2831 results about "Tandem mass spectrometry" patented technology

During the structural analysis of a protein or peptide by tandem mass spectroscopy, a peptide ion derived from a protein that has already been measured and that is expressed in great quantities is avoided as a tandem mass spectroscopy target. A peptide derived from a minute amount of protein, which has heretofore been difficult to analyze, can be automatically determined as a tandem mass spectroscopy target within the real time of measurement. Data concerning a protein that has already been measured and a peptide derived from the protein is automatically stored in an internal database. The stored data is collated with measured data with high accuracy to determine an isotope peak. In this way, the process of selecting a peptide peak that has not been measured as the target for the next tandem analysis can be performed within the real time of measurement and a redundant measurement of peptides derived from the same protein can be avoided. The information contained in the MSn spectrum is effectively utilized in each step of the MSn involving a multi-stage dissociation and mass spectroscopy (MSn), so that the flows for the determination of the next analysis content and the selection of the parent ion for the MSn+1 analysis, for example, can be optimized within the real time of measurement and with high efficiency and accuracy. Thus, a target of concern to the user can be subjected to tandem mass spectroscopy without wasteful measurement.

This invention relates to tandem mass spectrometry and, in particular, to tandem mass spectrometry using a linear ion trap and a time of flight detector to collect mass spectra to form a MS / MS experiment. The accepted standard is to store and mass analyze precursor ions in the ion trap before ejecting the ions axially to a collision cell for fragmentation before mass analysis of the fragments in the time of flight detector. This invention makes use of orthogonal ejection of ions with a narrow range of m / z values to produce a ribbon beam of ions that are injected into the collision cell. The shape of this beam and the high energy of the ions are accommodated by using a planar design of collision cell. Ions are retained in the ion trap during ejection so that successive narrow ranges may be stepped through consecutively to cover all precursor ions of interest.

Disclosed is an apparatus for performing mass spectrometry and a method of analyzing a sample through mass spectrometry. In particular, the disclosure relates to an apparatus capable of ambient mass spectrometry and mass spectral imaging and a method for the same. The apparatus couples laser ablation, flowing atmospheric-pressure afterglow ionization, and a mass spectrometer.

An ion mobility / mass spectrometry method and instrument using aerosolized samples and dual positive and negative mode detection is described. Sample preparation methods are also described.

The invention discloses hot pepper and a determining method for 96 pesticide residues in a product of the hot pepper. The determining method comprises the following steps: homogenously extracting residual pesticide in a sample with 1% acetic acid-acetonitrile solution, purifying the extracting solution with a Florisil solid phase extraction column, dispersing and purifying the extracting solution with ethylenediamine-N-propyl silane (PSA) and octadecyl silane bonded phase (C18) substrate, detecting 69 pesticide residuals in the purified concentrated liquid of the Florisil column by GC-MS (gaschromatographic mass spectrometry), detecting 27 pesticide residuals in the substrate dispersed purified liquid by liquid chromatography-tandem mass spectrometry (LC-MS / MS), using the black substrate solution dilution standard to construct the updated calibration curves, adopting an internal standard method to quantify when using GC / MS to detect the residuals, and adopting an external standard method to quantify when using LC-MS / MS to detect the residuals. The average recovery rate of the method is 70.7-118.6%; the average relative standard deviation (RSD) is 3.2-11.4%; the detection limit is 0.13-28.2 ug / kg. The determining method has the advantages of simplicity and convenience in operation, high speed, accuracy, high sensitivity and good repeatability.

Systems and methods are used to store an electronic record of all product ion spectra of all detectable compounds of a sample. A plurality of product ion scans are performed on a tandem mass spectrometer one or more times in a single sample analysis across a mass range using a plurality of mass selection windows. All sample product ion spectra of all detectable compounds for each mass selection window are produced. All sample product ion spectra for each mass selection window are received from the tandem mass spectrometer using a processor. All sample product ion spectra for each mass selection window are stored as an electronic record of all detectable compounds of the sample using the processor. The electronic record is used to characterize compounds known at the time the electronic record is stored or to characterize compounds that became known after the electronic record was stored.

An electrospray-assisted laser desorption ionization device includes: an electrospray unit including a nozzle; a voltage supplying member disposed to establish between the nozzle and a receiving unit a potential difference such that liquid drops of the electrospray medium formed at the nozzle are laden with charges, and such that the liquid drops are forced to leave the nozzle toward the receiving unit along a traveling path; a laser desorption unit adapted to irradiate a sample such that, upon irradiation, analytes contained in the sample are desorbed to fly along a flying path which intersects the traveling path so as to enable the analytes to be occluded in the liquid drops, and such that as a result of dwindling in size of the liquid drops when moving along the traveling path, charges of the liquid drops will pass on to the analytes occluded therein to form ionized analytes.

