926 results about "Magnetic nanoparticles" patented technology

The invention relates to the technical field of soil conditioners, and particularly discloses an intelligent controlled-release core-shell alginate soil conditioner and a preparation method thereof.The conditioner is of a core-shell-layer three-layer structure and comprises a core layer, a middle shell layer and an outer layer, the three layers account for 30%, 40% and 30% of the total weight respectively, and the core layer mainly comprises improved alginate and nutrients; the middle shell layer mainly comprises chitosan and a microbial preparation; and the outer layer mainly comprises modified charcoal and magnetic nano # imgabs0 #. The preparation method comprises the four steps of core layer preparation, middle shell layer coating, outer layer coating and forming post-treatment, and multiple functions of accurate nutrient supply, efficient heavy metal fixation and soil microenvironment regulation and control are achieved through a core-shell-layer three-layer structure design and a pH / temperature / microorganism triple response mechanism by adopting a coaxial electronic injection and layer-by-layer self-assembly technology; the fertilizer has a remarkable improvement effect on sandy soil and saline-alkali soil, and the organic matter increasing rate reaches 40%.

A carbon dioxide (CO2) stream reacts with an amine-modified magnetic nanoparticle in solution to form an amine-CO2 adduct. The solution that includes the amine-modified magnetic nanoparticle is heated by an external alternating magnetic field. The heat provided by the external alternating magnetic field is localized such that only the amine-CO2 adduct is heated to release the CO2, without heating the entire solution. This process helps with the capture and release of CO2 with a significantly reduced energy during the CO2 release step.

The invention relates to a double-color magnetic nanoparticle imaging method based on a single-harmonic system matrix, which comprises the following steps: respectively moving two different types of magnetic nanoparticle samples to a central zero magnetic field point, applying a scanning magnetic field to enable the zero magnetic field point to scan the whole imaging field of view, applying an excitation magnetic field to magnetize magnetic nanoparticles, and applying an excitation magnetic field to magnetize the magnetic nanoparticles; acquiring magnetization frequency spectrum signals of the two magnetic nanoparticle samples; the method comprises the following steps: constructing single harmonic system matrixes A1 and A2 based on single harmonic of magnetization spectrum signals of two kinds of magnetic nanoparticle samples; measuring a to-be-measured object formed by the two kinds of magnetic nanoparticles to obtain a measurement magnetization signal U; transversely splicing the single harmonic system matrixes A1 and A2 of the two different types of magnetic nanoparticles to obtain a new single harmonic system matrix A; the concentration distributions c1 and c2 of two different types of magnetic nanoparticles are obtained by combining a new single-harmonic system matrix A with a measurement magnetization signal U, and the concentration distributions of the two different types of magnetic nanoparticles are respectively sent into different color channels to be displayed in different colors. The method has important significance in promoting the application of the magnetic nanoparticle imaging technology in clinical medicine.

The invention relates to a kitchen waste oil recovery treatment method, which comprises: S1, carrying out multi-field synergistic pretreatment: sequentially carrying out ultrasonic wave and high-frequency pulse electric field treatment on waste oil to break an emulsion layer, adding magnetic nanoparticles to adsorb polar impurities, and carrying out magnetic field separation to obtain high-purity oil; s2, supercritical catalytic reaction: under the CO2 supercritical condition, using a core-shell structure composite catalyst to synchronously perform transesterification reaction and glycerol dehydration reaction; s3, dynamic membrane separation: separating biodiesel and glycerol in real time through an intelligent membrane assembly; s4, gradient utilization of energy: recovering reaction waste heat to drive membrane distillation to concentrate wastewater, and using tail gas CO2 for carbonation reaction to generate calcium carbonate. Through four core technologies of multi-field collaborative pretreatment, low-temperature supercritical catalysis, dynamic membrane separation and energy gradient utilization, triple limitations on efficiency, cost and environmental protection in the prior art are remarkably broken through.

