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124 results about "Protein precipitation" patented technology

Protein precipitation is widely used in downstream processing of biological products in order to concentrate proteins and purify them from various contaminants. For example, in the biotechnology industry protein precipitation is used to eliminate contaminants commonly contained in blood. The underlying mechanism of precipitation is to alter the solvation potential of the solvent, more specifically, by lowering the solubility of the solute by addition of a reagent.

Method for isolating and / or enriching extracellular vesicles

The invention provides a method for separating extracellular vesicles from a milk source, which comprises the step of adding a dispersing agent before adding a precipitator into the milk source to precipitate casein so as to reduce the wrapping of protein precipitation on the extracellular vesicles and improve the yield of the extracellular vesicles, thereby obtaining a milk source extract rich in the extracellular vesicles.
Owner:BEIJING CHANGXIANG BIO-PHARM CO LTD

Active peptide and brain peptide enzymolysis extract for improving memory as well as preparation method and application of active peptide and brain peptide enzymolysis extract

The invention belongs to the technical field of active peptides, and particularly relates to an active peptide capable of improving memory, a brain peptide enzymolysis extract and a preparation method and application of the brain peptide enzymolysis extract. The amino acid sequence of the active peptide is shown as SEQ ID NO.1 Ala-Ala-Val-Pro, and the active peptide can improve sleep and improve memory; on the other hand, the invention provides a preparation method of the brain peptide enzymolysis extract. The preparation process comprises the steps of raw material pretreatment and grinding, microwave treatment and centrifugal separation, protein precipitation and enzymolysis, microwave-assisted enzymolysis and purification and nanofiltration membrane filtration. Pepsase is added in the microwave treatment, and the temperature is not more than 50 DEG C in the enzymolysis process, so that the small molecule peptide keeps relatively high activity; furthermore, carbon dioxide gas is introduced in the microwave treatment for aeration, and the aeration pressure and the pH value are optimized, so that the activity and the yield of the brain peptide enzymolysis extract are further improved.
Owner:HANGZHOU BIBAU BIOTECHNOLOGY CO LTD

Nucleic acid isolation and inhibitor removal from complex samples

The present disclosure provides methods for isolating nucleic acids from a sample, comprising: (a) contacting a sample, a lysate of the sample, a supernatant of the lysate, or a portion of the sample, the lysate or the supernatant with one or more first agents (e.g., protein precipitating agents) and one or more second agents (e.g., inhibitor removing agents) to generate a mixture, (b) separating the mixture of step (a) into a solid phase and a liquid phase, wherein the one or more second agents are primarily in the solid phase, and (c) isolating nucleic acids from the liquid phase of step (b). Compositions and kits useful in such methods are also disclosed. Further disclosed are methods, compositions and kits for preparing a lysate using a lytic reagent comprising one or more relatively mild chaotropic agents and one or more phosphates from a sample, especially a complex sample, such as a soil or stool sample.
Owner:QIAGEN SCIENCES LLC

Preparation method of squid skin chelated calcium peptide powder

The invention belongs to the technical field of food processing methods, and particularly relates to a preparation method of squid skin chelated calcium peptide powder. Squid skin is used as a raw material, small-molecular-weight squid skin peptide powder is obtained through enzymolysis, ultrafiltration and membrane separation, then the small-molecular-weight squid skin peptide powder, calcium chloride and ethyl alcohol are subjected to a chelation reaction and protein precipitation, centrifugation is conducted, precipitates are collected, and the squid skin chelated calcium peptide powder is obtained. According to the preparation method, the utilization rate of the squid skin leftovers is increased, and active substances contained in the squid skin leftovers are fully developed and utilized. Moreover, according to the embodiment, the operation is simple, and the prepared squid skin chelated calcium peptide powder has relatively strong oxidation resistance and relatively high calcium chelation rate, and the highest calcium chelation rate can reach 63.18%; and the calcium absorption rate and the calcium content are relatively high and can reach 77.14% and 65.82 mg / g respectively.
Owner:NINGBO ACAD OF AGRI SCI +1