A method and apparatus are provided for effecting multiple mass selection or analysis steps. Fundamentally, the technique is based on moving ions in different directions through separate components of a mass spectrometer apparatus. To effect different steps, a precursor ion is selected in a first mass selector, and then passed into a collision cell, to effect fragmentation or reaction with a gas, to generate fragment or product ions. The generated product ions are then passed back into the first mass selector, and preferably back into an upstream ion trap. The product ions then pass through the first mass selector again, to select a desired product ion, for further fragmentation and analysis. These steps can be repeated a number of times. A final mass analysis step can be effected in either a time-of-flight section or other mass analyzer. The invention enables conventional triple quadrupole mass spectrometers and QqTOF mass spectrometers to effect multiple MS steps.

The invention relates to ions guided by gas flows in mass spectrometers, particularly in RF multipole systems, and to RF quadrupole mass filters and their operation with gas flows in tandem mass spectrometers. The invention provides a tandem mass spectrometer in which the RF quadrupole mass filter is operated at vacuum pressures in the medium vacuum pressure regime, utilizing a gas flow to drive the ions are through the mass filter. Vacuum pressures between 0.5 to 10 pascal are maintained in the mass filter. The mass filter may be enclosed by a narrow enclosure to guide the gas flow. The quadrupole mass filter may be followed by an RF multipole system, operated at the same vacuum pressure, serving as fragmentation cell to fragment the selected parent ions. The fragmentation cell may be enclosed by the same enclosure which already encloses the mass filter, so the ions may be driven by the same gas flow at the same vacuum pressure, greatly simplifying the required vacuum pumping system in tandem mass spectrometers. There are many other applications utilizing gas flows including supersonic gas jets in mass spectrometry.

An ion mobility / mass spectrometry method and instrument using aerosolized samples and dual positive and negative mode detection is described. Sample preparation methods are also described.

A mass spectrometer includes an ion source and at least one vacuum stage, a means for delivering ions from the ion source to the vacuum stage, a collision cell, a detector, at least two multipole ion guide segments, and independent RF frequency and DC voltage sources applied to the multipole ion guide segments, the RF frequency and DC voltage sources being controlled independently of each other.

The invention provides methods for isolating a modified peptide from a complex mixture of peptides, the method comprising the steps of: (a) obtaining a proteinaceous preparation from an organism, wherein the preparation comprises modified peptides from two or more different proteins; (b) contacting the preparation with at least one immobilized modification-specific antibody; and (c) isolating at least one modified peptide specifically bound by the immobilized modification-specific antibody in step (b). The method may further comprise the step of (d) characterizing the modified peptide isolated in step (c) by mass spectrometry (MS), tandem mass spectrometry (MS—MS), and / or MS3 analysis, or the step of (e) utilizing a search program to substantially match the spectra obtained for the modified peptide during the characterization of step (d) with the spectra for a known peptide sequence, thereby identifying the parent protein(s) of the modified peptide. Also provided are an immunoaffinity isolation device comprising a modification-specific antibody, and antibodies against novel UFD1 and PTN6 phosphorylation sites.

The invention provides methods for isolating a modified peptide from a complex mixture of peptides, the method comprising the steps of: (a) obtaining a proteinaceous preparation from an organism, wherein the preparation comprises modified peptides from two or more different proteins; (b) contacting the preparation with at least one immobilized modification-specific antibody; and (c) isolating at least one modified peptide specifically bound by the immobilized modification-specific antibody in step (b). The method may further comprise the step of (d) characterizing the modified peptide isolated in step (c) by mass spectrometry (MS), tandem mass spectrometry (MS—MS), and / or MS3 analysis, or the step of (e) utilizing a search program to substantially match the spectra obtained for the modified peptide during the characterization of step (d) with the spectra for a known peptide sequence, thereby identifying the parent protein(s) of the modified peptide. Also provided are an immunoaffinity isolation device comprising a modification-specific antibody, and antibodies against novel UFD1 and PTN6 phosphorylation sites.

