72 results about "Mass spectral database" patented technology

Methods of compensating for drift in fingerprint spectra of microorganisms caused by changes in their environment are disclosed. These methods of compensating for drift permit identification of microorganisms from their fingerprint spectra regardless of the environment from which the microorganisms are obtained. Furthermore, the disclosed methods may be used to construct coherent databases of fingerprint spectra that may be expanded even though the standard database conditions are no longer experimentally achievable. In particular embodiments, methods of compensating for drift in pyrolysis mass spectra, constructing coherent pyrolysis mass spectral databases, and identifying bacteria from their pyrolysis mass spectra are disclosed.

The invention relates to a liquid-mass database for detecting residual drugs in animal-derived food and a use method thereof; preparation of the database includes the following steps: (1) preparing a standard work solution; (2) treating before analyzing, namely using an extraction purification technology combining fast enzymolysis and fast solid phase extraction (SPE) to treat to-be-detected samples before analyzing; (3) performing one-time sample introduction chromatographic analysis; and (4) building the liquid-mass spectral database.

The invention provides a screening method for fragrance raw material used for tobacco on the basis of thermal cracking-gas chromatography mass spectrography co-technique. The method of the invention is characterized in that chemical compositions contributed in the cigarette smoke by the fragrance raw material after the fragrance raw material is added into the cigarette is mainly determined by separating and measuring the pyrolsis products of the fragrance raw material in the smoking process of the simulated cigarette; the method of the invention comprises the specific steps as follows: standby fragrance raw material used for the tobacco of suitable quantity is weighed; nitrogen or air with different proportions are pumped into a pyrolyzer so as to change the nitrogen content; different pyrolyzing temperature and pyrolysis time are controlled by electric heating wires so as to combust the fragrance raw material used for the tobacco and simulate the burning process of the tobacco during the smoking process of the cigarette; subsequently, the pyrolsis products are separated and detected by GC-MS; the pyrolyzis products are determined by the remained time and mass spectrometry database query, thus investigating the effects of the adding of the fragrance raw material on the chemical composition of the smoke further. Compared with other screening methods, the method of the invention has the advantages of simple process, quick analysis speed, good repeatability, large information quantity, and unlimited physical states of the samples, etc.

The invention discloses a method used for screening and identifying saxitoxins in complex matrix. The method comprises following steps: 1, preparation of a matrix sample; 2, matrix sample purification, and toxin separation; 3, establishment of a mass spectrometry database; 4, sample information acquisition and result determination; 5, high resolution mass spectrum measuring of suspected positive samples and metabolic products of the suspected positive samples; and 6, qualitative measurement used for determining accurate molecule mass. According to the method, the mass spectrometry databases of 24 kinds of saxitoxins are established, the method can be used for high precision qualitative analysis in sample screening processing, realizing blind measuring of toxic-free standard samples and accurate qualitative determination, solving problems in the prior art that standard substances are expensive, arrival period is long, and the standard substances are controlled by entry and exit administration, and reducing detection cost in daily monitoring; requirement on the technical level of operation staff in saxitoxin detection is reduced; and operation is convenient.

The invention aims to provide an establishment method and application of a mass spectrum database of a prohibited colorant in foods. The method provided by the invention comprises the steps of: (1) establishing a first-level mass spectrum database and a second-level mass spectrum database of the colorants; and (2) separating the colorants with similar properties in the established mass spectrum databases. According to the establishment method and the application, the technical evaluation foundations are provided for the law enforcement; a purpose of fast screening the unknown prohibited added colorants is achieved by virtue of the mass spectrum databases; and the establishment method and the application can be helpful for strengthening the food detection of markets and carrying out preventive measures to effectively protect life safety of people.

The invention discloses a non-targeting multi-index electronic method for rapid detection of pesticide residues in edible agricultural products. The method comprises the following steps: 1, establishing a primary accurate mass spectrum database and a secondary fragment ion mass spectrum database of 1200 pesticides frequently used in the worldwide, applying the two mass spectrum databases to screening and confirmation of pesticide compounds and establishing a unique electronic identity card for each pesticide so as to replace real-pesticide standards used as references in traditional identification methods with electronic standards; 2, developing high-resolution-mass-spectrometry qualitative identification and intelligent screening software for automatic matching of mass spectra of pesticide residues and implanting a software program into an instrument so as to realize high-speed high-flux high-precision high-reliability high-informatization high-automation comparison between a test sample and the mass spectrum databases of the pesticides; and 3, carrying out sample preparation once and rapidly detecting 1200 or more pesticides at the same time by using two detection technologies. The method provided by the invention realizes multi-index non-targeting rapid detection of pesticide residues in edible agricultural products and is greatly improved in detection efficiency.

