251 results about "Daughter Ion" patented technology

The invention relates to time-of-flight mass spectrometers for the measurement of daughter ion spectra (also called fragment ion spectra or MS / MS spectra) and corresponding measurement methods.According to the invention, the ions of an ion source are initially accelerated only to an intermediate level of energy, allowing them to decompose at that energy level by metastable decomposition or by collisionally induced fragmentation (CID). The ions are then accelerated in a second step to a high energy level. Light fragment ions gain a higher velocity than heavier fragment ions or non-decomposed parent ions. The spectrum of fragment ions can be detected separated by mass in either linear or reflector mode. An ion selector at the low energy level selects a single type of parent ion in order to avoid superpositions with fragment ions of other parent ions. A particularly preferred embodiment raises the potential of ions, for there second acceleration, during their flight through a small electrically isolated flight path chamber.

The invention discloses a method which can carry out qualitative screening to 242 compounds (drugs or toxicants) simultaneously. A mode of liquid chromatogram-mass spectrometry (LC-MS / MS) multi-reaction monitoring (MRM) is adopted to carry out determinedness to objects by two pairs of parent ion-daughter ion pair and retention time. The 242 drugs or toxicants comprise toxic products such as opioids, amphetamine and cocaines and the like, bromazepam such as benzodiazepines and barbiturates, and common drugs, alkaloid, pesticide (including organophosphates, carbamates, pyrethroid pesticide residues and organochlorine pesticide), weed killer, raticide and the like.

A method for identifying and characterizing components of interest in complex samples includes subjecting both a sample and its control samples to chromatography / high resolution mass spectrometry analysis to detect ions of the samples. The method includes defining sections of control sample data within specified chromatographic fluctuation time and mass precision windows around each ion or each group of the same ions of question in the test sample data. The defined sections of the control sample data are examined and the maximal intensities are subtracted from respective ions in the test sample. Components of interest are determined from the resultant data of the test sample. The method can be used for identifying molecular ions and / or their fragment ions for components of interest in complex samples.

The present teachings provide methods for analyzing one or more amine-containing compounds in one or more samples using isobaric labels and parent-daughter ion transition monitoring (PDITM). In various embodiments, the methods comprise the steps of: (a) labeling one or more amine-containing compounds with different isobaric tags from a set of isobaric tags, each isobaric tag comprising a reporter ion portion; (b) combining at least a portion of each of the isobarically labeled amine-containing compounds to produce a combined sample; (c) subjecting at least a portion of the combined sample to PDITM; (d) measuring the ion signal of one or more of the transmitted reporter ions; and (e) determining the concentration of one or more of the isobarically labeled amine-containing compounds based at least on a comparison of the measured ion signal of the corresponding reporter ion to one or more measured ion signals of a standard compound.

The invention provides a simulative-target metabonomics analytic method based on combination of liquid chromatography and mass spectrum. The method includes following steps: respectively manufacturing to-be-analyzed samples into merged samples according to groups; automatically collecting secondary mass spectrums of metabolites in each merged samples through data of UHPLS / Q-TOF MS with dependence on a collecting mode; extracting a retaining time and information of parent ions and daughter ions of the metabolites by qualitative analytic software; screening out characteristic ion pair information of the metabolites according to daughter ion response intensity; summing the characteristic ion pair information of each merged samples; and scanning the obtained characteristic ion pair of the metabolites by UHPLC / QQQ MS through a dynamic multi-reaction monitoring mode in an actual sample for obtaining a corresponding spectrogram; and performing integration through quantitative analytic software to obtain the metabolites in the to-be-analyzed samples and content information thereof.

The present invention discloses a graphene matrix and an application of the graphene matrix in matrix-assisted laser desorption / ionization-time of flight-mass spectrometry (MALDI-TOF-MS) detection. According to the present invention, in the MALDI-TOF-MS, the graphene is adopted as an assisted matrix, such that the analysis and the detection of the materials including from the small molecule compounds to the biological macromolecules can be efficiently and rapidly achieved; importantly the background interference of the molecular ion peak of the traditional organic matrix can be effectively eliminated so as to achieve the analysis and the detections of amino acids, lipid compounds, peptides, proteins, oligonucleotides, and other structural molecules; the MALDI-TOF-MS adopting the graphene as the matrix is the desorption ionization method, which does not require addition of any organic matrixes, such that the decomposition of the analyte can be avoided, and good reproducibility and high salt tolerance are provided; the efficient and rapid detection method is provided for the natural products and the biological metabolites; the method further can be used for the detection of the common biological macromolecules, and can be popularized and applied in all the MALDI-TOF mass spectrometry so as to achieve the deep application of the graphene.