The invention provides reagents, kits and methods for detecting and / or quantifying proteins in complex mixtures, such as a cell lysate. The methods can be used in high throughput assays to profile cellular proteomes. In one aspect, the invention provides a peptide internal standard labeled with a stable isotope and corresponding in amino acid sequence to the amino acid sequence of a subsequence of a target polypeptide. In another aspect, the peptide internal standard is labeled at a modified amino acid residue and is used to determine the presence of, and / or quantitate the amount of a particular modified form of a protein.

The invention belongs to the technical field of food detection methods, and particularly relates to a method for determining multiresidue of veterinary drugs in animal-derived foods. The method comprises the following steps of weighing a sample, adding an acetic acid-acetonitrile solution, carrying out vibrating extraction, centrifuging to obtain acetonitrile extracting solution, loading the extracting solution obtained by centrifuging into a centrifuge tube with a mixed filler, carrying out vibrating centrifugation, sucking purified liquid, concentrating by blowing nitrogen, diluting to constant volume and detecting by UPLC / MS / MS (ultra performance liquid chromatography-tandem mass spectrometry). The method disclosed by the invention is firstly applied in detecting animal-derived foods and 107 kinds of veterinary drugs such as sulfonamides, quinolones, beta agonists in animal products are subjected to fast qualitative and quantitative detection, the detection limit is completely capable of meeting the detection requirements and the detection efficiency is greatly promoted.

In a tandem mass spectrometer ions are created only once and stored in an ion reservoir. A particular ion species to be analyzed is then exported from the reservoir through a mass selective ion gate without damaging the other ion species remaining in the reservoir. All subsequent analyses are conducted on these stored ions, without adding further ions so that no changes in the concentrations of the stored ion species occur. The exported ions are fragmented, and a fragment ion mass spectrum is measured in a mass analyzer, preferably in a time-of-flight mass analyzer with orthogonal ion injection. The processes of exporting a selected ion species with subsequent fragmentation and the acquisition of the fragment ion spectrum can be repeated for any number of ion species stored in the reservoir.

There is disclosed a method of selectively extracting ions comprising the steps of:providing a supply of ions in a body of gas;generating a ponderomotive ion trapping potential generally along an axis;generating further potentials to provide an effective potential which prevents ions from being extracted from an extraction region;trapping ions in said effective potential; andselectively extracting ions of a predetermined m / z ratio or ion mobility from the extraction region;in which the characteristics of the effective potential which prevent ions from being extracted from the extraction region are caused, at least in part, by the generation of the ponderomotive ion trapping potential.

The invention provides a method for simultaneously determining one hundred pesticide residuals in a traditional Chinese medicine through ultrahigh performance liquid chromatography-tandem quadrupole mass spectrum. The method comprises the following steps: immersing traditional Chinese medicine powder with ultrapure water, extracting with acetonitrile containing 0.1% acetic acid through a homogenate method, carrying out solid phase dispersing purification with N-propylethylenediamine and graphitized carbon, detecting in a timesharing multi-reaction monitoring mode through the ultrahigh performance liquid chromatography-tandem quadrupole mass spectrum, and quantifying with an external standard curve method. 88% of pesticides have good linear relations in a range of 5-500ng / mL, correlation coefficients are above 0.99, and the correlation coefficients of above 98% of the pesticides are above 0.97; the average recovery rate of the pesticides with the low concentration of 10mug / kg, the middle concentration of 50mug / kg and the high concentration of 100mug / kg is 70-130%, and the relative standard deviation is less than 0.15; and the detection limit is equal to or less than 0.01mg / kg, so routine detection requirements can be completely satisfied. The method has the advantages of strong versatility, good selectivity, high sensitivity, and rapidness and simplicity.

Systems and methods are used to store an electronic record of all product ion spectra of all detectable compounds of a sample. A plurality of product ion scans are performed on a tandem mass spectrometer one or more times in a single sample analysis across a mass range using a plurality of mass selection windows. All sample product ion spectra of all detectable compounds for each mass selection window are produced. All sample product ion spectra for each mass selection window are received from the tandem mass spectrometer using a processor. All sample product ion spectra for each mass selection window are stored as an electronic record of all detectable compounds of the sample using the processor. The electronic record is used to characterize compounds known at the time the electronic record is stored or to characterize compounds that became known after the electronic record was stored.

The present invention is directed to ion source and vacuum housings for use in MALDI-TOF mass spectrometry which operates with any type of mass analyzer including linear, reflector, or tandem TOF-TOF instruments. By removing the requirement for the vacuum lock, the present invention allows operation of the ion source vacuum chamber at a pressure at least two orders of magnitude higher than conventional instruments. The present invention also requires only a single valve that isolates the ion source vacuum housing from the TOF analyzer vacuum housing. This is a significant improvement over vacuum locks in the art where the valve opening must be sufficiently large to allow the sample plate to pass through.

