285 results about "Fe3o4 magnetic nanoparticles" patented technology

The invention relates to a preparation method of magnetic graphene, in particular to a chemical preparation method of magnetic graphene. The preparation method aims at solving the problems of the existing synthesis method that the reaction process is toxic and harmful to the environment, large-scale production cannot be realized, the morphology, size and magnetism of magnetic nanoparticles in the magnetic graphene are not controllable and the magnetic graphene cannot be dispersed in water. The chemical preparation method comprises the steps of: 1) preparing aminated Fe3O4 magnetic nanoparticles; 2) preparing graphene; and 3) preparing magnetic graphene through chemical reaction. The chemical preparation method of the magnetic graphene has the advantages that the high temperature and the high pressure are not required, the equipment is simple, the process cost is low, the environment is protected, no pollution is caused, the grain size of the synthesized magnetic nanoparticles is uniform, the controllable growth of the magnetic nanoparticles can be realized by changing reaction conditions, the solubility of the synthesized magnetic graphene is 0.8-1.2mg / ml, the magnetic graphene can be stably dispersed in water and sediment does not occur within 1-2 months. The graphene prepared by adopting the method can be used in biomedical, energy, electronic fields and the like.

The present invention relates to a new phenylboronic-acid-functionalized graphene oxide composite nano material and preparation and application thereof. The material is prepared by immobilization of polydopamine-packed magnetic nanoparticles onto polyethyleneimine-modified graphene oxide and further introduction of phenylboronic acid monomers with carboxyl by amino of polyethyleneimine, and finally the material is used for enrichment of glycoproteins. The specific process is as follows: firstly, Fe3O4 magnetic nanoparticles are prepared by a solvothermal method, and auto polymerization of polydopamine can be performed on surface of the Fe3O4 magnetic nanoparticles under alkaline conditions; the magnetic graphene oxide composite nano material can be prepared by hydrogen bond and PI-PI interaction between the polydopamine and graphene oxide, then the positively charged polyethyleneimine is immobilized onto the surface of the negatively charged magnetic graphene oxide by electrostatic self-assembly; and finally the phenylboronic-acid-functionalized magnetic graphene oxide composite nano material can be prepared by introduction of the phenylboronic acid monomers by amidation reaction, and the phenylboronic-acid-functionalized magnetic graphene oxide composite nano material is successively used in the enrichment of the glycoproteins in bioanalysis.

The invention relates to a preparation method of a magnetic functionalized graphene oxide based molecularly imprinted hybrid material. The preparation method comprises the following steps: firstly, loading Fe3O4 magnetic nanoparticles on the surface of graphene oxide by chloroformylation reaction; and synthesizing the magnetic functionalized graphene oxide based molecularly imprinted hybrid material on the surface of the magnetic functionalized graphene oxide serving as a carrier by utilizing a molecular imprinting technology. The prepared magnetic functionalized graphene oxide based molecularly imprinted hybrid material can be used for selectively removing estrogen in drinking water. The preparation method of the magnetic functionalized graphene oxide based molecularly imprinted hybrid material has the advantages that the process is reasonable and easy to implement; when being used for removing endocrine disruptors, the material has good chemical stability and reusability, and active adsorption, identification and separation of the estrogen are easily carried out; and the preparation method has strong magnetic response, preordainment, identity and practicality, and can greatly improve the using efficiency of the molecular imprinting technology and expand the range of molecular imprinting applications.

The present invention discloses a single-stranded DNA aptamer modified SiO2 / Fe3O4 magnetic microsphere preparation method, which comprises: (1) adopting a chemical co-precipitation method to obtain Fe3O4 magnetic nanoparticles; (2) adopting a sol-gel method to obtain SiO2 / Fe3O4 magnetic microspheres; (3) obtaining -NH2 modified SiO2 / Fe3O4 magnetic microspheres; (4) dispersing the -NH2 modified SiO2 / Fe3O4 magnetic microspheres in water to obtain -COOH modified SiO2 / Fe3O4 magnetic microspheres; and (5) dispersing the -COOH modified SiO2 / Fe3O4 magnetic microspheres in a Tris-HCl buffer solution to obtain the aptamer modified SiO2 / Fe3O4 magnetic microspheres.