The invention relates to the technical field of material preparation, and discloses a magnetic basalt fiber reinforced wear-resistant self-lubricating coating and a preparation method thereof, and a coating and a preparation method thereof, and the preparation method comprises the following steps: step 1, treating short-cut basalt fibers with an acid and / or alkali solution, mixing with an iron salt solution to obtain a reaction solution, carrying out hydrothermal reaction to obtain the magnetic basalt fiber loaded by the magnetic nanoparticles; step 2, adding a filler into the resin matrix solution, dispersing, and grinding to obtain resin slurry; and 3, adding the magnetic basalt fiber in the step 1 into the resin slurry in the step 2, adding a curing agent, and uniformly mixing to obtain the required coating. According to the method, the contact behavior and the abrasion mechanism of a friction pair are optimized, the friction coefficient and the abrasion rate are reduced, the tribological performance of the obtained coating is improved, the service life of a mechanical kinematic pair is prolonged, and the reliability and the stability of equipment operation are improved.

The invention discloses an optical microscopy method, system and device for positioning magnetic nanoparticles, and the method comprises the steps: obtaining an interference pattern generated when laser passes through a to-be-detected sample, and distributing the magnetic nanoparticles in the to-be-detected sample; the interference pattern is formed by interference of incident laser and scattered light of the magnetic nanoparticles; determining a distribution function of the interference pattern, and determining the central position of the magnetic nanoparticle according to the interference pattern and the distribution function; the device comprises a laser, an amplification objective lens, a focusing lens, an imaging unit and a processor, light emitted by the laser passes through a to-be-detected sample to generate an interference pattern, the interference pattern is amplified by the amplification objective lens and focused by the focusing lens to be imaged in the imaging unit, and magnetic nanoparticles are distributed in the to-be-detected sample. According to the embodiment of the invention, micron-sized space positioning of the magnetic nanoparticles can be realized, and the method can be widely applied to the technical field of optical positioning.

The invention relates to the technical field of composite material preparation, in particular to high-mechanical-property granular hydrogel and a preparation method and application thereof.The high-mechanical-property granular hydrogel is prepared by mixing gelatin nano-particles, calcium carbonate nano-particles, ferric oxide nano-particles and a sodium alginate solution under the alkaline condition, then adding gluconic acid-delta-lactone, and conducting stirring, standing and drying to obtain the high-mechanical-property granular hydrogel. Particle hydrogel with high mechanical property is prepared and is simply recorded as Ca-Alg / MCG, and the gel system is endowed with the catheter injectable property, the blood vessel deliverable property and the intravascular hardenability property. The hydrogel can be delivered to small blood vessels of tumors, the mechanical property can be gradually enhanced along with the change of time, and the embolism effect of the granular hydrogel in the blood vessels is further improved. Meanwhile, the magnetic nanoparticles endow the hydrogel with the magnetic-thermal response capability, the temperature can be rapidly increased under an alternating magnetic field, tumor cells are further killed, and the hydrogel shows an excellent embolism effect in a rabbit kidney embolism model and a liver cancer rabbit embolism model.

Described herein are compositions, systems, and methods for targeted and controlled drug release. In some embodiments, the compositions, systems, and methods may comprise magnetoelectric silica nanoparticles for targeted and controlled release of chemotherapeutic drugs for cancer treatment. In some embodiments, an external magnetic field may be used to release one or more drugs from the magnetoelectric silica nanoparticles. The disclosed compositions, systems, and methods may improve drug targeting and reduce systemic drug toxicity.

The invention relates to the technical field of microbial fertilizers, in particular to a microbial fertilizer for improving a soil structure and a preparation method thereof, and the microbial fertilizer comprises the following components: microbial flora, a charcoal-based composite material, magnetic nanoparticles, a polymer water retention agent, a soil enzyme activator, peanut bran, molasses and a trace element supplement. By selecting and proportioning functional components such as various microbial florae, biochar-based composite materials, magnetic nanoparticles and the like, the invention aims to construct the microbial fertilizer with efficient nutrient utilization, excellent soil structure improvement capability and environmental adaptability, not only the instant effect of the fertilizer is concerned, but also the long-term benefit and ecological sustainability of the fertilizer are concerned, and the application prospect is wide. Powerful support is provided for green development of modern agriculture.