Method for determining concentration of letemovir in plasma by using liquid chromatography-tandem mass spectrometry

The invention discloses a method for determining the concentration of letemovir in plasma by using liquid chromatography-tandem mass spectrometry, which comprises the following steps: S1, preparing a calibrator working solution and a quality control working solution of letemovir, respectively adding the calibrator working solution and the quality control working solution into a plasma matrix to obtain a plasma calibrator and a plasma quality control, preparing an internal standard working solution taking the lenvatinib-d5 as an internal standard substance; s2, respectively adding a plasma calibration material and a plasma quality control material into the internal standard working solution obtained in the step S1, carrying out protein precipitation treatment, collecting supernate, carrying out liquid chromatography-tandem mass spectrometry analysis on the supernate, and drawing a liquid chromatography-tandem mass spectrometry standard curve; and S3, obtaining the concentration of letemovir in the plasma of a sample to be detected according to the liquid chromatography-tandem mass spectrometry in the step S2. According to the method, the sample pretreatment step is simplified, the operation difficulty and time consumption are reduced, a rapid, accurate and high-sensitivity analysis result is ensured, and the method is suitable for the requirements of rapid clinical and research fields.
Owner:PULAN (HANGZHOU) MEDICAL TECHNOLOGY CO LTD

Composition for protein precipitation, protein precipitation agent containing same, protein precipitation combination product, detection kit, and preparation method and detection method of blood analysis sample

The invention relates to the technical field of biological detection, in particular to a composition for protein precipitation, a protein precipitation agent containing the composition, a protein precipitation combined product, a detection kit and a preparation method and a detection method of a blood analysis sample. The composition for protein precipitation comprises zinc sulfate and ammonium acetate in a dosage ratio of (5-17) mg: (0.5-1) mmol. Compared with the prior art, the composition has the following beneficial effects that the zinc sulfate and the ammonium acetate are matched according to a specific proportion, so that the specific composition is formed, and hemoglobin in a blood sample can be effectively removed by taking the composition as a protein precipitation component.
Owner:RELAIS (HANGZHOU) MEDICAL TECH CO LTD

Protein precipitation supernate drainage device

The utility model relates to the field of protein purification, and discloses a protein precipitation supernate drainage device, a precipitation tank is mounted in a mounting cylinder, the upper half part of the precipitation tank is of a cylindrical structure, the inner diameter of the lower end of the precipitation tank is gradually reduced to form a conical part, a pipeline is welded at the bottom end of the conical part, and the lower end of the pipeline is provided with a liquid outlet. A valve is installed below the pipeline, a cover plate is rotationally installed above the centrifugal machine, the cover plate penetrates through the upper portion and the lower portion of the cover plate and is slidably connected with a liquid suction pipe in a sleeving mode, and a liquid suction hose is connected to the end, away from the sedimentation tank, of the liquid suction pipe and connected with a liquid inlet of an external peristaltic pump. The settling tank is fixed in the mounting cylinder, and the settling tank is combined with the centrifugal machine, so that the settling tank can be centrifuged after isoelectric point settling, secondary transfer of protein precipitate after settling is not needed, the loss is reduced, and the convenience is improved.
Owner:QUALITY PEPTIDE PHARMACEUTICAL (TAIZHOU) CO LTD

Method for simultaneously detecting multiple fat-soluble vitamins

The invention relates to the field of detection, in particular to a method for simultaneously detecting multiple fat-soluble vitamins, which comprises the following steps: (S.1) carrying out protein precipitation and liquid-liquid extraction on a sample to be detected to obtain an extract containing fat-soluble vitamins; (S.2) carrying out derivatization reaction on the extract by using a PTAD derivatization reagent; and (S.3) analyzing the derivatized product by adopting a liquid chromatography-tandem mass spectrometry method, wherein the detected target fat-soluble vitamins comprise vitamin A, vitamin E, 25-hydroxy vitamin D2, 25-hydroxy vitamin D3, vitamin K1, vitamin K2 and vitamin K2. According to the application, PTAD is creatively adopted as a unified derivatization reagent, simultaneous and efficient derivatization of seven fat-soluble vitamins is successfully realized, the detection sensitivity of low-content targets, especially vitamin D, K2 and the like, is greatly improved, and the core problems of weak signal response and difficulty in accurate quantification are solved.
Owner:CHANGCHUN INSTITUTE OF APPLIED CHEMISTRY CHINESE ACADEMY OF SCIENCES +1

