Fe3O4 (at) SiO2 (at) VTEs (at) MIPs composite material and preparation method and application thereof
Through the preparation and application of Fe3O4@SiO2@VTEs@MIPs composite materials, technical problems in cannabidiol purification and THC detection were solved, and efficient, accurate detection and strict control of THC were achieved.
Patent Information
- Application Number
- CN202510290889.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-12
- Publication Date
- 2025-06-13
Smart Images
Figure CN120137097A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of natural medicine separation, specifically to Fe 3 O 4 @SiO 2 @VTEs@MIPs composite materials, their preparation methods and applications. Background Art
[0002] The main chemical components contained in cannabis are cannabidiol, tetrahydrocannabinol and cannabidiolic acid. Tetrahydrocannabinol (THC) is one of the most important psychoactive components in cannabis plants and belongs to cannabinoid compounds. It is the main hallucinogenic component of cannabis. THC usually enters the human body through smoking, ingestion or other intake methods and binds to cannabinoid receptors in the human body, thereby affecting the functions of the brain and nervous system.
[0003] Cannabidiol (CBD) is a natural compound extracted from cannabis. Cannabidiol has a variety of beneficial effects and has been studied for the treatment of various indications, such as prolonging sleep, anti-inflammatory, anticonvulsant, anti-anxiety and relieving neuropathic pain. Although the chemical structure of CBD is similar to that of tetrahydrocannabinol, it is not addictive and has basically no toxic and side effects.
[0004] At present, the purification processes of CBD mainly include resin adsorption and chromatography separation. Among them, chromatography separation includes silica gel chromatography process, alumina chromatography process, polyamide column chromatography process. However, the purification processes using the existing technologies have the defects of small batch production, low yield and low product purity, and there are also problems of complex process and cumbersome extraction and purification procedures, which are not suitable for industrial production.
[0005] Tetrahydrocannabinol is addictive and its content in drugs is strictly controlled. The existing detection methods for tetrahydrocannabinol mainly rely on chromatography-mass spectrometry. However, when using chromatography-mass spectrometry for detection, there are certain requirements for the concentration and content of cannabidiol, and trace amounts of tetrahydrocannabinol cannot be detected; at the same time, a dedicated column is required for adsorption and desorption, and the cost is relatively high.
[0006] Molecularly imprinted polymers have shown great potential in many scientific research and industrial applications due to their selectivity, stability, tunability, economy and reusability. However, there is currently no molecularly imprinted polymer specifically for the selective detection of tetrahydrocannabinol. Summary of the Invention
[0007] Aiming at the deficiencies of the above-mentioned existing technologies, the purpose of the present invention is to provide Fe 3 O 4 @SiO 2@VTEs@MIPs composite materials, their preparation methods and applications. In the present invention, first, iron oxide nanoparticles and tetraethyl orthosilicate are used to prepare Fe 3 O 4 @SiO 2 , and then Fe 3 O 4 @SiO 2 is coated with vinyltriethoxysilane to obtain Fe 3 O 4 @SiO 2 @VTEs. ChCl-AA and tetrahydrocannabinol are pre-assembled to obtain a precursor solution; then a cross-linking agent, an initiator, Fe 3 O 4 @SiO 2 @VTEs and the precursor solution are subjected to a cross-linking reaction, and finally the template tetrahydrocannabinol is removed to obtain Fe 3 O 4 @SiO 2 @VTEs@MIPs composite materials. The method provided by the present invention provides a new material for specifically recognizing tetrahydrocannabinol. The Fe 3 O 4 @SiO 2 @VTEs@MIPs composite materials of the present invention can achieve strict control of THC, and the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite materials can also be reused, overcoming the technical defects of the prior art in detecting tetrahydrocannabinol in cannabidiol.
[0008] To solve the above technical problems, the present invention adopts the following technical solutions:
[0009] Fe 3 O 4 @SiO 2 A preparation method of @VTEs@MIPs composite materials, comprising the following steps:
[0010] Using choline chloride as the hydrogen bond acceptor of the deep eutectic solvent and acrylic acid as the hydrogen bond donor of the deep eutectic solvent, at 70 °C to 90 °C, the two are mixed until homogeneous and transparent to obtain the deep eutectic solvent ChCl-AA.
[0011] Among them, the molar ratio of the hydrogen bond acceptor choline chloride to the hydrogen bond donor acrylic acid is 1:3 to 7.
[0012] The Fe₃O₄ nanoparticles were ultrasonically dispersed in an ethanol aqueous solution. After adding ammonia water and mixing evenly, tetraethyl orthosilicate was dropped into it and mixed evenly. During the mixing process, tetraethyl orthosilicate hydrolyzed under the condition of ammonia water to form silicic acid, and the silicon alkane coated the Fe₃O₄ nanoparticles and continued to hydrolyze into SiO 2 , and it was separated under the action of an external magnetic field to obtain Fe 3 O 4 @SiO 2 .
[0013] Among them, the mass ratio of Fe₃O₄ nanoparticles, the volume of ethanol, and the volume of deionized water was 0.05 g: 45 mL: 15 mL; the mixing conditions of Fe₃O₄ nanoparticles, ethanol aqueous solution, and ammonia water were: reacting at 30 °C - 60 °C for 1 h at 50 rmp - 400 rmp.
