134 results about "Resolution (mass spectrometry)" patented technology

The invention relates to the technical field of ion characterization and preparation, in particular to a high-throughput preparation mass spectrum device and method giving consideration to high-resolution characterization. The device comprises an ion source, an ion transmission cavity, a quadrupole mass screening cavity, an ion dissociation cavity, an ion deflection cavity, an ion deceleration and deposition cavity and a high-resolution mass spectrum characterization cavity which are sequentially arranged, wherein the high-resolution mass spectrum characterization cavity is formed in one side of the ion deflection cavity in the vertical direction; soft ionization is combined with a quadrupole analyzer to screen ions, the ions are dissociated through a dissociation cavity, an ion deflection cavity is used for selecting a high-resolution characterization or high-throughput preparation function, a high-resolution mass spectrum characterization cavity is used for achieving high-resolution characterization of screened and fragmented ions, and an ion deceleration and deposition cavity is used for high-throughput preparation of the ions. According to the method, perfect compatibility of high-throughput preparation and high-resolution mass spectrum characterization is realized through ion deflection design, and the method has a wide application prospect in the fields of efficient preparation of biological macromolecules, synthetic macromolecules and the like and the like.

The invention provides a tissue high-resolution mass spectrum imaging technology based on light-driven expansion hydrogel, and belongs to the field of mass spectrum imaging. The technology comprises preparation of light-driven hydrogel, preparation of a light-driven gelation biological sample, digestion and expansion of the gelation biological sample and mass spectrum imaging of the expanded gelation biological sample. The gelation process of the light-driven expansion hydrogel is not inhibited by oxygen, the gelation time is short (only 3 minutes), the gel thickness can be controlled by controlling the addition amount of a gel monomer solution, and the adaptability to a mass spectrum imaging technology is higher; according to the method, 6 times of linear expansion of the hydrogel is successfully realized, and spatial distribution characterization of lipid in liver lobules is realized under the spatial resolution of 100 microns. The method is low in cost and simple and convenient to operate, and has a wide application prospect in popularization of a high-resolution mass spectrum imaging technology at a biological tissue molecule level.

The invention discloses a quantitative detection method for tobacco components. The quantitative detection method comprises the following steps: extracting a tobacco sample to obtain extract liquor; performing component analysis on the extracting solution by adopting high-resolution liquid chromatography-mass spectrometry to obtain a spectrogram of the tobacco sample; the high-resolution liquid chromatography mass spectrometry adopts two ion sources of an ESI source and an APCI source for detection, and the two ion sources both adopt reversed-phase chromatographic columns for detection; in detection, under the ESI source condition, positive and negative ion modes are adopted for scanning respectively, and under the APCI source condition, a positive ion mode is adopted for scanning. According to the quantitative detection method, two different ion sources are adopted, and high coverage and detection precision are both considered; corresponding chromatographic columns are adopted for liquid phase separation, separation of tobacco metabolism components with different properties in a complex natural tobacco matrix is facilitated, and the separation efficiency and the coverage degree are improved; by combining the ultrahigh resolution and high precision of the high-resolution liquid chromatography-mass spectrometry, the to-be-detected substance and the interfering substance are effectively distinguished, and the detection accuracy of various samples is improved.

The invention discloses a tissue slice high-resolution mass spectrum imaging method and system based on multi-modal data fusion, and belongs to the technical field of mass spectrum imaging and biomedical detection. The method comprises the steps of multi-modal data acquisition, data preprocessing, feature extraction, multi-modal data fusion and high-resolution imaging reconstruction. High-resolution mass spectrum data and high-stability auxiliary modal data are synchronously collected, after preprocessing and feature extraction, feature weights are dynamically distributed and fused by using a fusion model based on an attention mechanism, and then a high-resolution and high-sensitivity imaging result is output through an imaging reconstruction model of a U-Net improved architecture. On the premise that the spatial resolution is not reduced and the sample is not damaged, the mass spectrum signal intensity is effectively enhanced, the low-abundance biomarker recognition capability is improved, the imaging efficiency is high, the adaptability is high, and the method is suitable for biomedical research and clinical diagnosis scenes.

