOFs, but also have a three-dimensional chiral structure.

[0004] Molecularly imprinted polymers (MIPs) are a class of polymers that have specific recognition for target molecules (template molecules). Chiral molecularly imprinted polymers (CMIPs) are prepared using a single enantiomer of a chiral compound as the template molecule. Due to the memory effect of the imprinted cavity of CMIPs, they can effectively recognize the template molecule and thus play a role in chiral separation. Moreover, they are simple to prepare and have low costs. Therefore, CMIPs have attracted much attention in the field of chiral separation.

[0005] In previous studies, chromatographic columns with CMOFs as the stationary phase had problems such as complex preparation processes and low resolution, while chromatographic columns with CMIPs as the stationary phase had problems such as uneven imprinting sites and low resolution. So far, there have been few reports on using novel nanomaterials synthesized from CMOFs and CMIPs as the stationary phase of open-tubular capillary electrochromatography columns, and there is still a large amount of research space.

[0006] The large specific surface area of CMOFs greatly increases the loading amount of CMIPs on the stationary phase, and the rigid framework of CMOFs can effectively prevent the deformation of the imprinted cavity of CMIPs. In addition, the presence of CMIPs can also improve the stability of the CMIP@CMOF stationary phase. More importantly, CMOFs and CMIPs play a synergistic role in the chiral separation process, which can greatly improve the chiral separation ability of the composite material. All in all, the strategy of using novel nanomaterials synthesized from CMOFs and CMIPs for preparing the stationary phase of CEC columns is highly innovative. Summary of the Invention

[0007] The object of the present invention is to provide a new nanomaterial synthesized based on chiral metal-organic frameworks and chiral molecularly imprinted polymers. The open-tubular capillary electrochromatography column with this new nanomaterial as the stationary phase can be used to construct a CEC chiral separation system to complete the enantiomeric separation of chiral drugs / compounds such as histidine and the optical purity inspection of drug substances, and can solve technical problems such as small chiral separation degree and low separation efficiency existing in the current CEC.

[0008] To achieve the above object, the specific technical solutions adopted by the present invention are as follows:

[0009] A novel nanomaterial synthesized based on chiral metal-organic framework materials and chiral molecularly imprinted polymers uses L-glutamic acid as the chiral organic ligand, terephthalic acid as the achiral organic ligand, and tetrabutyl titanate (Ti(OC4H9)4) as the metal salt to prepare the chiral metal-organic framework material (denoted as L-Glu / MIL-125(Ti)); the dispersion of the chiral metal-organic framework material is mixed evenly with the template molecule, functional monomer, crosslinking agent, and initiator, and reacted at room temperature. After the reaction, it is filtered, and then washed with the eluent to remove the template molecule, and dried to obtain the novel nanomaterial.

[0010] Preferably, the nanomaterial is prepared by mixing the achiral organic ligand, chiral organic ligand, and metal salt evenly in a mixed solution of N,N-dimethylformamide (DMF) and methanol, heating at 120-180 °C for 10-15 h, centrifuging, washing, and drying to obtain the chiral metal-organic framework material. Then the chiral metal-organic framework material is dispersed in ethanol / water to obtain the dispersion of the chiral metal-organic framework material. The template molecule and functional monomer are dissolved in ethanol / water, and the dispersion of the chiral metal-organic framework material, crosslinking agent, and initiator are added and mixed evenly, and reacted at room temperature. After the reaction, it is filtered, and then washed with the eluent to remove the template molecule, and dried to obtain the novel nanomaterial.

[0011] Preferably, the heating temperature is 150 °C and the heating time is 12 h.

[0012] A capillary electrochromatography open-tubular column of a nanomaterial synthesized based on chiral metal-organic framework and chiral molecularly imprinted polymers (denoted as CMIP@L-Glu / MIL-125(Ti)@capillary) is a capillary electrochromatography open-tubular column using the novel nanomaterial synthesized based on chiral metal-organic framework materials and chiral molecularly imprinted polymers as the stationary phase.