[0014] The Fe 3 O 4 @SiO 2 was ultrasonically dispersed in toluene, and an alcohol solution of vinyltriethoxysilane (VTEs) was added. Vinyltriethoxysilane was used to modify the surface of Fe 3 O 4 @SiO 2 to make the next polymerization reaction more efficient and the generated polymer molecular imprint clearer. Without vinyltriethoxysilane, the polymerization reaction efficiency decreases; the alkylation reaction was carried out under nitrogen protection. At this time, vinyltriethoxysilane was coated on the outside of Fe 3 O 4 @SiO 2 . After the reaction ended, it was separated under the action of an external magnetic field to obtain Fe 3 O 4 @SiO 2 @VTEs.
[0015] Among them, in the alcohol solution of triethoxyvinylsilane, the volume ratio of triethoxyvinylsilane to ethanol was 1: 5 - 10.
[0016] Using tetrahydrocannabinol as a template and ChCl-AA as a functional monomer, the two were co-dispersed in ethanol, and then left standing to complete pre-assembly. ChCl-AA was used to fix tetrahydrocannabinol to obtain a precursor solution; the protagonist of imprinting is the template molecule. Without fixation, it is not molecular imprinting. In the present invention, THC is used as the template molecule. First, the template molecule is fixed, and after the polymer is formed, the template molecule is removed, leaving the cavity of the THC molecular imprint to adsorb THC in the CBD extract.
[0017] The cross-linking agent, initiator, and Fe 3 O 4 @SiO 2@VTEs were added to the precursor solution and cross-linking reaction was carried out under nitrogen protection, so that the cross-linking agent, Fe 3 O 4 @SiO 2 @VTEs and ChCl-AA were cross-linked together to obtain a polymer; after the reaction, the template of the polymer was removed and washed to neutrality to obtain Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material.
[0018] Preferably, the mass ratio of the magnetite nanoparticles, the amount of tetraethyl orthosilicate in terms of the number of moles, and the volume of ammonia water is 0.5 g: 0.01 mol to 0.05 mol: 5 mL to 10 mL, and the volume percentage of ammonia water is 25% to 28%. Excessive amount of tetraethyl orthosilicate will lead to excessive amount of generated silicon dioxide, resulting in reduced magnetism of Fe 3 O 4 @SiO 2 , increased particle size, and reduced specific surface area; too little amount of tetraethyl orthosilicate will lead to too little amount of generated silicon dioxide, and SiO 2 cannot completely coat the Fe 3 O 4 nanoparticles, resulting in insufficient surface modification and low cross-linking polymerization reaction efficiency.
[0019] Preferably, the mass ratio of Fe 3 O 4 @SiO 2 to the volume of vinyltriethoxysilane is 0.05 g: 3 mL to 7 mL. Excessive vinyltriethoxysilane will increase the particle size, and the specific surface area of the Fe 3 O 4 @SiO 2 @VTEs material will decrease; too little vinyltriethoxysilane will not play a role in improving the surface characteristics and the polymerization reaction efficiency is low.
[0020] Preferably, the conditions for the alkylation reaction are: in a water bath at 40 °C to 50 °C, stirring at 200 rpm for 6 h.
[0021] Preferably, the molar ratio of THC to ChCl-AA is 1: 3 to 8. Excessive amount of ChCl-AA increases the cost, and too little amount of ChCl-AA cannot fix the template.
[0022] Preferably, the amount of ChCl-AA in terms of the number of moles, the volume of the cross-linking agent, the mass of the initiator, Fe 3 O 4 @SiO 2The mass ratio is 0.06 mmol: 0.6 mL to 0.9 mL: 0.04 g to 0.05 g: 0.05 g to 0.06 g.
[0023] Preferably, the conditions for the crosslinking reaction are: water bath for 9 h to 12 h at a stirring speed of 100 rpm to 400 rpm, and the water bath temperature is 50 °C to 70 °C.
[0024] Preferably, the crosslinking agent is selected from ethylene glycol dimethacrylate, ethylene glycol dimethacrylate, trimethoxypropane trimethacrylate, N,N-methylenebisacrylamide, epichlorohydrin or divinylbenzene; the initiator is selected from azobisisobutyronitrile or azobisisoheptonitrile. Under the action of the initiator, the crosslinking agent, Fe 3 O 4 @SiO 2 @VTEs and ChCl-AA are crosslinked together.
[0025] Preferably, the method for removing the template is: using a mixed solution of methanol and acetic acid as the eluent to elute tetrahydrocannabinol and leaving a site specifically recognizing tetrahydrocannabinol; wherein, the volume ratio of methanol to acetic acid is 7 to 10:1.
[0026] The present invention also protects the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material prepared by the above preparation method. In the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material, using iron oxide nanoparticles as the magnetic core and silica to provide a rigid structure. The silica is coated on the outside of the iron oxide nanoparticles to prevent the aggregation of the iron oxide nanoparticles. Vinyltriethoxysilane is used to coat the silica and modify it on the surface of Fe 3 O 4 @SiO 2 to make Fe 3 O 4 @SiO 2 @VTEs facilitate crosslinking polymerization with the crosslinking agent and ChCl-AA in the precursor solution, and then specifically recognize the target molecule tetrahydrocannabinol using the cavities left after the elution of the tetrahydrocannabinol template.
[0027] The present invention also protects the application of the above Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material in the preparation of a tetrahydrocannabinol remover.