Purification method of cord blood mesenchymal stem cell source exosome

The invention discloses a purification method of cord blood mesenchymal stem cell source exosome, and relates to the technical field of bioengineering. The method comprises the following steps: firstly, carrying out pH regulation pretreatment on cell culture supernate through a technical path of combining gradient centrifugation and membrane filtration, and sequentially removing cell debris and large-particle impurities by adopting multi-stage differential centrifugation; then carrying out selective protein precipitation by utilizing polyethylene glycol with specific molecular weight, and realizing fine separation of the exosome by combining sucrose-meglumine diatrizoate density gradient centrifugation; and finally, terminal purification is completed under low-temperature and low-pressure conditions through a polyethersulfone membrane filtration system with an optimized pore size. According to the method, centrifugal parameters, reagent concentration and filtering conditions are precisely regulated and controlled, so that the particle size of the obtained exosome is intensively distributed in the range of 30-150nm, the protein purity reaches 95% or above, the recovery rate exceeds 85%, and the separation efficiency and quality of the exosome are remarkably improved.
Owner:XIAMEN SERBANGKE BIOTECHNOLOGY CO LTD

A rapid detection method for simultaneously detecting four oxidative stress-related biomarkers and its application.

This invention provides a method for the simultaneous and rapid detection of four oxidative stress-related biomarkers and its application. The detection method includes: (S1) pretreatment of samples using a protein precipitation extract to simultaneously extract four target compounds: 8-hydroxydeoxyguanosine, 8-isoprostaglandin F2β, 8-isoprostaglandin F2α, and acetyllysine, and preparing a test solution; the protein precipitation extract is a methanol-acetonitrile-perchloric acid mixed solution containing formic acid, wherein the volume ratio of methanol, acetonitrile, and perchloric acid is (8-10):(8-10):(0.5-1), and the volume concentration of formic acid is 0.1-0.5%; (S2) detection of the test solution and standard solution using liquid chromatography-tandem mass spectrometry, and matrix calibration using an internal standard method; plotting a standard curve with the peak area ratio of the target compound to the internal standard as the ordinate and the concentration as the abscissa; and calculating the concentration of the target compound in the test solution based on the standard curve.
Owner:SHANGHAI CITY PUDONG NEW AREA GONGLI HOSPITAL +1

Method for detecting components of a cosmetic fluid and method for detecting the penetration properties of a cosmetic fluid

The application relates to a component detection method of a cosmetic liquid and a permeability detection method of the cosmetic liquid, and the component detection method comprises the following steps: adding a protein precipitant to purify the cosmetic liquid; performing liquid chromatography-tandem mass spectrometry on the purified cosmetic liquid to obtain chromatographic peak response values of nicotinamide, ascorbic acid and VC ethyl ether; wherein, the positive ion and the negative ion are alternately ionized in the mass spectrometry, and multiple reaction monitoring is performed on the nicotinamide, the ascorbic acid and the VC ethyl ether; and the concentrations of the nicotinamide, the ascorbic acid and the VC ethyl ether in the cosmetic liquid are obtained according to the chromatographic peak response values. The method improves the detection precision of low-concentration and multi-target component.
Owner:SIWEIRUI TECHNOLOGY (SHENZHEN) CO LTD

An LC-MS / MS method for detecting neurotransmitter metabolites in a biological sample

