CN111318265B

CN111318265B - Preparation method and application of mosaic type magnetic imprinting adsorbent

Info

Publication number: CN111318265B
Application number: CN202010097210.2A
Authority: CN
Inventors: 王盼; 潘建明
Original assignee: Jiangsu University
Current assignee: Hefei Jiuzhou Longteng Scientific And Technological Achievement Transformation Co ltd
Priority date: 2020-02-17
Filing date: 2020-02-17
Publication date: 2022-01-11
Anticipated expiration: 2040-02-17
Also published as: WO2021164146A1; CN111318265A

Abstract

The invention relates to a method for preparing a mosaic-type magnetic imprinting adsorbent, belonging to the technical field of preparation of specific separation functional materials; firstly, amino _- modified _Fe3O4 particles and Janus nanosheets are prepared, and then Janus molecular imprinting is prepared by ATRP molecular imprinting technology polymer; then combined Alg-Ca ²⁺ with Pickering emulsion and anisotropy of Janus-MIPs nanosheets and filled with Fe ₃ O ₄ -NH ₂ to prepare a mosaic-type Alg-Ca ²⁺ core magnetic molecularly imprinted adsorbent; The mosaic-type magnetic imprinting adsorbent prepared by the invention has high adsorption capacity, which can effectively solve the problem of easy stacking of molecularly imprinted nanosheet materials; at the same time, it is filled with paramagnetic particles, so that the Pickering emulsion has a magnetic response and is easy to separate and collect; Distinct recognition properties of dA molecules for selective recognition and separation of dA in aqueous solution.

Description

Preparation method and application of mosaic type magnetic imprinting adsorbent

Technical Field

The invention belongs to the technical field of preparation of specific selective separation functional materials, and particularly relates to a preparation method of a mosaic magnetic imprinting adsorbent.

Background

The nanosheet adsorbent has good physical and chemical properties, and is widely concerned in the field of adsorption separation due to the advantages of high specific surface area and easiness in modification. Two surfaces of the nano-sheet can be modified or grafted with different types of functional groups or polymer chains through covalent interaction to obtain the functionalized nano-sheet. However, the traditional nanosheet adsorbent still has the defects that the selectivity of adsorption separation needs to be improved, the site loss caused by agglomeration and stacking of flaky materials and the problem of difficult separation and collection limit the application in the separation of complex system targets. Therefore, there is an urgent need to develop a new strategy to solve the above limitations of the conventional nanosheet adsorbent.

Surface-initiated atom transfer radical polymerization (SI-ATRP) is a common method for grafting polymers on the surface of a substrate, generates molecular imprinted polymers (SI-MIPs) on the surface of a substrate material, and builds molecular imprinted sites on the surface of the substrate material, thereby bringing brand-new possibility for surface functionalization of the substrate material. In general, the generated polymer has highly controllable structure, high binding capacity, rapid mass transfer and rapid binding kinetics, and can be used as an ideal reaction platform for further chemical modification. At present, the nano sheet has high specific surface area and high transverse-longitudinal ratio, so that the nano sheet has differentiation directionality, and the nano sheet is used as a substrate of molecular imprinting to prepare the molecularly imprinted nano sheet material through a surface imprinting process, so that the selectivity of the nano sheet material is obviously improved. The bernous (Janus) material refers to an anisotropic material with two different structures and chemical compositions, and has wide application in many fields and great attention from the scientific community. Therefore, a suitable method can be adopted to combine the Janus material and the molecularly imprinted nanosheet, so that the multifunctional nanosheet adsorbent (Janus-MIPs) is prepared, and the versatility of the nanosheet material is endowed.

The Pickering emulsion is an emulsion which utilizes solid particles to be adsorbed on an oil-water interface to reduce the surface energy of the oil-water interface, thereby improving the stability of the oil-water interface. The anisotropic Janus nanosheet is provided with two opposite wetting surfaces, the Pickering emulsion can be well stabilized, the embedding depth of the nanosheet can be controllably adjusted according to the wettability of the two surfaces of the nanosheet, the Pickering emulsion similar to a mosaic type is generated, and the problem that molecularly imprinted nanosheet materials are easy to stack is solved. Alginate (Alg)^-) Is a natural ion-reactive polysaccharide, due to its biocompatibility and degradability, and is associated with divalent cations (especially Ca)²⁺) Has good gelation and good biomedical application, so that Alg-Ca can be prepared by a suitable method²⁺Combined with Pickering emulsion and Janus-MIPs nanosheet anisotropy while filled with paramagnetic particles (Fe)₃O₄-NH₂) Preparation of mosaic type Alg-Ca²⁺The core magnetic molecular imprinting adsorbent (J-SNs-MMIPs-Pickering) is used for selectively adsorbing and separating 2' -deoxyadenosine (dA) molecules.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a preparation method of a mosaic type magnetic imprinting adsorbent for solving the technical bottlenecks of selectivity of the existing nanosheet adsorbent, site loss caused by agglomeration and stacking of flaky materials, difficult separation and collection and the like, and is used for selective adsorption and separation of dA.