The invention discloses a method for detecting the flavoring uniformity of cut tobacco based on a main component analysis technology. The method comprises the following steps: (1) preparing samples: uniformly taking samples by time or position from the flavoring outlet of a cut cigarette making line; (2) placing every sample in a brown headspace bottle, adding an internal standard solvent, and screwing bottle caps to seal the bottles; (3) detecting the content of volatile and semi-volatile components in every sample in a headspace-gas chromatograph/mass spectrometer (HS-GC/MS) full-scanning manner, performing mass spectrum database retrieval to achieve qualitative diagnosis, and performing quantification through an internal standard technology; (4) performing dimension reducing processingon the detection data of every sample through a PCA main component analysis technology, and projecting the data in a two-dimensional plane or a three-dimensional space; and (5) drawing a PCA map by using computer software, and detecting the flavoring uniformity of the cut tobacco according to the discrete degree of distribution of data points. The method provides a scientific and intuitive methodfor evaluating the flavoring uniformity of the cut cigarette, and can be used for detecting the flavoring uniformity of cut tobacco in different cut tobacco flavoring devices or different flavoring processes.

An electronic method for non-target multi-index rapid detection of pesticide residues in edible agricultural products is disclosed. The method includes 1) building a primary accurate-mass mass spectrum database and a secondary fragment ion mass spectrum database for 1200 or above pesticides commonly used in the world, applying the two databases for pesticide compound screening and identification,and establishing a unique electronic identity for each pesticide so that traditional identification methods adopting pesticide material standards as references are replaced by electronic standards; 2)developing intelligent screening software for automatic matching between a high resolution mass spectrum and a pesticide residue mass spectrum and qualitative identification, implanting the softwareprogram into an instrument to achieve high-speed, high-throughput, high-precision, high-reliability, highly informationized and highly automatic comparison of a test sample with pesticide mass spectrum databases; and 3) preparing samples by one time, and rapidly detecting 1200 pesticides simultaneously by adopting two detection techniques. Non-target multi-index rapid detection of pesticide residues in edible agricultural products is achieved, and the detection efficiency is greatly increased.

The invention provides a method for analyzing non-data-dependent acquisition mode mass spectral data, comprising the steps of mixing standard ones not present and heavily isotope-labeled among a plurality of analysis samples into samples under test; analyzing the samples by jointly using gas or liquid chromatography and mass spectrometry; acquiring the standard samples heavily isotope-labeled from data acquired in various DDA modes, and mass spectral information of ingredients in the samples under test, and making corresponding mass spectral database files; searching for mas spectral information of the standard samples heavily isotope-labeled from data acquired in various DIA modes; making mass spectral database files suitable for the analysis of data files acquired in each DIA mode; searching DIA data by using mass spectral data commercial software to obtain qualitative and quantitative results of the ingredients of each sample. The mass spectral DIA analysis method provided herein is a brand-new method, ingredients can be massively detected in samples, and the ingredients can be more accurately and quantitatively analyzed.

The invention discloses a method for detection of electronegative element containing pesticides by a negative chemical ionization mass spectrum database. The method includes the steps of: establishment of the negative chemical ionization mass spectrum database and detection of pesticide residue in unknown sample. And establishment of the negative chemical ionization mass spectrum database consists of mass spectrum acquisition and mass spectral library establishment. The database involved in the invention includes full scan mass spectrum data of over 300 common electronegative element containing pesticides in a Thermofisher gas chromatography negative chemical ionization mass spectrum, after installation and operation on a Thermofisher gas chromatograph-mass spectrometer, spectrum library search comparison with an unknown sample can be carried out, or according to the ion information provided by the spectrum library, a selected ion monitoring (SIM) scan mode can be set directly to perform qualitative and quantitative detection on designated pesticides. The negative chemical ionization mass spectrum database is convenient to use, the impurity interference is small, the selectivity is high and the comparison result is accurate.