[0013] A preparation method of a capillary electrochromatography open-tubular column of a nanomaterial synthesized based on chiral metal-organic framework and chiral molecularly imprinted polymers includes:

[0014] Step (1), activation of the capillary: successively rinse the empty silica capillary with sodium hydroxide solution, hydrochloric acid, and methanol, and dry it with nitrogen and dry to obtain the activated capillary;

[0015] Step (2), Preparation of chiral metal-organic framework (L-Glu / MIL-125(Ti)): Using L-glutamic acid as the chiral organic ligand, terephthalic acid as the achiral organic ligand, and tetrabutyl titanate (Ti(OC4H9)4) as the metal salt, dissolve the achiral organic ligand and the chiral organic ligand in a mixed solution of N,N-dimethylformamide and methanol, add the metal salt, stir evenly at room temperature, transfer the mixture to a hydrothermal reaction kettle, heat at 120 - 180 °C for 10 - 15 h, centrifuge, wash the precipitate with DMF, and dry to obtain the chiral metal-organic framework (L-Glu / MIL-125(Ti)) powder;

[0016] Step (3), Disperse the chiral metal-organic framework in ethanol / water, and ultrasonically disperse it evenly to obtain a chiral metal-organic framework dispersion;

[0017] Step (4), Dissolve the template molecule in ethanol / water, add the functional monomer, stir evenly, add the chiral metal-organic framework dispersion, stir evenly, then add the cross-linking agent and the initiator, oscillate and mix evenly, quickly inject the mixed solution into the activated capillary, seal both ends of the capillary, and react at room temperature for 16 - 24 h; after the reaction, rinse with the eluent for 1 - 3 h to remove the template molecule, dry with nitrogen to obtain a novel open-tubular capillary electrochromatography column.

[0018] In step (1), the empty silica capillary is an unmodified fused silica capillary with an inner diameter of 75 microns.

[0019] The concentration of the sodium hydroxide solution is 1 mol / L; the concentration of the hydrochloric acid is 1 mol / L.

[0020] Specifically, the activation of the capillary: Rinse the empty silica capillary with the sodium hydroxide solution for 1 h, rinse with deionized water until neutral, then rinse the empty silica capillary with hydrochloric acid for 0.5 h, rinse with deionized water until neutral, rinse the empty silica capillary with methanol for 0.5 h, dry with nitrogen, place it in an oven at 110 °C and dry for 1 h to obtain the activated capillary, and store it at -4 °C.

[0021] In step (2), the molar ratio of L-glutamic acid to terephthalic acid is 1:1.

[0022] The molar ratio of L-glutamic acid to tetrabutyl titanate is 2:1.

[0023] In the mixed solution of N,N-dimethylformamide and methanol, the volume ratio of N,N-dimethylformamide to methanol is 6:1 - 12:1, preferably 9:1.

[0024] The dosage ratio of L-glutamic acid to N,N-dimethylformamide is 1.5 mmol:9 mL.

[0025] The drying conditions are as follows: vacuum drying at 80°C for 12 h.

[0026] In step (3), preferably, the chiral metal-organic framework is dispersed in ethanol / water with a volume ratio of ethanol to water of 1:1 to 2:1.

[0027] More preferably, the chiral metal-organic framework is dispersed in ethanol / water with a volume ratio of ethanol to water of 1:1.

[0028] The time of ultrasonic treatment is 30 min.

[0029] The concentration of the chiral metal-organic framework dispersion is 0.5 - 3 mg / mL, preferably 2 mg / mL.

[0030] In step (4), the template molecule is L-histidine.

[0031] The mass-volume ratio of the template molecule to ethanol / water is (2 - 4) mg:(9 - 21) mL, preferably 2.5 mg:15 mL.

[0032] Preferably, the template molecule is dissolved in ethanol / water with a volume ratio of ethanol to water of 1:1 to 2:1.