PendingCN122361692ANeurotransmitter metabolismMetabolite
The application relates to an LC-MS / MS method for detecting neurotransmitter metabolites in a biological sample, comprising the following steps: S1, constructing a mass spectrum database containing neurotransmitter metabolites and isotope internal standards; S2, preparing a mixed standard solution containing neurotransmitter standards and drawing standard curves of each neurotransmitter metabolite standard; S3, extracting a biological sample by a protein precipitation method to obtain a sample solution to be detected; S4, separating the sample solution to be detected by using liquid chromatography, wherein a mobile phase A of the liquid chromatography is an aqueous solution containing ammonium fluoride and formic acid, and a mobile phase B is an organic phase containing formic acid; and S5, performing mass spectrum detection on the sample separated by the liquid chromatography. The method can realize baseline separation of 57 metabolites within 9 minutes.
Owner:WUHAN METWARE BIOTECHNOLOGY CO LTD

A method for quantitatively determining the concentration of dapsone in human plasma by high performance liquid chromatography tandem mass spectrometry

The application provides a method for quantitatively detecting the concentration of dapsone in human plasma by using liquid chromatography-tandem mass spectrometry (LC-MS / MS). By optimizing the chromatography and mass spectrometry conditions, the detection specificity and sensitivity are improved. The protein precipitation pretreatment and rapid chromatography separation technology are adopted, the analysis time is shortened, the sampling amount is reduced, and the automation adaptability is good. The method can be used for efficient and accurate quantification, and is suitable for clinical pharmacokinetic research and treatment monitoring.
Owner:SHANDONG ANJIE BIODETECTION TECHNOLOGY CO LTD

Method for determining D-psicose in processed food and application of method

The invention provides a method for determining D-psicose in processed food and application of the method. The method specifically comprises the following steps: extracting a sample with warm water at 50-60 DEG C, precipitating protein by adopting a Carrez reagent, and removing interference impurities; chromatographic conditions are defined as follows: a calcium type strong cation exchange column is adopted, pure water containing 50 mg / L of EDTA-Ca is adopted as a mobile phase, the flow rate is 0.4-0.6 mL / min, and the column temperature is 80 DEG C. The result shows that the linear relation of the D-psicose is good in the concentration range of 1.0 mg / mL to 20.0 mg / mL, and the correlation coefficient is 0.999999; according to the method, the LOD is 0.002 g / 100g, and the LOQ is 0.005 g / 100g. Under the experimental conditions of standard addition before simulation processing, the average recovery rate of 18 matrixes including dairy products, bakery products and the like is 81.5-128.1%, and the RSD is less than 3.0%. The determination method provided by the invention is simple in pretreatment, high in sensitivity, strong in interference resistance and good in accuracy, effectively solves the ubiquitous problems of matrix wrapping, matrix interference, difficulty in isomer separation and the like when the D-psicose in the processed food is detected, can realize rapid and accurate detection of the D-psicose in all dosage forms of processed food, and has a wide prospect.
Owner:HENAN ZHONGDA HENGYUAN BIOTECH CO LTD

Compound stabilizer and milk coffee beverage

The invention discloses a compound stabilizer and a milk coffee beverage, and relates to the technical field of food additives, the compound stabilizer is used in the milk coffee beverage, and the compound stabilizer comprises the following components in parts by mass: 5-8 parts of an emulsifier, 1.2-2.5 parts of a thickener and 1.2-2.5 parts of phosphate. Meanwhile, the mass parts of the emulsifier, the thickening agent and the phosphate are controlled within the range, so that a stable beverage system can be formed after the compound stabilizer is added into the milk coffee beverage, and the aroma and taste stability of the milk coffee beverage after high-temperature sterilization and the system stability after high-temperature storage are improved; the quality problems of protein precipitation, water separation, product layering, oil slick and the like after the milk coffee beverage is placed for a long time are reduced, and the storage stability and consumption experience of the product are remarkably improved.
Owner:CHINA RESOURCES CESTBON BEVERAGE CHINA CO LTD

Method for simultaneously detecting dichloroacetic acid and trichloroacetic acid in urine