The invention discloses a rapid and accurate detection method for pathogenic bacteria. The method comprises the following steps: immobilizing bacteriophages on the surfaces of magnetic nanoparticles through physical adsorption or chemical reaction, selectively enriching pathogenic bacteria in a complex sample by adopting the bacteriophage functionalized magnetic nanoparticles, quickly cracking the pathogenic bacteria on the surfaces of the magnetic nanoparticles by using CTAB (cetyltrimethyl ammonium bromide), releasing ATP in the bacteria, and quantitatively analyzing ATP by using bioluminescence. Further calculating the content of the pathogenic bacteria; the detection method is free of enrichment and amplification, can complete capture, enrichment and detection of pathogenic bacteria within 20 minutes, and can specifically detect viable bacteria of target bacteria in various complex matrix (such as food) samples due to the fact that bacteriophages are adopted as recognition molecules.

The invention provides an easy-to-scale efficient biological magnetic separation system and method and application. The magnetic separation method comprises the following steps: marking a target object in a to-be-detected suspension by adopting magnetic nanoparticles, and putting the marked to-be-detected suspension into a separation container; a modularized magnet array is arranged in the separation container, the modularized magnet array is composed of permanent magnets, and the permanent magnets are assembled into the cuboid modularized magnet array; the surface of the permanent magnet is coated with a polytetrafluoroethylene coating; the modularized magnet array moves in the suspension under the control of a driving magnet arranged outside the separation container to generate a dynamic gradient magnetic field, and a target object is captured by the modularized magnet array under the action of the gradient force of the magnetic field; removing the liquid in the separation container; adding the resuspension into a separation container, and recovering a target object by physical ultrasonic washing; or adding a chemical dissociation solution into the separation container to recover the target object.

The invention belongs to the technical field of microbiological detection, and discloses a composite probe for detecting salmonella enteritidis and a preparation method. The composite probe for detecting the salmonella enteritidis comprises magnetic nanoparticles FeO, wherein the surface of the magnetic nanoparticles FeO is modified with an aptamer apt which is specifically combined with the salmonella enteritidis; the surface of the long afterglow nano particle PLNPs is modified with a DNA (Deoxyribose Nucleic Acid) sequence cDNA (Complementary Deoxyribonucleic Acid) complementary with the aptamer; the aptamer apt and the complementary DNA sequence cDNA are subjected to hybridization to form a composite probe structure FeO-SEapt (at) PLNPs-cDNA (complementary deoxyribonucleic acid). The long afterglow luminescence characteristic of PLNPs (ZnGaO: Cr) is utilized, and an excitation light source is stopped before detection, so that signal acquisition completely avoids autofluorescence of a sample matrix, background fluorescence interference is thoroughly eliminated, and the signal-to-noise ratio is remarkably improved.

The invention discloses a coating, a preparation method and application, and relates to the technical field of anticorrosive coatings. A dry film of the coating comprises 0.1 wt%-6wt% of a lamellar filler; the lamellar filler is prepared by loading magnetic nanoparticles on the surfaces of two-dimensional nanoparticles and coating a layer of high-molecular polymer. After the coating forms a film, a specific magnetic control orientation curing method is matched, so that high dispersion stability and planar orientation arrangement of the two-dimensional nano filler in a resin matrix are realized, and corrosion of water and oxygen to a base material can be effectively blocked. When the thickness of the coating dry film is only 1-2 microns, the coating dry film still has no obvious corrosion phenomenon after being subjected to a neutral salt spray test for 2000 hours. The metal base material with the thin coating thickness has heat conductivity, corrosion resistance and weather resistance, the preparation process is simple, the cost is low, and the metal base material has extremely high market application value.