The disclosure relates to methods of detecting Host Cell Proteins (HCPs) in biopharmaceutical samples containing a drug product. More specifically, the disclosure relates to methods of assaying HCPs in biopharmaceutical samples using enzymatic digestion protocols, liquid chromatography (LC) gradients, immunoaffinity capture protocols, and High-Resolution Mass Spectrometry (HRMS) to enhance the recovery, detection, and profiling of HCPs, which can impact the efficacy, shelf-life, and therapeutic response of drug products.

The invention belongs to the technical field of chemical screening, and particularly relates to a systematic screening method for rubber-related chemicals in a plasma sample, which comprises the following steps: S1, taking the plasma sample, adding a mixed extraction solvent, extracting, centrifugally layering, collecting supernate, repeatedly extracting, merging the supernate, concentrating, and freezing to obtain a rubber-related chemical sample; centrifuging again, adding an isotope internal standard, and carrying out data dependence acquisition in a positive and negative ion analysis mode by adopting liquid chromatography-tandem high-resolution mass spectrometry. According to the invention, the comprehensive coverage type monitoring of 1300-1500 RDCs in the plasma sample is realized. By means of combination of a positive and negative ion double analysis mode and data dependence acquisition, the detection range and the signal response stability of the RDCs with different polarities are effectively considered, and the technical problem that in the prior art, the composite effect generated by coexistence of multiple RDCs is ignored is solved.

The invention discloses a method for analyzing and identifying chemical components of Mingzhi astragalus decoction based on high-resolution mass spectrometry, and relates to the technical field of traditional Chinese medicine compound analysis. The method comprises the following steps: preparing a Mingzhi Radix Astragali decoction test solution; the method comprises the following steps: respectively acquiring mass spectrum data in positive and negative ion modes under specific chromatography and mass spectrum conditions by adopting an ultra-high performance liquid chromatography-time-of-flight mass spectrometry technology; and comparing the obtained data with a pre-constructed specific chemical component database of the Mingzhi Astragalus decoction, and realizing systematic identification of the chemical components in the compound and medicinal material attribution according to a principle that an accurate mass number error is in a range of + / -3 ppm. The method provided by the invention efficiently, accurately and successfully identifies 53 chemical components in the Mingzhi radix astragali decoction and clarifies the source medicinal materials of the 53 chemical components, and provides a reliable technical scheme for comprehensively illuminating the basis of the compound substance, quality control and subsequent research.

The present invention provides an ion detector that can suppress variations in ion detection time for ions with the same mass-to-charge ratio, and a mass spectrometer that can improve the resolution of mass spectrometry. [Solution] The ion detector 1A includes a conversion unit 2A that emits electrons e to the other side of direction D when ions i are incident from one side in direction D, and an output unit 3 that outputs an electrical signal in response to the incidence of electrons e emitted from the conversion unit 2A. The conversion unit 2A includes a support having a support surface perpendicular to direction D, and an electron generation layer disposed on the support surface that generates electrons e in response to the incidence of ions i. The support has a plurality of passages through which ions i or electrons e pass. The plurality of passages are arranged two-dimensionally along the support surface.

The invention provides an ion measurement device with high-resolution mass spectrum detection and charge state measurement functions, and the device comprises a deflection system which is used for introducing solar wind ions into a geometric factor control system; the geometric factor control system is used for introducing the solar wind ions into the hemispherical electrostatic analyzer and adjusting the flux measurement range by adjusting the voltage; the electrostatic analyzer is used for performing energy analysis on the solar wind ions through voltage; the flight time system is used for recording an initial charge signal and a termination charge signal of ion flight and measuring ion deposition energy; the pre-amplification system multiplies and amplifies weak signals of ions and electrons, identifies and processes the signals and outputs digital signals; and the electronic processing unit is used for processing a signal output by the pre-amplification system, obtaining information of components, charge states, directions, energy and flux of solar wind ions, and providing multiple paths of high voltage required by the device. The device has the advantage that mass spectrum detection and charge state measurement are simultaneously realized on one device.