Firstly, Graphene Oxide (GO) nanosheets are used as stable particles to generate Pickering emulsion of solid paraffin in water, bromine is modified on the outer surface of the Pickering emulsion through bromo-isobutyryl bromide (BIBB), and paraffin is removed to generate a beltJanus nanosheets (J-SNs) with one side of bromine not modified; then, bromine on the surface is used as an initiator of Atom Transfer Radical Polymerization (ATRP), dA is used as a template molecule, 5- (2-methoxyvinyl) -2' -deoxyuridine (AcrU) which forms hydrogen bond with dA and has better matching property is used as a functional monomer, and dA molecularly imprinted polymers (J-SNs-MIPs) are grafted on the hydrophobic surface of the Janus nanosheets; then J-SNs-MIPs are used as stable particles to obtain Ca as the inner phase respectively²⁺And Fe₃O₄-NH₂The Pickering emulsion B and the internal phase are Alg^-With Fe₃O₄-NH₂The Pickering emulsion A of (1) mixing the two emulsions by mild mechanical stirring, dynamically combining, inducing Alg-Ca²⁺Gelatinizing to obtain Alg-Ca²⁺The material is a mosaic magnetic imprinting adsorbent (J-SNs-MMIPPs-Pickering) which is used as a core, and the obtained material is applied to the efficient selective adsorption and separation of dA in an aqueous solution.

In order to achieve the above purpose, the specific steps of the invention are as follows:

(1)Fe₃O₄-NH₂preparing;

adding a certain amount of FeCl₃·6H₂Mixing O, 1, 6-hexamethylene diamine, anhydrous sodium acetate and ethylene glycol to obtain a mixed solution, stirring at a certain temperature of 50 ℃ until the mixed solution is transparent, and transferring the mixed solution into a high-pressure kettle for heating reaction; heating to 200 deg.C for 6 hr, washing with water and ethanol, separating with magnet, and vacuum drying at 50 deg.C to obtain black modified amino Fe₃O₄Nanoparticles, denoted Fe₃O₄-NH₂(ii) a Dispersing the obtained product in toluene at a concentration of 10 mg/mL;

(2) preparing J-SNs nanosheets;

first by Hummer^’Preparing GO nano-sheets by a method s; taking GO nano-sheets as stable particles, respectively taking water and solid paraffin as a continuous phase and a dispersed phase, adding a certain amount of saturated sodium chloride (NaCl) solution as electrolyte, and stirring at a certain rotating speed to generate GO-Pickering emulsion; then centrifugally collecting and vacuum drying; obtain GO-Dispersing a Pickering product in N, N-Dimethylformamide (DMF) solution, adding a certain amount of BIBB and triethylamine for reaction, centrifugally collecting after reaction, cleaning to remove oil phase, ultrasonically crushing, and drying in vacuum to obtain J-SNs nanosheets for later use;

(3) preparing J-SNs-MIPs nanosheets;

firstly, mixing dimethyl sulfoxide and acetonitrile, adding 2 '-deoxyadenosine (dA) and 5- (2-methoxyvinyl) -2' -deoxyuridine (AcrU), introducing nitrogen gas at normal temperature for reaction, and then carrying out self-assembly in a dark place; then, adding Ethylene Glycol Dimethacrylate (EGDMA) and the J-SNs nanosheet prepared in the step (2), stirring at a certain temperature, and adding N, N, N, N, N-Pentamethyldiethylenetriamine (PMDEIA) and copper bromide (CuBr)₂) Continuously stirring and carrying out water bath heating reaction with ascorbic acid (VC), centrifuging after reaction, collecting a product, washing twice with methanol and acetone, carrying out Soxhlet extraction on the product by using a methanol/hydrochloric acid mixed solution as an eluent (7:3, V: V), and finally drying to obtain J-SNs-MIPs nanosheets;

(4) J-SNs-preparation of MMIPPs-Pickering;

taking the J-SNs-MIPs nanosheet prepared in the step (3) as a stable particle, adding a certain amount of span80 for assisting stabilization, and then adding water, toluene, a certain amount of Alg-Na and Fe prepared in the step (1)₃O₄-NH₂Stirring the particles for 30min under mechanical stirring at a certain rotating speed to obtain Pickering emulsion A;

taking the J-SNs-MIPs nanosheets prepared in the step (3) again as stable particles, adding a certain amount of span80 for assisting in stabilization, and then adding water, toluene and CaCl₂And Fe₃O₄-NH₂Granulating to obtain Pickering emulsion B; adding the emulsion A into the emulsion B to obtain a mixed solution, stirring and mixing under a certain rotation speed condition, stirring under the same rotation speed mechanical stirring, adding ethanol for stirring, centrifuging, washing off toluene, and drying under vacuum to obtain the mosaic type magnetic imprinting adsorbent, which is recorded as J-SNs-MMIPs-Pickering.