The invention relates to a vulcanizing-agent-modified Fe3O4 magnetic nanoparticle adsorbent and a preparation method and an application thereof. The adsorbent is Fe3O4 magnetic nanoparticles which are subjected to surface vulcanization by a sulfur compound, and the weight percentage of sulfide on the adsorbent is 10-15 percent. The adsorbent is added into heavy metal wastewater and fully contacts with heavy metal ions through stirring, Fe2+ ions of the surface of the adsorbent material are utilized to exchange with the heavy metal ions so as to adsorb the heavy metal ions in the wastewater, and the adsorbent is separated from the wastewater by utilizing a magnet. Compared with the prior art, the prepared adsorbent has the advantages of low cost, large adsorption capacity, high reaction speed, significant processing effect and the like. Meanwhile, the magnetism can be quickly enriched under the action of an external magnetic field, and therefore, the adsorbent can be effectively separated and recycled and cannot cause secondary pollution.

The invention relates to a method for preparing a TiO2 / PS / Fe3O4 magnetic nanoparticle photocatalyst, comprising the following steps of: (1) preparing oleic acid modified Fe3O4 nanoparticles; (2) preparing an aqueous-phase magnetic fluid; (3) preparing styrene miniemulsion; (4) preparing magnetic polystyrene beads PS / Fe3O; and (5) preparing the magnetic photocatalyst TiO2 / PS / Fe3O4, which specifically comprises the following steps of: mixing absolute ethyl alcohol with tetra-n-butyl titanate, and performing magnetic stirring to form a solution A; adding the magnetic polystyrene beads PS / Fe3O to de-ionized water and performing ultrasonic treatment to form a solution B; under magnetic stirring, adding the solution A to the solution B, thereby obtaining sol after 30-40 min, wherein TiO2 covers the PS / Fe3O at the moment; after condensing and refluxing the sol in a water bath, filtering the sol to obtain the TiO2 / PS / Fe3O4, washing the TiO2 / PS / Fe3O4 by using ethanol, filtering, washing by using distilled water and filtering, thus obtaining a solid; and drying the solid until the weight thereof is constant, thereby obtaining the magnetic photocatalyst TiO2 / PS / Fe3O4 with the polystyrene PS as an isolating layer, the Fe3O4 as a magnetic core and the TiO2 as a shell. The product obtained by using the method is low in energy consumption, high in catalytic activity and recyclable.

The invention discloses a preparation method of a core-shell structure magnetic nano-molecular imprinting polymer for separating starch polysaccharides, relates to the preparation method of the magnetic molecular imprinting polymer for separating the starch polysaccharides and aims at solving the problem that the molecular imprinting polymer capable of separating the starch polysaccharides is absent at present. The preparation method is as follows: 1) preparing Fe3O4 magnetic nanoparticles; 2) silylanizing the Fe3O4 magnetic nanoparticles; 3) performing amino-modification on the silylanized Fe3O4 magnetic nanoparticles; 4) performing aldehyde modification on the amino-derived Fe3O4 magnetic nanoparticles; and 5) preparing the magnetic nano-molecular imprinting polymer. The maximum saturated adsorption amount of the magnetic nano-molecular imprinting polymer disclosed by the invention to the starch polysaccharides is 8-9mg / g, which is about 2 times of that of the existing molecular imprinting polymer for separating monosaccharides, the adsorption efficiency is high, when the magnetic nano-molecular imprinting polymer is stored in a nitrogen atmosphere, the adsorption efficiency is still 90% of the original level after 30 days, the repeated utilization rate is high, and the magnetic nano-molecular imprinting polymer can be applied to the field of separating the starch polysaccharides.

