110 results about "Mass spectrum" patented technology

The invention relates to a method for analysing mass spectral data obtained from a sample in GC×GC (2-dimensional) mass spectrometry, comprising: (a) comparing mass spectral data of an analyte with mass spectral data of candidate compounds of known structure in a data library; (b) identifying a plurality of candidate compounds from the library based on similarities of mass spectral data; (c) predicting, for each candidate compound, a value of at least one analytical property using a quantitative model based on a plurality of molecular descriptors; and (d) calculating a match score for each candidate compound based on the value predicted in step (c) and a measured value of the analytical property for the analyte.

A preparative mass spectrometer system includes an ionizer which converts the mixture into gas phase ions of the molecules in the mixture, and a separator which separates the ions according to their mass to charge ratio or mobility. The separator is a linear ion trap mass analyzer that accumulates the ions based on their mass to charge ratio. A surface is in cooperative relationship with the separator so that the separated molecules are soft landed onto the surface at different locations such that the collected molecules can be stored or further processed / analyzed.

The invention discloses a tandem mass spectrum detection kit capable of simultaneously measuring 16 types of bile acid. The kit comprises a standard substance, a quality control substance, an interiorlabel substance, precipitant, diluent and a flowing phase, wherein the precipitant is at least one of methyl alcohol, ethyl alcohol and acetonitrile; the diluent consists of water, methyl alcohol, ethyl alcohol and acetonitrile, wherein the volume ratio of water, methyl alcohol, ethyl alcohol to acetonitrile is (1-50):(0-90):(0-50):(0-50), and methyl alcohol, ethyl alcohol and acetonitrile are not zero at the same time; and the flowing phase comprises a flowing phase A and a flowing phase B, wherein the flowing phase A is the aqueous solution of ammonium formate or ammonium acetate-methanoicacid or acetic acid, and the flowing phase B is methyl alcohol and / or acetonitrile. The invention also discloses the application of the tandem mass spectrum detection kit. The tandem mass spectrum detection kit disclosed by the invention has the characteristics of high sensitivity, good specificity and the like, can accurately, simply and quickly simultaneously detect 16 types of bile acid in a matrix, and has a high application value.

The invention belongs to the field of a tea quality identifying method, and relates to a method for identifying the quality of jasmine tea. The method comprises the following steps of: 1, measuring the relative content of aroma ingredients by using a method combining the head space solid phase microextraction in combination with a gas chromatography-mass spectrometry, wherein the sweet smell ingredients comprise alpha-farnesene, cis-3-hexenyl benzoate, methyl anthranilate, indol and linalool; 2, computing the aroma index of the jasmine tea; and 3, determining the quality of the jasmine tea according to the aroma index of the jasmine tea. According to the relevency among various main aroma ingredients and the quality of the jasmine tea, the JTF index (relative content specific value) is determined to be equal to [(alpha-farnesene+cis-3-hexenyl benzoate+methyl anthranilate+indol) / linalool]. According to the method, the quality of the jasmine tea can be effectively and objectively determined, the quality of the jasmine tea with accordant tea base levels can be distinguished, the hard work of specialists can be avoided, and the identifying cost can be saved as well.

Mass spectrometry techniques for determining the status of sepsis in an individual are provided. A biomarker profile resolved from a biological sample, taken from the individual, using a mass spectrometry technique is compared to a reference biomarker profile. A single such comparison classifies the individual as belonging to or not belonging to a reference population. The individual's biomarker profile and the reference biomarker profile comprise a plurality of ions each having a mass-to-charge ratio of about 100 Daltons to about 1000 Daltons. The plurality of ions can be detected by electrospray ionization mass spectrometry in positive mode. The comparison uses a decision rule, such as a classification tree, that determines the status of sepsis in the individual without requiring knowledge of the identity of the biomarkers in the biomarker profile from the individual and without requiring knowledge of the identity of the biomarkers in the reference biomarker profile.