Preferably, FeCl as described in step (1)₃·6H₂O, 1, 6-hexanediamine, anhydrous sodium acetate and ethylene glycolThe dosage ratio is as follows: 1.0g, 6.0-7.0g, 50-70mg, 1.5-2.5g, 20-40 mL.

Preferably, in the step (2), the dosage ratio of the GOGO nano sheets, water, solid paraffin and saturated sodium chloride (NaCl) solution is as follows: 0.8-1.2mL of 1.0mg and 0.08-0.12g and 0.07-0.08mL of the total weight of the composition.

Preferably, in the step (2), the dosage ratio of GO-Pickering, N-dimethylformamide, BIBB and triethylamine is as follows: 1.0g, 60 mL: 45-55 mu L of 90-110 mu L.

Preferably, the high-speed stirring in the step (2) is carried out at 14000rpm for 5-10 min; the reaction time is 24 hours when certain amount of BIBB and triethylamine are added.

Preferably, in the step (3), the ratio of the 2 '-deoxyadenosine, the 5- (2-methoxyvinyl) -2' -deoxyuridine, the dimethyl sulfoxide and the acetonitrile is 1.0g: 4.0-5.0 g: 40-60 mL: 140-160 mL.

Preferably, in the step (3), the dosage ratio of the 2' -deoxyadenosine to the ethylene glycol dimethacrylate to the J-SNs nanosheets is 1.0g: 10-12 mL: 900 and 1100 mg.

Preferably, in step (3), the 2' -deoxyadenosine, the PMDEIA and the CuBr are used₂The dosage ratio of VC and VC is 1.0g:1.0mL:70-80mg:60-65 mg.

Preferably, in the step (3), the reaction time of introducing nitrogen is 30-40 min; the time for self-assembly in a dark place is 90-100 min; the stirring temperature under a certain temperature condition is 30 ℃, and the stirring time is 30-40 min; the temperature of the water bath heating reaction is 60-70 ℃, and the time is 12-15 h; the temperature of the drying was 45 ℃.

Preferably, in the step (4), the dosage ratio of J-SNs-MIPs, water and toluene in the emulsion A is as follows: 0.225-0.275mL of 1.0mg and 0.35-0.4mL of the total amount of the mixture.

Preferably, in step (4), the emulsion A contains J-SNs-MIPs, span80, Alg-Na and Fe₃O₄-NH₂The dosage ratio of the components is 1.0mg to 0.01-0.02g to 0.003-0.004g to 0.2-0.3 g.

Preferably, in the step (4), the dosage ratio of J-SNs-MIPs, water and toluene in the emulsion B is as follows: 0.225-0.275mL of 1.0mg and 0.35-0.4mL of the total amount of the mixture.

Preferably, in the step (4), J-SNs-MIPs, span80 and CaCl in the emulsion B₂And Fe₃O₄-NH₂The dosage ratio of the components is 1.0mg to 0.01-0.02g to 0.015-0.020g to 0.2-0.3 g.

Preferably, the volume ratio of the emulsion A, the emulsion B and the ethanol in the step (4) is 1: 5.

preferably, the rotation speed of the mechanical stirring in the step (4) is 800rpm, and the stirring time is 30-50 min; and the time for adding the ethanol and stirring is 5-10 min.

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, a Janus nano sheet is used as a substrate, a polymer prepared by an ATRP technology is used as a reaction platform, AcrU is used as a functional monomer, a novel nano sheet adsorbent (J-SNs-MIPs) with high selectivity is constructed, and the selectivity of a nano sheet material is obviously improved; then J-SNs-MIPs are used as stable particles to obtain Ca with magnetic particles in the internal phase²⁺And Alg^-The Pickering emulsions A and B are dynamically combined to induce Alg-Ca²⁺Gelation, and the prepared J-SNs-MMIPPs-Pickering can effectively solve the problem that the molecularly imprinted nano-sheet material is easy to stack; simultaneously filled with paramagnetic particles (Fe)₃O₄-NH₂) The Pickering emulsion has magnetic response and is easy to separate and collect.

Drawings

FIG. 1 is a scanning electron micrograph of J-SNs (a), J-SNs-MIPs (b), J-SNs-MMIPs-Pickering (c, d) prepared in example 1.