The invention relates to a magnetic bionic adsorbent and an application of the magnetic bionic adsorbent in treating acid wastewater containing uranium. A solvothermal method for preparing Fe3O4 by taking PSSMA (poly (4-styrene sulfonate-copolymer-maleic acid) sodium salt) as a surfactant is improved, grain sizes are uniform, and Fe3O4 magnetic nanoparticles can be synthesized on a large scale; biomolecule dopamine is polymerized in a trihydroxymethyl aminomethane buffer system and coats the surfaces of the Fe3O4 magnetic nanoparticles, and the novel magnetic bionic adsorbent with a core-shell structure is established. The magnetic bionic adsorbent has excellent hydrophilicity and larger specific surface area due to the the polydopamine structure of a shell layer, rich functional groups on the surface of the magnetic bionic adsorbent have high uranium adsorption capacity in a wider acidity range, the magnetic bionic adsorbent has higher uranium adsorption capacity and good selectivity, and uranium adsorbed on the surface of the adsorbent can be easily washed with a 0.1 mol / L (NH4)2CO3 solution and can be recycled conveniently.

The invention aims at providing a simple and efficient method for preparing a high-performance magnetic fluorescent composite microsphere. Due to the existence of Fe3O4 magnetic nanoparticles, electrons of a fluorescent substance which are located at a conductance band are subjected to electron transfer in a process of returning to a valence band, the electrons of the conductance band are transferred on the Fe3O4 magnetic nanoparticles and fluorescence is subjected to quenching. The method provided by the invention is emphasized on solving the problem that the Fe3O4 magnetic nanoparticles cause large influence on the fluorescence performance of the fluorescent substance in a process of preparing a magnetic fluorescent microsphere. According to the preparing method provided by the invention, through changing a doping sequence and adopting different doping methods, the prepared magnetic fluorescent microsphere can minimize the influence on the fluorescent substance caused by magnetism on the basis of ensuring the magnetic fluorescent microsphere to have excellent magnetic property in actual use and enable the fluorescence performance to be optimal; and the fluorescent substance is introduced by adopting a high-temperature swelling method, so that fluorescent substances inside the microsphere cannot leak, and the stability of fluorescent signals is ensured. The mean particle diameter of the prepared magnetic fluorescent composite microsphere is 5-50 microns, and the particle diameter is even and has perfect appearance.

The invention discloses a preparing method of a magnetic hydrogel microsphere, and belongs to the field of sewage treatment. The method includes firstly preparing graphene oxide (GO@Fe<3>O4) loaded with Fe<3>O4 magnetic nanometer particles through a coprecipitation process, mixing the GO@Fe<3>O4 with a water soluble polymer (such as sodium carboxymethylcellulose (CMC)), and preparing the magnetic composite hydrogel microsphere (such as CMC / GO@ Fe<3>O4) through a spray drying process. The prepared composite hydrogel microsphere has good swelling properties and a large specific surface area. The adsorption efficiency for pollutants is increased, and pollutant adsorption varieties and adsorption amounts of hydrogel are increased. The composite hydrogel microsphere is easy to separate, and can be adopted as adsorbents for organic dye and heavy metal ions in industrial waste water.

The invention discloses a strong magnetic core-shell structural nano copper-based hydrotalcite catalyst and a preparation method thereof, and belongs to the technical field of nano catalysts. The catalyst consists of a strong magnetic core-shell structural nano copper-based hydrotalcite catalyst CuM2+Al hydrotalcite shell and a Fe3O4 magnetic nano particle core; the strong magnetic core-shell structural nano copper-based hydrotalcite catalyst is expressed as Fe3O4@CuM2+Al-LDH and consists of 60 to 80 percent of Fe3O4 magnetic nano particles and 20 to 40 percent of CuM2+Al-LDH hydrotalcite in percentage by mass; the particle size of the core-shell structural magnetic nano catalyst is 500 to 540 nanometers; the specific saturation magnetization intensity sigma s is 40.2 to 60.7emu / g; and the phenolic conversion rate is 38.28 to 55.47 percent. The preparation method has the advantages of simple catalyst preparation process, low cost, suitability for phenolic hydroxylation reaction and phenol-containing wastewater treatment, and convenient enrichment, reclamation and reutilization through an additional magnetic field after the reaction is finished.