The invention discloses a method for measuring the release rate of a non-polar or low-polar flavor component in a smoke-free tobacco product, which is mainly used for determining the release rate of the non-polar or low-polar flavor component in the smoke-free tobacco product by performing preliminary treatment and apparatus analysis on the smoke-free tobacco product. The method specifically comprises the following steps: weighing two parts of equivalent smoke-free tobacco products, adding artificial saliva and a methylene dichloride standard substance solution respectively, sealing and oscillating the mixture, extracting saliva extract twice with the equivalent methylene dichloride standard substance solution, combining the extract liquors, drying the combined extract liquor for cold storage and then feeding a sample in a concentration way; performing separation and detection on an extracted component with GC and GC-MS, retrieving and determining the content of the non-polar or low-polar flavor component according to a retaining time and a mass spectrum database, and comparing the content of the extracted component in the saliva with the content of the directly extracted component of the methylene dichloride solution so as to obtain the release rate of the flavor extracted component of the smoke-free tobacco product. The method has the advantages of simple process, high analysis speed, good accuracy, unlimited sample physical state and the like.

The invention provides a method for detecting allergens in cosmetics. The method comprises the steps of preparing a mixed standard solution of 56 allergen substances by a mixed solution of methanol and a 2g/L ascorbic acid aqueous solution, wherein single standard solutions are independently prepared for seven groups of isomers such as eugenol, isoeugenol and the like; carrying out mass spectrometry analysis in modes of positive-negative ion primary mass spectrometry full scanning and data-dependent secondary mass spectrometry scanning of a high-resolution mass spectrum of an electrostatic field orbitrap; collecting an accurate mass number of primary parent ions, retention time and secondary fragment ion information to establish a high-resolution mass spectrum database; carrying out mass spectrometry analysis on a to-be-detected sample by adopting extraction of the mixed solution of the methanol and the 2g 2g/L ascorbic acid aqueous solution; by utilizing the database, establishing screening and quantitative analysis methods by using Tracerfinder software; and detecting the allergen substances in the sample. The method is rapid, high in sensitivity and high in specificity.

The invention discloses a method for detecting the fatty acid content of a nematode by a gas chromatography and mass spectrometry combined technology, and belongs to the technical field of analyticalchemistry. The method comprises the following steps: (1), preparing a standard product, detecting by a gas chromatography and mass spectrometry combined method, and comparing with a mass spectrometrydatabase to obtain fatty acid components corresponding to different retention times, wherein when the similarity is higher than or equal to 95%, a compound is confirmed; (2), preparing a standard mixed solution, and establishing a gas chromatography and mass spectrometry combined qualitative and quantitative method by an internal standard method; (3), pretreating a nematode sample to obtain an analytical sample; (4), performing analytical detection on the analytical sample to be detected by the gas chromatography and mass spectrometry combined qualitative and quantitative method established inthe step (2); (5), determining the content of each fatty acid in the nematode sample through calculation. The detection method is high in detection speed, low in detection limit and high in sensitivity, and is suitable for rapid analysis of the fatty acid composition and the fatty acid content of the nematode.

The invention provides a screen method and screen device for protein markers for gastric cancer classification, and application of a screened protein marker. The screen method comprises steps of screening proteins meeting retaining conditions from a protein expression mass spectrometry database formed by multiple samples, and using the proteins as an effective protein set; performing twice dimension reducing processing on the effective protein set in sequence, so as to obtain a dimension-reduced protein set; performing clustering analysis on the dimension-reduced protein set, so as to obtain different types of protein markers. In the method, protein markers with remarkable high expression in cancer samples are screened out from a protein mass spectrometry database comprising a large quantity of gastric cancer samples, gastric cancer falls into different types of protein markers according to a relationship between different protein markers and survival rates, and the markers of different types have remarkable differences, helping classify gastric cancers more accurately.

A method for determining the fragrance stabilizing capacity of a tobacco humectant on additional flavors in cut tobaccos aims at determining the fragrance stabilizing ratio of the tobacco humectant to the additional flavors in the cut tobaccos mainly by comparing the contents of the additional flavors in the cut tobaccos before and after the humectant is added. The method is characterized by taking two parts of flavored cut tobaccos in the same mass, one part of which is added with the evenly distributed humectant; after a certain period of placement, using dichloromethane solution containing certain concentration of standard substances for ultrasonic extraction; after filtration by microfiltration membranes, employing gas chromatography/mass spectrometer instruments for determination and determining the content of the additional flavor ingredients by time retention and mass spectral database retrieval; comparing the quantity of the additional flavors in the cut tobaccos added with the humectant with the quantity of the additional flavors in the cut tobaccos without the humectant, thereby determining the fragrance stabilizing ratio of the tobacco humectant to the additional flavors in the cut tobaccos. The method can rapidly and correctly judge the fragrance stabilizing capacity of the tobacco humectant on the additional flavors in the cut tobaccos and has the advantages of simple process, fast analysis speed, certain resistance to interference of external factors and the like.

