CN112808256A - Magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial and preparation method thereof - Google Patents
Magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial and preparation method thereof Download PDFInfo
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Abstract
The invention relates to a magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial and a preparation method thereof, belonging to the technical field of molecularly imprinted polymers. The material is black powder, and the average particle size of powder particles is 200-300 nm; the specific surface area is 327.6 cm2(ii)/g, saturation magnetization of 54.9 emu/g. The method prepares a novel magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial by improving a baby method to synthesize double-layer silicon dioxide-coated magnetic core-shell mesoporous nano composite particles as a carrier, bonding amino on the carrier, using diisononyl phthalate as a virtual template and using a surface molecularly imprinted technology; based on the fact that the material is magneticThe solid phase extractant is used for detecting phthalate substances, has low detection limit and high precision, and is suitable for detecting trace phthalate in liquid drinks such as water, wine, beverages and the like.
Description
Technical Field
The invention belongs to the technical field of molecularly imprinted polymers, and particularly relates to a preparation method of a magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial, and also relates to application of the composite nanomaterial as a magnetic solid phase extractant in extraction and detection of phthalate compounds in food.
Background
Phthalate compounds (PAEs) are plasticizers widely used in food packaging, plastic processing and other industries, and become pollutants widely existing in food. Researches find that the phthalate compounds have the function of estrogen-like, can interfere the endocrine system, cause the pathological changes of the reproductive system of human beings and have potential health risks. The phthalate-based compounds do not have covalent bonds with plastic molecules and therefore tend to migrate from the packaging material to the food and environment during use and contact. At present, the detection process of phthalate substances can be basically divided into three steps of organic solvent liquid-liquid extraction, Solid Phase Extraction (SPE) separation and purification and detection on a computer, but because the content of the phthalate substances in food samples is low and the influence of matrixes is large, the traditional solid phase extraction method is complex to operate, the enrichment and concentration capacity is small, the speed is low, and the existence of PAEs with low concentration is difficult to detect. And has a series of defects of slow mass transfer speed, time consumption, consumption of a large amount of organic reagents, easy blockage of the extraction column, high price of the commercialized solid phase extraction column, incapability of being repeatedly used and the like.
The magnetic solid phase extraction technology (MSPE) based on the magnetic mesoporous material is a promising extraction and purification technology in the sample pretreatment process at present, the functionalized magnetic mesoporous material has the characteristics of large specific surface area, strong magnetic property, easy magnetic separation, material reusability and the like, one step of the magnetic solid phase extraction replaces two steps of liquid-liquid extraction and solid phase extraction separation and purification in the traditional sample detection, and the defects of time consumption, consumption of a large amount of organic reagents, high price of a solid phase extraction column, easy blockage and the like in the traditional solid phase extraction are overcome, but the adsorption process of the common magnetic mesoporous material to a target object mainly belongs to physical adsorption, the specific selectivity is poor and the adsorption capacity is low. The composite material synthesized by combining the magnetic mesoporous material with the molecular imprinting technology shows good application prospect in the field of solid phase extraction, the Molecular Imprinting Technology (MIT) is a technology for preparing a polymer material with specific recognition capability on target molecules, the solid phase extraction technology taking Molecular Imprinting Polymers (MIPs) as an adsorbent is gradually applied to extraction and purification of phthalate esters, and the defects of poor selectivity and low adsorption capacity of the traditional magnetic mesoporous material are overcome, but the problems of serious crosslinking, nonuniform distribution of imprinting sites, too deep or too tight embedding of imprinting molecules, low adsorption capacity, poor dynamic performance, poor regeneration effect and the like of the molecular imprinting polymers prepared by the traditional method exist. The imprinting active sites are modified on the surfaces of various carriers by a Surface Molecular Imprinting Technology (SMIT), so that the mass transfer speed can be improved, and the problems of too deep embedding of imprinting molecules and the like can be solved.
The specific magnetic mesoporous carrier material is synthesized, and phthalate target molecules are imprinted on the surface of the carrier material through a surface molecular imprinting technology, so that the selectivity, adsorption capacity and dynamic performance of the material to phthalate substances are greatly improved, but the surface molecular imprinting polymer material synthesized by taking the magnetic mesoporous carbon material as the carrier is only suitable for extracting PAEs in drinking water and environmental water, and because a large cavity exists between a mesoporous shell and a magnetic core, the adsorption equilibrium speed is low, about 20 minutes is needed, the magnetic performance is greatly weakened (the saturation susceptibility is only 21.5 emu/g), and the magnetic separation is not easy to realize. The mesoporous silica has the characteristics of large specific surface area, good compatibility, sufficient surface silicon hydroxyl (Si-OH) groups and easy modification, and is an ideal material for magnetic particle modification and surface molecular imprinting carriers. The magnetic core-shell mesoporous surface molecular imprinting composite nanospheres synthesized by combining the surface molecular imprinting technology based on the magnetic mesoporous silicon as the carrier maintain the developed pore structure, have large specific surface area, have the advantages of strong PAEs (polycyclic aromatic acids) recognition capability, high saturated adsorption capacity, material reusability and the like, greatly improve the adsorption equilibrium rate and the saturated magnetic strength of the material, and are an ideal magnetic solid-phase extraction material for detecting phthalate substances.
Disclosure of Invention
In order to realize the detection of phthalate substances with low cost, rapidness, high efficiency and sensitivity, the invention provides a magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial and a preparation method of the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial.
A magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial for phthalate compound detection is in a black powder shape, and the average particle size of powder particles is 200-300 nm; the powder particles are spherical and have obvious core-shell structures, and the outer layer is a regular mesoporous silicon pore channel; the specific surface area is 327.6 cm2(ii)/g; the saturation magnetization is 54.9 emu/g, and the magnetic material has good superparamagnetism; the magnetic solid phase extraction material has excellent affinity and selectivity to phthalate substances, high adsorption capacity and fast adsorption kinetics, achieves adsorption balance within 5 minutes, and is a good magnetic solid phase extraction material for extraction and purification of the phthalate substances;
the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial is suitable for detecting trace Phthalic Acid Esters (PAEs) in liquid drinks, and a rapid, efficient and sensitive matrix dispersion-magnetic solid phase extraction-gas chromatography-mass spectrometry (DMSPE-GC/MS) method established under optimized experimental conditions based on the material is used for detecting the phthalic acid ester substances, and the detection limit is 1.17-3.03 ng/L.