FIG. 2 is the contact angle for GO, J-SNs-MIPs and GO-MIPs prepared in this example 1.

FIG. 3 shows Fe prepared in example 1₃O₄-NH₂(a) IR spectra of GO (B), J-SNs-MIPs (c) and J-SNs-MMIPPs-Pickering (d).

FIG. 4 shows Fe prepared in example 1₃O₄-NH₂And XRD spectra of J-SNs-MMIPPs-Pickering.

FIG. 5 is a graph showing the adsorption kinetics of J-SNs-MMIPPs-Pickering and J-SNs-MNIPs-Pickering prepared in example 1 and a model-fitted curve thereof.

FIG. 6 shows the adsorption equilibrium of J-SNs-MMIPPs-Pickering and J-SNs-MNIPs-Pickering in example 1 and a model-fitted curve thereof.

FIG. 7 shows the regenerated adsorption capacities of J-SNs-MMIPs-Pickering and J-SNs-MNIPs-Pickering in example 1.

Detailed Description

In order to better understand the technical solutions of the present invention for those skilled in the art, the following further describes the technical solutions of the present invention with reference to specific embodiments and drawings.

The identification performance evaluation in the embodiment of the invention is carried out according to the following method:

completing by using a static adsorption experiment; adding 5mL of dA solution with a certain concentration into a centrifuge tube, adding a certain amount of J-SNs-MMIPs-Pickering adsorbent, standing in a constant-temperature water area at 25 ℃ for several hours, measuring the content of dA after adsorption by using an ultraviolet-visible spectrophotometer, and calculating the adsorption capacity according to the result; 5mL of dA solution with the initial concentration of 300 mu mol/L is added into a centrifuge tube, a certain amount of J-SNs-MMIPs-Pickering adsorbent is added, the dA solution is taken out under a certain time gradient, and the adsorption capacity is calculated according to the result and is used for participating in the study on the kinetic performance of the J-SNs-MMIPs-Pickering adsorbent. Several nucleoside compounds with similar structures and properties, such as 2-deoxyguanosine (dG), 2-deoxycytidine (dC), 5' -monophosphate-Adenosine (AMP) and the like, are selected as selective adsorbates and participate in researching the recognition performance of the adsorbents.

The invention is further illustrated by the following examples.

Example 1:

(1)Fe₃O₄-NH₂preparing;

1.0g FeCl₃·6H₂O, 6.5g of 1, 6-hexanediamine, 2.0g of anhydrous sodium acetate and 30mL of ethylene glycol were stirred at 50 ℃ to be transparent. The mixture was transferred to an autoclave and heated to 200 ℃ for 6 hours. After the reaction is finished, washing the black amino-modified Fe by water and ethanol₃O₄Nanoparticles (Fe)₃O₄-NH₂) And separated by a magnet, 50Vacuum drying at deg.C. The product was redispersed in toluene at a concentration of 10 mg/mL.

(2) Preparing J-SNs nanosheets;

by Hummer^’And(s) preparing GO nano-sheets by using a method. 50mg GO nano-sheets are taken as stable particles, 50mL of water and 5g of solid paraffin are respectively taken as a continuous phase and a dispersed phase, 3.75mL of saturated sodium chloride (NaCl) solution is added as electrolyte, and the mixture is stirred at the rotating speed of 14000rpm for 5min at a high speed to generate GO-stable Pickering emulsion (GO-Pickering). Then, the mixture was collected by centrifugation and dried in vacuum. 8.0g of GO-Pickering is dispersed in 60mL of N, N-Dimethylformamide (DMF) solution, 400 mu of LBIBB and 800 mu of triethylamine are added for reaction for 24 hours, and then the mixture is centrifugally collected, the oil phase is washed off, and the mixture is ultrasonically crushed to obtain J-SNs nanosheets which are dried in vacuum.

(3) Preparing J-SNs-MIPs nanosheets;

dissolving 0.1g of 2 '-deoxyadenosine (dA) and 0.45g of 5- (2-methoxyvinyl) -2' -deoxyuridine (AcrU) in a mixed solution of 5mL of dimethyl sulfoxide and 15mL of acetonitrile, introducing nitrogen at normal temperature for 30min, and self-assembling for 1.5h in a dark place; then 1.09mL of Ethylene Glycol Dimethacrylate (EGDMA) and 100mg of J-SNs nanosheet are added, stirred at 30 ℃ for 0.5h, and then 0.4mL of N, N, N, N, N-Pentamethyldiethylenetriamine (PMDEIA) and 30mg of copper bromide (CuBr) are added₂) And 25mg of ascorbic acid (VC), the mixed solution was continuously stirred and heated in a water bath at 70 ℃ for 12 hours of reaction, the product was collected by centrifugation, followed by washing twice with methanol and acetone, Soxhlet extraction of J-SNs-MIPs using a mixed solution of methanol/hydrochloric acid as an eluent (7:3, V: V) to remove unreacted template molecules and organic solvents, and finally, the purified J-SNs-MIPs were dried at 45 ℃.