The invention discloses enzyme-based magnetic nanoparticles, a preparation method, an application and a detection method for glucose. The preparation method comprises the following steps of 1) mixing Fe3O4 magnetic nanoparticles and dopamine with water according to a mass ratio of Fe3O4 magnetic nanoparticles to dopamine being (1:1)-(1:4) uniformly, adding the above mixture in an alkali buffering system, and stirring for 8-48 hours to obtain Fe3O4 coated by polydopamine; 2) mixing a horseradish peroxidase solution, a glucose oxidase solution and Fe3O4 coated by polydopamine with dopamine uniformly to obtain a solution B, and reacting for 5-25 hours. In the solution B, the concentrations of horseradish peroxidase, glucose oxidase and Fe3O4 coated by polydopamine and dopamine are 0.025-0.2 mg / mL, 0.025-0.2 mg / mL, 0.5-25 mg / mL and 1-5 mg / mL respectively. The enzyme-based magnetic nanoparticles can detect glucose and can be used repeatedly, and waste can be treated by combustion or high temperature, so that zero-pollution can be achieved.

The invention provides a preparation method of a target compound nano particle, relating to a preparation method of target treatment integration compound nano particles. The invention solves the technical problems of poor carrier stability and small drug-loading quantity of the traditional antineoplastic drugs. The method comprises the following steps of: preparing a methanol solution of an integrated nano particle of a Fe3O4-HCPT@SiO2 coupling porphyrin photosensitizer; and stirring the methanol solution of the integrated nano particle of the Fe3O4-HCPT@SiO2 coupling porphyrin photosensitizer, N,N-dimethylformamide and target biomolecule or antitumor drug for reacting at the room temperature, and centrifuging to obtain the target compound nano particle. Polystyrolsulfon acid (PSS) and 10-hydroxycamptothecine are absorbed on a Fe3O4 magnetic nano particle through a self-assembly mode. The preparation method is high feasibility; the target compound nano particle has a physical target function of the magnetic nano particle and an active target function of further functionally modifying the biomolecule on the surface; and the medicine concentration can be increased under a dual-target function.

The invention provides a method for preparing a nanocomposite material by assembling ferriferrous oxide in a halloysite tube, and belongs to the technical field of deep processing of nonmetallic minerals. The method comprises the following four steps: (1) pretreatment, tube expansion and purification of the halloysite minerals; (2) modification in the halloysite tube; (2) preparation of Fe3O4 magnetic nanoparticles through a mixed hydrothermal solution technology; and (4) vacuum impregnation for obtaining the compoiste material with the nano-Fe3O4 assembled in the halloysite tube. The halloysite / Fe3O4 composite material prepared in the invention has no residual magnetization or coercive force, and has a typical paramagnetic performance. The material prepared through the method has good biocompatibility, and broadens the application prospect of mineral magnetic materials in the fields of biomedicines and composite magnetic materials.

The invention provides a preparation method and application of a pH sensitive type magnetic demulsifier with surface charges and hydrophilic-hydrophobic properties controlled. Based on magnetic Fe3O4 nanoparticles, through surface modification with silicon dioxide and a grafting copolymerization reaction, surface active monomers and pH sensitive monomer copolymer chains are introduced on the surfaces of the nanoparticles, and the surface grafting structure and the pH value are further adjusted to control the surface charges and hydrophilic-hydrophobic properties of the magnetic nanoparticles. The reduction of the pH value can enhance the hydrophobic property of the magnetic nanoparticles and reduce negative charge repulsive interaction between the demulsifier and oil droplets so that the demulsifier can be absorbed onto the surfaces of the emulsified oil droplets and quickly isolate the emulsified oil droplets under the action of an external magnetic field. Recycling of the magnetic nanoparticles can be achieved, and the demulsifier is be unlikely to be affected by pollution of negative-ion surface active materials in emulsified oil wastewater. According to the magnetic demulsifier, the preparation method is simple, the recycling process is convenient and efficient, the recycling performance is excellent, and therefore the magnetic demulsifier has very board application prospects in the fields of emulsified oil wastewater treatment and oil-water separation.