The technical scheme for further limiting is as follows:
the Phthalate (PAEs) compounds are one or more of dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), dipentyl phthalate (DPP), Butyl Benzyl Phthalate (BBP) and (2-ethyl) hexyl phthalate (DEHP).
The liquid beverage is one of water, wine and beverage.
The synthesis and preparation operation steps of the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial are as follows:
(1) synthetic ferroferric oxide magnetic nanoparticles
Fe is prepared by taking ferroferric oxide as a nucleus and Tetraethoxysilane (TEOS) as a precursor3O4Magnetic nanoparticles;
(2) preparation of magnetic core-shell mesoporous nanocomposite particles
Tetraethoxysilane (TEOS) and hexadecyl trimethyl ammonium bromide (CTAB) are continuously used as template agents, and magnetic core-shell mesoporous nano composite particles (Fe) coated with double-layer silicon dioxide layers are synthesized through an improved ribbon method3O4@ SiO2@mSiO2）；
(3) Preparation of amino-modified magnetic core-shell mesoporous nanocomposite particles
Amino (-NH 2) is bonded on the magnetic core-shell mesoporous nano composite particle coated by the double-layer silicon dioxide layer by a grafting method to prepare the magnetic core-shell mesoporous nano composite particle (Fe) modified by the amino3O4@SiO2@mSiO2-NH2）；
(4) Preparation of magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial
Using diisononyl phthalate (DINP) as a virtual template, methacrylic acid (MAA) as a functional monomer and Ethylene Glycol Dimethacrylate (EGDMA) as a cross-linking agent to prepare the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial (Fe) by a surface molecular imprinting technology3O4@SiO2@mSiO2-MIPs)。
The specific synthesis preparation operation steps of the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial are as follows:
(1) synthetic ferroferric oxide magnetic nanoparticles
0.5 g of ferroferric oxide (Fe)3O4) Mixing 150 mL of absolute ethyl alcohol and 150 mL of deionized water, and ultrasonically dispersing for 10 min; adding 0.6 g of resorcinol and 4.8 mL of 28% strong ammonia water, and stirring for 1 h at 30 ℃; 0.8 mL of formaldehyde with the mass concentration of 37% and 1.4 mL of Tetraethoxysilane (TEOS) are added dropwise, and the mixture is stirred for 6 hours at the temperature of 30 ℃; stirring and reacting for 10h at 80 ℃, separating a product, washing for 3 times by using deionized water and ethanol respectively, and drying in a 60 ℃ oven for 8-10 h to obtain ferroferric oxide (Fe)3O4) Magnetic nanoparticles;
(2) preparation of magnetic core-shell mesoporous nanocomposite particles
Adopting an improved baby method to synthesize magnetic core-shell mesoporous nano composite particles, and mixing 1.0 g of ferroferric oxide (Fe)3O4) Adding magnetic nanoparticles into 10mL of hydrochloric acid (HCL) solution with the mass concentration of 0.1mol/L, performing ultrasonic dispersion for 5min, washing with deionized water, adding a mixed solution of 64 mL of absolute ethyl alcohol, 16mL of deionized water and 3mL of ammonia water, performing ultrasonic dispersion for 5min, dropwise adding 5mL of Tetraethoxysilane (TEOS), stirring for reaction for 6-6.5 h, performing magnet separation, respectively cleaning a separated substance with deionized water and absolute ethyl alcohol until the solution is neutral, and performing vacuum drying at 60 ℃ for 12 h to obtain nano composite particles coated with a silicon dioxide layer; adding the nano composite particles coated by the silicon dioxide layer into a mixed solution of 40 mL of absolute ethyl alcohol, 50mL of deionized water and 1.0 mL of ammonia water, ultrasonically dispersing for 5min, adding 2 g of Cetyl Trimethyl Ammonium Bromide (CTAB) template agent, stirring and reacting for 30min, dropwise adding 3mL of TEOS under vigorous stirring, and stirring and reacting for 6h at 50 ℃; separating the product by magnet, washing with deionized water and anhydrous ethanol for 3 times, and vacuum drying at 60 deg.C for 6 hr; dispersing the obtained product in 60mL ammonium nitrate-ethanol solution with mass concentration of 6 g/L-7 g/L, removing template agent CTAB, stirring in water bath at 60 ℃ for 2 h, repeating the stirring in water bath for 3 times, separating by using a magnet, standing for 4h, cleaning with absolute ethyl alcohol for 3 times, and vacuum-drying at 50-60 ℃ for 6h to obtain the ammonium nitrate/ethyl sulfate/sodium chloride/sodium sulfateTo magnetic core-shell mesoporous nanocomposite particles (Fe)3O4@ SiO2@mSiO2）；
(3) Preparation of amino-modified magnetic core-shell mesoporous nanocomposite particles
Adding 1.0 g of the magnetic core-shell mesoporous nano composite particles prepared in the step (2) into 60mL of toluene, ultrasonically dispersing for 5min, slowly adding 6mL of 3- (2-aminoethyl) -aminopropyltrimethoxysilane (TSD), and carrying out reflux reaction at 80-85 ℃ for 3-4 h to enable a silane reagent to be adsorbed to silicon dioxide (SiO)2) Cooling to room temperature in the mesoporous channel, separating with magnet, sequentially washing with toluene and deionized water for 2 times to remove unreacted or unadsorbed silicon dioxide (SiO)2) Drying the silane reagent in the mesoporous pore channel for 6h at 60 ℃ in vacuum to obtain the amino modified magnetic core-shell mesoporous nano composite particles (Fe)3O4@SiO2@mSiO2-NH2）；
(4) Preparation of magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial
Taking 0.5 g of aminated magnetic core-shell mesoporous nano composite particles (Fe)3O4@SiO2@mSiO2-NH2) 1 mmol of diisononyl phthalate (DINP), 4 mmol of methacrylic acid (MAA) and 40 mL of chloroform for 15 min by mixed ultrasound; adding 20 mmol of Ethylene Glycol Dimethacrylate (EGDMA) and 50 mg of Azobisisobutyronitrile (AIBN), wherein the molar ratio of the functional monomer MAA to the cross-linking agent EGDMA is 1: 5-1: 6, and performing ultrasonic treatment for 10 min; introducing nitrogen for 10 min; stirring for 12-14 h at 70 ℃; washing the product with methanol to neutrality, and drying; removing a diisononyl phthalate (DINP) template by Soxhlet extraction to obtain the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial (Fe)3O4@SiO2@mSiO2-MIPs）。
Compared with the prior art, the beneficial technical effects of the invention are reflected in the following aspects:
(1) the invention realizes the synthesis of a new material, namely a magnetic core, by taking the synthesized magnetic mesoporous silicon core-shell composite nano particles as a carrier and diisononyl phthalate as a virtual template and combining the surface molecular imprinting technology for the first timeShell mesoporous surface molecularly imprinted composite nanomaterial (Fe)3O4@SiO2@mSiO2MIPs). The characteristic results of a transmission electron microscope and a scanning electron microscope of the material in fig. 2 d and fig. 3 show that the material has an obvious core-shell structure, the outer layer is a regular mesoporous pore canal, the whole material is distributed in a spherical shape, the average particle size is about 200-300 nm, and fig. 6 shows that the material has a mesoporous structure and high specific surface area which is 327.6 cm2The magnetic hysteresis curve chart in figure 8 shows that the saturation magnetization of the material of the invention is 54.9 emu/g, the material has good superparamagnetism, high magnetic saturation intensity and easy magnetic separation, and compared with the prior magnetic mesoporous carbon PAEs surface molecularly imprinted magnetic solid phase extraction material, the magnetic performance is obviously enhanced.