[0028] Preferably, the application method is: adding Fe 3O 4 @SiO 2 @VTEs@MIPs composite material is dispersed in the cannabidiol extraction solution, and Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material adsorbs tetrahydrocannabinol in the cannabidiol extraction solution.
[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0030] 1. In the present invention, first, using iron oxide nanoparticles and tetraethyl orthosilicate as raw materials, tetraethyl orthosilicate hydrolyzes under the action of ammonia water to generate silicic acid, which coats on the surface of the iron oxide nanoparticles, and continues to hydrolyze to obtain Fe 3 O 4 @SiO 2 ; then using vinyltriethoxysilane and Fe 3 O 4 @SiO 2 as raw materials, an alkylation reaction is carried out under nitrogen protection, so that vinyltriethoxysilane coats on the outside of Fe 3 O 4 @SiO 2 to obtain Fe 3 O 4 @SiO 2 @VTEs; then pre-assemble the template tetrahydrocannabinol with ChCl-AA to obtain a precursor solution; finally, under the action of an initiator, crosslink the crosslinking agent, Fe 3 O 4 @SiO 2 @VTEs and ChCl-AA in the precursor solution to obtain a polymer, and elute the template tetrahydrocannabinol on the polymer to obtain Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material, MIPs is a molecularly imprinted polymer, and Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material leaves holes on the surface for specific recognition of the target molecule tetrahydrocannabinol.
[0031] 2. In the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material of the present application, using iron oxide nanoparticles as the magnetic core, utilizing the magnetic field force provided by Fe 3 O 4 to achieve Fe 3 O 4@SiO 2 @VTEs@MIPs composite material's rapid adsorption of tetrahydrocannabinol; SiO 2 It can prevent the aggregation of iron oxide nanoparticles in MIPs, increase the specific surface area, and at the same time can be used as an interfacial modifier to enhance Fe 3 O 4 @SiO 2 The adhesion, water resistance, chemical resistance and heat resistance between materials; MIPs are used to specifically recognize tetrahydrocannabinol.
[0032] SiO 2 SiO, VTEs, and MIPs interact with each other. After being coated with vinyltriethoxysilane, SiO 2 has hydrophilicity, which is convenient for mixing and polymerization with cross-linking agents and precursor solutions to form a core-shell structure. At the same time, SiO 2 enhances the heat resistance, weather resistance and mechanical properties of the polymer; enabling the obtained Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material has a core-shell structure. The core-shell structure increases the specific surface area and improves the recognition efficiency. Using iron oxide nanoparticles as the magnetic core and the polymer as the shell, the pores left after the elution of the THC template are used to specifically recognize the target molecule. This structure gives MIPs a large specific surface area and greatly improves the adsorption rate of THC.
[0033] 3. The Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material's molecular imprinting method has high specificity. The one-time removal rate of trace components of THC is close to 100%. Because the results show that after removing tetrahydrocannabinol from the cannabidiol extract, THC concentration cannot be detected by HPLC, and HPLC is a detection method at the ppm level. Description of the Drawings
[0034] Figure 1 For Fe 3 O 4 nanoparticles, Fe 3 O 4 @SiO 2 of Example 1, Fe 3 O 4 @SiO 2 @VTEs of Example 1, Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material of Example 1, Fe 3 O 4 @SiO2 Infrared spectrum of @VTEs@NIPs composite material.
[0035] Figure 2 Among them, (a) is Fe of Example 1 3 O 4 @SiO 2 Scanning electron microscope and transmission electron microscope images of @VTEs; (b) is Fe of Example 1 3 O 4 @SiO 2 Scanning electron microscope and transmission electron microscope images of @VTEs@MIPs composite material.
[0036] Figure 3 is Fe 3 O 4 nanoparticles, Fe of Example 1 3 O 4 @SiO 2 、, Fe of Example 1 3 O 4 @SiO 2 @VTEs, Fe of Example 1 3 O 4 @SiO 2 @VTEs@MIPs composite material, Fe of Comparative Example 1 3 O 4 @SiO 2 Thermogravimetric analysis chart of @VTEs@NIPs composite material.
[0037] Figure 4 is Fe 3 O 4 nanoparticles, Fe of Example 1 3 O 4 @SiO 2 、, Fe of Example 1 3 O 4 @SiO 2 @VTEs, Fe of Example 1 3 O 4 @SiO 2 @VTEs@MIPs composite material, Fe of Comparative Example 1 3 O 4 @SiO 2 XRD analysis chart of @VTEs@NIPs composite material.
[0038] Figure 5 is Fe 3 O 4 nanoparticles, Fe of Example 1 3 O 4 @SiO 2, Fe of Example 1 3 O 4 @SiO 2 @VTEs, Fe of Example 1 3 O 4 @SiO 2 @VTEs@MIPs composite material's magnetic property analysis diagram. Specific implementation manners
[0039] The following describes the specific implementation manners of the present invention in detail, but it should be understood that the protection scope of the present invention is not limited by the specific implementation manners. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention. The experimental methods described in each embodiment of the present invention are conventional methods unless otherwise specified.
[0040] It should be noted that for this experiment, SiO 2 @VTEs@MIPs composite material can also be used to detect tetrahydrocannabinol, and the reason for compounding with Fe 3 O 4 is that: Fe 3 O 4 provides a magnetic core for the molecularly imprinted polymer to obtain magnetic MIPs, which brings great convenience for the rapid separation of MIPs and the treatment of large-scale samples while improving the conductivity of MIPs.