The invention discloses a preparation method of a demulsifier for oil-water separation of full fermentation broth, and relates to the technical field of demulsifier preparation.The preparation method comprises the steps of magnetic nanoparticle preparation, nanoparticle coating and demulsifier preparation.The preparation method has the advantages that salt is dissolved in a three-neck flask, nitrogen is introduced to discharge oxygen in the solution, and the demulsifier is obtained; according to the preparation method, the magnetic nanoparticles are added into the mixture A, so that the generated nanoparticles can be prevented from being oxidized, the mixture A is added in the process of adding the potassium nitrate and the 2-methylimidazole, and the polydopamine in the mixture A has good adhesion and biocompatibility, so that a'bridge '-like connection effect can be achieved between the magnetic nanoparticles and a subsequently generated nanoparticle coated sample; and polyvinylpyrrolidone can be used as a dispersant to prevent agglomeration of generated nano particle coated sample particles, and polar groups on molecular chains of polyvinylpyrrolidone can generate certain interaction with raw materials in a reaction system to optimize the growth process of the nano particle coated sample.

According to the high-temperature-resistant nitrogen-fixing bacteria microcapsule fertilizer and the preparation method thereof, aiming at the problems of thallus inactivation and nutrient loss in a high-temperature environment, a sodium alginate-chitosan double-layer embedding technology is combined with magnetic nanoparticle modification, and a stable double-layer structure is formed by optimizing the ratio of an embedding material, so that the high-temperature-resistant nitrogen-fixing bacteria microcapsule fertilizer is prepared. The survival rate and activity of the nitrogen-fixing bacteria at high temperature are remarkably improved, and meanwhile, the functions of intelligent nutrient release and magnetic recovery are achieved. The fertilizer is prepared from composite microcapsules, amino acid, humic acid and other raw materials according to a specific ratio through magnetic field orientation treatment, multi-stage mixing, atomization granulation and magnetic field screening processes, the particle size is controlled to be 0.5-3.35 mm, and the shelf life is prolonged to 12 months. The method has the technical effects that trehalose-glycerol / sorbitol synergistically forms a glassy protective film to maintain the stability of thalli, gamma-aminobutyric acid activates nitrogenase gene expression, magnetic nanoparticles construct a photosynthetic symbiotic system to optimize rhizosphere oxygen supply, and silanized FeO nanoparticles fix heavy metal ions through electrostatic adsorption, so that the heavy metal ions in the thalli are effectively adsorbed, and the heavy metal ions in the thalli are effectively adsorbed. And the humic acid buffers the pH fluctuation of the soil, so that the nitrogen fixation efficiency is finally improved by 30-50%, and the crop yield is increased by 15-25%.

The invention belongs to the field of adsorption materials, and discloses a porous lignin fiber adsorption material and a production process thereof, the porous lignin fiber adsorption material comprises the following raw materials by weight: 40-60 parts of lignin fiber, 20-30 parts of bamboo fiber, 5-15 parts of chitosan, 5-10 parts of sodium bicarbonate, 5-10 parts of attapulgite, 5-10 parts of zeolite, and 2-5 parts of magnetic nanoparticles; the invention aims to provide the production process of the porous lignin fiber adsorption material, the problems that the existing lignin fiber adsorption material is poor in pore structure, limited in adsorption performance, difficult to separate and the like are solved through an innovative raw material formula and an optimized production process, efficient adsorption of light components in asphalt is realized, the stability of an asphalt mixture is enhanced, and the service life of the asphalt mixture is prolonged. Meanwhile, heavy metal ions, organic pollutants and the like are efficiently adsorbed and rapidly separated, the production energy consumption is reduced, and the environmental protection property and economical efficiency of the process are improved.

A magnetic nanoparticle composite microcapsule, and a preparation method therefor and the use thereof. The preparation method comprises: diluting concentrated ammonia water with absolute ethanol in which nano-Fe3O4 is dispersed, stirring same and adding ethyl orthosilicate, centrifuging same, and then performing washing to obtain Fe3O4 / SiO2 particles; dispersing same in anhydrous ethanol, then adding isopropanol containing tetrabutyl titanate, and performing a treatment to obtain Fe3O4 / SiO2 / TiO2 nanoparticles; adding polyurethane TDI prepolymer to the Fe3O4 / SiO2 / TiO2 nanoparticles, adding same to a core material, then dripping an emulsifier, and stirring same to obtain a core material emulsion; and heating same in a water bath, dropwise adding butanediol, and performing heating, stirring and vacuum filtration to obtain a magnetic nanoparticle composite microcapsule. By means of the loading with a core material having a repair function, the prepared magnetic microcapsule can actively repair damage to an insulating material caused by electrical and mechanical stress, thereby improving the reliability of a device.