(2) Material of the invention (Fe)3O4@SiO2@mSiO2MIPs) has excellent affinity and selectivity to phthalate substances, has high equilibrium speed (adsorption equilibrium can be achieved within 5 min), has high adsorption capacity and can be repeatedly used, and is a good magnetic solid phase extraction material for extracting and purifying phthalate substances. Table 1 shows that two analogues of Butyl Benzoate (BB) and Dodecylbenzene (DB) with similar structures to six PAEs of the invention are selected for selective adsorption performance test comparison, and are simultaneously compared with materials (Fe) without molecular imprinting templates3O4@SiO2@mSiO2-NIPs) were compared. Results of competitive adsorption experiments of six PAEs and two analogues show that the imprinting sites on the material of the invention have excellent specific adsorption performance for identifying the PAEs, and the non-molecular imprinting material has no obvious specific identification performance. The thermodynamic adsorption isotherm of fig. 9 shows that the saturated equilibrium adsorption capacity of the material for PAEs reaches 523.9 mg/g. The characterization result of fig. 10 shows that the material is beneficial to rapid identification and adsorption of PAEs target substances, has faster adsorption kinetics, can reach adsorption balance within 5min, and greatly improves the equilibrium adsorption speed of the prior PAEs surface molecularly imprinted magnetic solid phase extraction material. The material has stable structure and property and good repeated use performance. When the composite material is repeatedly used for 6 times, the saturated equilibrium adsorption quantity of six PAEs is still 335.6 mg/g, recovery ranged from 81.7% to 96.2%, see FIG. 11 for reuse evaluation.
(3) The invention establishes a matrix dispersion-magnetic solid phase extraction-gas chromatography-mass spectrometry combined method, and the material is suitable for measuring trace Phthalate (PAEs) in liquid drinks such as water, wine, beverages and the like. The sample to be tested was treated with the material (Fe) of the present invention3O4@SiO2@mSiO2MIPs) extraction enrichment, matrix dispersion-magnetic solid phase extraction and magnetic separation followed by GC-MS determination. FIG. 12 is a chromatogram of six PAEs mixed standard solutions and samples, the PAEs separation effect is good, the detection Limit (LOD) of the method is in the range of 1.17-3.03 ng/L, the detection limit is obviously reduced compared with that of the traditional method, and the trace PAEs content in the liquid beverage can be detected. The recovery rate of the tested sample is between 90.6% and 105.8%. The preparation method of the material is simple and convenient to operate, high in separation and enrichment efficiency, quick and effective, low in detection limit and wide in application range. The defects that the operation steps of the conventional PAEs detection process are complex and time-consuming, organic solvents are consumed more, the cost is high, and other surface molecular imprinting magnetic solid-phase extraction materials of the PAEs are low in adsorption balance speed and only suitable for drinking water and environmental water samples and the like are overcome.
(4) The preparation method of the magnetic core-shell mesoporous surface molecularly imprinted composite nanospheres is simple to operate, and the raw materials are cheap and easy to obtain. Selected magnetic core Fe3O4The nano particles have the characteristics of good magnetic property and small toxic and side effect; the selected mesoporous silica modified material has the characteristics of large specific surface area, good compatibility, sufficient surface silicon hydroxyl groups and easy modification, and is an ideal material for magnetic particle modification and surface molecular imprinting technology carriers. The improved baby method solves the problems that the outer layer of a magnetic material is difficult to coat silicon dioxide, the particle size of prepared nano particles is uneven, the size is difficult to control and the like, has the characteristic that the magnetic material layer and the mesoporous material layer are relatively independent, the inner silicon dioxide layer plays the role of stabilizing and protecting the nano particles, the outer silicon dioxide layer has a porous structure and has a rich pore structure and a large specific surface area, and the composite material has good adsorption performance. Easy grafting on the surface by grafting methodFunctional group of complex-forming amino (-NH)2) And sufficient coordinated hydrogen atoms are provided for the synthesis of the surface molecular imprinting material.
The magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial prepared by the invention has an obvious core-shell structure, the outer layer is a regular mesoporous pore canal, the whole material is in spherical distribution, the average particle size is about 200-300 nm, the specific surface area and the saturation magnetization are high, the composite nanomaterial has good superparamagnetism, and the composite nanomaterial has the characteristics of high adsorption speed, strong specific selective adsorption property, high saturation adsorption capacity and reusability for PAEs, and is an ideal enrichment pretreatment material for trace PAEs in a liquid beverage sample. The material establishes a matrix dispersion-magnetic solid phase extraction-gas chromatography-mass spectrometry combined method for the magnetic solid phase extraction agent, has wide linear range, low detection limit and good repeatability, and is suitable for measuring the trace Phthalate (PAEs) in liquid drinks such as water, wine, beverages and the like.
Drawings
FIG. 1 shows a magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial (Fe) prepared by the method3O4@SiO2@mSiO2MIPs) preparation flow sheet.