The invention provides a method for simultaneously detecting dichloroacetic acid and trichloroacetic acid in urine, and belongs to the technical field of analysis detection and occupational health / environmental health. According to the method disclosed by the invention, a synergistic pretreatment strategy of acidic sample loading, WAX / reversed-phase mixed mode solid-phase extraction, water / low-proportion organic phase step-by-step leaching and ammonia-water-containing organic phase elution is adopted; a technical route of protein precipitation, acidification pH regulation, purification and enrichment by adopting WAX / reversed-phase mixed mode solid-phase extraction on a 96-well plate and stable isotope internal standard isotope dilution LC-MS / MS quantification is adopted, the method can effectively reduce the matrix effect and realize high-throughput analysis in a high-salinity urine matrix, the quantitation limits of DCEA and TCAA are not higher than 0.30 g / L and 0.20 g / L respectively, and the method has the advantages that the method is simple and convenient to operate, and the method is suitable for large-scale popularization and application. The method is suitable for biological monitoring and risk assessment of occupational and environmental low-level exposure crowds.
Owner:NINGBO CENTER FOR DISEASE CONTROL & PREVENTION (NINGBO HEALTH SUPERVISION INSTITUTE NINGBO HEALTH EDUCATION & PROMOTION CENTER)

Efficient detection method for six sugar alcohol compounds in dairy product

The invention relates to the technical field of food detection, discloses an efficient detection method for six sugar alcohol compounds in dairy products, and aims to solve the problems that in the prior art, dairy product protein precipitation and high-efficiency dissolution of strong-polarity sugar alcohol are difficult to consider at the same time, and toxic precipitants, high-temperature treatment or complex solid-phase extraction are often depended on. The problems of tedious operation, high equipment threshold and poor detection stability exist in the prior art, trichloroacetic acid with optimized concentration is used for constructing a water phase system, and dissolution of six sugar alcohols and preliminary precipitation of protein are synchronously realized; the high-protein matrix of the milk powder is supplemented with precise supplementary precipitation, and the liquid milk is simplified; a specific chromatographic column and gradient elution are combined, linear correlation is established by adopting an external standard method, synchronous detection of six sugar alcohols is completed, high-temperature and solid-phase extraction consumables are not needed, two matrixes of milk powder and liquid milk are adapted, the operation time is short, the detection recovery rate is high, the precision is excellent, the existing pain point is effectively solved, and the batch detection requirement of a conventional laboratory is met.
Owner:INNER MONGOLIA AUTONOMOUS REGION PROD QUALITY TEST INST

Method for producing sweet tea extract and use thereof

The present application relates to the technical field of plant extraction, and particularly relates to a preparation method of sweet tea extract and application thereof. The preparation method of the sweet tea extract comprises the following steps: extraction, concentration, fermentation, decolorization, cold precipitation and extraction. By controlling the alcohol concentration in the extraction step, the protein precipitation and the reduction of pectin substance precipitation are facilitated, and by combining with the step of air oxidation in the extraction process, the bitter and astringent taste of the prepared sweet tea extract in the prepared cigarette can be removed, and the yield of the sweet tea extract is greater than or equal to 90%.
Owner:JILIN TOBACCO IND CO LTD +1

Sample pretreatment method and method for detecting VK2 and VD in serum

The invention relates to the technical field of in-vitro detection, in particular to a sample pretreatment method and a method for detecting VK2 and VD in serum. According to the specific technical scheme, the method comprises the following steps: carrying out protein precipitation after carrying out enzymolysis on serum, taking supernate, mixing the supernate with activated magnetic beads, enabling the magnetic beads to adsorb a target object, finally eluting the magnetic beads adsorbed with the target object by using eluent, collecting the eluent, and detecting the eluent to obtain vitamin K2 (VK2) and 25-hydroxy vitamin D (VD) at the same time. The problems that pretreatment operation is tedious, health is harmed and flux is low are solved by adopting an automatic magnetic bead method; the problems that detection equipment is expensive and difficult to popularize are solved by adapting to a conventional mass spectrum platform; the technical path is not only suitable for detection of vitamin K2 and 25-hydroxyvitamin D, but also provides a solution normal form with popularization value for detection of trace micromolecular markers which are difficult to popularize due to complex pretreatment or high equipment threshold.
Owner:BEIJING JISHUITAN HOSPITAL

