25 results about "Protein precipitation" patented technology

The application provides a biological analysis method capable of accurately, simply and quickly detecting the concentration of adenosylcobalamin in human serum. The method is a liquid chromatography tandem mass spectrometry method, octadecylsilane bonded silica gel is used as the column filler, the liquid phase conditions, mass spectrometry parameters and sample processing method are designed and optimized, and the application first proposes and discloses a biological analysis method capable of accurately and quickly detecting the concentration of adenosylcobalamin in human serum: after simple treatment (need to avoid light) such as protein precipitation and nitrogen blowing dry, the sample can be injected, the analysis time is only 4.00 min, the lower limit of quantification is as low as 5 pg / mL, and the sample dosage is only 100 muL. The application can quickly monitor the change of vitamin B12 in the body, meet the requirements of adenosylcobalamin in vivo drug monitoring, pharmacokinetics and bioequivalence, and can effectively improve the safety and reliability of the drug.

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.

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.

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.

The application relates to the technical field of medicines, and discloses application of a traditional Chinese medicine composition in serum neurotransmitters, which comprises the following steps: selecting 6-8-week-old mice to establish normal models, chronic fatigue syndrome models and functional dyspepsia models; blood sampling is conducted on the mice of the normal models, the chronic fatigue syndrome models and the functional dyspepsia models to obtain normal blood samples, CFS blood samples and FD blood samples respectively; protein precipitation operation is conducted to obtain normal deproteinized supernatants, CFS deproteinized supernatants and FD deproteinized supernatants; separation is conducted by using a reversed-phase chromatographic column, and then mass spectrometry is conducted to obtain normal serum neurotransmitter mass spectra, CFS serum neurotransmitter mass spectra and FD serum neurotransmitter mass spectra respectively; concentration value calculation and rhythm fluctuation analysis are conducted to obtain a neurotransmitter function index and rhythm stability quantitative score respectively. Therefore, the mechanism of the traditional Chinese medicine composition in serum neurotransmitters is clearly quantitatively characterized.

This invention discloses a centrifugal microfluidic chip and a nucleic acid extraction method, specifically relating to the field of nucleic acid extraction technology. The method includes a pretreatment filtration module and a nucleic acid extraction and purification module. The sample solution undergoes primary and secondary filtration in the pretreatment filtration module to remove particulate impurities and protein precipitates, obtaining a clear sample supernatant. Nucleic acids in the supernatant are captured by a silica membrane in the nucleic acid extraction and purification module. Subsequently, a first washing solution and a second washing solution flow sequentially through the silica membrane to wash the adsorbed nucleic acids, removing residual impurities and reaction inhibitors. Finally, the eluent flows through the silica membrane, carrying the nucleic acids into the nucleic acid collection chamber, thereby obtaining the purified nucleic acid sample. This invention features a simple structure and reliable control, enabling sequential control of liquids in multiple chambers, effectively removing impurities and inhibitors from the sample, improving nucleic acid extraction efficiency and purity, and achieving a high degree of integration and automation in the nucleic acid extraction process for soil samples.

This invention discloses a single-sample multi-omics component extraction method for multi-omics joint analysis. The method includes: adding nucleic acid extraction solution to the sample, transferring it to a DNA adsorption column, centrifuging, and collecting the filtrate; washing the DNA adsorption column; eluting DNA; adding ethanol to the filtrate, transferring it to an RNA adsorption column, centrifuging, and collecting the filtrate; washing the RNA adsorption column; eluting RNA; and extracting proteins. This method integrates centrifugation column-based DNA / RNA co-extraction technology, a zinc ion-mediated protein precipitation and capture strategy, and an efficient Fe-IMAC phosphorylated peptide enrichment process. It achieves efficient protein precipitation and in-situ washing, thoroughly removing chemical components that interfere with mass spectrometry detection. It simultaneously achieves high-quality nucleic acid extraction and deep proteomics and phosphorylated proteomics coverage in a single sample, effectively solving the bottlenecks of traditional methods such as limited sample size, complex procedures, and poor reproducibility.

This invention provides a high-throughput analytical method based on UHPLC-MS / MS for screening 82 perfluorinated and polyfluoroalkyl substances in serum. The method employs a 96-well plate protein precipitation method for pretreatment, allowing direct injection of the extract, simplifying operation and reducing contamination. By optimizing chromatographic and mass spectrometric conditions, it achieves simultaneous separation and detection of 82 traditional and novel perfluorinated and polyfluoroalkyl substances, covering a wide range of categories including perfluorinated alkyl carboxylic acids, sulfonic acids, ethers, and fluorinated polymers. This method offers advantages such as simple pretreatment, broad coverage, high sensitivity, and high throughput, providing reliable technical support for population serum perfluorinated and polyfluoroalkyl substance exposure screening and health risk assessment.