FIG. 2 shows Fe prepared by the present invention3O4Magnetic nanoparticles and magnetic core-shell mesoporous nanocomposite particles (Fe)3O4@SiO2@mSiO2) Amino modified magnetic core-shell mesoporous nano composite particle (Fe)3O4@SiO2@mSiO2-NH2) And magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial (Fe)3O4@SiO2@mSiO2MIPs) infrared spectra.
FIG. 3 shows Fe prepared by the present invention3O4Magnetic nanoparticles and magnetic core-shell mesoporous nanocomposite particles (Fe)3O4@SiO2@mSiO2) Amino modified magnetic core-shell mesoporous nano composite particle (Fe)3O4@SiO2@mSiO2-NH2) And magnetic core-shell mesoporous surface molecular imprinting composite nanometerMaterial (Fe)3O4@SiO2@mSiO2MIPs) transmission electron microscopy.
FIG. 4 shows the final product (Fe) prepared by the present invention3O4@SiO2@mSiO2MIPs) scanning electron microscopy and transmission electron microscopy.
FIG. 5 shows the final product (Fe) prepared by the present invention3O4@SiO2@mSiO2MIPs) energy spectrum (EDS).
FIG. 6 shows the final product (Fe) prepared by the present invention3O4@SiO2@mSiO2MIPs) and amino-modified magnetic core-shell mesoporous nanocomposite particles (Fe)3O4@SiO2@mSiO2-NH2) Nitrogen adsorption-desorption curve of (1).
FIG. 7 shows Fe prepared by the present invention3O4Magnetic nanoparticles and magnetic core-shell mesoporous nanocomposite particles (Fe)3O4@SiO2@mSiO2) Amino modified magnetic core-shell mesoporous nano composite particle (Fe)3O4@SiO2@mSiO2-NH2) And magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial (Fe)3O4@SiO2@mSiO2-MIPs).
FIG. 8 shows Fe prepared by the present invention3O4Magnetic nanoparticles and magnetic core-shell mesoporous nanocomposite particles (Fe)3O4@SiO2@mSiO2) Amino modified magnetic core-shell mesoporous nano composite particle (Fe)3O4@SiO2@mSiO2-NH2) And magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial (Fe)3O4@SiO2@mSiO2MIPs).
FIG. 9 shows the final product (Fe) prepared by the present invention3O4@SiO2@mSiO2MIPs) and non-molecularly imprinted composite materials (Fe)3O4@SiO2@mSiO2-NIPs).
FIG. 10 shows the final product prepared by the present invention（Fe3O4@SiO2@mSiO2MIPs) and non-molecularly imprinted composite materials (Fe)3O4@SiO2@mSiO2-NIPs).
FIG. 11 shows the final product (Fe) prepared by the present invention3O4@SiO2@mSiO2MIPs) reuse evaluation.
FIG. 12 is a GC-MS graph of a typical standard solution and an actual sample.
Detailed Description
The following provides a further explanation of the preparation of the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial and the application effect of the composite nanomaterial as a magnetic solid phase extraction material in the extraction and detection of trace phthalic acid substances in liquid food by specific examples.
Example 1
The preparation operation steps of the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial are as follows:
(1) synthesis of Fe3O4Magnetic nanoparticles
0.5 g of Fe3O4Adding 150 mL of absolute ethyl alcohol and 150 mL of deionized water into a 500 mL three-neck flask, and performing ultrasonic dispersion for 10 min; adding 0.6 g of resorcinol and 4.8 mL of 28% strong ammonia water, and stirring for 1 h at 30 ℃; dropwise adding 0.8 mL of formaldehyde with the mass concentration of 37% and 1.4 mL of TEOS, stirring for 6h at 30 ℃, then stirring for reaction for 10h at 80 ℃, separating a product, washing with deionized water and ethanol for 3 times respectively, and drying in an oven at 60 ℃ for 10h to obtain Fe3O4Magnetic nanoparticles.
(2) Preparation of magnetic core-shell mesoporous nanocomposite particles
Adopting an improved baby method to synthesize magnetic core-shell mesoporous nano composite particles, and adding 1.0 g of Fe3O4Adding magnetic nanoparticles into 10mL of hydrochloric acid solution (HCL) with the mass concentration of 0.1mol/L, performing ultrasonic dispersion for 5min, washing with deionized water, performing redispersion, adding into a mixed solution of 64 mL of absolute ethyl alcohol, 16mL of deionized water and 3mL of ammonia water, performing ultrasonic dispersion for 5min, dropwise adding 5mL of Tetraethoxysilane (TEOS), and performing stirring reactionAnd 6h, separating by using a magnet, respectively cleaning by using deionized water and absolute ethyl alcohol until the solution is neutral, and drying in vacuum at 60 ℃ for 12 h to obtain the nano composite particles coated by the silicon dioxide layer.
Dispersing the nano composite particles coated by the silicon dioxide layer in a mixed solution of 40 mL of absolute ethyl alcohol, 50mL of deionized water and 1.0 mL of ammonia water by ultrasonic for 5min, adding 2 g of Cetyl Trimethyl Ammonium Bromide (CTAB) template agent, stirring for reaction for 30min, dropwise adding 3mL of TEOS under vigorous stirring, and stirring for reaction for 6h at 50 ℃; separating with magnet, washing with deionized water and anhydrous ethanol for 3 times, and vacuum drying at 60 deg.C for 6 hr; dispersing the obtained product in 60mL ammonium nitrate-ethanol solution with mass concentration of 6g/L to remove template agent CTAB, stirring in water bath at 60 ℃ for 2 h, repeating for 3 times, separating with magnet, standing for 4h, washing with anhydrous ethanol for 3 times, and vacuum drying at 60 ℃ for 6h to obtain magnetic core-shell mesoporous nanocomposite particles (Fe)3O4@ SiO2@mSiO2）。
(3) Preparation of amino-modified magnetic core-shell mesoporous nanocomposite particles
Adding 1.0 g of the magnetic core-shell mesoporous nano composite particles prepared in the step (2) and 60mL of toluene into a three-neck flask, ultrasonically dispersing for 5min, slowly adding 6mL of 3- (2-aminoethyl) -aminopropyltrimethoxysilane (TSD), and carrying out reflux reaction for 3h at the temperature of 80 ℃ to enable a silane reagent to be adsorbed to SiO2Cooling to room temperature in the mesoporous channel, separating with magnet, sequentially washing with toluene and deionized water for 2 times to remove unreacted or unadsorbed SiO2Drying the silane reagent in the mesoporous pore channel for 6h under the condition of 60 ℃ in vacuum to obtain the amino modified magnetic core-shell mesoporous nano composite particles (Fe)3O4@SiO2@mSiO2-NH2）。
(4) Preparation of magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial
Respectively taking 0.5 g of Fe3O4@ SiO2@mSiO2-NH21 mmol of diisononyl phthalate (DINP), 4 mmol of methacrylic acid (MAA) and 40 mL of chloroform for 15 min; 20 mmol of ethylene glycol dimethyl ether was addedAcrylate (EGDMA) and 50 mg Azobisisobutyronitrile (AIBN), ultrasonic treatment for 10 min, and nitrogen gas introduction for 10 min; stirring at 70 deg.C for 12 h. The product was washed neutral with methanol and dried. Removing the template by Soxhlet extraction to obtain the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial (Fe)3O4@SiO2@mSiO2MIPs). Non-imprinted polymers (Fe)3O4@SiO2@mSiO2-NIPs) and the above Fe3O4@SiO2@mSiO2MIPs-like, only the reaction process does not add the template molecule DINP.
The magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial prepared in the embodiment 1 is black powder, and the average particle size of powder particles is 200-300 nm; the powder particles are spherical and have obvious core-shell structures, and the outer layer is a regular mesoporous silicon pore channel; the saturation magnetization is 54.9 emu/g, and the magnetic material has good superparamagnetism; the specific surface area is high and is 327.6 cm2(ii)/g; has excellent affinity and selectivity to phthalate substances, has faster adsorption kinetics, achieves adsorption balance within 5 minutes, and is a good magnetic solid phase extraction material for extracting and purifying the phthalate substances.
Testing the structure and performance of the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial:
referring to FIG. 2, the infrared spectrum of the material prepared by the present invention, a, b, c, d in FIG. 2 correspond to Fe in sequence3O4Magnetic nanoparticles and magnetic core-shell mesoporous nanocomposite particles (Fe)3O4@SiO2@mSiO2) Amino modified magnetic core-shell mesoporous nano composite particle (Fe)3O4@SiO2@mSiO2-NH2) And magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial (Fe)3O4@SiO2@mSiO2MIPs) infrared absorption line. 1633 cm-1Corresponding to the bending and stretching vibration of water hydroxyl, 580 cm-11092 cm for stretching and contracting iron-oxygen-1Is located at the strong and wide antisymmetric stretching vibration absorption peak of silicon-oxygen-silicon, 797 cm-1Symmetric stretching and bending of silicon-oxygen bondsThe absorption peak of the curved vibration, the absorption line of c in FIG. 2 and d in FIG. 2 is 1546 cm-1And a characteristic absorption peak of a nitrogen-hydrogen bond (N-H) appears, which indicates that the amino group is successfully modified on the surface of the magnetic composite microsphere. The characteristic absorption peak of N-H in d in FIG. 2 is weakened, indicating that the template molecule has been completely removed and the Molecularly Imprinted (MIP) layer has been modified to the surface of the mesoporous material.
Referring to FIG. 3, a, b, c, d in FIG. 3 correspond to Fe in sequence3O4Magnetic nanoparticles and magnetic core-shell mesoporous nanocomposite particles (Fe)3O4@SiO2@mSiO2) Amino modified magnetic core-shell mesoporous nano composite particle (Fe)3O4@SiO2@mSiO2-NH2) And magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial (Fe)3O4@SiO2@mSiO2MIPs) transmission electron microscopy. Fe shown in black3O4The surface of the core is coated with a grey layer of silicon dioxide, Fe3O4The material has a magnetic core at the center and nano particles of mesoporous silica material at the outer layer, and the composite nano particles have an obvious core-shell structure, smooth surface and average particle size of about 200-300 nm. After the surface of the composite nano microsphere is modified by amino and MIP layers, the morphology of the material is not changed, and high dispersibility is still presented. E in FIG. 4 and f in FIG. 4 are the products of the present invention (Fe), respectively3O4@SiO2@mSiO2MIPs) to show that the surface of the mesoporous material modified by amino group has been successfully modified by a thin molecularly imprinted polymer layer, and the outer layer can observe a regular pore channel structure.
Referring to FIG. 5, the product of the invention (Fe)3O4@SiO2@mSiO2MIPs) and the presence of iron, oxygen, silicon and nitrogen, the silicon being distributed mainly in Fe3O4The surface of the core, the sphere of the diameter map of nitrogen, is much larger than that of iron, confirming Fe3O4Core and SiO2The existence of the outer layer with obvious core-shell structure also indicatesThe amino and MIP layers are successfully modified on the surface of the magnetic mesoporous composite material.
Referring to FIG. 6, the product of the invention (Fe)3O4@SiO2@mSiO2MIPs) and amino-modified magnetic core-shell mesoporous nanocomposite particles (Fe)3O4@SiO2@mSiO2-NH2) And (3) nitrogen adsorption-desorption curves, wherein the nitrogen adsorption-desorption curves belong to typical IV curves and have obvious hysteresis loops, which indicates that the two materials are both in mesoporous structures. Fe product of the invention3O4@SiO2@mSiO2The specific surface area of the MIPs is higher and reaches 327.6 cm2And g, indicating that the surface molecularly imprinted polymer has higher adsorption capacity for the target substance.
Referring to FIG. 7, a, b, c, d in FIG. 7 correspond to Fe in sequence3O4Magnetic nanoparticles and magnetic core-shell mesoporous nanocomposite particles (Fe)3O4@SiO2@mSiO2) Amino modified magnetic core-shell mesoporous nano composite particle (Fe)3O4@SiO2@mSiO2-NH2) And magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial (Fe)3O4@SiO2@mSiO2MIPs) wide angle X-ray diffraction pattern. In the figure, 2 theta shows sharp characteristic diffraction peaks at 30.32 degrees, 35.62 degrees, 43.32 degrees, 53.76 degrees, 57.22 degrees and 62.78 degrees respectively, which correspond to Fe3O4The characteristic diffraction peaks (220), (311), (400), (422), (511) and (440) of the nanoparticles demonstrate the presence of magnetic particles in all composites. (b) And (c) no significant change in the position of the characteristic diffraction peak, indicating SiO2Coated with Fe3O4The surface of the nano-particles and the introduction of amino and MIP layers do not change Fe3O4Only because of wrapping SiO2The shell layer causes a slight decrease in the intensity of the characteristic peak 311, and the diffraction peak of (d) is narrower due to the enlargement of the crystal grains.