A tandem mass spectrometer includes a two-dimensional ion trap that has an elongated ion-trapping region extending along a continuously curving path between first and second opposite ends thereof. The elongated trapping region has a central axis that is defined substantially parallel to the curved path and that extends between the first and second opposite ends. The two-dimensional ion trap is configured for receiving ions through the first end and for mass selectively ejecting the ions along a direction that is orthogonal to the central axis, such that the ejected ions are directed generally toward a common point. The tandem mass spectrometer also includes a collision cell having an ion inlet that is disposed about the common point for receiving the ions that are ejected therefrom and for causing at least a portion of the ions to undergo collisions and form product ions by fragmentation. A mass analyzer in communication with the collision cell receives the product ions from the collision cell and obtains product ion mass spectra with a rapid scan rate. In this way, a plurality of product ion spectra may be obtained for a large number of precursor ions in a sample without the need for data-dependent operation.

The present invention relates to a spray needle for use in electrospray ionization (ESI) for mass spectrometry. A spray needle is disclosed which is constructed to have an opening along its length such that a sample solution may be more readily introduced or loaded therein. Further, the design of the spray needle of the invention is more durable than the prior art spray needles and may be reusable. Because sample loading is more readily achieved, the spray needle of the invention is appropriate for use with a fully automated system for the analysis of samples.

The invention provides a gas / liquid tandem mass spectrum system with a multimode ionization ion source. The gas / liquid tandem mass spectrum system is characterized by being formed by connecting a multimode ionization ion source, a gas chromatography, a Liquid Chromatography, a mass analyzer with purification and enrichment functions, and a flight time mass spectrometry in series. According to the invention, the applicability of a single-ion-source mass spectrometry specific to analysis of polymorphic samples is broadened, meanwhile, the high resolution performance of fragment ions on mass selection and analysis is enhanced, and the researches on an ionic reaction mechanism are realized.

The invention discloses a method and system for increasing judgment accuracy of monoisotopic peaks. The method comprises the following steps: according to selected tandem mass spectrums, determining candidate isotopic peak clusters; according to the similarity and the strength ratio of the chromatographic outflow curves of the candidate isotopic peak clusters, determining the start and stop of the isotopic peak clusters; according to the start and stop of the isotopic peak clusters, determining the quality of the monoisotopic peaks; and judging whether the monoisotopic peaks of the tandem mass spectrums are not determined or not, if yes, returning and selecting a new tandem mass spectrum to determine a candidate isotopic peak cluster, and if not, ending.

The present invention relates to a method of simultaneously detecting a plurality of agro-veterinary drug residues in bee products. The extracted liquid trichloroacetic acid or perchloric acid and the extracted liquid acetate, phosphate or borate solution are added into a sample; the pH value is controlled between 4.5 and 9.0; the mixed solution is centrifuged, the filtrate is added into a solid phase extraction column to be extracted, the extraction column is eluted and dried, the column is washed by oxalic acid-methanol solution, the volume of the eluent is defined by the aqueous solution of methanol, the eluent is added into liquid chromatography-tandem mass spectrometry to be analyzed and tested, the acquired chromatographic peak is contrasted with the known standard chromatographic peak of the drug, and according to the retention time and the abundance of the mass spectrum ions, the specific name of the detected drug is determined. The method only requires one pre-treatment of the sample, and thus can simultaneously extract 11 classes and more than 60 kinds of veterinary drug residues, such as sulfonamides, quinolones, macrolides, lincomycins, nitroimidazoles, beta-lactams, tetracyclines, chloromycetins, trinethoprims, chlordimeform, triadimenol and the like, the efficiency of analysis is high, and the detection cost is greatly reduced.

The invention concerns a method for surveying a subsurface formation containing hydrocarbons, comprising:injecting at least one tracer compound into the subsurface formation;recovering a fluid derived from the subsurface formation;detecting the tracer compound in the fluid by liquid chromatography analysis coupled with tandem mass spectrometry analysis, the liquid chromatography analysis being conducted with a stationary phase composed of particles having a mean size equal to or less than 2.1 μm.

Methods are described for determining the amount of insulin in a sample. More specifically, mass spectrometric methods are described for detecting and quantifying insulin in a biological sample utilizing purification methods coupled with tandem mass spectrometric or high resolution / high accuracy mass spectrometric techniques.