The invention discloses a preparation method of porous magnetic polystyrene microspheres. The method comprises steps of: (1) adding dry Fe3O4 magnetic nanoparticles into an aqueous ethanol solution, treating with ultrasonic, adding vinyltriethoxysilane, transferring into a reactor together, stirring under a constant temperature and a nitrogen atmosphere for aging, and then washing, drying under vacuum and grinding the obtained product into powder; (2) mixing the powder obtained in the step (1) and benzoyl peroxide, and then adding into styrene containing a pore forming agent and a cross-linking agent for the ultrasonic treating; (3) dissolving polyvinylpyrrolidone and sodium dodecyl sulfate into water by using the ultrasonic; and (4) adding the liquid obtained in the step (2) into the liquid obtained in the step (3), treating with the ultrasonic, pouring the obtained mixture into a reactor, heating for condensation reflux to obtain a suspension liquid, separating with magnet, washing with ethanol, re-separating with the magnet, re-washing with pure water, drying under vacuum and grinding to obtain claybank powdery product, extracting with a soxhlet way, and drying under vacuum to obtain the finish product.

The invention relates to a magnetic composite nanoparticle with selective adsorption to antibodies. The structural formula of the magnetic composite nanoparticle is shown as the specification. The method includes: taking an Fe3O4 nanoparticle with superparamagnetism as the core, using tetraethyl orthosilicate as the silicon source, and employing SiO2 or a polymer to coat the Fe3O4 magnetic nanoparticle, thus obtaining a core-shell structure Fe3O4SiO2 or Fe3O4 polymer magnetic composite particle; and bonding a silane coupling agent mercaptoethyl trimethoxy silane to the silica gel surface of the magnetic composite particle, and then carrying out mercapto-ene click reaction on product and double bond-containing vinylpyridine (MEP), thus obtaining the Fe3O4SiO2-S-MEP or Fe3O4 polymer-S-MEP magnetic composite nanoparticle adsorbent. The Fe3O4SiO2-S-MEP or Fe3O4 polymer-S-MEP magnetic composite nanoparticle is a novel bio-functional magnetic composite nano-material with selective adsorption to antibodies. The material has very good superparamagnetism, and can rapidly realize solid-liquid separation under the effect of an external magnetic field, also shows specificity to antibody adsorption, and can be used for rapid separation and preparation of antibodies.

The invention provides a nano composite material as well as a preparation method and application thereof to water treatment. The nano composite material provided by the invention comprises a matrix and nanoparticles loaded on the surface of the matrix, wherein the matrix comprises one or more of graphene and graphene derivatives; and the nanoparticles comprise Fe3O4 and Mg(OH)2. According to the nano composite material provided by the invention, a matrix material is used as the matrix, and the nanoparticle composite material has magnetism through loaded Fe3O4 magnetic nanoparticles and is easy to separate; and meanwhile, the saturation adsorbing capacity of the nano composite material is enlarged, and heavy metal ions are efficiently adsorbed through loaded Mg(OH)2 nanoparticles. According to the nano composite material provided by the invention, the removal rates of Pb<2+>, Cu<2+>, Ag<+> and Zn<2+> with the initial concentration of 50ppm within 90min can reach 99.9%, 99.9%, 88% and 85% respectively.

The invention relates to a preparation method of a targeted MRI (magnetic resonance imaging) contrast medium based on folic acid modified iron oxide nanoparticles. The method comprises the following steps of: connecting FA to NH2-PEG-COOH to form COOH-PEG-FA; synthesizing PEI coated Fe3O4 nanoparticles (Fe3O4-PEI) by a hydrothermal method; performing surface modification on the Fe3O4-PEI nanoparticles by use of fluorescein isothiocyanate (FI); connecting COOH-PEG-FA to the surface of the Fe3O4 nanoparticles; and finally performing acetylation modification of the residual PEI aminos on the surface of the Fe3O4 nanoparticles to improve the biocompatibility for MRI diagnosis. The preparation method provided by the invention has simple technology and mild reaction conditions, and is easy to operate; and the prepared Fe3O4 magnetic nanoparticles have good colloidal stability, biocompatibility and tumor targeting performance as well as potential application value in the field of in-vivo tumor targeted diagnosis.