(4) J-SNs-preparation of MMIPPs-Pickering;

20mg of J-SNs-MIPs nano-sheet as a stable particle, 0.3g of span80 as auxiliary stability, 5mL of water and 7.5mL of toluene as a dispersed phase and a continuous phase respectively, and 0.075g of Alg-Na and 5mg of Fe are added into the water phase₃O₄-NH₂Stirring the particles for 30min under mechanical stirring at a certain rotating speed to obtain Pickering emulsion A; under the same conditions, 0.35g of CaCl was added to the aqueous phase₂And 5mg Fe₃O₄-NH₂Granulating to obtain Pickering emulsionB; adding the emulsion A into the emulsion B, mixing, stirring at the same rotation speed for 30min under mechanical stirring, adding 5ml ethanol, stirring for 5min, centrifuging, washing off toluene to obtain J-SNs-MMIPs-Pickering, and vacuum drying.

The preparation procedure of J-SNs-MNIPs-Pickering was the same as that of J-SNs-MMIPs-Pickering except that no template molecule, 2' -deoxyadenosine (dA), was added.

FIG. 1 is a scanning electron micrograph of J-SNs (a), J-SNs-MIPs (b), J-SNs-MMIPs-Pickering (c, d) prepared in the examples. The figure shows that J-SNs-MIPs obviously generate polymers relative to the surface of J-SNs, the molecularly imprinted polymers are successfully modified on the nanosheets, the size of J-SNs-MMIPPs-Pickering is 15 micrometers, the surface can obviously see the distribution of the nanosheets, and the successful preparation of the J-SNs-MMIPPs-Pickering is shown.

FIG. 2 is the contact angle of GO, J-SNs-MIPs and GO-MIPs prepared in the examples. The figure shows that the hydrophobicity of GO, J-SNs-MIPs and GO-MIPs nano-sheets is sequentially increased, the structures on two sides of the nano-sheets are different, and the J-SNs-MIPs nano-sheets are successfully prepared.

FIG. 3 is Fe prepared in example₃O₄-NH₂(a) IR spectra of GO (B), J-SNs-MIPs (c) and J-SNs-MMIPPs-Pickering (d). The figure shows that the peak voltage is at 576cm^-1、669cm^-1、1108～1729cm^-1、2920cm^-1Several characteristic absorption peaks are generated, which indicates that the mosaic magnetic imprinting adsorbent is successfully prepared.

FIG. 4 shows Fe prepared in example₃O4-NH₂And XRD spectra of J-SNs-MMIPPs-Pickering. The diagram shows the Fe produced₃O₄-NH₂And J-SNs-MMIPPs-Pickering and Fe₃O₄And (4) matching standard cards to show that the mosaic type magnetic imprinting adsorbent is successfully prepared.

Example 2:

(1)Fe₃O₄-NH₂preparing;

1.0g FeCl₃·6H₂O, 6g of 1, 6-hexanediamine, 1.5g of anhydrous sodium acetate and 20mL of ethylene glycol are stirred at the temperature of 50 ℃ to be transparent; transferring the mixture to an autoclave and addingHeat to 200 ℃ for 6 h. After the reaction is finished, washing the black amino-modified Fe by water and ethanol₃O₄Nanoparticles (Fe)₃O₄-NH₂) Separating with magnet, and vacuum drying at 50 deg.C. The product was redispersed in toluene at a concentration of 10 mg/mL.

(2) Preparing J-SNs nanosheets;

by Hummer^’Preparing GO nano-sheets by a method s; 50mg GO nano-sheets are taken as stable particles, 40mL of water and 4g of solid paraffin are respectively taken as a continuous phase and a dispersed phase, 3.5mL of saturated sodium chloride (NaCl) solution is added as electrolyte, and the mixture is stirred at the rotating speed of 14000rpm for 5min at a high speed to generate GO-stable Pickering emulsion (GO-Pickering). Then, the mixture was collected by centrifugation and dried in vacuum. 8.0g of GO-Pickering is dispersed in 60mL of N, N-Dimethylformamide (DMF) solution, 360 mu of LBIBB and 720 mu of triethylamine are added for reaction for 24 hours, and then the mixture is centrifugally collected, washed to remove an oil phase, ultrasonically crushed to obtain J-SNs nanosheets, and dried in vacuum.