[0033] More preferably, the template molecule is dissolved in ethanol / water with a volume ratio of ethanol to water of 2:1.

[0034] The mass ratio of the template molecule to the chiral metal-organic framework is 2.5:2 to 2.5:12, preferably 2.5:4 to 2.5:8, and more preferably 2.5:8.

[0035] The functional monomer is (3-aminopropyl)triethoxysilane (APTES).

[0036] The dosage ratio of the template molecule to the functional monomer is (2 - 4) mg:(30 - 60) μL, preferably 2.5 mg:50 μL.

[0037] The crosslinking agent is tetraethyl orthosilicate (TEOS).

[0038] The dosage ratio of the template molecule to the crosslinking agent is (2 - 4) mg:(30 - 60) μL, preferably 2.5 mg:50 μL.

[0039] The initiator is ammonia water, and the mass fraction of ammonia water is 25% - 28%.

[0040] The dosage ratio of the template molecule to the initiator is (2 - 4) mg:(30 - 60) μL, preferably 2.5 mg:50 μL.

[0041] Preferably, the template molecule is dissolved in ethanol / water (2:1, V / V), then the functional monomer is added, and magnetic stirring is carried out for 30 min. Then, the chiral metal-organic framework dispersion is added, and magnetic stirring is carried out for 30 min. Next, the cross-linking agent and the initiator are added, and oscillation is carried out for 3 min.

[0042] The eluent is a mixed solution of methanol and acetic acid with a volume ratio of 9:1.

[0043] Preferably, the elution time with the eluent is 2 h.

[0044] The open-tubular capillary electrochromatography column is stored at 4 °C.

[0045] The open-tubular capillary electrochromatography column described in the present invention can be efficiently applied to the enantiomeric separation of chiral drugs / compounds, the optical purity inspection of active pharmaceutical ingredients, etc.

[0046] Another object of the present invention is to provide the application of the open-tubular capillary electrochromatography column in the chiral separation of DL-histidine.

[0047] A method for chiral separation of DL-histidine based on capillary electrochromatography includes:

[0048] Sample preparation: A DL-histidine sample solution is prepared using a mixed solution of methanol and water with a volume ratio of 1:1, and the concentration is 0.5 mg·mL -1 , and it is filtered through a 0.45 μm organic filter membrane;

[0049] Separation operation: Take the open-tubular capillary electrochromatography column with a total length of 38 cm and an effective length of 29.5 cm, and rinse the capillary column with a buffer solution for 10 - 30 min to obtain a stable baseline;

[0050] The running voltage is 5 - 25 kV, the injection volume is 50 mbar×3 s, the running temperature is 25 °C, and CEC data is collected and analyzed at 210 nm.

[0051] The buffer solution is acetonitrile (ACN): disodium hydrogen phosphate dodecahydrate solution (20 mM, pH 6.2 - 7.0) = 76:24 - 84:16 V / V, preferably acetonitrile (ACN): disodium hydrogen phosphate dodecahydrate solution (20 mM, pH 6.6) = 80:20 V / V.

[0052] The preparation method of the buffer solution: Dissolve the disodium hydrogen phosphate dodecahydrate solution in water to prepare a disodium hydrogen phosphate dodecahydrate solution with a concentration of 20 mM, adjust the pH with phosphoric acid, and then mix the disodium hydrogen phosphate dodecahydrate solution and acetonitrile evenly.