The invention discloses a screening method for 110 types of medicines in feed, which specifically includes the following steps: preparation of standard work solution, pre-analysis treatment of sample to be assayed, creation of database and qualitative analysis. By utilizing the high-sensitivity MSMS (Tandem Mass Spectrometry) function of a liquid chromatography-tandem quadrupole time-of-flight mass spectrometer, the screening method can accurately determine parent ions and daughter ions in medicines and rapidly determine added medicine ingredients, moreover, an assay method for a variety of antibacterial medicines in feed is also established, and for a variety of added antibacterial medicines in the feed industry in China, the screening method has a highly efficient, accurate and precise assay measure, and is at the advanced level in china at present. The screening method established by the invention greatly solves the phenomenon of arbitrary addition in the feed industry, the more precise and accurate assay method is perfected for the inspection department, more time is saved, most of experimental consumables are saved, and the invention makes an immeasurable contribution to food safety and human healthy life.

Prior to multiple reaction monitoring (MRM) measurement condition optimization, an analysis operator prepares, for each precursor ion of an objective compound, two lists on a product-ion selection condition setting screen 200, i.e. a list 203 which shows ions to be preferentially selected as product ions for which the optimization needs to be performed and a list 202 which shows ions to be excluded from the optimization. When a measurement is performed, a product-ion scan measurement for the precursor ion of the objective compound is performed and a spectrum is obtained. Among the ions extracted from this spectrum, any ion registered in the excludable-ion list 202 is excluded, while any ion registered in the preferred-ion list 203 is preferentially selected as a product ion. For each combination of the m / z values of the precursor ion and the product ions thus determined, optimum conditions of the MRM measurement are searched for.

This invention relates to chemical ionization base on medium resisting discharging and mass spectrum ion source, it belongs to chemical engineering technique field. It especially relates to active base group ionization to organic matter molecular based on medium resisting discharging technique and mass spectrum ion source used for organic matter detecting. The features are that the medium resisting discharging device is used to ionize the reaction gas that can be used to chemical ionization, the reaction gas is ionized to generate ion and the reaction ion is ion-molecular react with the measuring organic matter to make the organic matter ionization, so mass spectrum can be used t realize detecting. The discharging voltage is 220V-10000V, frequency is 50 Hz to 50MHz, and reaction gas flow velocity is 10ml / min-1000ml / min. The corresponding mass spectrum is also provided. The measuring organic matter can be ionized in this invention, and it can be realized in atmospheric pressure environment, the device volume is small, energy consumption is low.

The present invention relates to a polypeptide group for identification of donkey components in gelatin and products thereof, and a mass spectrometry method to identify the donkey derived components in gelatin and products thereof by using the polypeptide. The polypeptides in the polypeptide group has a specific sequence structure and a specific m / z value (including a specific parent ion and a pair of daughter ions), and the sequence is shown in SEQIDNO.1-35; and the peptide segment and its m / z are specific in donkey source gelatin and are not seen in bovine gelatin.

The present teachings provide methods for analyzing one or more thyroxine compounds in one or more samples using isobaric labels and parent-daughter ion transition monitoring (PDITM). In various embodiments, the methods comprise the steps of: (a) labeling one or more thyroxine compounds with different isobaric tags from a set of isobaric tags, each isobaric tag comprising a reporter ion portion; (b) combining at least a portion of each of the isobarically labeled thyroxine compounds to produce a combined sample; (c) subjecting at least a portion of the combined sample to PDITM; (d) measuring the ion signal of one or more of the transmitted reporter ions; and (e) determining the concentration of one or more of the isobarically labeled thyroxine compounds based at least on a comparison of the measured ion signal of the corresponding reporter ion to one or more measured ion signals of a standard compound.

The invention discloses a series quadrupole-rod gas-chromatographic mass spectrometry detection method for 35 toxic medicaments in urine. The series quadrupole-rod gas-chromatographic mass spectrometry detection method comprises the steps of constructing a multiple-reaction detection method on a series quadrupole-rod gas chromatograph-mass spectrometer through standard substances of 35 toxicants (medicines), and determining 2-3 pairs of feature parent ions and daughter ions and the retention time of each toxicants (medicines); extracting a urine sample to be detected through diethyl ether, performing ultrasonic and centrifugal treatment, blow-drying and dissolving, and then qualitatively and quantitatively analyzing the toxicants (medicines) through a tandem mass spectrum MRM. By the adoption of a series quadrupole-rod gas-chromatographic-mass spectrometry / mass spectrometry method (GC-MS / MS), the method disclosed by the invention can quickly screen 35 conventional toxicants (medicines) in the urine of a human body; a detection result is accurate, sensitive and quick; the recycling rate of toxicants (medicines) is 80.82-118.56 percent; the detection limit is up to 0.0014-1.8 micrograms per microliter.