The invention provides a preparation method for increasing the content of total saponin, low polarity saponins and argininyl fructosy glucose in red ginseng. Fresh ginseng is cleaned and sealed in a food steamer of a ginseng steaming box to be steamed for 1.5-9h within the temperature range of 100-120 DEG C; after being steamed, the ginseng is naturally cooled in the ginseng steaming box to be 60 DEG C, and then is taken out and put into a baking box to be dried at 50 DEG C for 4-5 days, so that the red ginseng is obtained. High pressure liquid chromatographic detection proves that the content of the total saponin of the red ginseng is improved by 6.00-238.15% compared with the traditional method; the content of the low polarity saponins Rk5, Rg6, Rk1, Rh4, Rg3 and Rs3 can be remarkably increased; when mass spectrum is used for semiquantitative analysis, the content of the argininyl fructosy glucose is higher than that of the generally processed red ginseng by 7.14-311.6%.

Methods and apparatus for obtaining a mass spectrum of a sample and determining a concentration of a component of the sample by utilizing a model of chemical and electron ionization and the obtained mass spectrum.

The invention discloses a method for simultaneously determining multiple plant growth regulators in exported vegetables. The method comprises the following steps: extraction, purification, concentration, ultrahigh-performance liquid chromatography-triple quadrupole / composite linear ion hydrazine mass spectrometer (UHPLC-QTRAP) determination and the like. The method can simultaneously determine the 17 plant growth regulators, including gibberellin, indolyl-3-butyric acid, p-chlorophenoxyacetic acid, abamectin, diethyl aminoethyl hexanoate, atrazine, simazine, 6-benzyl aminopurine, 2,4-dichlorphenoxyacetic acid, forchlorfenuron, mepiquat chloride, chlormequat chloride, paclobutrazol, uniconazole, abscisic acid, thidiazuron and p-fluorophenoxyacetic acid. The method disclosed by the invention has the advantages of simple steps, short time consumption, high accuracy and high precision.

The present invention discloses a chemical derivatization-based phosphatide classification detection and quantification method, and belongs to the quantitative detection method technical field. According to the method, trimethylsilyldiazomethane is used for methylation derivation of a phosphate group in a phosphatide molecule in a to-be-tested sample; a plurality of ions to be tested by mass spectrometer are produced by the methylation derivatived phosphatide molecule in the ionized sample; in the selection of corresponding ions to be tested by the mass spectrometer, the ions added with H <+> or NH4 <+> are selected by different phosphatide kinds; different neutral loss or precursor ion scanning models can be set according to mass spectrometer fragmentation rules of different kinds of ions, and amounts of mass spectrometer ion models of different kinds of ions can be obtained; and finally, by comparison with the internal standard and calculation, the amounts of different types of phosphatide molecules in the sample can be obtained. The method is fast in detecting speed and high in sensitivity.

The invention discloses a sample pretreatment method for detecting special nitrosamine in tobacco and tobacco products by LC-MS / MS (liquid chromatogram-mass spectrum / mass spectrum). The sample pretreatment method comprises the following steps of: (1) preparing ammonium acetate buffering solution; (2) drying and crushing the tobacco and tobacco products; (3) adding the ammonium acetate buffering solution in the crushed sample, and ultrasonically extracting; (4) carrying out high-speed centrifugation on the extracted sample at room temperature to obtain a first supernatant; (5) adding ethyl acetate in the first supernatant and carrying out extraction and purification, and then centrifuging to obtain a second supernatant; (6) taking the second supernatant, blow-drying by nitrogen and redissolving by deionized water to prepare sample to be detected; and (7) detecting tobacco special nitrosamine in the sample to be detected by virtue of LC-MS / MS. The sample pretreatment method disclosed by the invention has the advantages that the sample pretreatment method is simple and practicable; the tobacco special nitrosamine is dissolved out by the ammonium acetate buffering solution, and purified by the extraction of ethyl acetate solution, and proteins and interference substances are removed to obtain refined sample solution after impurity removal, thus the sample detection is high in accuracy, high in extraction efficiency, simple and convenient to operate, time-saving, and low in reagent consumption.

Aspects of the present disclosure include methods for detecting a low abundance protein and methods for identifying a site of N-glycosylation on a protein. In practicing methods according to certain embodiments, a eukaryotic cell is contacted with an isotopic labeling composition and isotopically labeled N-glycosylated peptides obtained from the eukaryotic cell are assessed by liquid chromatography-tandem mass spectrometry. A predetermined isotopic pattern in the mass spectrum is identified and amino acid sequences of the peptides containing the predetermined isotopic pattern are determined. Systems for identifying a predetermined isotopic pattern in mass spectra and determining amino acid sequences of peptides containing the predetermined isotopic pattern are also described.