[0041] Compared with the prior art tetrahydrocannabinol adsorbent, the preparation method of the present application does not use precious metals and flammable and explosive dangerous goods, and the preparation method is simple and short-time, solving the technical defects existing in the preparation of the prior tetrahydrocannabinol adsorbent.
[0042] The following uses examples to study the technical solutions of the present invention, and the specific research methods and results are as follows:
[0043] Example 1
[0044] Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material's preparation method, including the following steps:
[0045] S1. Preparation of eutectic solvent ChCl-AA: Using choline chloride as the hydrogen bond acceptor of the eutectic solvent and acrylic acid as the hydrogen bond donor of the eutectic solvent, with a molar ratio of 1:5, magnetically stir and mix the two at 80 °C until the solution is homogeneous and transparent to obtain the eutectic solvent ChCl-AA.
[0046] S2. Ultrasonically disperse the iron oxide nanoparticles in an ethanol aqueous solution, then quickly add ammonia water, mix evenly, and gradually add tetraethyl orthosilicate (TEOs). After mechanical stirring in a 50 °C water bath for 1 h, cool to room temperature, and then separate under the action of an external magnetic field. Wash with absolute ethanol and distilled water to remove the excess silane, and dry in vacuum to obtain the product Fe 3 O 4 @SiO 2 .
[0047] Among them, the mass ratio of the iron oxide nanoparticles, the concentration of tetraethyl orthosilicate, and the volume of ammonia water is 0.5 g: 0.03 mol: 5 mL; and the mass ratio of the iron oxide nanoparticles, the volume of ethanol, and the volume of deionized water is 0.05 g: 45 mL: 15 mL.
[0048] S3. Ultrasonically disperse Fe 3 O 4 @SiO 2 in toluene, add vinyltriethoxysilane (VTEs), and under nitrogen protection, stir at 40 °C and 200 rpm for 6 h to carry out the alkylation reaction. After the reaction is completed, separate the cooled product by an external magnetic field, wash the product with absolute ethanol and distilled water, and then dry in vacuum to obtain the vinyl-modified product Fe 3 O 4 @SiO 2 @VTEs.
[0049] Among them, the mass ratio of Fe 3 O 4 @SiO 2 to the volume of vinyltriethoxysilane is 0.1 g: 10 mL.
[0050] S4. Preparation of magnetic molecularly imprinted polymer Fe 3 O 4 @SiO 2 @VTEs@MIPs:
[0051] Disperse tetrahydrocannabinol (template molecule) and ChCl-AA (functional monomer) together in ethanol, first carry out ultrasonic treatment, and then stand still to complete the pre-assembly to obtain the precursor solution.
[0052] Among them, the molar ratio of tetrahydrocannabinol to ChCl-AA is 1:5.
[0053] Disperse Fe 3 O 4 @SiO 2@VTEs, ethylene glycol dimethacrylate (crosslinker), and azobisisobutyronitrile (initiator) were added to the precursor solution. The mixture was stirred at 50 °C in a water bath under nitrogen protection at 150 rmp for 10 h. The product was collected using a magnet. Then, a methanol / acetic acid solution with a volume ratio of 8:1 was used as the eluent to elute the tetrahydrocannabinol template, leaving pores that could specifically recognize. The residual acetic acid in the polymer was washed with methanol until the waste liquid was neutral. The product was dried to obtain the molecularly imprinted polymer Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material.
[0054] Among them, the mass of Fe 3 O 4 @SiO 2 @VTEs, the volume of ethylene glycol dimethacrylate, the mass of azobisisobutyronitrile, and the molar ratio of ChCl-AA in the precursor solution were 0.05 g: 0.8 mL: 0.05 g: 0.06 mmol.
[0055] Example 2
[0056] Fe 3 O 4 @SiO 2 Preparation method of @VTEs@MIPs composite material, including the following steps:
[0057] S1. Preparation of the deep eutectic solvent ChCl-AA: Using choline chloride as the hydrogen bond acceptor of the deep eutectic solvent and acrylic acid as the hydrogen bond donor of the deep eutectic solvent, with a molar ratio of 1:3. The two were magnetically stirred and mixed at 70 °C until the solution was homogeneous and transparent to obtain the deep eutectic solvent ChCl-AA.
[0058] S2. Ultrasonically disperse the iron oxide nanoparticles in an ethanol aqueous solution, then quickly add ammonia water. After mixing evenly, dropwise add tetraethyl orthosilicate (TEOs). After mechanical stirring in a 30 °C water bath for 1 h, cool to room temperature, and then separate under the action of an external magnetic field. Wash with absolute ethanol and distilled water to wash away the excess silane, and dry in vacuum to obtain the product Fe 3 O 4 @SiO 2 。
[0059] Among them, the mass of the iron oxide nanoparticles, the concentration of tetraethyl orthosilicate, and the volume ratio of ammonia water were 0.5 g: 0.01 mol: 7 mL; and the mass of the iron oxide nanoparticles, the volume of ethanol, and the volume of deionized water were 0.05 g: 45 mL: 15 mL.