The invention discloses a magnetic nanoparticle concentration distribution inversion method and a related device, and relates to the technical field of biomedical engineering.The method comprises the steps that firstly, magnetic nanoparticles in biological tissue are excited through an external magnetic field to generate infinitesimal displacement; and then ultrasonic equipment is adopted to collect ultrasonic ultrafast plane wave imaging data and carry out axial vibration displacement detection, axial vibration displacement actual measurement data and corresponding discrete space and time coordinates are input into the inversion model for iterative inversion, and a magnetic nanoparticle concentration distribution inversion result is obtained. A loss function of the inversion model includes a data-driven loss item and a physical information-driven loss item (based on a Navie equation). Compared with the prior art, the method has the advantages that the physical information neural network is introduced, control equations such as a nano-dimension equation and the like are encoded to the full-connection neural network, physical equations do not need to be excessively simplified, complex and time-consuming modeling for an experimental environment is not needed to obtain simulation data, and higher accuracy and stability are achieved.

The invention relates to the field of demulsifiers, in particular to an oil sludge demulsifier as well as a preparation method and application thereof. The oil sludge demulsifier comprises the following components in parts by mass: 20-35 parts of a surface active compound, 7-12 parts of a sodium alkyl sulfate cosolvent, 0.6-1.8 parts of a stabilizer and 48-55 parts of water, wherein the surface active compound comprises hyperbranched polyamidoamine and polyether amine modified magnetic nanoparticles. According to the oil sludge demulsifier, the problems that most of existing demulsifiers are small in dehydration amount, low in dehydration speed, poor in demulsification effect and low in treated oil content are solved, the demulsification performance of the oil sludge demulsifier is improved, the demulsification and dehydration efficiency is improved, and effective separation of oil sludge is achieved.

The invention provides a magnetic polymer composite film and a preparation method and application thereof, and belongs to the technical field of friction materials. The magnetic polymer composite membrane comprises a P (VDF-TrFE) base membrane and a plurality of rod-shaped CoFe2O4 (RCFO) (at) PDA magnetic nano particles dispersed in the P (VDF-TrFE) base membrane, the RCFO (at) PDA magnetic nanoparticle has a core-shell structure, a core layer is rod-like nanometer CoFe2O4, and a shell layer is polydopamine. The RCFO nanoparticles with dielectric properties are embedded into the P (VDF-TrFE) base film, and a stripe-shaped surface microstructure is successfully constructed through a magnetic field orientation assisted thermal film forming process, so that the contact area of the friction material is effectively increased, and meanwhile, the dielectric constant is also improved. The magnetic polymer composite film provided by the invention is used as a positive electrode friction material of a friction nanometer generator, and the electric output performance of the friction nanometer generator is obviously improved.

The invention provides eye protection liquid for improving eye microcirculation and a preparation method thereof, and belongs to the technical field of medical configuration products. The composition comprises the following components: surface-modified magnetic nanoparticles, a calendula extract, a fermented dogwood extract, xanthophyll, taurine, sodium hyaluronate, hydrolyzed sodium hyaluronate, soya bean lecithin, borneol and fermented vegetable oil. The efficiency of active ingredients is improved through a double-fermentation technology, magnetic targeting and multi-channel compounding are combined, and the preparation method has remarkable advantages in the field of improving periorbital microcirculation. The traditional Chinese medicine composition has an obvious relieving effect on asthenopia and dry skin around eyes; the components of the eye microcirculation eye protection liquid are mild, and adverse reactions such as allergy cannot be caused.