Referring to FIG. 8, a, b, c, d in FIG. 8 correspond to Fe in sequence3O4Magnetic nanoparticles and magnetic core-shell mesoporous nanocomposite particles (Fe)3O4@SiO2@mSiO2) Amino modified magnetic core-shell mesoporous nano composite particle (Fe)3O4@SiO2@mSiO2-NH2) And magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial (Fe)3O4@SiO2@mSiO2MIPs) magnetic composite nanospheres. When Fe3O4Nano particle coated with SiO2After the material is wrapped and amino is modified, the saturation magnetization of the nano particles is only slightly reduced, the saturation magnetization of d in a figure 8 of the magnetic nano surface molecularly imprinted composite nano material of the final product reaches 54.9 emu/g, the magnetic nano surface molecularly imprinted composite nano material has good superparamagnetism, and can be easily separated from other matrixes under the action of an external magnetic field.
Example 2
The preparation operation steps of the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial are as follows:
(1) fe3O4 magnetic nanoparticles were synthesized as in example 1.
(2) Magnetic core-shell mesoporous nanocomposite particles were prepared as in example 1.
(3) Preparation of amino-modified magnetic core-shell mesoporous nanocomposite particles
Adding 1.2 g of the magnetic core-shell mesoporous nano composite particles prepared in the step (2) and 60mL of toluene into a three-neck flask, ultrasonically dispersing uniformly for 5min, slowly adding 5mL of 3- (2-aminoethyl) -aminopropyltrimethoxysilane (TSD), and carrying out reflux reaction for 4h at 85 ℃ to enable a silane reagent to be adsorbed to SiO2Cooling to room temperature in the mesoporous channel, separating with magnet, sequentially washing with toluene and deionized water for 2 times to remove unreacted or unadsorbed SiO2Drying the silane reagent in the mesoporous pore channel for 6h under the condition of 60 ℃ in vacuum to obtain the amino modified magnetic core-shell mesoporous nano composite particles (Fe)3O4@SiO2@mSiO2-NH2）。
(4) Preparation of magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial
0.6 g of Fe was taken out3O4@ SiO2@mSiO2-NH21 mmol of diisononyl phthalate (DINP), 4 mmol of methacrylic acid (MAA) and 40 mL of chloroform for 15 min by mixed ultrasound; adding 24 mmol Ethylene Glycol Dimethacrylate (EGDMA) and 50 mg Azobisisobutyronitrile (AIBN), performing ultrasonic treatment for 10 min, and introducing nitrogen for 10 min; stirring for 14 h at 70 ℃. The product was washed neutral with methanol and dried. Removing the template by Soxhlet extraction to obtain the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial (Fe)3O4@SiO2@mSiO2-MIPs）；
According to characterization and adsorption performance tests, the material prepared in the example 2 is the same as the material prepared in the example 1, and the saturation magnetization is 49.6 emu/g.
Example 3
The magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial has excellent specific adsorption performance on six PAEs, has high adsorption capacity (saturation adsorption capacity of 523.9 mg/g), is high in adsorption kinetic speed, achieves adsorption balance within 5 minutes, can be repeatedly used, and is an ideal magnetic solid phase extraction material for extracting and purifying phthalate substances.
In order to evaluate the selective adsorption performance of the material, 2 analogues of Butyl Benzoate (BB) and Dodecylbenzene (DB) with structures similar to PAEs are selected for comparison of adsorption amounts, and meanwhile, the adsorption performance of the material is compared with that of a non-molecular imprinting composite material. Respectively and accurately weighing 10mg of the product or the non-molecular imprinting composite material (Fe)3O4@SiO2@mSiO2NIPs) were placed in a tube with a stopper, and 10mL of an aqueous solution containing the same concentration of DMP, DEP, DBP, DPP, BBP, DEHP, BB, DB was added. Sealing the test tube, performing vortex oscillation for 6 min, adsorbing polymer material with magnet, separating, discarding water phase, accurately adding 1.0 mL chloroform, performing ultrasonic elution for 10 min, adding 0.5 g anhydrous sodium sulfate to remove excessive water, performing magnetic separation, taking out organic analysis solution, filtering with 0.22 μm filter membrane, loading into a chromatographic bottle, and performing GC-MS sample analysis. Results of competitive adsorption experiments for six PAEs and 2 analogues are shown in table 1. The present invention can be found from Table 1Material (Fe)3O4@SiO2@mSiO2MIPs) has higher adsorption capacity for six PAEs, and has adsorption capacity lower than 15mg/g for two analogues BB and DB, which is far lower than the adsorption capacity of PAEs. The adsorption effects of the non-molecular imprinting composite material on target PAEs and two analogues have no obvious difference, which shows that the imprinting sites on the non-molecular imprinting composite material only show excellent adsorption performance and higher adsorption capacity for identifying the PAEs, and the non-molecular imprinting composite material has no obvious specific identification performance. Phthalate having higher structural similarity to virtual template DINP, adsorption capacity and imprinting factor (IF = Q)MIP/QNIP) Are also larger than other PAEs.
Referring to FIG. 9, 10mg of the final product (Fe) of the present invention was weighed out separately3O4@SiO2@mSiO2MIPs) and non-molecularly imprinted composite materials (Fe)3O4@SiO2@mSiO2NIPs) are added into 10mL of six PAEs absolute ethyl alcohol with different concentrations (100-1000 mg/L): thermodynamic adsorption isotherm in water (V: V =1: 2) solution. End product of the invention (Fe)3O4@SiO2@mSiO2MIPs) surface formed molecular imprinting active sites enable the active sites to have excellent affinity and selectivity on PAEs, the active sites have higher equilibrium adsorption capacity, the maximum equilibrium adsorption capacity reaches 523.9 mg/g, and the active sites are not molecular imprinting composite materials (Fe)3O4@SiO2@mSiO2-NIPs) of only 150.6 mg/g.