[0053] The present invention has the following beneficial effects:

[0054] The present invention prepares a capillary electrochromatography open tubular column modified with CMIP@L-Glu / MIL-125(Ti) by using the "one-pot method". Compared with the CEC open tubular columns using L-Glu / MIL-125(Ti) or CMIPs alone as the stationary phase, the novel CEC open tubular column using CMIP@L-Glu / MIL-125(Ti) as the stationary phase has greatly improved chiral separation ability for histidine enantiomers (resolution: 0.66 / 0.57 → 4.56). The introduction of the CMIPs layer improves the stability of the CMIP@L-Glu / MIL-125(Ti) stationary phase; the large specific surface area of L-Glu / MIL-125(Ti) greatly increases the loading amount of CMIPs on the inner wall of the capillary, and the rigid skeleton of L-Glu / MIL-125(Ti) can also effectively prevent the deformation of the imprinted cavity of CMIPs. More importantly, L-Glu / MIL-125(Ti) and CMIPs play a synergistic role in chiral separation, achieving the effect of 1 + 1 > 2. Brief Description of the Drawings

[0055] Figure 1 It is the preparation flow chart of the capillary electrochromatography open tubular column CMIP@L-Glu / MIL-125(Ti)@capillary of the present invention.

[0056] Figure 2 It is the scanning electron microscope image of the prepared novel capillary electrochromatography open tubular column at a scale of 10 micrometers.

[0057] Figure 3 It is the transmission electron microscope image of CMIP@L-Glu / MIL-125(Ti).

[0058] Figure 4 It is the Fourier transform infrared absorption spectra of L-Glu / MIL-125(Ti) and CMIP@L-Glu / MIL-125(Ti).

[0059] Figure 5 It is the CEC chiral separation result of DL-histidine by the capillary electrochromatography open tubular column CMIP@L-Glu / MIL-125(Ti)@capillary of the present invention and the electrophoresis diagrams of L-histidine and D-histidine.

[0060] Figure 6 It is the comparison of the CEC chiral separation results of DL-histidine by the open tubular columns using L-Glu / MIL-125(Ti) or CMIPs as the stationary phase and CMIP@L-Glu / MIL-125(Ti) as the stationary phase. Detailed Embodiments

[0061] To better understand the present invention, the following embodiments further illustrate the present invention. The content described below is illustrative rather than restrictive and should not be used to limit the protection scope of the present invention.

[0062] Example 1

[0063] As Figure 1 , the preparation method of the open tubular capillary electrochromatography column CMIP@L-Glu / MIL-125(Ti)@capillary is as follows:

[0064] Activation of the capillary: Take an unmodified fused silica capillary (inner diameter 75 μm); rinse the capillary with NaOH solution (1 mol / L) for 1 h, rinse with deionized water until neutral, then rinse the capillary with HCl (1 mol / L) for 30 min, rinse with deionized water until neutral, and rinse with methanol for 30 min; dry with nitrogen, place the capillary column in a blast drying oven at 100 °C for 1 h, take it out and set aside.

[0065] Preparation of chiral metal-organic framework L-Glu / MIL-125(Ti): Weigh 1.5 mmol terephthalic acid (BDC) and 1.5 mmol L-glutamic acid (L-Glu), dissolve terephthalic acid and L-glutamic acid in a mixed solution of 9 mL N,N-dimethylformamide (DMF) and 1 mL methanol, add 0.75 mmol tetrabutyl titanate, stir at room temperature for 20 min, transfer the mixture to a 50 mL hydrothermal reaction kettle, and heat at 150 °C for 12 h; centrifuge, wash the obtained precipitate three times with DMF to remove unreacted residues, and vacuum dry overnight at 80 °C to obtain L-Glu / MIL-125(Ti) powder.

[0066] Disperse the L-Glu / MIL-125(Ti) powder in 4 mL ethanol / water (1:1, V / V), and ultrasonicate for 30 min to obtain an L-Glu / MIL-125(Ti) dispersion with a concentration of 2 mg / mL.

[0067] Dissolve 2.5 mg of L-His in 15 mL of ethanol / water (2:1, V / V), add 50 μL of APTES, then add 4 mL of L-Glu / MIL-125(Ti) dispersion, and stir magnetically for 30 min; then add 50 μL of TEOS and 50 μL of ammonia water (mass fraction 25%), mix well, inject the mixture into the activated capillary within 20 minutes, seal both ends of the capillary column, and react at room temperature for 22 h; after the reaction, use methanol-acetic acid (9:1, V / V) as the eluent to elute for 2 h to remove the template molecules, and dry with nitrogen to obtain the novel open-tubular capillary electrochromatography column, denoted as CMIP@L-Glu / MIL-125(Ti)@capillary, and store it at 4 °C for standby.