The invention relates to a method and kit of particularity recognition and mass spectrum sequencing of protein N-end peptide section. The method and kit can be used for particularity recognition of protein N-end peptide section, increase determinacy and reliability of identification for protein N-end peptide section, and be adapted for protein identification and N-end analysis in biology, medicine and medicament research and application field.

The invention discloses a high-throughout medicament screening method built on primary hepatocytes serving as a carrier, which relates to the field of biotechnology. After a medicament and a substrate are incubated together, liquid-chromatogram connection is adopted to detect two or more than two kinds of metabolins at the same time. The method comprises: (a), culturing primary hepatocytes by a 'sandwich gel' process; (b) adding a medicament to be screened and a corresponding positive inducer, culturing for three days, and adding at least two or more than two kinds of substrates for metabolism evaluation; and (c) establishing a liquid phase and tandem mass spectrum combined process capable of detecting two or more than two kinds of metabolins at the same time, evaluating the influence of the medicament on the activity of hepatocytes by detecting the two or more than two kinds of metabolins at the same time by liquid-chromatogram connection, and thus evaluating if there is a potential medicament application risk from an overall perspective.

The invention discloses a detection method for single-cis and double-cis lutein isomers. The method adopts a diode array detector and a YMC carotenoid C30 chromatographic column, and takes methyl alcohol, acetonitrile and dichlormethane as mobile phases, wherein the ratio of methyl alcohol to acetonitrile to dichlormethane is 50 to 30 to 20; according to the method, the time is 13 minutes, the flow velocity is 1.0mL / minute, the column temperature is 25 DEG C, the sample injection amount is 20 microliters, the scanning wavelength is 300-500nm, and the detection wavelength is 450nm; after the method is adopted, the single-cis and double-cis lutein isomers can be well separated; furthermore, an atmospheric pressure chemical ionization (APCI) positive ion mass spectrum is utilized, the flow velocity of chromatographic column outflow components entering a mass spectrometer is 10 microliters per minute, the scanning range m / z=80-900, the vaporization temperature is 350 DEG C, the flow velocity of dry gas is 5L / minute, the corona current is 4 microamperes, the crushing voltage is 150 V, and the capillary voltage is 2,500V. According to the mass spectrum and optical spectrum information, the single-cis and double-cis lutein isomers are respectively determined to be 13, 15-double-cis form, 9, 15-double-cis form, 15-cis form, 13-cis form, 13'-cis form, 9, 9'-double-cis form, 9-cis form and 9'-cis form lutein. The method has the advantages of being rapid, effective, good in reproducibility, high in recycling rate and the like, and can be used for carrying out qualitative and quantitative analysis on the single-cis and double-cis lutein isomers.

The invention discloses a phosphorylated and / or glycosylated protein or peptide one-step enrichment modification determination method. The method includes the following steps: 1) modification on end alkynyl or triazon of protein or peptide; 2) resin capturing of protein or peptide with modified end alkynyl; 3) cutting of the peptide / protein with modified alkynyl on resin. The protein or peptide enrichment modification determination method provided by the invention not only can enrich and purify the modified protein or peptide after translation but also can add one molecule segment on the protein or peptide, and the molecule segment has the functions of mass spectrum label and mass spectrum signal gain. The method has wide application prospect in the science analysis field.

The invention discloses a method for screening key genes of notoginseng saponin synthesis based on metabolites and gene expression. Specifically, the high-performance liquid chromatography-mass spectrometry system was used to analyze the metabolite content of different parts of the annual Panax notoginseng, and the fluorescence quantitative PCR technology was used to quantitatively analyze the gene expression of key enzymes in the saponin synthesis pathway. Gene-metabolite correlation graph to screen key genes. The invention provides important information for further elucidating the synthesis mechanism of saponins in Panax notoginseng, and at the same time provides an important basis for increasing the content of Panax notoginseng saponins by means of gene regulation and the like.