The invention relates to an ionic liquid functionalized magnetic nanoparticle and a preparation method and application thereof. FeCl3.6H2O and anhydrous sodium acetate are dissolved in glycol, and react under 200 DEG C, so that Fe3O4 magnetic nanoparticles are obtained; the Fe3O4 magnetic nanoparticles are weighed and mixed with H2O and ethanol, pH is regulated to 9 to 10, tetraethoxysilane is added for reaction, and after vacuum drying, Fe3O4 / SiO2 is obtained; the Fe3O4 / SiO2 is dispersed and suspended in toluene, and after 3-chloropropyltrimethylsilane and triethylamine are added for reaction, chloropropyl magnetic nanoparticles are obtained by way of vacuum drying; the chloropropyl magnetic nanoparticles are added into toluene, N-alkylimidazole derivative is added for reaction, and after vacuum drying, the ionic liquid functionalized magnetic nanoparticles are obtained. When being used for separating target standard protein, the ionic liquid functionalized magnetic nanoparticle has the characteristics of good selectivity and high adsorbing capacity, and cannot contaminate target separated product.

A preparation method of Fe3O4@PEG@SiO2 artificial antibody for detecting thifensulfuron methyl comprises modifying the surface of Fe3O4 magnetic nanoparticles with polyethylene glycol 2000, coating the surface with SiO2 shell layer to form a core-shell-shell structure, diluting marker molecules in the SiO2 shell layer to form specific recognition site holes complementary with marker molecular structure, size and functionality so as to arrive at molecular selective recognition and detection for target analyses. The preparation method of the artificial antibody comprises the steps of first, preparing Fe3O4 magnetic nanoparticles, and modifying their surface with polyethylene glycol; second, adding the target molecule thifensulfuron methyl, a crosslinking agent and a catalyst, and hydrolyzing to obtain Fe3O4@PEG@SiO2 particles with surface-marked thifensulfuron methyl; third, diluting template molecule with a mixed solution of acetic acid and acetone having a volume ratio of 1:4 to obtain the Fe3O4@PEG@SiO2 artificial antibody with selective recognition marker molecules, the antibody having maximum saturated binding capacity of 41.28 mg / g for thifensulfuron methyl, the absorption rate reaches 0.45 mg / g.min within first 30 min which is 5.34 times and 3.46 times that of a non-marking method.

The invention discloses a group enhanced type magnetic nanometer water treatment agent and a preparation method and application thereof. The preparation method is characterized by comprising the following steps: accurately weighting hexahydrate ferric chloride and anhydrous sodium acetate as reaction raw materials; firstly, dissolving the raw materials into ethylene glycol; then, adding polyethylene glycol to disperse; adding solution into a high-pressure reaction reactor container to react; carrying out magnetic adsorption to obtain Fe3O4 magnetic nanoparticles; taking ethyl orthosilicate as a silicon source to enable silicon dioxide to cover the surface of the Fe3O4 magnetic nanoparticles; taking silane coupling agent as an amino source to graft an -NH2 group to the surface of the silane coupling agent to obtain Fe3O4@SiO2-NH2 magnetic nanoparticles; finally, under a constant temperature, stirring to modify the amino and sulfydryl group of cysteine on the surfaces of the Fe3O4@SiO2-NH2 magnetic nanoparticles to obtain group-enhanced magnetic nanometer water treatment agent Fe3O4-SiO2-NH2-L-Cys. The preparation method has the advantages of simpleness in preparation process operation and easiness in realizing reaction conditions. In addition, the group enhanced type magnetic nanoparticles prepared with the preparation method has the advantages of narrow particle size distribution, good stability, good adsorption function for various heavy metal ions and high adsorption efficiency.