Referring to FIG. 10, 10mg of the final product of the present invention (Fe) was weighed out separately3O4@SiO2@mSiO2MIPs) and non-molecularly imprinted composite materials (Fe)3O4@SiO2@mSiO2NIPs) to 10mL of water samples of DMP, DEP, DBP, DPP, BBP and DEHP at a concentration of 100. mu.g/mL, the results of the determination showing Fe3O4@SiO2@mSiO2Equilibrium rate of MIPs adsorptionThe rate is greatly improved, and the equilibrium can be reached in 5min, and the adsorption kinetics is faster. Non-molecular imprinting material (Fe)3O4@SiO2@mSiO2-NIPs) the adsorption capacity increased rapidly within 10 min and reached equilibrium within 20 min.
See FIG. 11 for final product (Fe) of the present invention3O4@SiO2@mSiO2MIPs) was used 6 times, the saturated equilibrium adsorption capacity and recovery data of six PAEs. The result shows that the saturated equilibrium adsorption capacity of the PAEs is still 335.6 mg/g when the material is repeatedly used for 6 times, and the enrichment pretreatment of trace PAEs in a liquid food sample can be met. The material which is repeated for 6 times is used for a recovery rate test, the recovery rate range is 81.7% -96.2%, and the result shows that the structure of the material is not damaged after the material is used for many times, the property is stable, and the material has better adsorption performance.
Example 4
The material of the invention is used for detecting the phthalate substances in the wine
The detection process of the matrix dispersion-magnetic solid phase extraction-gas chromatography-mass spectrometry method established by the invention comprises the following steps: accurately weighing 10mg of the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial, putting the composite nanomaterial into a test tube with a plug, and adding 10mL of wine to be tested. Sealing the test tube, performing vortex oscillation for 6 min, adsorbing a polymer material by a magnet, separating to remove a water phase, accurately adding 1.0 mL of chloroform, performing ultrasonic elution for 10 min, adding 0.5 g of anhydrous sodium sulfate to remove redundant water, performing magnetic separation, taking out an organic analysis solution, filtering through a 0.22-micron filter membrane, filling into a chromatographic bottle, and performing GC-MS sample injection analysis, wherein chromatograms of a standard solution and a tested wine are shown in figure 12, a in figure 12 is a chromatogram of a mixed standard solution of six PAEs, b in figure 12 is a chromatogram of a white wine sample, and evaluation parameters of the method are shown in table 2. The actual detection samples are 50-degree white spirit, 12.5-degree grape wine, 38-degree medlar wine and 42-degree ginseng wine respectively, and comprise distilled wine, fermented wine and prepared wine taking the distilled wine as wine base and the fermented wine as wine base.
Table 2 shows the evaluation parameters of the methods, and the data in the table show the correlation coefficients (R) of six phthalates, DMP, DEP, DBP, DPP, BBP and DEHP2) All are above 0.9971, have excellent linear range and better correlation coefficient. The Relative Standard Deviation (RSD) of the method is also between 3.5% and 5.7%, the detection Limit (LOD) is calculated according to the signal-to-noise ratio (S/N) which is 3 times of the lowest detection concentration signal, and the LOD of six PAEs is in the range of 1.17 ng/L to 3.03 ng/L. The DBP content detected by 52-degree white spirit in an actual sample is 7.80 mu g/mL, the DEHP content is 0.25 mu g/mL, the DBP content detected by 12.5-degree grape wine, 38-degree medlar wine and 42-degree ginseng wine is 1.34 mu g/mL, 0.49 mu g/mL and 1.30 mu g/mL respectively, and the standard recovery rate of the sample at the concentration levels of 0.05 mu g/mL, 1.0 mu g/mL and 5.0 mu g/mL is 96.1-105.8 percent.
Example 5
Detection of phthalate substances in beverage by using material of the invention
The sample pretreatment and detection process are the same as example 4, and 5 different beverages are selected and tested by the method established by the invention for six PAEs, wherein the sample 1 is orange juice, the sample 2 is apple juice, the sample 3 is protein beverage, the sample 4 is carbonated beverage, the sample 5 is tea beverage, and simultaneously, the standard addition recovery test is carried out, the standard addition level is 10 mug/L, and the test result and the recovery rate are shown in the table 3.
As can be seen from the data in Table 3, the detected phthalate substance labeling recovery rate is between 90.6% and 105.1%, and the Relative Standard Deviation (RSD) is between 3.6% and 5.1%.
Claims (5)
1. A magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial is characterized in that: the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial is black powder, powder particles are spherical, and the average particle size of the powder particles is 200-300 nm; the specific surface area is 327.6 cm2(ii)/g, saturation magnetization of 54.9 emu/g;
the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial is suitable for extraction detection of trace Phthalic Acid Esters (PAEs) in liquid drinks, and the detection limit of the method is 1.17-3.03 ng/L.
2. The magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial according to claim 1, characterized in that: the Phthalate (PAEs) compounds are one or more of dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), dipentyl phthalate (DPP), Butyl Benzyl Phthalate (BBP) and (2-ethyl) hexyl phthalate (DEHP).
3. The magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial according to claim 1, characterized in that: the liquid beverage is one of water, wine and beverage.