The invention relates to a method for detecting alkaloid compounds based on UPLC-MSMS (ultra performance liquid chromatography-mass spectrometry) and application. The method comprises the following steps: after a sample is extracted, detecting a sample extracting solution and a standard solution by adopting an ultra performance liquid chromatography-mass spectrometry combined method; a mobile phase adopted by the ultra-high performance liquid chromatography is as follows: a mobile phase A is an aqueous solution containing 0.1% of formic acid; the mobile phase B is an acetonitrile solution containing 0.1% of formic acid. According to the method disclosed by the invention, after the extracted tissue sample is subjected to liquid chromatography separation, the alkaloid metabolites are qualitatively and quantitatively detected in a targeted manner, and due to the high selectivity of the high-resolution mass spectrum, parameter optimization does not need to be performed on each metabolite.

The invention belongs to the field of biological medicine, and particularly relates to an anti-inflammatory and anti-helicobacter pylori compound separated from agilawood and a preparation method thereof. The method comprises the following steps: by taking the agilawood corasta as a raw material, carrying out reflux extraction with ethanol, extracting with petroleum ether to remove volatile components, separating and purifying by adopting various chromatographic technologies such as silica gel column chromatography, reversed-phase column chromatography and semi-preparative HPLC (High Performance Liquid Chromatography) to obtain a monomeric compound, and identifying the structure of the monomeric compound by adopting spectroscopy methods such as ultraviolet, high-resolution mass spectrometry and nuclear magnetic resonance. The structure of a compound 1 is identified as a new 2-(2-phenethyl) chromone dimer, and the compound 1 is named as aquicrasone V. The invention further discloses a preparation method of the compound 1. A biological activity test verifies that the compound has relatively strong anti-inflammatory activity and anti-helicobacter pylori activity.

The application belongs to the field of biological analysis, and provides a method for precise metabolic flow analysis of TCA cycle based on isotope tracing technology combined with high-resolution mass spectrometry. By optimizing mass spectrometry parameters and liquid chromatography method, one injection within 6 min is realized, and high-throughput, high-sensitivity and high-resolution detection is realized on 11 biomarkers related to TCA cycle metabolic pathways. At the same time, the application innovatively uses LC-MS / MS to decipher 13 C the stepwise position-specific transfer from glucose to subsequent metabolites by glycolysis and TCA cycle, thereby calculating 13 C the integrated steady-state analysis of key metabolic rates of position-specific transfer from sequential precursors to their products (pyruvate dehydrogenase, beta-oxidation, pyruvate carboxylase, isocitrate dehydrogenase and pyruvate cycle). This technology has wide applicability and can potentially characterize mitochondrial metabolism of any tissue or cell.

This invention discloses a method for determining the content and simultaneously identifying the source of polyglutamic acid (PCA) in fertilizers based on microwave digestion-high-resolution liquid chromatography-mass spectrometry (LC-MS), belonging to the field of analytical detection technology. The method includes: microwave-assisted acid hydrolysis of fertilizer samples to obtain a hydrolysate; injecting the hydrolysate into a liquid chromatography-high-resolution mass spectrometry (LC-MS) instrument, performing a single injection analysis in data-independent acquisition (DIA) mode, and simultaneously acquiring a mass spectrometry dataset containing a full-scan fingerprint of the parent ion and fragment information of the daughter ion by alternating between low and high collision energies; extracting the precise mass number of PCA from the dataset for accurate quantification, and calculating the PCA content using the difference method; simultaneously retrieving the total ion chromatogram and inferring the source of PCA based on the response of other amino acids. This invention is the first to introduce microwave digestion pretreatment and high-resolution mass spectrometry DIA acquisition mode into the field of PCA detection in fertilizers, requiring only a single injection to simultaneously complete accurate quantification and source identification, effectively avoiding false positives caused by background of plant and animal protein hydrolysates, and significantly improving the efficiency and confidence of PCA detection in complex matrix fertilizers.