[0068] Figure 2 This is the scanning electron micrograph of the open-tubular capillary electrochromatography column prepared in this example, indicating that there is material attachment on the inner wall of the open-tubular capillary electrochromatography column.

[0069] Figure 3 This is the transmission electron micrograph of CMIP@L-Glu / MIL-125(Ti) prepared in this example, indicating that the synthesized CMIP@L-Glu / MIL-125(Ti) is spherical.

[0070] Figure 4 This is the Fourier transform infrared absorption spectra of L-Glu / MIL-125(Ti) (Comparative Example 1) and CMIP@L-Glu / MIL-125(Ti) (Example 1). Compared with the infrared spectrum of L-Glu / MIL-125(Ti), the infrared spectrum of CMIP@L-Glu / MIL-125(Ti) shows a strong absorption peak near 1070 cm -1 and absorption peaks also appear near 790 cm -1 and 466 cm -1 , indicating the successful synthesis of CMIP@L-Glu / MIL-125(Ti).

[0071] Example 2

[0072] Activation of the capillary: Take an unmodified fused silica capillary (inner diameter 75 μm); rinse the capillary with NaOH solution (1 mol / L) for 1 h, rinse with deionized water until neutral, then rinse the capillary with HCl (1 mol / L) for 30 min, rinse with deionized water until neutral, and rinse with methanol for 30 min; dry with nitrogen, place the capillary column in a forced-air drying oven at 100 °C for 1 h, take it out, and store it for standby.

[0073] Preparation of Chiral Metal-Organic Framework L-Glu / MIL-125(Ti): Weigh 1.5 mmol of terephthalic acid and 1.5 mmol of L-glutamic acid. Dissolve terephthalic acid and L-glutamic acid in a mixed solution of 9 mL of N,N-dimethylformamide (DMF) and 1 mL of methanol. Add 0.75 mmol of tetrabutyl titanate and stir at room temperature for 20 min. Transfer the mixture to a 50 mL hydrothermal reaction kettle and heat at 150 °C for 12 h. Centrifuge, wash the obtained precipitate three times with DMF, and dry it under vacuum at 80 °C overnight to obtain L-Glu / MIL-125(Ti) powder.

[0074] Disperse the L-Glu / MIL-125(Ti) powder in 4 mL of ethanol / water (1:1, V / V), and ultrasonicate for 30 min to obtain an L-Glu / MIL-125(Ti) dispersion with a concentration of 1 mg / mL. Dissolve 2.5 mg of L-His in 15 mL of ethanol / water (2:1, V / V), add 50 μL of APTES, and then add 4 mL of the L-Glu / MIL-125(Ti) dispersion, and stir magnetically for 30 min. Then add 50 μL of TEOS and 50 μL of ammonia water (mass fraction of 25%), mix well, inject the mixture into the activated capillary within 20 min, seal both ends of the capillary column, and react at room temperature for 22 h. After the reaction, use methanol-acetic acid (9:1, V / V) as the eluent to elute for 2 h to remove the template molecules, and dry with nitrogen to obtain the novel capillary chromatographic open tubular column CMIP@L-Glu / MIL-125(Ti)@capillary, and store it at 4 °C for standby.

[0075] Comparative Example 1

[0076] Preparation of a Capillary Open Tubular Column with L-Glu / MIL-125(Ti) Alone as the Stationary Phase

[0077] Activation of the capillary: Rinse the capillary with a NaOH solution (1 mol / L) for 1 h, rinse with deionized water until neutral, then rinse the capillary with HCl (1 mol / L) for 30 min, rinse with deionized water until neutral, rinse with methanol for 30 min, dry with nitrogen, place the capillary column in a forced-air drying oven and dry at 100 °C for 1 h, take it out and set aside.