The invention provides a targeted metabo lomics analysis method for determining metabolites of a living body. The targeted metabo lomics analysis method can simultaneously determine 700 main metabolites of a living body based on series connection of ultra-high performance liquid chromatography and triple quadrupole and comprises the following steps: firstly, 700 main metabolites in a living body are screened; standard products of compounds are optimized to obtain optimal parent ions, daughter ions and mass spectrography conditions of the metabolites; the metabolites in samples are extracted by methanol, acetonitrile and water; liquid chromatograph conditions are optimized; a hydrophilic interaction is adopted to separate the metabolites; the separated metabolites enters a mass spectrum; the 700 main metabolites are determined at the same time by use of a real-time scheduled multi-reaction monitoring mode with quick positive and negative polarity switching function; the metabolite differences between all the samples are analyzed via partial least square analysis; changes of the metabolic pathway are found by pathway enrichment analysis. The targeted metabo lomics analysis method remarkably increases the number of detected compounds, and greatly shortens the analysis time.

The invention belongs to the technical field of medicine detection, and particularly relates to a method for detecting 43 types of medicines in blood by liquid chromatogram tandem mass spectrum. Aiming at the problem of lack of a method capable of simultaneously detecting seven types of common poisons, eleven types of antihypertensive drugs, eleven types of hypoglycemic agents and fourteen types of psychiatric drugs in the prior art, the invention provides the method. The method comprises the following steps of (a) performing protein precipitation on a to-be-detected sample with acetonitrile;and (b) detecting a selected drug by a multi-reaction monitoring (MRM) mode of high performance liquid chromatography-tandem mass spectrometry, and mass spectrum screening analysis is performed in a segmented way according to compound retention time and by two or three pairs of parent ions / daughter ions. By the method, the screening analysis of 43 types of drugs such as common antihypertensive drugs, common hypoglycemic agents, psychiatric drugs and poisons can be rapidly and accurately completed within 25 minutes in one time, the detection efficiency is high, and the method is good in sensitivity and is suitable for promotion and application.

In an RF ion trap mass spectrometer, selected parent ions are fragmented by collisions or electrons and a spectrum of the ion fragments is measured. The measured fragment ion spectrum is then analyzed for the presence of a dominant ion species and, when a dominant ion species is present, selected parent ions are fragmented and a spectrum of the ion fragments is again measured, but with an additional collision excitation of the dominant ion species. The resulting daughter ion spectrum is qualitatively improved.

The invention provides a method for determining multiple kinds of animal origin meat based on the liquid chromatographic-tandem mass spectrometric technology. The method includes the steps of pretreating samples, screening multiple standard meat sample feature polypeptides, and detecting feature polypeptides in meat samples to be detected through the liquid chromatographic-tandem mass spectrometric technology and the like. Components of the multiple kinds of animal origin meat can be identified by adopting the method, the scanning function of liquid chromatography-tandem mass spectrometry is brought into full play in the technology, the selected ion monitoring mode is monitored to collect signals in real time, second-level daughter ion intensity triggering is used, corresponding parent ion second-level fragmentation full-scanning spectrograms are collected to obtain a more exact qualitative information function, interference of a complex matrix is avoided, and the false positive possibility is reduced. In addition, the method is simple in pretreatment and facilitates operation on samples in batches.

In various aspects, the present teachings provide systems, methods, assays and kits for the absolute quantitation of protein expression. In various aspects, the present teachings provide methods of determining the concentration of one or more proteins of interest in one or more samples of interest. In various aspects, the present teachings provide methods of determining the absolute concentration of one or more isoforms of a protein using standard samples of signature protein fragments and parent-daughter ion transition monitoring (PDITM). In various embodiments, the absolute concentration of multiple isoforms of a biomolecule in a sample, multiple proteins in a biological process, a combination of multiple samples, or combinations thereof, can be determined in a multiplex fashion using the present teachings. In various aspects, provided are methods of assessing the response of a biological system to a chemical agent.