(3) Preparing J-SNs-MIPs nanosheets;

dissolving 0.1g of 2 '-deoxyadenosine (dA) and 0.4g of 5- (2-methoxyvinyl) -2' -deoxyuridine (AcrU) in a mixed solution of 4mL of dimethyl sulfoxide and 16mL of acetonitrile, introducing nitrogen at normal temperature for 30min, and self-assembling for 1.5h in a dark place; then adding 1.0mL of Ethylene Glycol Dimethacrylate (EGDMA) and 90mg of J-SNs nanosheet, stirring at 30 ℃ for 0.5h, and then adding 0.4mL of N, N, N, N, N-Pentamethyldiethylenetriamine (PMDEIA) and 28mg of copper bromide (CuBr)₂) And 24mg of ascorbic acid (VC), the mixed solution was continuously stirred and heated in a water bath at 70 ℃ for 12 hours of reaction, the product was collected by centrifugation, followed by washing twice with methanol and acetone, Soxhlet extraction of J-SNs-MIPs using a mixed solution of methanol/hydrochloric acid as an eluent (7:3, V: V) to remove unreacted template molecules and organic solvents, and finally, the purified J-SNs-MIPs were dried at 45 ℃.

(4) J-SNs-preparation of MMIPPs-Pickering;

20mg of J-SNs-MIPs nanosheet as a stable particle, 0.2g of span80 as auxiliary stability, 4.5mL of water and 7mL of toluene as a dispersed phase and a continuous phase respectively, and 0.06g of Alg-Na and 4mg of Fe are added into the water phase₃O₄-NH₂Particles in a constant rotationStirring for 30min under rapid mechanical stirring to obtain Pickering emulsion A; under the same conditions, 0.3g of CaCl was added to the aqueous phase₂And 4mg Fe₃O₄-NH₂Granulating to obtain Pickering emulsion B; adding the emulsion A into the emulsion B, mixing, stirring at the same rotation speed for 30min under mechanical stirring, adding 5ml ethanol, stirring for 5min, centrifuging, washing off toluene to obtain J-SNs-MMIPs-Pickering, and vacuum drying.

Example 3:

(1)Fe₃O₄-NH₂preparing;

1.0g FeCl₃·6H₂O, 7g of 1, 6-hexanediamine, 2.5g of anhydrous sodium acetate and 40mL of ethylene glycol were stirred at 50 ℃ to be transparent. The mixture was transferred to an autoclave and heated to 200 ℃ for 6 h. After the reaction is finished, washing the black amino-modified Fe by water and ethanol₃O₄Nanoparticles (Fe)₃O₄-NH₂) Separating with magnet, and vacuum drying at 50 deg.C. The product was redispersed in toluene at a concentration of 10 mg/mL.

(2) Preparing J-SNs nanosheets;

by Hummer^’And(s) preparing GO nano-sheets by using a method. 50mg GO nano-sheets are taken as stable particles, 60mL of water and 6g of solid paraffin are respectively taken as a continuous phase and a dispersed phase, 4mL of saturated sodium chloride (NaCl) solution is added as electrolyte, and the mixture is stirred at 14000rpm for 5min at high speed to generate GO-stable Pickering emulsion (GO-Pickering). Then, the mixture was collected by centrifugation and dried in vacuum. 8.0g of GO-Pickering is dispersed in 60mL of N, N-Dimethylformamide (DMF) solution, 440 mu L of BIBB and 880 mu L of triethylamine are added for reaction for 24 hours, and then the mixture is centrifugally collected, the oil phase is washed away, and the mixture is ultrasonically crushed to obtain J-SNs nanosheets which are dried in vacuum.

(3) Preparing J-SNs-MIPs nanosheets;

dissolving 0.1g of 2 '-deoxyadenosine (dA) and 0.5g of 5- (2-methoxyvinyl) -2' -deoxyuridine (AcrU) in a mixed solution of 6mL of dimethyl sulfoxide and 14mL of acetonitrile, introducing nitrogen at normal temperature for 30min, and self-assembling for 1.5h in a dark place; then adding 1.2mL of Ethylene Glycol Dimethacrylate (EGDMA) and 90mg of J-SNs nanosheet, stirring at 30 ℃ for 0.5h, and adding 0.4mL of N, N, N, N, N-pentamethyldiethylenetriamine(PMDEIA), 32mg copper bromide (CuBr)₂) And 26mg of ascorbic acid (VC), the mixed solution was continuously stirred and heated in a water bath at 70 ℃ for 12 hours of reaction, the product was collected by centrifugation, followed by washing twice with methanol and acetone, Soxhlet extraction of J-SNs-MIPs using a mixed solution of methanol/hydrochloric acid as an eluent (7:3, V: V) to remove unreacted template molecules and organic solvents, and finally, the purified J-SNs-MIPs were dried at 45 ℃.