[0078] Weigh 1.5 mmol of terephthalic acid and 1.5 mmol of L-glutamic acid. Dissolve terephthalic acid and L-glutamic acid in a mixed solution of 9 mL of N,N-dimethylformamide (DMF) and 1 mL of methanol. Add 0.75 mmol of tetrabutyl titanate and stir at room temperature for 20 min. Transfer the mixture to a 50 mL hydrothermal reactor and heat at 150 °C for 12 h; centrifuge, wash the obtained precipitate three times with DMF, and dry it under vacuum at 80 °C overnight to obtain L-Glu / MIL-125(Ti) powder.

[0079] Disperse the L-Glu / MIL-125(Ti) powder in 4 mL of ethanol / water (1:1, V / V), and ultrasonicate for 30 min to obtain an L-Glu / MIL-125(Ti) dispersion with a concentration of 2 mg / mL. Disperse 4 mL of the L-Glu / MIL-125(Ti) dispersion in 15 mL of ethanol / water (2:1, V / V), and then inject it into a capillary within 20 min. Seal both ends of the capillary column and react at room temperature for 22 h. Blow dry with nitrogen to obtain L-Glu / MIL-125(Ti)@capillary, and store it at 4 °C for later use.

[0080] Comparative Example 2

[0081] Preparation of a capillary open tubular column with CMIPs alone as the stationary phase

[0082] Activation of the capillary: Rinse the capillary with NaOH (1 mol / L) for 1 h, rinse with deionized water until neutral, then rinse the capillary with HCl (1 mol / L) for 30 min, rinse with deionized water until neutral, rinse with methanol for 30 min, and blow dry with nitrogen. Place the capillary column in a forced-air drying oven and dry at 100 °C for 1 h, take it out and set aside.

[0083] Dissolve L-His (2.5 mg) in 15 mL of ethanol / water (2:1, V / V), add 50 μL of APTES, stir magnetically for 30 min, then add 50 μL of TEOS and 50 μL of ammonia water (mass fraction 25%), mix well, and inject the mixture into the activated capillary within 20 min. Seal both ends of the capillary column and react at room temperature for 22 h; after the reaction, use methanol-acetic acid (9:1, v / v) as the eluent and elute for 2 h to remove the template molecules, and finally blow dry with nitrogen to obtain CMIPs@capillary, and store it at 4 °C for later use.

[0084] Example 3

[0085] The new CEC open-tubular column CMIP@L-Glu / MIL-125(Ti)@capillary prepared in Example 1, the capillary open-tubular column L-Glu / MIL-125(Ti)@capillary with L-Glu / MIL-125(Ti) prepared in Comparative Example 1 alone as the stationary phase, and the capillary open-tubular column CMIPs@capillary with CMIPs prepared in Comparative Example 2 alone as the stationary phase were used for CEC chiral separation of histidine.

[0086] The total length of the capillary taken was 38 cm, and the effective length was 29.5 cm.

[0087] Buffer solution: Acetonitrile (ACN): Disodium hydrogen phosphate dodecahydrate solution (20 mM, pH 6.6) = 4:1 V / V. Preparation method: Dissolve the disodium hydrogen phosphate dodecahydrate solution in water to prepare a disodium hydrogen phosphate dodecahydrate solution with a concentration of 20 mM, adjust the pH to 6.6 with 0.5 mol / L phosphoric acid, and then mix the disodium hydrogen phosphate dodecahydrate solution and acetonitrile evenly according to a volume ratio of 1:4.

[0088] The test samples (DL-histidine, D-histidine, L-histidine) were dissolved in a mixed solution of methanol / water (1:1, V / V), and the sample concentration was 0.5 mg / mL. All sample solutions were filtered through a 0.45 μm organic filter membrane before injection.