Application of traditional Chinese medicine composition in serum neurotransmitter

The invention relates to the technical field of medicines, and discloses an application of a traditional Chinese medicine composition in serum neurotransmitter, which comprises the following steps: selecting 6-8 weeks old mice to establish a normal model, a chronic fatigue syndrome model and a functional dyspepsia model; the method comprises the following steps: sampling blood from mice of a normal model, a chronic fatigue syndrome model and a functional dyspepsia model to respectively obtain a normal blood sample, a CFS blood sample and an FD blood sample, and performing protein precipitation operation to obtain normal deproteinized supernatant, CFS deproteinized supernatant and FD deproteinized supernatant; separating by using a reversed-phase chromatographic column, and then carrying out mass spectrometric detection to respectively obtain a normal serum neurotransmitter mass spectrogram, a CFS serum neurotransmitter mass spectrogram and an FD serum neurotransmitter mass spectrogram; and carrying out concentration value calculation and rhythm fluctuation analysis to respectively obtain a neurotransmitter function index and a rhythm stability quantitative score. Therefore, the action mechanism of the serum neurotransmitter of the traditional Chinese medicine composition can be clearly and quantitatively represented.
Owner:RUIJIN HOSPITAL AFFILIATED TO SHANGHAI JIAO TONG UNIV SCHOOL OF MEDICINE +1

Synchronous detection method for L-asparagine monohydrate and L-alanyl-L-glutamine in assisted reproduction culture solution

The invention discloses a method for synchronously detecting L-asparagine monohydrate and L-alanyl-L-glutamine in an assisted reproduction culture solution. The L-asparagine monohydrate and the L-alanyl-L-glutamine in the assisted reproduction culture solution are used as a detection reagent. According to the method, a pretreatment mode of combining protein precipitation with diluted hydrochloric acid extraction is adopted, a target object is separated through ion exchange chromatography, and a ninhydrin post-column derivatization technology is adopted to establish an external standard method quantitative analysis system. The method has the following advantages: (1) synchronous and efficient separation and accurate quantification of two amino acid substances are realized; (2) methodology verification shows that good repeatability (RSD (Relative Standard Deviation) is 1.05) and high sensitivity (the detection results of L-asparagine monohydrate and L-alanyl-L-glutamine are 0.00038 mg / mL and 0.00036 mg / mL respectively); (3) the operation is simple and convenient, and the single analysis time is about 60 minutes; and (4) the recovery rate is stabilized in a range of 93%-105%. The method provides a reliable analysis means for quality control of the assisted reproduction culture solution, and is particularly suitable for quantitative determination of key amino acid components in the assisted reproduction culture solution.
Owner:EPINTEK +1

A patterned bio-barrier membrane with self-adhesive function and a preparation method thereof

This invention belongs to the field of medical materials, specifically relating to a patterned bio-barrier membrane with self-adhesive function and its preparation method. The preparation method includes: dissolving the adhesive matrix in a buffer solution, then adding reactive amino acids and a stabilizer to obtain a first mixture; adding ethanol and a hydrophobic agent to the first mixture, and stirring under heating conditions to obtain a second mixture; adding a thickener, a calcium supplement, and a reinforcing agent to the second mixture, continuing stirring, and then adding a protein precipitation reagent to precipitate the mixture, obtaining a hydrogel; covering a collagen membrane with a patterned porous mold, and adding the hydrogel to allow it to flow into the pores and solidify. This invention achieves precise adhesive loading through patterned design, combining advantages such as simple operation, reliable fixation, good biocompatibility, and high osteogenic efficiency, effectively solving the barrier membrane fixation problem in GBR technology, and is suitable for bone defect treatment in dental implant prosthesis restoration.
Owner:SICHUAN ACADEMY OF MEDICAL SCI SICHUAN PROVINCIAL PEOPLES HOSPITAL