(4) J-SNs-preparation of MMIPPs-Pickering;

20mg of J-SNs-MIPs nanosheet as a stable particle, 0.4g of span80 as auxiliary stability, 5.5mL of water and 8mL of toluene as a dispersed phase and a continuous phase respectively, and 0.08g of Alg-Na and 6mg of Fe are added into the water phase₃O₄-NH₂Stirring the particles for 30min under mechanical stirring at a certain rotating speed to obtain Pickering emulsion A; under the same conditions, 0.4g of CaCl was added to the aqueous phase₂And 6mg Fe₃O₄-NH₂Granulating to obtain Pickering emulsion B; adding the emulsion A into the emulsion B, mixing, stirring at the same rotation speed for 30min under mechanical stirring, adding 5ml ethanol, stirring for 5min, centrifuging, washing off toluene to obtain J-SNs-MMIPs-Pickering, and vacuum drying.

Test example 1:

respectively adding 5mL of 2' -deoxyadenosine (dA) solution with the initial concentration of 300 mu mol/L into a centrifuge tube, respectively adding 5mg of J-SNs-MMIPs-Pickering and J-SNs-MNIPs-Pickering adsorbents in example 1, and respectively taking out at the time of 5min, 15 min, 30min, 60min, 120 min, 240 min, 360 min, 480 min and 720 min; the blot adsorbent was separated from the solution by a magnet. The concentration of dA in the filtrate was determined by calculation using an ultraviolet spectrophotometer at a wavelength of 259nm, and from the results, FIG. 5 was obtained and the time to equilibrium of adsorption was calculated; the results show that the adsorption capacity of J-SNs-MMIPPs-Pickering and J-SNs-MNIPs-Pickering increases rapidly during the first 60min, indicating that the template molecules can diffuse into the adsorbent easily. And the adsorption efficiency of J-SNs-MMIPPs-Pickering is obviously faster than that of J-SNs-MNIPs-Pickering, the adsorption capacity of dA is larger than that of J-SNs-MNIPs-Pickering, and a large number of empty imprinting sites are formed on the surface of J-SNs-MMIPPs-Pickering. After rapid adsorption, the adsorption rate drops sharply and reaches equilibrium at 100min due to the drop in dA concentration and the reduction in the number of binding sites.

Test example 2:

5mL of dA solutions having initial concentrations of 20, 40, 70, 100, 300, 500, 700 and 1000. mu. mol/L were added to a centrifuge tube, 5mg of J-SNs-MNIPs-Pickering adsorbent of example 1 was added, the test solution was left to stand in a water bath at 25 ℃ for 4 hours, the blotting adsorbent and the solution were separated by a magnet, the concentrations of dA molecules not adsorbed were measured by an ultraviolet-visible spectrophotometer at a wavelength of 259nm, and from the results, FIG. 6 was obtained and the adsorption capacity was calculated. The result shows that the maximum adsorption capacity of J-SNs-MMIPs-Pickering to dA is 73.04 mu mol/g when adsorption equilibrium is achieved, the maximum adsorption capacity of J-SNs-MNIPs-Pickering to dA is 53.39 mu mol/g respectively when adsorption equilibrium is achieved, and the maximum adsorption capacity of J-SNs-MMIPs-Pickering is higher than that of J-SNs-MNIPs-Pickering at the same temperature, which indicates that J-SNs-MMIPs-Pickering is an adsorbent for effectively identifying dA.

Test example 3:

2-deoxyguanosine (dG), 2-deoxycytidine (dC), 5' -monophosphate-Adenosine (AMP), and the like were selected as selective adsorbates, solutions of the above three compounds were prepared at a concentration of 300. mu. mol/L, 5mL of each was added to a centrifuge tube, 5mg of the imprinted adsorbent and the non-imprinted adsorbent prepared in example 1 were added, respectively, the test solution was placed in a water bath oscillator at 25 ℃ for 10 hours, the imprinted adsorbent and the solution were separated by a magnet, the concentration of unadsorbed dA molecules was measured by an ultraviolet-visible spectrophotometer at a wavelength of 259nm, and FIG. 7 was obtained based on the results. The result shows that the adsorption capacity of J-SNs-MMIPs-Pickering on four compounds follows the sequence of dA & gt dG & gt dC & gt AMP, so that the existence of imprinted sites with the shape and the size consistent with that of dA on the surface of J-SNs-MMIPs-Pickering can be inferred, and the J-SNs-MMIPs-Pickering has better adsorption specificity on dA.

Description of the drawings: the above embodiments are only used to illustrate the present invention and do not limit the technical solutions described in the present invention; thus, while the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted; all such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and protected by the following claims.