The invention belongs to the technical field of reliability analysis of devices, and particularly relates to a quantitative analysis method for migration characteristics of an indium component in an epitaxial wafer. Comprising the following steps: providing epitaxial wafers with consistent initial characteristics, and carrying out uniform cleavage; taking one small block as a reference sample, and performing external disturbance treatment on other small blocks; the method comprises the following steps: respectively carrying out non-destructive structure characterization treatment on a reference sample and a sample subjected to external disturbance treatment, including high-resolution X-ray diffraction test, photoluminescence and cathode fluorescence combined test and time-resolved photoluminescence spectrum measurement; comprising high-resolution transmission electron microscope and EDS energy spectrum combined imaging and secondary ion mass spectrum; finally, FP lasers are prepared respectively, and electrical characterization processing is carried out. And quantitatively analyzing the influence of indium component migration on the electrical properties of the FP laser according to the result. The method has the advantages that the migration of indium atoms is analyzed according to a method for changing the microstructure in the quantum well and changing the dynamic behavior of a carrier.

The invention provides a blood concentration prediction model based on artificial intelligence and a construction method and application thereof.A whole blood sample of a patient taking sirolimus is collected, the blood concentration is detected through liquid chromatography tandem mass spectrometry, CYP 3A4 / 5, CYP 2C8 and P-gp gene polymorphism is detected in combination with a high-resolution dissolution curve technology, and the blood concentration prediction model based on artificial intelligence is obtained. And constructing a database containing the multi-dimensional data. And training the database by using an extreme gradient lifting algorithm, establishing a high-precision sirolimus blood concentration artificial intelligence prediction model, and developing a mobile equipment end application to realize remote data acquisition and result display. The model is especially suitable for children with Carboxi-like vascular endothelioma, can dynamically monitor the blood concentration in real time, provides refined guidance for clinical treatment, reduces the treatment cost, and improves the treatment effect and safety.

The invention relates to a method for evaluating the stability of heavy oil based on composition distribution of hydrocarbon, which comprises the following steps: detecting composition distribution data of hydrocarbon in a heavy oil sample by adopting high-resolution mass spectrometry equipment, and calculating the instability index of the heavy oil sample according to a specific formula. The sample amount and the solvent amount used for analysis are small, the test process is short in time consumption, the evaluation result is accurate, the reproducibility is good, and the discrimination degree is high; the method is especially suitable for analysis requirements of heavy oil stability in processes of heavy crude oil on-site modification, asphaltene deposition research, heavy oil separation and component refining, heavy ship fuel component blending, inferior residual oil fixed bed hydrogenation, slurry bed hydrogenation, fluidized bed hydrogenation and the like.

This invention belongs to the field of daily chemical product testing and analysis technology. It discloses an intelligent screening method, device, equipment, and storage medium for sulfur / sulfonate surfactants. The method involves pretreatment of the sample and high-resolution mass spectrometry (UHPLC-MS / MS) scanning, converting the sample into an mzXML file. All secondary mass spectrometry peaks in the file are screened to identify target secondary mass spectrometry peaks containing characteristic ions. The mass and peak intensity of all corresponding precursor ions are extracted. If the mass difference between two precursor ions is within the range of sulfur isotope mass difference and the peak intensity ratio is within a specified range, the precursor ion with the lower mass is selected as the quasi-molecular ion. A predicted molecular formula is generated, and matching structural information is retrieved from a database. Simulated fragmentation is used to obtain a simulated secondary mass spectrum, which is compared with the actual secondary mass spectrum to determine the predicted structure and identify sulfur / sulfonate surfactants. This intelligent processing of high-resolution mass spectrometry data improves data processing efficiency, sensitivity, and accuracy.