The invention belongs to the field of cosmetic safety and chemical mass spectrum detection and particularly relates to establishment and application of a high-throughput screening mass spectrum database for cosmetic safety risk substances. According to the method, a high-throughput screening mass spectrum database for the safety risk substances in the cosmetics is constructed according to an ultra-high performance liquid chromatography-quadrupole time-of-flight high-resolution mass spectrometer (UPLC-Q-TOF), SCIEX OS and Library View software; the safety risk substances in the sample are rapidly screened and qualitatively determined according to the retention time of the compounds in the database, the precise quality information of parent ions and fragment ions, the isotope abundance ratio and the like, and an effective technical support is provided for risk monitoring and hidden danger investigation; compared with the prior art, the established database is greatly advantaged in that the qualitative speed is high and accurate when the database is used for screening unknown substances in a sample, multiple types of forbidden and limited substances in the sample can be rapidly, qualitatively and quantitatively detected at the same time under the condition that no standard substance exists, detection cost is reduced, and the detection speed and efficiency are greatly improved.

The invention discloses an edible oil identification method based on mass spectrum and principal component analysis. According to the method, a mass spectrometer is used as an analytical tool, mass spectrum data of edible oil standard samples are acquired, feature mass spectrum data capable of significantly distinguishing all the edible oil standard samples through principal component analysis are extracted with a mass spectrum data pre-screening method, and an edible oil standard sample mass spectrum database is established to effectively identify unknown edible oil samples. According to the method, the edible oil identification capacity is improved through the improvement on a follow-up mass spectrum data processing method, increase of a sample preprocessing step and improvement on technical levels of analytical instruments are not required, large quantities of manpower, material resources and time costs are saved, and the method is a new edible oil identification method.

A tandem mass spectrometry method for a trace substance adopts an ion trap mass analyzer or a quadrupole rod and ion trap combined mass analyzer. A quadrupole can realize simultaneous selective transmission of multi-target parent ions by coupling a low-voltage auxiliary alternating current signal, free from a multi-frequency window in a frequency spectrum, on a high-voltage radiofrequency, and anion trap can realize simultaneous selective isolation of the multi-target parent ions; after the ion trap binds selected ions, the multi-frequency low-voltage auxiliary alternating current signal is used together with a buffer gas to complete the simultaneous fragmentation of the multiple parent ions; then a single-frequency low-voltage auxiliary alternating current signal is coupled to the ion trap, and the radiofrequency voltage is scanned to realize the resonance excitation mass spectrometry analysis of corresponding fragment ions; and then the obtained mass spectrogram is compared with thetandem mass spectrogram database corresponding to each parent ion in order to resolve the tandem mass spectrogram corresponding to each target parent ion. The method can realize simultaneous tandem mass spectrometry analysis of multiple ions by one-shot injection without noise ion interference, and has a good application prospect in the field of trace sample analysis.

The invention discloses a method for screening chemical risk substances such as chloramphenicol antibiotics in toiletries. The method comprises (1) establishing an accurate mass database and a mass spectral database of compounds to be detected, (2) pre-treating a toiletry sample through extraction, centrifugation, purification and filtration, and carrying out high-pressure liquid chromatography-quadrupole-electrostatic field orbitrap high resolution mass spectrometry analysis detection on the sample solution, and (3) comparing and analyzing the test result in the step (2) and the built accurate mass database and mass spectral database in the step (1) and carrying out chemical risk substance screening. The method has high accuracy, strong specificity and high sensitivity and can be appliedto daily detection and quality control of the toiletries.

The invention discloses a computer-aided analysis system and method for components of polymer type pharmaceutical excipients. The method comprises the following steps of creating a polymer sample database; collecting to-be-measured sample data; inputting data; identifying first-level mass spectrometry ion peak of first-level mass spectrometry data of a to-be-measured sample, and matching the first-level mass spectrometry ion peak with a first-level mass spectrometry database of the sample; identifying first-level mass spectrometry ion peak meeting matching conditions, and matching preservationtime of the first-level mass spectrometry ion peak meeting matching conditions with first-level mass spectrometry database of the sample; extracting first-level mass spectrometry ion peak data meeting matching conditions, calculating actual isotope abundance distribution, and matching the actual isotope abundance distribution with a sample isotope theoretical abundance distribution database and scoring; and outputting a to-be-measured sample component analysis result. Through adoption of the analysis system and method, the components of the polymer type pharmaceutical excipients can be analyzed comprehensively, rapidly and accurately, and solves the problems of time consuming and misjudging in manual analysis.