A method is disclosed for operating a mass spectrometer having a Fourier Transform (FT) analyzer, such as an orbital electrostatic trap mass analyzer, to avoid peak coalescence and / or other phenomena arising from frequency-shifting caused by ion-ion interactions. Ions of a first group are mass analyzed, for example in a quadrupole ion trap analyzer, to generate a mass spectrum. The estimated frequency shift of the characteristic periodic motion in the FT analyzer is calculated for one or more ion species of interest based on the intensities of adjacent (closely m / z-spaced) ion species. If the estimated frequency shift(s) for the one or more ion species exceeds a threshold, then a target ion population for an FT analyzer scan is adjusted downwardly to a value that produces a shift of acceptable value. An analytical scan of a second ion group is performed at the adjusted target ion population.

The invention relates to the field of beef origin place identification, in particular to a marker screening method for beef origin place and application thereof. The method comprises the following steps of: 1) using a chromatography-mass spectrometer to perform detection on lipid samples of the beef from different origin places; 2) analyzing the detection results by adopting a non-targeted lipid profile analysis and a principal component analysis; 3) performing significant difference analysis on the analysis results to obtain difference factors among lipids of the beef of different origin places; and 4) comparing the difference factors with a lipidomics database to obtain a marker. The screening method is based on the analysis of non-targeted lipidomics, and adopts the stoichiometry to analyze a difference marker. In this way, the markers selected by the method are used for identification of the origin place, and the method has high accuracy.

The present invention provides a method of determining the absolute amount of a target polypeptide in a sample, said method comprising the following steps: (a) adding (aa) a fusion polypeptide to said sample, said fusion polypeptide comprising (i) at least one tag sequence and (ii) a subsequence of the target polypeptide; and (ab) a known absolute amount of a tag polypeptide comprising or consisting of said tag sequence according to (aa) to said sample, wherein said fusion polypeptide on the one hand is mass-altered as compared to said target polypeptide and said tag polypeptide on the other hand, for example, said fusion polypeptide on the one hand and said target polypeptide and said tag polypeptide on the other hand are differently isotope labeled; (b) performing proteolytic digestion of the mixture obtained in step (a); (c) subjecting the result of proteolytic digestion of step (b), optionally after chromatography, to mass spectrometric analysis; and (d) determining the absolute amount of said target polypeptide from (i) the peak intensities in the mass spectrum acquired in step (c) of said fusion polypeptide, said tag polypeptide and said target polypeptide and (ii) said known absolute amount of said tag polypeptide.Furthermore provided is a fusion polypeptide for the quantification of a target polypeptide by mass spectroscopy, wherein: said fusion polypeptide consists of 35 to 455 amino acid residues and comprises (i) a target region, which is a fragment of the target polypeptide, and (ii) a tag region, which is not a fragment of the target polypeptide, said target region consists of 15 to 205 amino acid residues and comprises at least two signature regions; said tag region consists of 20 to 250 amino acid residues and comprises at least two signature regions; and each signature region has the structure Y-Z-X4-28-Y-Z, wherein all Y:s are selected from one of (i)-(iv), wherein (i) is R or K, (ii) is Y, F, W or L, (iii) is E and (iv) is D and each X and each Z are independently any amino acid residue, provided that the Z:s are not P if the Y:s are selected from (i)-(iii); and each signature region comprises at least one amino acid residue comprising a heavy isotope.

The invention relates to microbial-source pesticide, in particular to a Destruxin depsipeptide derivative and a preparation method and application thereof. The Destruxin depsipeptide derivative is as shown in formula (I) and formula (II). The Destruxin depsipeptide derivative is prepared by the strain BeauveriafelinaAS-70 through fermentation, culture, extraction and separation. By authentication using technologies such as nuclear magnetic resonance and mass spectrum, the chemical structure of the Destruxin depsipeptide derivative is good in pesticide activity.

The invention discloses a method for rapidly classifying and identifying mycobacterium tuberculosis by the aid of the mass-spectrometric technique. The method includes the steps of PCR (polymerase chain reaction) amplification, SAP (severe acute pancreatitis) enzymatic digestion, transcription and nuclease digestion, purification, mass spectrometer detection and the like. A nucleic acid fingerprint spectrum database of the mycobacterium tuberculosis is established based on the method. The mycobacterium tuberculosis in samples to be detected can be rapidly identified according to mass spectrum peak diagrams generated by experiments, and results can be widely applied to typing and classification of the mycobacterium tuberculosis and the fields of environmental sanitation, public security quarantine and the like.