The application discloses a method for simultaneously detecting 18 kinds of amino acids in Daqu based on high-resolution liquid chromatography-mass spectrometry, and belongs to the technical field of liquor detection. Chromatographic conditions of the method include that an ethylene bridge hybrid particle with surface-bonded amide groups is used as a filler, ammonium acetate-formic acid aqueous solution is used as mobile phase A, and acetonitrile is used as mobile phase B for gradient elution; mass spectrometry conditions include that an H-ESI ion source is used, the spray voltage in the positive ion mode is 3000-4000 V, and the spray voltage in the negative ion mode is 2000-3000 V; qualitative analysis is performed according to mass-to-charge ratios of the 18 kinds of amino acids, and quantitative analysis is performed by using a standard curve method. The method has the characteristics of simple pretreatment operation, easy-to-obtain reagents, high extraction efficiency and good stability, can realize synchronous and accurate qualitative and quantitative analysis of the 18 kinds of amino acids, and provides reliable data support for flavor substance research of Daqu.

The application provides an ion cyclotron resonance device for mass spectrometry, a control method and a mass spectrometer. The device comprises a cylindrical space region for ion introduction, excitation and detection. In the ion excitation process, the ions are excited radially outward from the center of the cylindrical space region. A pair of magnets are arranged axially parallel to the cylindrical space region for generating a magnetic field in the space region. The magnets have opposite polarities. The opposite surfaces of the magnets are perpendicular to the axial direction. The magnetic field intensity of the central region of the space region is greater than that of the outer peripheral region along the radial direction. An electrode array is arranged between the pair of magnets. An alternating voltage is applied to the electrodes of the electrode array for exciting the ions. The ion cyclotron resonance device can solve multiple problems such as device miniaturization, resolution, equipment and manufacturing cost.

This application relates to a method for identifying organic matter in high-salt coal chemical wastewater based on ultra-high performance liquid chromatography and high-resolution mass spectrometry (UHPLC). Specifically, it provides a slime remover, the active ingredient of which is prepared by purifying coal pyrolysis wastewater. This active ingredient contains the first fraction of the coal pyrolysis wastewater, which is prepared by the following method: (1) the coal pyrolysis wastewater is purified and extracted using SPE to obtain a purified product of the coal pyrolysis wastewater; (2) the purified product of the coal pyrolysis wastewater from step (1) is separated using HPLC, and the first peak product is collected to obtain the first fraction of the coal pyrolysis wastewater. The slime remover of this application reduces the emissions from coal pyrolysis waste treatment and simultaneously realizes the comprehensive utilization of coal pyrolysis products.

The invention discloses a method for screening, identifying and risk evaluating PFAS in surface water and application, and belongs to the technical field of environment monitoring analysis and risk evaluation. The technical problem to be solved is to provide a method with the advantages of high pretreatment efficiency, wide screening range, accurate quantitative analysis, fine risk assessment and the like aiming at the problems of incomplete PFAS screening coverage, inextreme quantitative sensitivity and non-detailed risk assessment in the prior art. According to the technical scheme, the method is characterized in that the pretreatment process of a surface water sample is optimized through full-automatic solid-phase extraction equipment, and comprehensive identification and accurate analysis of traditional and emerging PFAS are achieved in combination with non-targeted screening of Orbitrap Explores 120 high-resolution mass spectrometry and targeted quantification of 7500 triple quadrupole mass spectrometry; and comprehensive evaluation of ecological and health risks is completed through a risk entropy model and a human body multi-tissue cell toxicity experiment.