This invention relates to the field of indophenol sulfate and p-cresol sulfate technology, and particularly to a method for determining the concentrations of indophenol sulfate and p-cresol sulfate in plasma. The method involves pretreating the sample, followed by determination of the concentrations of indophenol sulfate and p-cresol sulfate in the sample using liquid chromatography-mass spectrometry and an internal standard method. The sample includes plasma, and the pretreatment involves protein precipitation. This method exhibits good linearity, a low limit of quantitation, strong anti-interference capabilities, and high precision and accuracy.

This invention provides a method for preparing low-fat lactose-free milk, belonging to the field of dairy product technology. Based on raw milk, the method involves centrifuging to obtain low-fat milk, adding lactase (produced through aerobic fermentation using Aspergillus oryzae CICC 40228 and Kluyveromyces lactis BNCC 186193 and then immobilizing it) for enzymatic hydrolysis. The milk is then subjected to vacuum degassing, VTIS instantaneous sterilization, and two-stage homogenization to obtain low-fat lactose-free milk. The immobilized lactase prepared by the combined microbial fermentation has high activity and good compatibility, enabling deep lactose hydrolysis without introducing undesirable flavors. Vacuum degassing removes gases and trace amounts of off-flavors from the milk base and prevents oxidative denaturation. VTIS instantaneous sterilization achieves commercial sterility while maximizing the preservation of milk nutrients and natural flavor. Two-stage homogenization optimizes the low-fat milk colloidal dispersion system through the synergistic effect of high-pressure crushing and low-pressure stabilization, solving the problems of fat floating and protein precipitation.

The application discloses a method for improving the determination accuracy of the content of malondialdehyde in a biological sample, which comprises adding a buffer solution, a protease solution and a thiobarbituric acid (TBA) into a malondialdehyde standard solution, and determining the absorbance of the malondialdehyde standard solution; subsequently, a standard curve is constructed, and the actual concentration of the malondialdehyde in the biological sample is calculated through the measured absorbance of the biological sample solution. The sample processing process of the method is simple, the Buffer A buffer solution and the protease used can release the MDA combined with the protein, can not only avoid the adsorption interference of the protein precipitation on the red complex of the MDA and the TBA and the extraction limitation of the supernatant, but also can detect the protein combined state MDA, can significantly improve the detection limit of the sample, is good in selectivity, improves the accuracy of the detection result, and can be used for the trace detection of clinical precious samples.

The application discloses a method for determining the concentration of sofosbuvir in blood plasma and screening a non-isotope labeled internal standard, wherein anlotinib, imatinib, olaparib, osimertinib and pralsetinib are used as internal standards, quantitative analysis is performed by combining LC-MS / MS with protein precipitation pretreatment. The internal standard screening method is screened from candidate compounds by systematically evaluating four dimensions of protein precipitation compatibility, matrix effect, detection stability and extraction recovery, and an internal standard consistent with the behavior of the measured substance is screened. The application solves the problem of the lack of commercial isotope internal standards for sofosbuvir, and provides a reliable and efficient detection and internal standard screening scheme.

The application discloses a method for quantitatively analyzing 21 arginine synthesis metabolites in mouse liver, kidney and serum based on liquid chromatography-mass spectrometry technology and application of the method in cantharidin hepatorenal toxicity research. The method comprises the following steps: preparing 21 metabolites and two internal standard solutions; optimizing mass spectrometry multiple reaction monitoring parameters; performing sample analysis after protein precipitation by acetonitrile, nitrogen blowing dry and 50% methanol water reconstitution; and establishing eight concentration level standard curves and adopting a weighted least square method to fit a linear equation. Methodology verification shows that the linear relationship of each metabolite is good (r 2 >0.99), and the precision, accuracy, matrix effect, recovery rate and stability all meet the requirements of biological sample analysis. The method has simple sample pretreatment, high sensitivity and strong specificity, is successfully applied to determination of the content of 21 arginine metabolites in a mouse hepatorenal toxicity model caused by cantharidin, and provides a reliable analysis tool for arginine metabolism research and cantharidin toxicity mechanism exploration.