[0060] S3. Add Fe 3 O4 @SiO 2 It was ultrasonically dispersed in toluene, vinyltriethoxysilane (VTEs) was added, and under nitrogen protection, it was stirred at 45 °C and 200 rpm for 6 h to carry out the alkylation reaction. After the reaction, the cooled product was separated by an external magnetic field, washed with absolute ethanol and distilled water, and then dried in vacuo to obtain the vinyl-modified product Fe 3 O 4 @SiO 2 @VTEs.
[0061] Among them, the mass ratio of Fe 3 O 4 @SiO 2 to the volume of vinyltriethoxysilane was 0.05 g: 3 mL.
[0062] S4. Preparation of magnetic molecularly imprinted polymer Fe 3 O 4 @SiO 2 @VTEs@MIPs:
[0063] Tetrahydrocannabinol (template molecule) and ChCl-AA (functional monomer) were co-dispersed in ethanol, first ultrasonically treated, and then left standing to complete pre-assembly to obtain a precursor solution.
[0064] Among them, the molar ratio of tetrahydrocannabinol to ChCl-AA was 1:8.
[0065] Fe 3 O 4 @SiO 2 @VTEs, ethylene glycol dimethacrylate (crosslinker) and azobisisobutyronitrile (initiator) were added to the precursor solution, and under nitrogen protection, it was water-bathed at 60 °C and stirred at 100 rmp for 12 h. The product was collected with a magnet, and then methanol / acetic acid solution with a volume ratio of 7:1 was used as the eluent to elute the tetrahydrocannabinol template and leave pores that can specifically recognize. The residual acetic acid in the polymer was washed with methanol until the waste liquid was neutral. The product was dried to obtain the molecularly imprinted polymer Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material.
[0066] Among them, the mass of Fe 3 O 4 @SiO 2 @VTEs, the volume of ethylene glycol dimethacrylate, the mass of azobisisobutyronitrile, and the molar amount of ChCl-AA in the precursor solution were in the ratio of 0.06 g: 0.6 mL: 0.04 g: 0.06 mmol.
[0067] Example 3
[0068] Fe 3 O 4 @SiO 2 Preparation method of @VTEs@MIPs composite material, comprising the following steps:
[0069] S1. Preparation of eutectic solvent ChCl-AA: Using choline chloride as the hydrogen bond acceptor of the eutectic solvent and acrylic acid as the hydrogen bond donor of the eutectic solvent, with a molar ratio of 1:7 between the two. Mix them under magnetic stirring at 90 °C until the solution is homogeneous and transparent to obtain the eutectic solvent ChCl-AA.
[0070] S2. Ultrasonically disperse the magnetite nanoparticles in an ethanol aqueous solution, then quickly add ammonia water, mix evenly, and dropwise add tetraethyl orthosilicate (TEOs). After mechanical stirring in a 60 °C water bath for 1 h, cool to room temperature, and then separate under the action of an external magnetic field. Wash with absolute ethanol and distilled water to remove the excess silane, and dry in vacuum to obtain the product Fe 3 O 4 @SiO 2 .
[0071] Wherein, the mass ratio of the magnetite nanoparticles, the concentration of tetraethyl orthosilicate and the volume of ammonia water is 0.5 g: 0.05 mol: 10 mL; and the mass ratio of the magnetite nanoparticles, the volume of ethanol and the volume of deionized water is 0.05 g: 45 mL: 15 mL.
[0072] S3. Ultrasonically disperse Fe 3 O 4 @SiO 2 in toluene, add vinyltriethoxysilane (VTEs), and stir at 50 °C and 200 rpm for 6 h under nitrogen protection for alkylation reaction. After the reaction, separate the cooled product under an external magnetic field, wash the product with absolute ethanol and distilled water, and then dry in vacuum to obtain the vinyl-modified product Fe 3 O 4 @SiO 2 @VTEs.
[0073] Wherein, the mass ratio of Fe 3 O 4 @SiO 2 and the volume of vinyltriethoxysilane is 0.05 g: 7 mL.
[0074] S4. Preparation of magnetic molecularly imprinted polymer Fe 3 O 4 @SiO 2 @VTEs@MIPs:
[0075] Dissolve tetrahydrocannabinol (template molecule) and ChCl-AA (functional monomer) together in ethanol, first perform ultrasonic treatment, and then let it stand to complete pre-assembly to obtain a precursor solution.
[0076] Among them, the molar ratio of tetrahydrocannabinol to ChCl-AA is 1:3.
[0077] Add Fe 3 O 4 @SiO 2 @VTEs, ethylene glycol dimethacrylate (crosslinking agent), and azobisisobutyronitrile (initiator) to the precursor solution. Under nitrogen protection, carry out a water bath at 70 °C and stir and react at 400 rmp for 5 h. Collect the product with a magnet, and then use a methanol / acetic acid solution with a volume ratio of 10:1 as the eluent to elute the tetrahydrocannabinol template and leave pores that can specifically recognize. Wash the residual acetic acid in the polymer with methanol until the waste liquid is neutral. The product is dried to obtain the molecularly imprinted polymer Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material.
[0078] Among them, the mass of Fe 3 O 4 @SiO 2 @VTEs, the volume of ethylene glycol dimethacrylate, the mass of azobisisobutyronitrile, and the molar ratio of ChCl-AA in the precursor solution are 0.06 g:0.9 mL:0.05 g:0.06 mmol.