The invention relates to spatially resolved mass spectrometric measurement and visualization of the distribution of small molecules in a mass range from approximately 150 to 500 Daltons, for example drugs and their metabolites, in thin sections or other two-dimensional samples, preferably with ionization of the molecules by matrix-assisted laser desorption. The invention includes the steps measuring a daughter ion produced by forced decomposition of the molecular ion instead of the ionized analyte molecule itself, the daughter ion having a much better signal-to-noise ratio. The daughter ions are detected in a relatively simple reflector time-of-flight mass spectrometer instead of using an expensive time-of-flight tandem mass spectrometers for the measurement of the daughter ions. Advantageously, substantially faster and less expensive scanning of the thousands of mass spectra which serve as the basis for visualizing the spatial distribution of the analyte molecule is achieved, while the mass resolution and sensitivity are at least equally good.

The invention belongs to the technical field of food detection, and particularly relates to a fast instrumental analysis method for aflatoxins in foods. The invention discloses a fast instrumental analysis method for aflatoxins B1, B2, G1 and G2 in foods. The method comprises the following steps of: weighing a certain amount of sample; adding an acetonitrile-water solution in a certain ratio; performing ultrasonic extraction; and selecting specific parent ions and daughter ions by using a super-efficient liquid phase chromatography-mass spectrometer under a gradient elution condition to measure the content of the four types of aflatoxins. The method is simple and is high in efficiency and the precision of measurement results is high. By the method, four monomers of the aflatoxins are completely separated, and the recovery rate is high; and compared with the prior art, the method has the advantages of high speed and accuracy of detection and simple pretreatment, and can be used for accurately determining the nature and the quantity to meet requirements on research and detection.

The invention discloses a molecule ion reaction mass spectrum system, a molecule ion reaction method and a cleaning method. The molecule ion reaction mass spectrum system comprises a molecule reagent vessel for storing the liquid reaction reagent molecule of the molecule, a molecule reagent vessel heating device for heating the molecule reagent vessel and generating the gaseous reaction reagent molecule of the molecule, a rectangular ion trap system for generating an interesting reagent ion, a molecule ion reaction vessel for reacting the gaseous reaction reagent molecule with the reagent ion and detecting the reacted product, and an ion trap heating system for heating the molecule ion reaction vessel to increase the molecule ion reaction activity and control the reaction condition, wherein the air pressure in the rectangular ion trap system is higher than the air pressure in the molecule ion reaction vessel, and high-purity air is filled into the molecule ion reaction vessel.

The bi-ionic-source rectangular ion trap mass spectrometer comprises: an electric field of rectangular ion trap enclosed by x electrode (1), y electrode (2) and z electrode (3), a rectangular hole on x electrode, a circular hole (5) on z electrode center to inject ion, two ion sources (8) on end covers of mass analyzer; or when bombarding ion source (9) by inner-ionized electron, injecting electron and ion through hole (4) and (5) respectively. This invention increases device capability-price ratio, and benefit to deep research on molecular ion reaction mechanism.

Provided is a method for determining the presence or amount of 5-α-dihydro-3-keto steroids (ADKSs) comprising the steps of preparing a sample for chromatographic separation, subjecting the sample to chromatographic separation, subjecting the chromatographically separated sample to atmospheric pressure photoionization (APPI), and detecting the amount of alkylated parent ions using mass spectrometry or methylated daughter ions by mass spectrometry after collisionally induced dissociation of the alkylated parent ions. Tandem mass spectrometry of ADKSs with a 6-member A ring and a 3-keto group using APPI and methanol as the alkoxy donor will produce methylated daughter ions with a mass / charge ratio of 85.0. Quantitation of this alkylated daughter ion provides a method to detect very low levels of ADKSs such as DHT. This method can also be used for the simultaneous detection of ADKSs and non-ADKSs.

The invention discloses a method used for separating and identifying flavonoid matters in tobacco by adopting liquid chromatography-mass spectrography. The method comprises the following steps: a sample is ground and dried, an extractant is added according to the standard that 0.1 ml of the extractant is added into 1 mg of the sample for extraction and centrifugation, a supernatant liquor is collected, water and chloroform are added according to the standard that 0.5 ml of the water and 1 ml of the chloroform are added into 1 ml of the supernatant liquor for centrifugation, and the supernatant liquor is collected for analysis; 153+ and 151- are adopted as characteristic ions for scanning, parent ions are extracted for second level mass spectrum scanning, and an obtained spectrogram is compared with a spectral library to determine a chemical structure and verified through a reference substance; the molecules and ions of the identified matters and myricetin, dihydromyricetin, catechinic acid / epicatechin, daidzein, glycitein and glycyrrhizin / isoliquiritigenin are adopted as characteristic ions for scanning, the molecules and ions of the searched glycosylation flavonoid matters are used as the parent ions for the second level mass spectrum scanning, an obtained spectrogram is compared with the spectral library to determine a chemical structure and verified through the reference substance. According to the invention, the method is suitable for the analyzing and detecting micro even trace flavonoid matters.