The invention provides a surface plasmon resonance sensing element and a manufacturing method thereof, belonging to the technical field of a sensor for biological system detection. The sensing element comprises a metallic membrane (2), a sensitive membrane and a magnet (3), wherein, the metallic membrane with a chromium membrane and a gold membrane as the sensing elements is plated on the bottom surface of a glass prism (1), the sensitive membrane composed of magnetic nanoparticles (4) subject to surface hydroformylation and an antibody (5) linked with an aldehyde group through a covalent bond is made on the metallic membrane, and the magnet is arranged under the glass prism. The manufacturing method of the sensing element comprises the following steps: preparation of the metallic membrane, preparation of Fe3O4 magnetic nanoparticles, preparation of ammoniated SiO2-coated magnetic nanoparticles, preparation of magnetic nanoparticles subject to surface hydroformylation and preparation of the sensitive membrane. The invention has the advantages of simple manufacturing process, high sensitivity, good biocompatibility and good selectivity and can be used in all antibody and antigen detection and protein and drug measurement.

The invention provides a new cell sorting magnetic bead, which is a 50-70 nm gold plated Fe3O4 magnetic nanoparticle (Fe3O4 and Au nanoparticle) ostensibly coupled with proteinA by covalent bonds, interacted with the specificity of a Fc section of IgG through the proteinA, and directionally coupled with IgG type mouse CD3 antibodies. The invention relates to a method for synthesizing and modifying the magnetic bead, and a method for carrying out cell sorting by using the magnetic bead. The magnetic bead of the invention is used for removing the CD3 T cells in the mouse splenocytes so as to reduce the CD3 T cell content of the splenocytes from 36.5 percent to 0.7 percent, and has extremely high sorting efficiency. The magnetic bead also has the advantages of high protein-coupled quantity and superparamagnetism, and the preparation method has the advantages of simpleness, environmental protection, low cost and good application prospect.

The invention relates to chiral magnetic nano-particles and preparation and application thereof. The preparation comprises the following steps of: (1) preparing Fe3O4 magnetic nano-particles; (2) preparing Fe3O4 / SiO2 composite magnetic nano-particles; (3) preparing cellulose-2,3-di(3,5-dimethyl phenyl carbamate); and (4) performing surface chiral modification on the Fe3O4 / SiO2 composite magnetic nano-particles by using the cellulose-2,3-di(3,5-dimethyl phenyl carbamate). The chiral magnetic nano-particles are used for separating a racemic compound DL-1-phenethyl alcohol, and an optical rotation value test for obtaining components through singly spinning a guide sample and separation proves that laevo-rotation and dextro-rotation are separated very well. The chiral magnetic nano-particles have the advantages of short separation time, simple and convenient operation, and good separation effect of chiral compounds; besides, the chiral magnetic nano-particles can be thoroughly separated from base solution under an external magnetic field, and not only cannot cause pollution to a target separation object but also can be completely recycled, thereby fulfilling two aims of ecumenical efficiency and environmental protection.

The invention provides a group of oligonucleotide aptamers Apt-1, Apt-2 and Apt-3 which are capable of simultaneously identifying clenbuterol hydrochloride and salbutamol, an oligonucleotide aptamer CLB-2 which is capable of identifying the clenbuterol hydrochloride with high specificity, an oligonucleotide aptamer SAL-5 which is capable of identifying the salbutamol with high specificity and two oligonucleotide aptamers RAC-5 and RAC-6 which are capable of identifying ractopamine with high specificity. Through an SELEX (Systematic Evolution of Ligands by Exponential Enrichment) technology based on Fe3O4 magnetic nanoparticle separation, a random oligonucleotide library is immobilized on avidin-enveloped magnetic nanoparticles by virtue of a complementary chain of a biotinylation marker, and the oligonucleotide aptamers, which are high in specific affinity, are finally obtained by conducting screening by 16 turns. The aptamers are broad in application prospect; and the aptamers, by virtue of marker function genes or fluorescent dyes, are applicable to detection of the clenbuterol hydrochloride, the salbutamol and the ractopamine in food; therefore, a new choice is provided for existing detection methods which depend on antibodies.