[0079] Comparative Example 1
[0080] Fe 3 O 4 @SiO 2 The preparation method of the @VTEs@NIPs composite material is the same as the preparation steps in Example 1, except that the assembly of the template tetrahydrocannabinol is not carried out, and it includes the following steps:
[0081] S1. Preparation of the eutectic solvent ChCl-AA: Use choline chloride as the hydrogen bond acceptor of the eutectic solvent and acrylic acid as the hydrogen bond donor of the eutectic solvent. The molar ratio of the two is 1:5. Magnetically stir and mix the two at 80 °C until the solution is homogeneous and transparent to obtain the eutectic solvent ChCl-AA.
[0082] S2. Ultrasonically disperse the iron oxide nanoparticles in an ethanol aqueous solution, then quickly add ammonia water, mix evenly, and gradually add tetraethyl orthosilicate (TEOs). After mechanical stirring in a water bath at 50 °C for 1 h, cool to room temperature, then separate under the action of an external magnetic field, wash with absolute ethanol and distilled water to remove the excess silane, and dry in vacuum to obtain Fe 3 O 4 @SiO 2 。
[0083] Among them, the mass ratio of the iron oxide nanoparticles, the concentration of tetraethyl orthosilicate and the volume of ammonia water is 0.5 g: 0.03 mol: 5 mL; and the mass ratio of the iron oxide nanoparticles, the volume of ethanol and the volume of deionized water is 0.05 g: 45 mL: 15 mL.
[0084] S3. Ultrasonically disperse Fe 3 O 4 @SiO 2 in toluene, add vinyltriethoxysilane (VTEs), and under nitrogen protection, stir at 40 °C and 200 rpm for 6 h to carry out the alkylation reaction. After the reaction is completed, separate the cooled product by an external magnetic field, wash the product with absolute ethanol and distilled water, and then dry in vacuum to obtain the vinyl-modified product Fe 3 O 4 @SiO 2 @VTEs.
[0085] Among them, the mass ratio of Fe 3 O 4 @SiO 2 and the volume of vinyltriethoxysilane is 0.1 g: 10 mL.
[0086] S4. Preparation of magnetic molecularly imprinted polymer Fe 3 O 4 @SiO 2 @VTEs@NIPs:
[0087] Disperse ChCl-AA (functional monomer) in ethanol, first ultrasonicate and then let it stand to obtain a precursor solution.
[0088] Add Fe 3 O 4 @SiO 2 @VTEs, ethylene glycol dimethacrylate (crosslinker) and azobisisobutyronitrile (initiator) into the precursor solution, stir and react in a water bath at 50 °C under nitrogen protection at 150 rmp for 10 h, collect the product with a magnet, then use a methanol / acetic acid solution with a volume ratio of 8:1 as the eluent, and finally wash the residual acetic acid in the polymer with methanol until the waste liquid is neutral. The product is dried to obtain Fe3 O 4 @SiO 2 @VTEs@NIPs composite material.
[0089] Among them, Fe 3 O 4 @SiO 2 The mass ratio of @VTEs, the volume of ethylene glycol dimethacrylate, the mass of azobisisobutyronitrile, and the molar ratio of ChCl-AA in the precursor solution is 0.05 g: 0.8 mL: 0.05 g: 0.06 mmol.
[0090] In Examples 1 to 3 of the present invention, Fe 3 O 4 @SiO 2 @VTEs@MIPs composite materials capable of specifically adsorbing tetrahydrocannabinol in cannabidiol were all prepared. Taking the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material prepared in Example 1 as an example, the structure analysis and research were carried out, and the specific results are as follows:
[0091] Figure 1 The results show that by analyzing the changes of functional groups at each stage of the synthesis of Fe 3 O 4 @SiO 2 @VTEs@MIPs composite materials by infrared spectroscopy, a characteristic absorption peak of Fe-O appeared at 596 cm -1 . And in the subsequent Fe 3 O 4 @SiO 2 , Fe 3 O 4 @SiO 2 @VTEs and Fe 3 O 4 @SiO 2 @VTEs@MIPs composite materials, there are characteristic absorption peaks of Fe-O, indicating that during the synthesis of MIP, Fe 3 O 4 nanoparticles are very stable and do not change due to changes in external conditions. In Fe 3 O 4 @SiO 2 , an obvious antisymmetric stretching vibration peak of Si-O-Si appeared at 1070 cm -1 , indicating that through the hydrolysis of tetraethyl orthosilicate, SiO 3 O 4 was successfully coated outside Fe 2, and during the subsequent synthesis of the polymer, the characteristic peaks of SiO 2 still exist, indicating that SiO 2 is not affected during the polymerization process. After vinyl modification of Fe 3 O 4 @SiO 2 , Fe 3 O 4 @SiO 2 @VTEs is obtained, and a characteristic peak of C═C is observed at 765 cm -1 . After polymerization, MIP and NIP are synthesized. Since the template molecules in MIP are removed, the groups of MIP and NIP are roughly the same, and a C═O absorption peak in EGDMA (ethylene glycol dimethacrylate) appears at 1717 cm -1 . Combining the presence of Fe and Si characteristic peaks, it shows that the polymerization is successfully achieved and the polymer is successfully coated on the magnetic carrier.