Liquid treatment system

The utility model discloses a liquid treatment system which comprises a liquid working station, the liquid working station is provided with a working platform, the top end of the working platform is provided with a liquid transferring mechanical arm used for transferring liquid and a plate transferring mechanical arm used for transferring a pore plate, one end of the working platform is provided with a CO2 incubator, and the other end of the working platform is provided with a film sealing machine and a positive pressure module. The positive pressure module comprises a liftable base as well as a protein precipitation plate placing area and a sample receiving plate placing area which are positioned on the base, the protein precipitation plate placing area and the sample receiving plate placing area are respectively used for placing a protein precipitation plate and a sample receiving plate, and a pressurizing part is arranged at the top end of the protein precipitation plate placing area; a sample receiving plate placing area is arranged at the bottom end of the protein precipitation plate placing area and is used for collecting the to-be-analyzed liquid purified by the protein precipitation plate. According to the liquid treatment system disclosed by the utility model, the functions of sample adding, incubation, termination and solid-liquid separation are realized at the same time, and complicated liquid transfer operation is not needed.
Owner:XBL-CHINA INC +1

Liquid chromatography-mass spectrometry detection kit and detection method for serum seleno-amino acid based on mass spectrometry probe labeling

The invention belongs to the technical field of health, clinical and medical related detection, and relates to a liquid chromatography-mass spectrometry detection kit and a detection method for serum seleno-amino acid labeled on the basis of a mass spectrometry probe. The detection kit comprises a mass spectrum probe solution, a protein precipitant solution and a buffering agent solution, the mass spectrum probe is 6-aminoquinolyl-N-hydroxysuccinimido carbamic acid ester, and the mass spectrum probe is 2-aminoquinolyl-N- The buffer solution contains a seleno-amino acid isotope internal standard. According to the kit, a mass spectrum probe is used for labeling, a serum sample is subjected to protein precipitation and then mixed with the mass spectrum probe at room temperature, and simultaneous high-flux accurate quantification of multiple seleno-amino acids can be directly achieved through liquid chromatography-tandem mass spectrometry in a conventional reversed-phase chromatography mode. The 6-aminoquinolyl-N-hydroxysuccinimido carbamate mass spectrum probe adopted in the kit disclosed by the invention has the advantages of high reaction activity, convenience in operation, high sensitivity and the like.
Owner:HUBEI GEOLOGY EXPERIMENTATION & RES INST

A method for purifying umbilical cord blood mesenchymal stem cell-derived exosomes

The application relates to a method for purifying umbilical cord blood mesenchymal stem cell-derived exosomes, and relates to the technical field of bioengineering. The method combines gradient centrifugation and membrane filtration. First, the cell culture supernatant is pretreated by adjusting the pH, and cell debris and large-particle impurities are removed by multi-stage differential centrifugation. Then, selective protein precipitation is carried out by using polyethylene glycol with a specific molecular weight, and the exosomes are finely separated by sucrose-meglumine diatrizoate density gradient centrifugation. Finally, terminal purification is completed under low-temperature and low-pressure conditions by using a polyether sulfone membrane filtration system with optimized pore size. By precisely controlling the centrifugation parameters, reagent concentration and filtration conditions, the exosomes obtained by the method have a particle size concentrated in the range of 30-150 nm, a protein purity of more than 95%, and a recovery rate of more than 85%, and the separation efficiency and quality of the exosomes are significantly improved.
Owner:XIAMEN SERBANGKE BIOTECHNOLOGY CO LTD