The invention provides a reagent and a method for measuring magnetic field intensity by using magneto discoloration. The reagent is a three-phase material system consisting of superparamagnetic nano colloid clusters (CNCs), liquid solvent, and a liquid resin; each CNCs consists of a plurality of single-domain Fe3O4 magnetic nanoparticles coated by silicon dioxide; the method comprises the following steps that: 1, the reagent is placed in an external magnetic field, the magnetic attraction caused by the superparamagnetic nano colloid clusters, and electrostatic repulsion and solvating power are leveled off under the action of the magnetic field so as to form chain structures along a magnetic line of force, and a large number of chain structures are uniformly distributed so as to form photonic crystal; and 2, the lattice constant of the photonic crystal determines the color of diffraction beams, different colors of the reagent are displayed according to different magnetic field intensities, and the corresponding magnetic field intensity can be obtained by looking up a color-magnetic field intensity comparison table according to the corresponding relation between the color and the magnetic field intensity.

The invention relates to an immunodetection method of organophosphorus pesticide multi-residue in the technical field of pesticide detection, and the immunodetection method comprises the following steps: synthesizing an organophosphorus generic hapten, and coupling with protein to prepare an immunogen and a coating antigen; using the immunogen to perform animal immunization so as to get an organophosphorus pesticide generic antibody; synthesizing Fe3O4 magnetic nanoparticles and performing surface modification; coupling the Fe3O4 magnetic nanoparticles after surface modification with the organophosphorus pesticide generic antibody to form immune magnetic beads; adding a nitrocellulose membrane on a baseplate of a test strip, coating the immunogen prepared by coupling the organophosphorus generic hapten with the protein on the membrane, closing to form a detection part, and finally determining the optimal coating, the closing conditions and the using quantity of the immune magnetic beads; and performing qualitative and semi-quantitative detection. The detection method is simple and convenient to operate, sensitive and fast; large-scale instruments are not required; and the detection method is suitable for field sampling detection and large-batch detection tasks.

The invention provides a method for preparing monodisperse Fe3O4 magnetic nanoparticles. Precursor is Fe2O3 or iron oxide yellow which has the chemical formula of Fe2O3.H2O; stabilizing agent is oleic acid; high temperature organic solvent is 1-octadecylene (b. p. 318DEG C); precipitating agent is prepared by mixing any two of toluene, dimethyl benzene, ethanol, isopropanol and acetone according to the volume ratio of 1:4-2:3; the mol ratio between the precursor and the stabilizing agent is 1:4-1:9; the mol ratio between the precursor and the high temperature organic solvent is 1:10; inert gas protection is not needed, and the Fe3O4 magnetic nanoparticles which have small sizes, monodisperse, narrow distribution, high saturation magnetization intensity and superparamagnetism. The method can be widely applied to biomedicine fields such as magnetic resonance imaging, biological magnetic separation, magnetic target drug carrier, biological magnetic marker and the like, and the high technical fields such as magnetic sealing, aerospace lubrication, magnetic anti-counterfeiting ink material, etc.

The invention provides a preparation method of a magnetic nano molecularly imprinted polymer for separating a nicotinic pesticide IPP, aiming to solve the problem that methods for preparing magnetic nano molecularly imprinted polymers capable of separating the nicotinic pesticide IPP do not exist at present. The preparation method comprises the following steps: I. preparation of Fe3O4 magnetic nanoparticles; II. modification of the Fe3O4 magnetic nanoparticles; III. silanization of the Fe3O4 magnetic nanoparticles; IV. preparation of double bond modified Fe3O4@SiO2 particles; and V. preparation of the magnetic nano molecularly imprinted polymer for separating the nicotinic pesticide IPP. The preparation method has the beneficial effects that the maximum saturation adsorption quantity of the product towards IPP is 17.305+ / -0.403mg / g and is 2.0 times that of a non-molecularly imprinted polymer; the adsorption quantity is still kept at about 85.3% after five-time repeated adsorption; and the repeated utilization rate is high.