[0092] Figure 2 The results show that (a) is the electron micrograph of Fe 3 O 4 @SiO 2 @VTEs, and (b) is the electron micrograph of the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material. It can be seen from the figure that the outer surface of Fe 3 O 4 @SiO 2 @VTEs is relatively smooth, and the coating outside the core of the magnetite nanoparticles can be clearly seen in the transmission electron microscope in the upper right corner of Figure (a). After a series of operations, the synthesized Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material is smoother than Fe 3 O 4 @SiO 2 @VTEs. The surface of the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material is significantly rougher, and it can be seen from the transmission electron micrograph that the coating outside the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material is significantly thickened, and two semi-transparent coating layers appear outside the core of the magnetite nanoparticles, indicating that MIPs are successfully coated outside the silica.
[0093] Figure 3 The results show that during the entire process of heating from room temperature to 800 °C by thermogravimetric analysis, Fe 3 O 4 , Fe 3 O 4 @SiO 2 and Fe 3 O 4 @SiO 2 @VTEs lost 1.087%, 4.57%, and 7.93% in weight respectively. Under the protection of N 2 , Fe 3 O 4 will not be oxidized. During the entire heating process, only a small part of the weight loss is due to the weight of the bound water and the impurities on the surface of the nanoparticles. The melting point of SiO 2 is above 1000 °C. Therefore, during the entire process, only partial weight loss occurs for Fe 3 O 4 @SiO 2 and Fe 3 O 4 @SiO 2 @VTEs, which is due to the bound water and impurities. The Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material lost 7.139% in weight at 110 °C. This part is mainly the evaporation of water. As the temperature gradually increases, when the temperature reaches 270 °C, the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material starts to lose weight rapidly until 700 °C, and the weight loss rate reaches 86.031%. This is mainly due to the decomposition of acrylic acid, DES (deep eutectic solvent), and EGDMA at high temperatures. The remaining part of the mass is the carrier wrapped in the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material, which proves that the synthesized polymer has successfully wrapped on the carrier, and the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material can withstand temperatures below 200 °C. Therefore, during the experiment, normal temperature changes will not affect the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material.
[0094] Figure 4 The results show that by using X-ray diffraction to analyze Fe 3 O 4@SiO 2 @VTEs@MIPs Composite Material Synthesis Process: Crystal Structure Changes, 2θ Angle from 10° to 80°. Fe 3 O 4 The six characteristic diffraction peaks of the Fe nanoparticles are at 30.26°, 35.6°, 43.1°, 53.78°, 57.16°, and 62.78°, and the corresponding lattice planes are (220), (311), (400), (422), (511), and (440), respectively. These are all consistent with the magnetic crystal data of Fe 3 O 4 . It can be seen from the figure that throughout the synthesis process of the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material, the obtained Fe 3 O 4 @SiO 2 、Fe 3 O 4 @SiO 2 @VTEs、Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material and the Fe 3 O 4 @SiO 2 @VTEs@NIPs composite material have characteristic diffraction peaks that are all the same as the six characteristic diffraction peaks of Fe 3 O 4 . Except for the change in peak intensity, the rest are basically the same, indicating that during the synthesis process of the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material, the Fe 3 O 4 lattice does not change, and the structure of Fe 3 O 4 is not damaged.
[0095] Figure 5 The results show that a comprehensive physical property measurement system is used to measure the magnetic force. As the magnetic field strength increases, the magnetic intensity of all samples also increases. Fe 3 O 4 、Fe 3 O 4 @SiO 2 、Fe 3 O 4 @SiO 2 @VTEs and Fe 3 O 4 @SiO2 The saturation magnetization intensities of the @VTEs@MIPs composites are 87.4621 emu / g, 75.7591 emu / g, 73.248 emu / g, and 3.7391 emu / g, respectively. Compared with Fe 3 O 4 nanoparticles, Fe 3 O 4 @SiO 2 、Fe 3 O 4 @SiO 2 @VTEs and Fe 3 O 4 @SiO 2 @VTEs@MIPs composites show a decreasing trend in saturation magnetization intensity with each modification. This is because with each modification, a non-magnetic substance is coated on the outside of the Fe 3 O 4 nanoparticles, reducing the magnetism compared to Fe 3 O 4 . The saturation magnetization intensity of Fe 3 O 4 @SiO 2 weakens slightly after vinyl modification. This may be due to the slight hydrolysis of vinyltriethoxysilane, which also coats a thin layer on the outside of the silica during modification, thus weakening the magnetic intensity. The synthesized Fe 3 O 4 @SiO 2 @VTEs@MIPs composites show a relatively large reduction in saturation magnetization intensity, probably because a thick non-magnetic polymer is coated on the outside of the magnetic carrier. However, even with a magnetic intensity of only 3.7391 emu / g, it can still meet the magnetic intensity required for separation by an external magnetic field in the experiment. The continuous weakening of the magnetic intensity also confirms from the side that the polymer has been successfully coated on the magnetic carrier.
[0096] The present invention also studied the reuse of the Fe 3 O 4 @SiO 2 @VTEs@MIPs composites. The reproducibility experiment includes the following steps:
[0097] S1. Weigh 20 mg of the Fe 3 O 4 @SiO 2 @VTEs@MIPs composites and add them to 10 mL of a 20 μg / mL tetrahydrocannabinol standard solution. Shake in a water bath at 25 °C for 90 min. After completion, separate the Fe 3 O 4 @SiO 2Elute the tetrahydrocannabinol adsorbed in the @VTEs@MIPs composite material, dry it, and then add it to 10 mL of a 20 μg / mL tetrahydrocannabinol standard solution for adsorption. Repeat this process five times, and use high-performance liquid chromatography to determine the adsorption capacity.