Claims

1. a preparation method of mosaic-type magnetic imprinting adsorbent, is characterized in that, concrete steps are as follows:

(1) Preparation of Fe ₃ O ₄ -NH ₂ ;

(2) Preparation of J-SNs nanosheets;

(3) First, mix dimethyl sulfoxide and acetonitrile, add 2'-deoxyadenosine, 5-(2-methoxyvinyl)-2'-deoxyuridine, the 2'-deoxyadenosine, The dosage ratio of 5-(2-methoxyvinyl)-2'-deoxyuridine, dimethyl sulfoxide and acetonitrile is 1.0 g: 4.0-5.0 g: 40~60 mL: 140~160 mL; under normal temperature conditions After the reaction with nitrogen gas, self-assembly is performed in the dark; then, ethylene glycol dimethacrylate and the J-SNs nanosheets prepared in step (2) are added, the 2'-deoxyadenosine, dimethacrylic acid The dosage ratio of ethylene glycol ester and J-SNs nanosheets is 1.0 g: 10-12 mL: 900-1100 mg; after stirring at a certain temperature, add N,N,N,N,N-pentamethylbismuth Ethylene triamine, copper bromide and ascorbic acid, the consumption ratio of described 2'-deoxyadenosine, N,N,N,N,N-pentamethyldiethylenetriamine, copper bromide and ascorbic acid is 1.0 g: 1.0 mL: 70-80 mg: 60-65 mg; continue to stir and carry out the heating reaction in a water bath. After the reaction, the product is collected by centrifugation, washed twice with methanol and acetone, and then the product is subjected to a mixed solution of methanol/hydrochloric acid as the eluent. Soxhlet extraction, and finally, J-SNs-MIPs nanosheets were obtained after drying; (4) Preparation of J-SNs-MMIPs-Pickering;

Take the J-SNs-MIPs nanosheets prepared in step (3) as stable particles, add a certain amount of span80 to assist stabilization, and then add water, toluene, Alg-Na and the Fe ₃ O ₄ -NH ₂ particles prepared in step (1) , stirring under the mechanical stirring at a certain speed to obtain Pickering emulsion A;

Take the J-SNs-MIPs nanosheets prepared in step (3) again as stable particles, add a certain amount of span80 to assist stabilization, and then add water, toluene, CaCl ₂ and Fe ₃ O ₄ -NH ₂ particles to obtain Pickering emulsion B; Add Emulsion A to Emulsion B to obtain a mixed solution, stir and mix at a certain speed, stir under mechanical stirring at the same speed, add ethanol for stirring, centrifuge, wash off toluene, and vacuum dry to obtain mosaic magnetic Blotted adsorbent, denoted as J-SNs-MMIPs-Pickering.

2 . The method for preparing a mosaic-type magnetic imprinted adsorbent according to claim 1 , wherein, in step (3), the reaction time for the introduction of nitrogen gas is 30-40 min; the time for self-assembly in the dark for 90~100min; the stirring temperature under a certain temperature condition is 30°C, and the time is 30~40min; the temperature of the water bath heating reaction is 60~70°C, and the time is 12h~15h; the drying temperature is 45°C °C.

3. The method for preparing a mosaic-type magnetic imprinting adsorbent according to claim 1, wherein in step (4), the dosage ratio of J-SNs-MIPs, water and toluene in the emulsion A is: : 1.0 mg: 0.225-0.275 mL: 0.35-0.4 mL.

4. The method for preparing a mosaic-type magnetic imprinted adsorbent according to claim 1, wherein in step (4), J-SNs-MIPs, span80, Alg-Na and Fe in the emulsion A The dosage ratio of ₃ O ₄ -NH ₂ is 1.0 mg : 0.01-0.02 g : 0.003-0.004 g : 0.2-0.3 g.

5. The method for preparing a mosaic-type magnetic imprinting adsorbent according to claim 1, wherein in step (4), the dosage ratio of J-SNs-MIPs, water and toluene in the emulsion B is: : 1.0 mg : 0.225-0.275 mL : 0.35-0.4 mL; the dosage ratio of J-SNs-MIPs, span80, CaCl ₂ and Fe ₃ O ₄ -NH ₂ in the emulsion B is 1.0 mg : 0.01-0.02 g : 0.015-0.020 g : 0.2-0.3 g.

6. The preparation method of a mosaic-type magnetic imprinted adsorbent according to claim 1, wherein the volume ratio of the emulsion A, the emulsion B and the ethanol described in step (4) is 1: 1: 5; The rotating speed of the mechanical stirring is 800 rpm, and the stirring time is 30 to 50 min; the time for adding ethanol to stir is 5 to 10 min.

7. The mosaic-type magnetic imprinting adsorbent prepared by the method according to any one of claims 1 to 6 is applied to the selective adsorption of 2'-deoxyadenosine.