4. The preparation method of the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial as claimed in claim 1, characterized in that the synthetic preparation operation steps are as follows:
(1) synthetic ferroferric oxide magnetic nanoparticles
Fe is prepared by taking ferroferric oxide as a nucleus and Tetraethoxysilane (TEOS) as a precursor3O4Magnetic nanoparticles;
(2) preparation of magnetic core-shell mesoporous nanocomposite particles
Tetraethoxysilane (TEOS) and hexadecyl trimethyl ammonium bromide (CTAB) are continuously used as template agents, and magnetic core-shell mesoporous nano composite particles (Fe) coated with double-layer silicon dioxide layers are synthesized through an improved ribbon method3O4@ SiO2@mSiO2）；
(3) Preparation of amino-modified magnetic core-shell mesoporous nanocomposite particles
Amino (-NH 2) is bonded on the magnetic core-shell mesoporous nano composite particle coated by the double-layer silicon dioxide layer by a grafting method to prepare the magnetic core-shell mesoporous nano composite particle (Fe) modified by the amino3O4@SiO2@mSiO2-NH2）；
(4) Preparation of magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial
Using diisononyl phthalate (DINP) as a virtual template, methacrylic acid (MAA) as a functional monomer and Ethylene Glycol Dimethacrylate (EGDMA) as a cross-linking agent to prepare the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial (Fe) by a surface molecular imprinting technology3O4@SiO2@mSiO2-MIPs)。
5. The preparation method of the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial according to claim 4, characterized by comprising the following specific operation steps:
(1) synthetic ferroferric oxide magnetic nanoparticles
0.5 g of ferroferric oxide (Fe)3O4) Mixing 150 mL of absolute ethyl alcohol and 150 mL of deionized water, and ultrasonically dispersing for 10 min; adding 0.6 g of resorcinol and 4.8 mL of 28% strong ammonia water, and stirring for 1 h at 30 ℃; 0.8 mL of formaldehyde with the mass concentration of 37% and 1.4 mL of Tetraethoxysilane (TEOS) are added dropwise, and the mixture is stirred for 6 hours at the temperature of 30 ℃; stirring and reacting for 10h at 80 ℃, separating a product, washing for 3 times by using deionized water and ethanol respectively, and drying in a 60 ℃ oven for 8-10 h to obtain ferroferric oxide (Fe)3O4) Magnetic nanoparticles;
(2) preparation of magnetic core-shell mesoporous nanocomposite particles
Adopting an improved baby method to synthesize magnetic core-shell mesoporous nano composite particles, and mixing 1.0 g of ferroferric oxide (Fe)3O4) Adding magnetic nanoparticles into 10mL of hydrochloric acid (HCL) solution with the mass concentration of 0.1mol/L, performing ultrasonic dispersion for 5min, washing with deionized water, adding a mixed solution of 64 mL of absolute ethyl alcohol, 16mL of deionized water and 3mL of ammonia water, performing ultrasonic dispersion for 5min, dropwise adding 5mL of Tetraethoxysilane (TEOS), stirring for reaction for 6-6.5 h, performing magnet separation, respectively cleaning a separated substance with deionized water and absolute ethyl alcohol until the solution is neutral, and performing vacuum drying at 60 ℃ for 12 h to obtain nano composite particles coated with a silicon dioxide layer; adding the nano composite particles coated by the silicon dioxide layer into a mixed solution of 40 mL of absolute ethyl alcohol, 50mL of deionized water and 1.0 mL of ammonia water, ultrasonically dispersing for 5min, adding 2 g of Cetyl Trimethyl Ammonium Bromide (CTAB) template agent, stirring and reacting for 30min, dropwise adding 3mL of TEOS under vigorous stirring, and stirring and reacting for 6h at 50 ℃; separating the product by magnet, washing with deionized water and anhydrous ethanol for 3 times, and vacuum drying at 60 deg.C for 6 hr; dispersing the obtained product in 60mL ammonium nitrate-ethanol solution with mass concentration of 6 g/L-7 g/L, removing template agent CTAB, stirring in water bath at 60 ℃ for 2 h, repeating the stirring in water bath for 3 times, separating by using a magnet, standing for 4h, cleaning for 3 times by using absolute ethyl alcohol, and drying in vacuum at 50-60 ℃ for 6h to obtain the magnetic core-shell mesoporous nano composite particle (Fe)3O4@ SiO2@mSiO2）；
(3) Preparation of amino-modified magnetic core-shell mesoporous nanocomposite particles
Adding 1.0 g of the magnetic core-shell mesoporous nano composite particles prepared in the step (2) into 60mL of toluene, ultrasonically dispersing for 5min, slowly adding 6mL of 3- (2-aminoethyl) -aminopropyltrimethoxysilane (TSD), and carrying out reflux reaction at 80-85 ℃ for 3-4 h to enable a silane reagent to be adsorbed to silicon dioxide (SiO)2) Cooling to room temperature in the mesoporous channel, separating with magnet, sequentially washing with toluene and deionized water for 2 times to remove unreacted or unadsorbed silicon dioxide (SiO)2) Drying the silane reagent in the mesoporous pore channel for 6h under vacuum at 60 ℃ to obtain the amino modified magnetic core-shell mesoporous nano-particlesRice composite particle (Fe)3O4@SiO2@mSiO2-NH2）；
(4) Preparation of magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial
Taking 0.5 g of aminated magnetic core-shell mesoporous nano composite particles (Fe)3O4@SiO2@mSiO2-NH2) 1 mmol of diisononyl phthalate (DINP), 4 mmol of methacrylic acid (MAA) and 40 mL of chloroform for 15 min by mixed ultrasound; adding 20 mmol of Ethylene Glycol Dimethacrylate (EGDMA) and 50 mg of Azobisisobutyronitrile (AIBN), wherein the molar ratio of the functional monomer MAA to the cross-linking agent EGDMA is 1: 5-1: 6, and performing ultrasonic treatment for 10 min; introducing nitrogen for 10 min; stirring for 12-14 h at 70 ℃; washing the product with methanol to neutrality, and drying; removing a diisononyl phthalate (DINP) template by Soxhlet extraction to obtain the magnetic core-shell mesoporous surface molecularly imprinted composite nanomaterial (Fe)3O4@SiO2@mSiO2-MIPs）。
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| CN113522229A (en) * | 2021-07-21 | 2021-10-22 | 南京工业大学 | Magnetic bead for efficiently adsorbing extracellular DNA in environment and preparation method thereof |
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| CN115554997A (en) * | 2022-09-22 | 2023-01-03 | 苏州海狸生物医学工程有限公司 | Magnetic solid-phase extraction material with core-shell structure, preparation method and application thereof |
| CN116371466A (en) * | 2023-02-28 | 2023-07-04 | 西安交通大学 | Molecularly imprinted polymer modified magnetic immobilized tryptophan catalyst and preparation method and application thereof |
| CN116371466B (en) * | 2023-02-28 | 2024-06-07 | 西安交通大学 | Molecularly imprinted polymer modified magnetic immobilized tryptophan catalyst and preparation method and application thereof |
| CN117079959A (en) * | 2023-08-15 | 2023-11-17 | 四川赛尔医学检验有限公司 | Magnetic nano material for detecting glycoprotein and preparation method thereof |
| CN117079959B (en) * | 2023-08-15 | 2024-03-22 | 四川赛尔医学检验有限公司 | Magnetic nano material for detecting glycoprotein and preparation method thereof |
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