[0098] S2. Use high-performance liquid chromatography to determine the adsorption capacity of the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material after five adsorption experiments. The first adsorption capacity is 9.98 mg / g, the second is 9.94 mg / g, the third is 9.83 mg / g, the fourth is 9.66 mg / g, and the fifth is 9.42 mg / g. The adsorption efficiency remains at 94.2% after repeating the adsorption 5 times, indicating that the Fe 3 O 4 @SiO 2 @VTEs@MIPs composite material has excellent regeneration performance at the adsorption sites, and the elution process does not significantly damage its structure, making it suitable for multiple cycle detections.
[0099] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.
Claims
1. A method for preparing a Fe3O4@SiO2@VTEs@MIPs composite material, characterized in that: The steps include: Choline chloride is used as a hydrogen bond acceptor of a low eutectic solvent, acrylic acid is used as a hydrogen bond donor of the low eutectic solvent, and the two are mixed until they are uniform and transparent to obtain a low eutectic solvent ChCl-AA; The ferroferric oxide nanoparticles are ultrasonically dispersed in an ethanol aqueous solution, ammonia water is added and mixed evenly, and then ethyl orthosilicate is added dropwise thereto and mixed evenly. During the mixing process, ethyl orthosilicate is hydrolyzed under the condition of ammonia water to generate silicic acid, and the silane coats the ferroferric oxide nanoparticles and continues to hydrolyze into SiO2 to obtain Fe3O4@SiO2; Fe3O4@SiO2 was ultrasonically dispersed in toluene, and an alcohol solution of vinyltriethoxysilane was added. The alkylation reaction was carried out under nitrogen protection to coat the outside of Fe3O4@SiO2 with vinyltriethoxysilane to obtain Fe3O4@SiO2@VTEs. Using tetrahydrocannabinol as a template and ChCl-AA as a functional monomer, the two are co-dispersed in ethanol, and then allowed to stand to complete pre-assembly, and the tetrahydrocannabinol is fixed with ChCl-AA to obtain a precursor solution; The crosslinking agent, initiator and Fe3O4@SiO2@VTEs are added to the precursor solution, and the crosslinking reaction is carried out under nitrogen protection, so that the crosslinking agent, Fe3O4@SiO2@VTEs and ChCl-AA are crosslinked together to obtain a polymer; after the reaction, the polymer template is removed and washed to neutrality to obtain a Fe3O4@SiO2@VTEs@MIPs composite material.
2. The method for preparing the Fe3O4@SiO2@VTEs@MIPs composite material according to claim 1, characterized in that: The ratio of the mass of ferrosilicate nanoparticles, the amount of ethyl orthosilicate substance and the volume of ammonia water is 0.5g: 0.01mol-0.05mol: 5mL-10mL, and the volume percentage of ammonia water is 25%-28%.
3. The method for preparing the Fe3O4@SiO2@VTEs@MIPs composite material according to claim 1, characterized in that: The mass ratio of Fe3O4@SiO2 to the volume ratio of vinyltriethoxysilane is 0.05g:3mL~7mL.
4. The method for preparing the Fe3O4@SiO2@VTEs@MIPs composite material according to claim 1, characterized in that: The conditions for the alkylation reaction are: stirring at 40°C to 50°C for 6 hours.
5. The method for preparing the Fe3O4@SiO2@VTEs@MIPs composite material according to claim 1, characterized in that: The molar ratio of tetrahydrocannabinol to ChCl-AA is 1:3-8.
6. The method for preparing the Fe3O4@SiO2@VTEs@MIPs composite material according to claim 1, characterized in that: The ratio of the amount of ChCl-AA substance, the volume of the cross-linking agent, the mass of the initiator, and the mass of Fe3O4@SiO2 is 0.06mmol: 0.6mL~0.9mL: 0.04g~0.05g: 0.05g~0.06g.
7. The method for preparing the Fe3O4@SiO2@VTEs@MIPs composite material according to claim 1, characterized in that: The method of removing the template is: using a mixed solution of methanol and acetic acid as an eluent to elute the tetrahydrocannabinol and leave a site that specifically recognizes the tetrahydrocannabinol; Wherein, the volume ratio of methanol to acetic acid is 7-10:
1.
8. A Fe3O4@SiO2@VTEs@MIPs composite material prepared by the preparation method according to any one of claims 1 to 7, characterized in that: In the Fe3O4@SiO2@VTEs@MIPs composite material, ferroferric oxide nanoparticles are used as the magnetic core, and silica provides a rigid structure. Silica is coated on the outside of the ferroferric oxide nanoparticles. Vinyltriethoxysilane coats silica and modifies the surface of Fe3O4@SiO2. Vinyltriethoxysilane is also cross-linked with a cross-linker and ChCl-AA in the precursor solution, leaving holes on the surface for specific recognition of the target molecule tetrahydrocannabinol.
9. Use of the Fe3O4@SiO2@VTEs@MIPs composite material according to claim 8 in the preparation of a tetrahydrocannabinol removal agent.
10. The use according to claim 9, characterized in that: The Fe3O4@SiO2@VTEs@MIPs composite material was dispersed in the cannabidiol extract, and the Fe3O4@SiO2@VTEs@MIPs composite material was used to adsorb tetrahydrocannabinol in the cannabidiol extract.