The present invention relates to the field of mass spectrometry, and more particularly to a method that can effectively improve data acquisition efficiency and / or resolution in mobility mass spectrometry. The method is applicable to DDA or DIA data acquisition and is also applicable to data acquisition in conventional ion mobility-first-order mass spectrometry. It can solve problems such as limitations in dynamic range and reduced scanning speed due to the effects of space charge in conventional data acquisition methods. This data acquisition method is applied to tandem analysis of UMA and mass spectrometer and includes a preliminary acquisition step, as well as steps for accumulating target ions and holding non-target ions in parallel. Furthermore, by adding an ion dissociation step, DDA or DIA data with high speed and a wide dynamic range can be easily obtained.

The application discloses a frozen mass spectrum imaging ion source and a mass spectrometer, and relates to the technical field of mass spectrum imaging. The mass spectrum imaging ion source comprises a freezing table and a laser source. The freezing table is used for freezing a sample to be measured in situ, so as to keep the real topographic features of the sample to be measured. The laser source is used for generating laser. The laser is incident on the sample to be measured and interacts with the sample to generate ions to be analyzed. The laser source selects a vacuum ultraviolet to extreme ultraviolet wave band. The laser of the wave band can be strongly absorbed by endogenous water molecules / solution of the frozen biological tissue. On one hand, local micro area thermal desorption generates neutral molecules / ions. On the other hand, the endogenous water molecules / solution releases enough H + and Na + / K + , so that the ionization efficiency of the neutral molecules is greatly improved. Since the laser of the vacuum ultraviolet to extreme ultraviolet wave band can obtain a nanometer scale focusing size, the mass spectrum imaging ion source can be used to obtain mass spectrum imaging information with a submicron to nanometer spatial resolution.

The utility model provides a kind of secondary ion mass spectrum analysis device, comprising: entrance slit subassembly, entrance slit subassembly includes: bottom plate, first drive component and second drive component, bottom plate is configured in the first direction along first panel subassembly and second panel subassembly of the activity connection of bottom plate both sides with bottom plate, first panel subassembly and second panel subassembly form the slit extending along vertical direction between it;First drive component is configured as the first panel subassembly and second panel subassembly are driven in the first direction on bottom plate and move towards each other and / or move away, to adjust the width of slit along the first direction;Second drive component is configured as the bottom plate is driven along vertical direction moves.The secondary ion mass spectrum analysis device disclosed in the utility model realizes the standby area of slit to be switched quickly without breaking the vacuum environment, effectively avoids the mass resolution decline caused by slit abrasion, while greatly improves the test efficiency and the continuous operation ability of device.

The application discloses a mass spectrum peak annotation method based on co-expression, co-flowing and similar secondary mass spectrum diagrams, and belongs to the technical field of mass spectrum data annotation.The application is based on the characteristics that different mass spectrum characteristics of the same substance have co-expression, co-flowing and similar secondary mass spectrum diagrams in different samples, and a set of efficient annotation method for high-resolution mass spectrum data is established by filtering the mass differences of common adducts, multimers, isotopes and in-source cleavage fragments, so that the time-consuming and labor-consuming difficulty of the structure annotation step of unknown substances in actual metabolomics and other fields due to redundant mass spectrum information can be solved.The mass spectrum data annotation method is accurate, time-saving and labor-saving, and has important significance for accurate annotation of redundant information of unknown substances in actual samples.

The present invention provides an ion detector that can suppress variations in ion detection time for ions with the same mass-to-charge ratio, and a mass spectrometer that can improve the resolution of mass spectrometry. [Solution] The ion detector 1A includes an incident electrode 20 which includes an incident section 21 through which ions i pass; a conversion electrode 30 which emits electrons e in response to the incidence of ions i that have passed through the incident section 21; an exit electrode 40 which is located on the incident electrode 20 side in the Z direction relative to the conversion electrode 30 and on one side in the X direction relative to the conversion electrode 30 and includes an exit section 41 which allows electrons e emitted from the conversion electrode 30 to pass through; and an electronic control electrode 90 which is located between the conversion electrode 30 and the exit section 41 in the Z direction and faces the conversion electrode 30 in the Z direction and includes a passing section 91 which allows ions i traveling from the incident electrode 20 to the conversion electrode 30 to pass through, and electrons e traveling from the conversion electrode 30 to the exit electrode 40 to pass through.