[0089] Before injecting into the CEC system, the capillary column was rinsed with the buffer solution for 20 min to obtain a stable baseline. The operating voltage was 15 kV, the injection volume was 50 mbar×3 s, the operating temperature was 25 °C, and CEC data were collected and analyzed at 210 nm.

[0090] From Figure 5 it can be seen that the new CEC open-tubular column prepared in Example 1 performed chiral separation of CEC for DL-histidine, with a resolution of 4.56 for histidine, and successfully separated D-histidine and L-histidine.

[0091] From Figure 6 it can be seen that the capillary open-tubular column with L-Glu / MIL-125(Ti) prepared in Comparative Example 1 alone as the stationary phase had a resolution of 0.57 for DL-histidine. The capillary open-tubular column with CMIPs prepared in Comparative Example 2 alone as the stationary phase had a resolution of 0.66 for DL-histidine.

[0092] Example 4

[0093] The new CEC open-tubular column prepared in Example 2 was used for CEC chiral separation of histidine. The total length of the CEC open-tubular column was 38 cm, and the effective length was 29.5 cm.

[0094] The test samples (DL-histidine, D-histidine, L-histidine) were dissolved in a mixed solution of methanol / water (1:1, V / V) with a sample concentration of 0.5 mg / mL and filtered through a 0.45-μm organic filter membrane before injection. Before injecting into the CEC system, the capillary column was rinsed with a buffer solution (Example 3) for 20 min to obtain a stable baseline. The running voltage was 15 kV, the injection volume was 50 mbar × 3 s, the running temperature was 25 °C, and the CEC data were collected and analyzed at 210 nm.

[0095] The novel CEC open tubular column prepared in Example 2 was used for chiral separation of the racemic drug / compound histidine by CEC. The resolution of histidine was 2.86, and D-histidine and L-histidine were successfully separated.

[0096] The above are only the preferred embodiments of the present invention and do not impose any formal limitations on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art of this patent, without departing from the scope of the technical solution of the present invention, can make some changes or modifications using the technical content prompted above to form equivalent embodiments with equivalent changes. However, as long as the content does not depart from the technical solution of the present invention, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the present invention.

Claims

1. A nanomaterial synthesized based on chiral metal-organic framework materials and chiral molecularly imprinted polymers, characterized in that: It uses L-glutamic acid as the chiral organic ligand, terephthalic acid as the achiral organic ligand, and tetrabutyl titanate as the metal salt to prepare a chiral metal-organic framework material; the dispersion of the chiral metal-organic framework material is mixed evenly with the template molecule, functional monomer, crosslinking agent, and initiator, and reacted at room temperature. After the reaction, it is filtered, and then washed with an eluent to remove the template molecule, and dried to obtain the nanomaterial.

2. An open-tubular capillary electrochromatography column made of a nanomaterial synthesized based on a chiral metal-organic framework and a chiral molecularly imprinted polymer, characterized in that: It is an open tubular column for capillary electrochromatography with the nanomaterial synthesized based on the chiral metal-organic framework material and chiral molecularly imprinted polymer described in Claim 1 as the stationary phase.

3. A preparation method of an open-tubular capillary electrochromatography column of a nanomaterial synthesized based on a chiral metal-organic framework and a chiral molecularly imprinted polymer according to claim 2, characterized in that: Including: Step (1), activation of the capillary: The empty silica capillary is rinsed successively with sodium hydroxide solution, hydrochloric acid, and methanol, and dried with nitrogen to obtain an activated capillary. Step (2), preparation of the chiral metal-organic framework: Using L-glutamic acid as the chiral organic ligand, terephthalic acid as the achiral organic ligand, and tetrabutyl titanate as the metal salt, dissolve the achiral organic ligand and chiral organic ligand in a mixed solution of N,N-dimethylformamide and methanol, add the metal salt, stir evenly at room temperature, transfer the mixture to a hydrothermal reaction kettle, heat at 120-180 °C for 10-15 h, centrifuge, wash the precipitate with DMF, and dry to obtain the chiral metal-organic framework powder. Step (3), disperse the chiral metal-organic framework in ethanol / water, and ultrasonicate to obtain a chiral metal-organic framework dispersion. Step (4), dissolve the template molecule in ethanol / water, add the functional monomer, stir evenly, add the chiral metal-organic framework dispersion, stir evenly, then add the crosslinking agent and initiator, oscillate and mix evenly, quickly inject the mixed solution into the activated capillary, seal both ends of the capillary, and react at room temperature for 16-24 h; after the reaction, rinse with an eluent for 1-3 h to remove the template molecule, and dry with nitrogen to obtain the open tubular column for capillary electrochromatography.