The invention relates to the field of DNA nanotechnology, and discloses a DNA origami structure based on functionalized magnetic nanoparticles, a preparation method and application, and the preparation method comprises the following steps: step 1, constructing a DNA origami structure with a cavity through a self-assembly method; the short chains in the DNA origami structure comprise a first short chain, a second short chain and a third short chain; 2, connecting a sulfydryl-functionalized first sequence to the first short chain, and chelating ferrous ions on the first sequence to obtain a sulfydryl-modified DNA origami structure; 3, ferrous ions chelated on the sulfydryl modified DNA origami structure are reduced, and a magnetic functionalized DNA origami structure internally loaded with Fe2O3 particles is obtained; and 4, connecting an antibody to a second short chain in the DNA origami structure through base complementary pairing to obtain the required DNA origami structure. According to the invention, DNA origami is combined with magnetic nanoparticles, efficient and controllable biological magnetic beads are obtained through dual immobilization and antibody modification, and a traditional application scene of DNA origami is broken through.

This disclosure relates to magnetic microgel beads, and in particular to magnetic microgel beads for biofunctionalization and methods of making and uses thereof, for example, in biosensing assays. In an embodiment, a magnetic microparticle comprising a magnetic nanoparticle encapsulated by a polymer hydrogel. In another embodiment, an assay for detecting the presence of a target analyte in a sample comprising a) the magnetic microparticle disclosed herein, wherein the biorecognition agent further comprises a reporter moiety; b) an electrochemical chip comprising a working electrode, a counter electrode and a reference electrode; and c) a capture probe functionalized on the working electrode; wherein binding of the biorecognition agent to the target analyte results in production of an electrochemical, electroluminescent or photoelectrochemical signal.

The invention discloses potato starch nano-carrier immobilized lipase and a preparation method thereof, and relates to the technical field of biological catalysis. The immobilized lipase comprises a lipase and a carrier, and the lipase is immobilized on the carrier; the carrier is potato starch modified magnetic nanoparticles. The immobilized lipase provided by the invention takes the magnetic potato starch nanoparticles as a carrier and has the advantages of being green and environment-friendly and easily available in materials, and the lipase is successfully immobilized on the magnetic nanoparticles by using the potato starch and the traditional glutaraldehyde as cross-linking agents. The method not only improves the activity and stability of the immobilized enzyme, but also has good biocompatibility and safety. By optimizing parameters such as potato starch dosage, enzyme concentration and immobilization time, the obtained immobilized enzyme shows excellent storage stability and repeated utilization rate. In addition, the method provides reference for preparation of other high-performance immobilized enzymes.

The invention provides a peptide fragment for modifying a Fe3O4 (at) Au magnetic nanoparticle and a preparation method of the Fe3O4 (at) Au magnetic nanoparticle, the peptide fragment is an alpha-peptide fragment 1 or / and a beta-peptide fragment 1, and the fragment of the peptide fragment is as shown in SEQ ID NO: 1. The method comprises the following steps: firstly, growing a layer of gold shell on the surface of Fe3O4 in situ to provide more modification sites, and then modifying PS binding peptide (PSBP) by using an Au-S bond to construct the PS NPs selective probe. The ultralow-concentration PS can be quantitatively detected only by monitoring the ultraviolet-visible absorption change of the probe. The peptide modified Fe3O4 (at) Au probe (Fe3O4 (at) Au-PSBP) has good linearity in a range of 0 to 80 pg mL <-1 >. The probe has been successfully applied to actual samples, such as bottled water, edible salt and milk. The adding standard recovery rate is 98.85%-112.10%, and the relative standard deviation (RSD) is 2.53%-13.80%. The provided Fe3O4 (at) Au-PSBP can be easily expanded to other types of NPs by simply replacing peptides, shows huge potential as a universal specific probe, and can sensitively and quickly detect low-concentration NPs in an actual sample.

The invention discloses a magnetic porous microsphere for in-vitro diagnosis and a preparation method of the magnetic porous microsphere, and belongs to the technical field of preparation of micro-nano materials. According to the invention, styrene is used as a polymerization monomer, and a dispersion polymerization method is adopted to prepare monodisperse polystyrene microspheres; ferric chloride and ferrous sulfate are selected as precursors, magnetic nanoparticles are synthesized through a coprecipitation method under the alkaline condition, the initial loading capacity is changed, the magnetic nanoparticles are loaded on the surfaces and in pore channels of polymer porous microspheres through a multi-step seed growth method, and the magnetic nanoparticles are prepared. The composite magnetic polystyrene microspheres with high magnetic content, good magnetic responsiveness and superparamagnetism are synthesized; finally, functional groups are introduced to the surfaces of the magnetic spheres by monomers containing the functional groups through a monomer swelling polymerization method, and the prepared magnetic porous microspheres have the advantages of uniform particle size, small coefficient of variation and large specific surface area, and can be better combined with antigens and antibodies, so that in-vitro diagnostic function detection such as nucleic acid extraction and chemiluminescence is carried out.