Method for extracting protein from human plasma for protein analysis

The invention discloses a method for extracting protein from human plasma for protein analysis, and relates to the technical field of plasma treatment, the key points of the technical scheme are as follows: the method effectively removes high-abundance protein, lipid and other interfering substances in the plasma through two steps of protein precipitation with acetone, degreasing and high-abundance protein removal; the method is suitable for subsequent protein identification and quantitative analysis. A stable and reliable method is provided for pretreatment of the plasma sample, a technical basis is provided for further use of protein in plasma for various medical analyses, and further development of the technology in the plasma detection field is facilitated.
Owner:THE FIRST AFFILIATED HOSPITAL OF GUANGZHOU UNIV OF CHINESE MEDICINE

Method for simultaneously determining branched chain amino acids and metabolites thereof in serum based on liquid chromatography-mass spectrometry

The invention provides a method for simultaneously determining branched chain amino acids and metabolites thereof in serum based on liquid chromatography-mass spectrometry, and belongs to the technical field of chemical analysis. The method provided by the invention adopts a protein precipitation method, is simple to operate, does not need derivation and concentration, simplifies the pretreatment step, shortens the pretreatment time, and avoids the influence of complex pretreatment on the stability of a determination result. According to the method, the absolute signal and the absolute concentration are converted into the relative signal and the relative concentration by using an internal standard method, so that a calibration curve with strong anti-interference capability and high accuracy is constructed, accurate quantification of an unknown blood sample to be detected is finally realized, and the method has excellent accuracy and reproducibility.
Owner:NAT INST FOR NUTRITION & HEALTH CHINESE CENT FOR DISEASE CONTROL & PREVENTION

A method of liquid chromatography tandem mass spectrometry for rapid analysis of multiple amino acids in plasma

The present invention discloses a method for liquid chromatography tandem mass spectrometry for rapid analysis of multiple amino acids in plasma. The method comprises the following steps: S1. Preparation of an amino acid standard curve working solution, including accurately weighing powders of 26 amino acid standards respectively, adding them to pure water, and fully mixing to prepare single amino acid stock solutions of 10 mg / mL. The present invention relates to the technical field of liquid chromatography tandem mass spectrometry for simultaneous detection of multiple amino acids. For the method of liquid chromatography tandem mass spectrometry for rapid analysis of multiple amino acids in plasma, after performing a protein precipitation reaction on the plasma, the treated sample can be used for liquid chromatography tandem mass spectrometry analysis. Combining with the pretreatment mode of 96-well plates, the pretreatment process of 96 plasma samples only takes 40 minutes. Additionally, by using an optimized combination of mobile phase and chromatographic column, the sample injection analysis time is only 10 minutes. The processing scheme of this device is simple and efficient, and no derivatization reaction is required.
Owner:INSTITUTE OF BIOPHYSICS CHINESE ACADEMY OF SCIENCES +1

A system for optimizing Cassia Tora gum production to increase yield and quality for applications in the food industry

ActiveDE202025104444U1BiotechnologySolvent
A system for optimizing Cassia Tora gum extraction to improve yield and quality for applications in the food industry, consisting of: (a) a seed processing unit configured to mechanically dehull and grind Cassia tora seeds to separate the endosperm; b) a defatting unit configured to remove fats from coarsely ground endosperm powder using hexane; (c) a hydration unit configured to hydrate the defatted endosperm powder in distilled water with continuous stirring to obtain a viscous suspension; (d) a filter unit configured to filter the mixture through a muslin cloth to remove insoluble residues; (e) a mucus extraction unit configured to subject the filtered residues to boiling in water for improved mucus extraction; (f) a protein precipitation unit configured to treat combined viscous extracts with 10% trichloroacetic acid to precipitate proteins; g) a solvent treatment unit configured to introduce a solvent selected from the group consisting of isopropanol, ethanol and acetone to induce mucus coagulation; (h) a drying unit configured to vacuum dry the coagulated mass at 40 °C; (i) a grinding unit configured to finely grind the resulting rubber, wherein the powdered rubber has been sieved and stored in an airtight container; and j) a Taguchi optimization controller configured to optimize extraction parameters such as CT powder-to-water ratio, solvent type, and mucus-to-solvent ratio using the orthogonal L9 array design.
Owner:KHANDEKAR SNEHAL PRANAV KOLHAPUR +4