The invention discloses an acanthosphere-shaped multi-interface type metal oxide magnetic particle and a preparation method and application thereof.The magnetic particle comprises a core composed of magnetic nanoparticles and a shell layer composed of titanium oxide nanosheet spines arranged in a radial mode, and the magnetic particle has superparamagnetism, high specific surface area and rich active sites; and a large number of trap spaces matched with the exosome scale range, so that the method can be used for efficiently enriching and separating the exosome from the biological fluid. Meanwhile, the magnetic core has an out-phase junction composed of amorphous phase titanium oxide and anatase phase titanium oxide, a heterojunction interface composed of titanium oxide and the magnetic core and an ordered spine microstructure, the synergistic effect of the multi-interface effect and the point effect is fully exerted under laser irradiation, the excellent ultraviolet absorption capacity and electron-hole separation efficiency are shown, and the magnetic core has the good application prospect. The method is used for laser desorption ionization mass spectrometry, efficient in-situ pyrolysis of the exosome is achieved, desorption and ionization of metabolite in a lysis solution are promoted, and a high-resolution mass spectrum of the metabolite of the exosome is obtained.

There is provided a method of analysing isotopes of an element present in a compound of interest from a mass spectrum obtained by a Fourier transform mass spectrometer. The method comprises generating simulated transients that would be measured in the mass spectrometer when measuring a sample of the compound of interest at one or more selected resolutions of the mass spectrometer, the simulated transients corresponding to samples of the compound of interest with different relative isotopic abundances. The simulated transients are processed to produce respective simulated mass spectra data. The simulated mass spectra data are compared to theoretical mass spectra data to determine a correction to be applied to real mass spectra data to account for changes in isotopolog peak sizes caused by interference between unresolved isotopolog peaks.

The invention discloses a detection method of a monacolin compound. According to the application, a non-targeted screening thought is adopted, four key daughter ions of the monacolin compound are found for the first time, and non-targeted screening methods of the monacolin compound based on key daughter ion detection are respectively established in a high-resolution mass spectrum and a triple quadrupole mass spectrum by utilizing the property that the compound is easy to crack in a source in a mass spectrum; the distribution and the content of the monacolin compound can be exclusively presented. Compared with a basic analysis method of original substances, the method has the advantages that secondary mass spectrum analysis is not needed, the retention time of the compounds can be quickly locked, and the monacolin compounds are subjected to non-targeted screening; compared with the original analysis method of the monacolin compound, the method can filter out a large part of interference of other compounds, and specifically shows the distribution and content of the monacolin compound. The method can be applied to fermentation products of monascus, aspergillus terreus and other monacolin compound producing strains and products of the fermentation products to detect distribution and relative content of the monacolin compounds, and can also be applied to quality control methods such as establishment of monacolin compound fingerprints, content determination and the like in the matrix.

The application relates to the field of natural medicines, and discloses an alkaloid, a preparation method and application thereof, the alkaloid having a structure shown in formula I and pharmaceutically acceptable salts thereof. The alkaloid is separated from a n-butanol extraction part of an ethanol extract of Dendrobium huoshanense stems through silica gel column chromatography and a preparation thin layer separation technology, and the structure is identified through nuclear magnetic resonance and high-resolution mass spectrometry. Through cell experiments, it is verified that the alkaloid prepared in the application can significantly relieve inflammation induced by LPS, inhibit human gastric cancer cell (AGS) proliferation and promote apoptosis; molecular docking analysis shows that the alkaloid prepared in the application can be significantly docked with active sites of induced iNOS, IL-6, TNF-alpha and MMP9, and the binding energy is-9.5~(-8.6) kcal / mol.