A method and apparatus for preparing tissue of interest in a patient for possible excision by surgery. In one embodiment, the method comprises the steps of: removing a biopsy sample from the tissue of interest; placing a magnetic marker at the biopsy site; performing a pathology analysis of the biopsy sample; and if the pathology analysis indicates that the tissue of interest should be removed, locating the tissue for surgery using a magnetic detection probe. In one embodiment, the marker comprises magnetic nanoparticles in a bioabsorbable matrix. A system for preparing tissue of interest in a patient for possible excision by surgery. In one embodiment, the system includes a magnetic marker and magnetic detection probe system.

The invention discloses a detection system and method for measuring trace Cr in tobacco, and relates to the technical field of tobacco detection.The system comprises a multi-stage dynamic digestion module, a two-channel solid-phase microextraction module, a high-resolution ICP-MS detection module, an intelligent data processing module, a collision reaction tank (CRC) based on the high-resolution ICP-MS module and a dynamic background correction algorithm. The detection limit of Cr is as low as 0.008 [mu] g / kg by combining the enrichment capacity of 50 times or more of two-channel solid-phase microextraction (DSPME), the detection limit is reduced by one order of magnitude compared with that of a traditional atomic absorption method (0.1 [mu] g / kg), the accurate determination requirement of trace Cr is met, the two-channel DSPME module is designed through physical isolation of amino magnetic nanoparticles (Cr (III) adsorption) and DTC mesoporous carbon (Cr (VI) adsorption), and the detection limit of the trace Cr is reduced by one order of magnitude compared with that of the traditional atomic absorption method (0.1 [mu] g / kg). And independent capture and elution of Cr (III) and Cr (VI) are realized.

The invention discloses a magnetic immobilized enzyme and a preparation method and application thereof in preparation of chitosan oligosaccharide, the immobilized enzyme comprises a carrier and an enzyme loaded on the carrier, the carrier is a magnetic nanoparticle modified double-hole silicon dioxide nanoparticle, the double-hole silicon dioxide nanoparticle simultaneously contains a plurality of macropores and a plurality of micropores, and the macropores and the micropores are uniformly distributed on the carrier. The aperture of the large hole is 20-40nm, the aperture of the small hole is 2-5nm, and the magnetic immobilized enzyme has strong magnetism, is more rapid and convenient to recover, has good reusability, is simple and convenient to operate, has a wide application prospect, and is suitable for industrial preparation of chitosan oligosaccharide.

The invention provides a Brown relaxation dominated magnetic nanoparticle nonlinear biological information parameter estimation method. The method comprises the following steps: putting a container of a magnetic nanoparticle sample into a to-be-detected object area; applying low and medium frequency alternating current magnetic field excitation to the magnetic nanoparticle sample; collecting magnetization response information of the magnetic nanoparticle sample in real time and extracting harmonic amplitude information from the magnetization response information; carrying out series expansion on the Fokker-Planck equation by using a disturbance expansion method, and deducing a harmonic analytical expression under the Brown relaxation condition; respectively establishing a corresponding temperature estimation model and a hydrodynamic diameter estimation model on the basis of the harmonic analytical expression; respectively substituting the measured harmonic amplitude information into a temperature estimation model or a hydrodynamic diameter estimation model based on a harmonic analytical expression; and respectively solving an equation set formed by the temperature estimation model or the hydrodynamic diameter estimation model to obtain temperature information or hydrodynamic diameter information. According to the invention, the measurement precision and the time resolution of the magnetic nanometer temperature measurement and biomarker identification tool can be improved.