The present application belongs to the technical field of blood product preparation, and particularly relates to a preparation method of intravenous human immunoglobulin, comprising the following steps which are sequentially performed: Cohn FIII supernatant is pretreated to obtain a sample I to be loaded; the sample I to be loaded is subjected to first anion exchange chromatography to obtain a first chromatography product; the first chromatography product is pretreated to obtain a sample II to be loaded; the sample II to be loaded is subjected to second anion exchange chromatography to obtain a second chromatography product; the second chromatography product is pretreated to obtain a sample III to be loaded; the sample III to be loaded is subjected to heparin affinity chromatography to obtain a third chromatography product; and the third chromatography product is configured into human immunoglobulin finished product. The technical scheme can solve the technical problems of the existing preparation method of intravenous human immunoglobulin, such as introduction of new materials, poor effect of impurity protein precipitation, high content of anti-A and anti-B, and the like, and has an ideal application prospect.

This invention discloses a protein-induced self-growing transparent hydrogel antifouling coating and its preparation method, belonging to the field of marine antifouling gel coatings. The preparation method involves culturing bacteria that secrete large amounts of extracellular polymers and obtaining a sterile supernatant; adding a protein precipitant to obtain a precipitate; adding a protein precipitation washing reagent and mixing thoroughly to obtain the target protein, which is then freeze-dried and purified; immersing a substrate sample in a bacterial protein solution to deposit a protein coating; preparing a hydrogel precursor solution; immersing the protein coating in the hydrogel precursor solution; and allowing it to grow statically to obtain a protein-induced self-growing transparent hydrogel antifouling coating. This invention overcomes the shortcomings of current hydrogels, such as poor adhesion to the substrate and high cost, and successfully prepares a robust, low-cost, and environmentally friendly hydrogel adhesion layer with in-situ initiation and subsequent self-growth. It is not limited by traditional environmental constraints such as light and heat, thus expanding the application scenarios of hydrogels.

A sesame meal protein isolate and a method for extracting the sesame meal protein isolate are disclosed. A method for extracting the sesame meal protein isolate according to an embodiment of the present invention comprises: a step of lowering the fat content of the sesame meal using an edible basic first solution; a step of generating a protein precipitate of the sesame meal using an edible acidic second solution; and a step of treating the protein precipitate with the sesame meal protein isolate.

The invention relates to protein particles comprising a cluster of one or more types of assembled self-contained protein, wherein the particle has a size from 50 nm to 50 micrometers; is in form of a pellet in aqueous media; is mechanically stable; and it release a particular percentage by weight of the self-contained protein within a predetermined period of time, and any other compound contained in the particle. Particular methods for obtaining the particles are also disclosed, said methods comprising the addition of salts to allow precipitation of proteins. Particular protein particles comprising lipids associated with the assembly of self-contained proteins are also disclosed. The invention also relates to several uses of the particle, in particular medical uses and to pharmaceutical and cosmetic compositions comprising the particles.

The application discloses a kind of brain tissue and blood plasma double matrix amino acid class matter pretreatment and detection method, the method includes the following steps: standard preparation;Differential sample preparation and homogenization;Double protein precipitation and preliminary purification;Solid phase extraction (SPE) depth purification and enrichment;Microenvironment control's pre-column derivatization;HPLC-FLD chromatographic separation and detection;Result calculation.The application is by optimizing sample pretreatment process, introduce SPE depth purification and pre-column derivatization technology under specific pH condition, effectively solve the problem of brain tissue and blood plasma matrix complex, many interferents and amino acid derivatization efficiency low.This method has the advantages of simple steps, high accuracy, good sensitivity and excellent reproducibility, can realize the rapid, synchronous detection of 13 kinds of amino acid class matters in rat brain tissue and plasma, provides reliable technical means for neurotransmitter and related metabolite research.

This invention belongs to the field of pharmaceutical analytical chemistry technology, and provides a method for detecting meropenem concentration in human serum based on UPLC-MS / MS. This method uses acetonitrile protein precipitation for serum sample pretreatment, with C... 18 Separation was performed using a reversed-phase column with gradient elution of water-methanol as the mobile phase, and the total run time was 3 min. Mass spectrometry was performed in positive ion electrospray ionization mode and multiple reaction monitoring mode. Method validation results showed that meropenem was effective in the range of 1.563–100 μg / mL. ‑1 The linear relationship was good within the range, and the lower limit of quantitation was 1.563 μg·mL. ‑1 The intra-day and inter-day precision RSD were <5.69%, and the accuracy RE was within ±14.20%. Matrix effect, recovery, and stability all met the requirements for biological sample analysis. This method was used to determine the concentration of meropenem in human serum, providing technical support for therapeutic drug monitoring (TDM).