In various aspects, the present teachings provide systems, methods, assays and kits for the absolute quantitation of protein expression. In various aspects, the present teachings provide methods of determining the concentration of one or more proteins of interest in one or more samples of interest. In various aspects, the present teachings provide methods of determining the absolute concentration of one or more isoforms of a protein using standard samples of signature protein fragments and parent-daughter ion transition monitoring (PDITM). In various embodiments, the absolute concentration of multiple isoforms of a biomolecule in a sample, multiple proteins in a biological process, a combination of multiple samples, or combinations thereof, can be determined in a multiplex fashion using the present teachings. In various aspects, provided are methods of assessing the response of a biological system to a chemical agent.

The invention discloses a method for determination of illegally added substances in traditional Chinese medicines and health-care products; with use of high performance liquid chromatography-tandem quadrupole linear ion trap mass spectrometry, the method which is capable of simultaneously qualitative and quantitative detection (multiple reaction monitoring sMRM-information dependent acquisition IDA-enhanced product ion scanning EPI detection) of 13 kinds of illegally added hypoglycemic hypotensive chemical drugs such as clonidine hydrochloride and gliclazide in the traditional Chinese medicines and the health-care products is developed. And through one-time sampling detection, not only can a quantitative result obtained, but also occurrence of a false positive result is effectively avoided through qualitative database screening. The establishment of the method provides a technical support for enacting detection standards of the illegally added hypoglycemic hypotensive chemical drugs in the traditional Chinese medicine and the health-care products.

The invention belongs to the technical field of mass spectrometric analysis and test, specifically to a desolvation and ionizationoun method through heating and an apparatus. The desolvation and ionizationoun method includes atomizing a sample to be tested, and heating the atomized liquid drops or particles of the sample through flame to be tested to evaporate solvent of ion sources and ionize neutral molecules. In this way, the gas phase sample ions are obtained. The apparatus comprises a sample atomizing device, a flame generator etc. The sample to be tested forms electriferous or neutral mist-like liquid drops at the outlet of an ion source sample atomizing device, solvent evaporation occurs to the electriferous or neutral mist-like liquid drops of the object to be analyzed when heated by flame to generate gas phase ions of which the mass spectrum can be detected, and proton-exchange reaction occurs to the neutral sample molecules and ions generated by flame to generate sample ions. The thermotropic solvent evaporation or proton-exchange reaction substantially improves the ionizationoun efficiency in the sample to be tested, the ion signal intensity of the sample is increased, and the sensitivity of mass spectrometry is effective improved.

A time-of-flight mass spectrometer includes a sample plate that supports a sample for analysis. A pulsed ion source generates a pulse of ions from the sample positioned on the sample plate. An ion accelerator receives the pulse of ions generated by the pulsed ion source and accelerates the ions. An ion detector includes an input in a flight path of the accelerated ions emerging from the field-free drift space and an output that is electrically connected to the sample plate. The ion detector converts the detected ions into a pulse of electrons.

An off-axis ion transport optical system (20) including a front-stage quadrupole ion guide (21), a rear-stage quadrupole ion guide (22), and an ion deflector (23) is disposed inside an intermediate vacuum chamber (2) in a stage next to an ionization chamber (1) maintained at an atmospheric pressure. Both of the quadrupole ion guides (21 and 22) have the same configuration as that of a conventional ion guide that transports ions while trapping the ions using a radio-frequency electric field. The ion deflector (23) includes a pair of parallel flat electrodes (231 and 232) and deflects ions using a direct-current electric field. By causing the deflected ions to reach the ion receiving range of the rear-stage quadrupole ion guide (22), it is possible to efficiency introduce ions while deflecting the ions. Meanwhile, the ions and neutral particles are separated from each other in the ion deflector (23). This provides an off-axis structure ion transport optical system that achieves a high ion transmission efficiency with a simple structure.

Methods of analysing peptides by mass spectrometry are disclosed. In particular, methods of analysing peptides by fragmentation mass spectrometry (MSn, where n is at least 2) are disclosed. The methods involve derivatisation of a peptide at its N-terminus such that peaks corresponding to both a and b (and y) daughter ions are identifiable in fragmentation mass spectra of the derivatised peptide. The fragmentation mass spectra of the derivatised peptide contain additional information (relative to the fragmentation mass spectra of the underivatised peptide) useful for determination of the amino acid sequence of the peptide.