4. The preparation method of an open-tubular capillary electrochromatography column of a nanomaterial synthesized based on a chiral metal-organic framework and a chiral molecularly imprinted polymer according to claim 3, characterized in that: In Step (2), the molar ratio of L-glutamic acid to terephthalic acid is 1:1; the molar ratio of L-glutamic acid to tetrabutyl titanate is 2:1; in the mixed solution of N,N-dimethylformamide and methanol, the volume ratio of N,N-dimethylformamide to methanol is 6:1-12:1, preferably 9:

1.

5. The preparation method of an open-tubular capillary electrochromatography column of a nanomaterial synthesized based on a chiral metal-organic framework and a chiral molecularly imprinted polymer according to claim 3, characterized in that: In Step (3), disperse the chiral metal-organic framework in ethanol / water with a volume ratio of ethanol to water of 1:1-2:

1. Preferably, disperse the chiral metal-organic framework in ethanol / water with a volume ratio of ethanol to water of 1:1; the concentration of the chiral metal-organic framework dispersion is 0.5-3 mg / mL, preferably 2 mg / mL.

6. The preparation method of an open-tubular capillary electrochromatography column of a nanomaterial synthesized based on a chiral metal-organic framework and a chiral molecularly imprinted polymer according to claim 3, characterized in that: In Step (4), the template molecule is L-histidine; the mass-volume ratio of the template molecule to ethanol / water is (2-4) mg:(9-21) mL, preferably 2.5 mg:15 mL; dissolve the template molecule in ethanol / water with a volume ratio of ethanol to water of 1:1-2:

1. Preferably, dissolve the template molecule in ethanol / water with a volume ratio of ethanol to water of 2:

1.

7. The preparation method of the open-tubular capillary electrochromatography column of the nanomaterial synthesized based on the chiral metal-organic framework and the chiral molecularly imprinted polymer according to claim 3, characterized in that: In step (4), the mass ratio of the template molecule to the chiral metal-organic framework is 2.5:2 to 2.5:12, preferably 2.5:4 to 2.5:8, and more preferably 2.5:

8.

8. The preparation method of an open-tubular capillary electrochromatography column of a nanomaterial synthesized based on a chiral metal-organic framework and a chiral molecularly imprinted polymer according to claim 3, characterized in that: In step (4), the functional monomer is (3-aminopropyl)triethoxysilane; the dosage ratio of the template molecule to the functional monomer is (2 - 4) mg:(30 - 60) μL, preferably 2.5 mg:50 μL; The cross-linking agent is tetraethyl orthosilicate; the dosage ratio of the template molecule to the cross-linking agent is (2 - 4) mg:(30 - 60) μL, preferably 2.5 mg:50 μL; The initiator is ammonia water; the dosage ratio of the template molecule to the initiator is (2 - 4) mg:(30 - 60) μL, preferably 2.5 mg:50 μL.

9. The preparation method of an open-tubular capillary electrochromatography column of a nanomaterial synthesized based on a chiral metal-organic framework and a chiral molecularly imprinted polymer according to claim 3, characterized in that: In step (4), the eluent is a mixed solution of methanol - acetic acid with a volume ratio of 9:

1.

10. Application of the open-tubular capillary electrochromatography column according to claim 3 in chiral separation of DL-histidine.

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