The invention relates to a microbe-derived pesticide, and concretely relates to a depsipeptide compound, and a preparation method and an application thereof. The depsipeptide compound is represented by formula (1). The depsipeptide compound is obtained by through fermenting culture of Beauveria felina AS-70 (preserved in China General Microbiological Culture Collection Center on Sep. 29, 2012 with the preservation number of CGMCC NO.6643), and through extraction and separation. A result of identification of the chemical structure of the compound through nuclear magnetic resonance and mass spectrum shows that the compound has good insecticidal activity.

The invention provides a synthetic method and a synthetic product of symmetric eight methyl cucurbit[6]uril, which are a synthetic method of organic chemistry macrocyclic supramolecular compounds symmetric eight methyl cucurbit[6]uril and a synthetic symmetric eight methyl cucurbit[6]uril. The symmetric eight methyl cucurbit[6]uril is formed by taking dimethyl replacing glycosides urea dimer, general glycoluril and paraformaldehyde as raw materials, replacing glycosides urea dimer with dimethyl through formaldehyde, and carrying out condensating selective formation between dimethyl and general glycoluril, so as to form the symmetric eight methyl cucurbit[6]uril. The invention discloses the synthetic method and a specific technology condition, and conducts sufficient structural characterization by analyzing measures such as nuclear magnetic resonance, single-crystal X-ray diffraction, mass spectrum, IR, and DSC-TG.

The invention discloses an analysis method for identifying vitex chinensis mill honey and syrup adulterated vitex chinensis mill honey, and particularly relates to a method combining the ultra-high performance liquid chromatography-quadrupole-orbitrap high-resolution mass spectrum technology with metabonomics. The method comprises the steps that pretreatment is conducted on a true vitex chinensis mill honey sample and a syrup adulterated vitex chinensis mill honey sample through organic solvents respectively, and the ultra-high performance liquid chromatography-quadrupole-orbitrap high-resolution mass spectrum technology is used for achieving separation and determination of chemical components in the pretreated samples; then obtained UHPLC-MS original data of the true vitex chinensis mill honey sample and the syrup adulterated vitex chinensis mill honey sample is preprocessed; finally, the multivariate statistical analysis method is used for analyzing and distinguishing the true vitex chinensis mill honey from the syrup adulterated vitex chinensis mill honey. According to the method, metabolite information of the true vitex chinensis mill honey and the syrup adulterated vitex chinensis mill honey is comprehensively obtained, multivariate statistical analysis is used, the vitex chinensis mill honey and the syrup adulterated vitex chinensis mill honey are comprehensively analyzed, and detection of the syrup adulterated vitex chinensis mill honey is completed.

The invention discloses a dispersive solid-phase extraction and gas chromatography-mass spectrometry detection method of organic tin environmental hormones in marine products. The organic tins in themarine products are measured by adopting ultrasonic extraction, freeze degreasing, first time dispersive solid-phase extraction purification, derivatization and back extraction, second time dispersivesolid-phase extraction purification, and gas chromatography-mass spectrometry method. The method is simple in operation, the sample pretreatment can be completed quickly, wherein twice dispersive solid-phase extraction is adopted for purification for the first time, the entire dispersive solid-phase extraction purification process plus the derivatization and back extraction only takes 20-30 min,the result is accurate, the detection limit of nine organic tins is 0.4-1.0 mu g / kg, the recovery rate is 80-117%, the relative standard deviation (n=5) is 3.8-7.5%, the sensitivity is relatively high, the recovery rate and reproducibility are satisfactory, and the dispersive solid-phase extraction and gas chromatography-mass spectrometry detection method can be used for the measurement of the content of the organic tins in the marine products.

The invention provides a method for quickly screening and authenticating edible oil through surface assisted laser desorption ionization mass spectrometry. In the method, a magnetic metal organic framework nanomaterial is used as matrix, the magnetic metal organic framework nanomaterial matrix is mixed with the edible oil and dropped on a target plate, and the target plate is dried at room temperature; then, mass spectrometric detection is executed, and a result is analyzed. The method overcomes a lot of problems, such as serious background interference of the conventional organic matrix at alow molecular weight region (m / z is less than 1000 Da), and can be directly used for quick screening and authentication of the edible oil. The method has the advantages of consuming less samples, being simple in sample preparation and fast in analysis, having high signal-to-noise ratio and excellent signal repeatability, and so on, and has better use value and potential application foreground in the food safety field.