This document provides workflows for separating metabolites and lipids (“2in1”) or separating metabolites, lipids, and proteins (“3in1”). The 2in1 method involves: treating a sample containing metabolites and lipids with a mixture of methanol and ethanol to precipitate proteins; adding water to improve metabolite recovery; and passing the treated sample through a lipid-affinity solid-phase extraction (SPE) matrix. The effluent from the SPE matrix contains metabolites, and lipids can be eluted from the SPE matrix using a lipid elution solution. The 3in1 method is similar to the 2in1 method, except that proteins are granulated prior to SPE extraction, and then the granules are analyzed for protein content.

A method for preparing a linseed food product includes pulverizing linseed cake into powder and dissolving it in water. A neutral salt is added to the solution to precipitate proteins, forming a protein layer. The supernatant is discarded, and the remaining protein layer is centrifuged. Flour, starch, sugar, and egg white are added to the separated protein to form a dough. The dough is molded, fried at 140° C. to 160° C. for 2 to 6 minutes, and then baked at 200° C. for 8 to 15 minutes. This process creates a shelf-stable linseed-based snack with specific nutritional properties.

The application provides a method and application for detecting protein-bound uremic toxins, which comprises the following steps: mixing a blood sample and a protein precipitation extractant, centrifugally separating to obtain supernatant, mixing the supernatant and the protein precipitation extractant, centrifugally separating, filtering the treated supernatant to obtain a sample solution to be detected; preparing a standard solution of each sample to be detected, mixing the standard solutions of all the samples to be detected, and preparing a plurality of mixed standard solutions with different concentrations of the samples to be detected; performing high performance liquid chromatography on the mixed standard solutions to draw a standard curve between the concentration and the peak area of each sample to be detected, performing high performance liquid chromatography on the sample solution to be detected to obtain the determination peak area of each sample to be detected, and calculating the content of each sample to be detected according to the corresponding standard curve. The application solves the problems of low detection sensitivity and difficulty in accurate detection of the existing detection methods.

This invention provides an LC-MS / MS method for the simultaneous detection of multiple major components of Shengmai Yin (Codonopsis pilosula formula) in plasma. The analytes include syringin, schisandrol A, gomisin D, schisandrol B, gomisin G, schisandrin A, schisandrin A, schisandrin B, codonopsis glycoside I, codonopsis alkynyl glycoside, methyl ophiopogon flavanone A, and methyl ophiopogon flavanone B. The method includes the following steps: preparation of a series of standard curve working solutions; preparation of standard curve samples; preparation of quality control working solutions; preparation of quality control samples; preparation of a mixed internal standard working solution; pretreatment of the standard curve, quality control, and analyte plasma samples using protein precipitation; sample detection; and quantitative determination based on the peak area ratio of the analyte to the internal standard to obtain the standard curve. The methodological investigation results of this invention show that the established method meets the requirements for in vivo biological sample determination, the pretreatment process is simple, and the method has good sensitivity, strong specificity, and high specificity, making it suitable for the detection of compounds with low concentrations.

This invention belongs to the field of analytical chemistry and biomedical detection, and discloses a method for detecting nucleotides in biological samples based on liquid chromatography-mass spectrometry (LC-MS). The method includes: pretreatment of the biological sample by homogenization with a weakly basic ammonium acetate buffer, protein precipitation with organic solvent, vacuum concentration, and reconstitution; separation using an alkali-resistant C18 column and a weakly basic mobile phase with gradient elution; and detection by multiple reaction monitoring (MRM) in negative ion mode using an electrospray ionization source. This invention can simultaneously detect more than 40 target substances, covering bases, nucleosides, deoxynucleosides, and their phosphorylated forms and modified metabolites, with a limit of quantitation at the ng / pg / mL level. It exhibits strong resistance to matrix interference and excellent chromatographic separation. This method is rapid, highly sensitive, and stable, suitable for high-throughput and precise detection of nucleotides in biological samples, providing a powerful tool for disease biomarker screening and related basic research.

The application discloses a detection kit for simultaneously determining the concentrations of 12 kinds of antibiotic drugs in trace serum and application, the 12 kinds of antibiotics including vancomycin, meropenem, imipenem, cilastatin, trimethoprim, linezolid, voriconazole, piperacillin, cefoperazone, sulfamethoxazole, cefepime and ceftazidime; the detection kit comprises pretreatment reagents and a liquid chromatography mobile phase; the pretreatment reagents comprise a protein precipitant and purified water; the protein precipitant comprises 50v / v% of methanol and 50v / v% of acetonitrile; the liquid chromatography mobile phase comprises phase A and phase B, the phase A comprises 0.02% of formic acid and 99.98% of water, and the phase B comprises 100% of acetonitrile. The method of the application only needs 10 muL of human serum sample, and can complete the detection within 4 min, can quantitatively determine 12 kinds of antibiotics with significant structural differences, and is simple, rapid, sensitive, accurate and specific.