11 results about "Collision-induced dissociation" patented technology

An apparatus fortime-of-flight, TOF, tandem mass spectrometry comprises an ion source for providing precursor ions, a linear ion trap comprising a set of electrodes configured for receiving the precursor ions into the ion trap. A voltage source is configured for applying to the set of electrodes a trapping voltage(s) configured to generate an axial trapping potential field forming a potential barrier to axially trap the received precursor ions within the linear ion trap, and for applying to the set of electrodes an RF voltage(s) configured to generate a radial trapping potential field to radially trap received precursor ions. The voltage source selectively changes the radial trapping potential field to increase the kinetic energy of precursor ions in the ion trapping region so that precursor ions can overcome the potential barrier thereby axially ejecting the selected precursor ions from the linear ion trap. A collision cell is configured to receive the ejected precursor ions and to apply to them a process of collision-induced dissociation to generate product ions therefrom. A mass analyser, such as a time-of-flight, TOF, mass analyser, receives the product ions (and / or any remaining unfragmented precursor ions) and to apply to them a process of mass analysis.

An interference ion removal device used in a mass spectrometry system or the like comprises a first ion guide and a second ion guide, a DC potential barrier being formed between the first ion guide and the second ion guide. In the first ion guide, collision-induced dissociation (CID) and kinetic energy discrimination (KED) are performed, and in the second ion guide, the velocity distribution of ions is caused to converge.

The invention discloses a quadrupole collision pool ion cleaning method based on an axial potential difference, which comprises the following steps: establishing a constant axial potential difference in a quadrupole collision pool to form a continuous potential gradient from an inlet to an outlet; after a sample is subjected to ionization and mass selection, primary ions with a specific mass-to-charge ratio enter a collision pool and collide with collision gas to induce dissociation to generate product ions, and the product ions move towards an outlet under the action of axial potential difference; the system monitors the ion signal intensity in real time, and stops inputting the primary ions to enter a cleaning stage after a preset threshold value is reached; and keeping the axial potential difference constant during cleaning, and judging that the cleaning is completed when the ion abundance is reduced to be below background noise. The continuous active driving force is provided through the axial potential difference, the defects that traditional passive cleaning is low in efficiency and incomplete are overcome, the cleaning time is remarkably shortened, interference of residual ions is eliminated, the analysis accuracy and efficiency are improved, and the method is particularly suitable for high-throughput tandem mass spectrometry.

To provide a technology for improving the accuracy of compound identification in liquid chromatograph mass spectrometers, including single quadrupole mass spectrometers. [Solution] In the analytical apparatus 100, the sample contains a target compound produced by the derivatization of a short-chain fatty acid or organic acid, which is the target compound in the analyte. The central control unit 5 causes the mass spectrometry unit 2 to measure the m / z intensity of the fragments while performing insource collision-induced dissociation on the sample during a given holding time in the liquid chromatograph, and also to measure the m / z intensity of the fragments on the sample during the same given holding time without performing insource collision-induced dissociation.

The present application belongs to the technical field of separation and analysis chemistry, and particularly relates to a mass spectrometric qualitative analysis method for iridoid glycoside isomers. The steps of the method are as follows: the sample is first extracted and separated by liquid chromatography, the separated sample is subjected to secondary mass spectrometric analysis under negative ion and positive ion modes under gradient collision energy, collision-induced dissociation is performed on the target parent ion, and secondary mass spectrometric spectra under various collision energies are collected; characteristic ions are screened, and isomers are identified by comparing the relative abundance differences of the characteristic ions between different isomers. The present application compares and analyzes the MS / MS cracking rules of iridoid glycoside isomers by LC-QTOF-MS / MS system, and the differences in cracking characteristics are determined by the relative intensity differences of multiple fragment ions under positive and negative modes under gradient collision, thereby improving the accuracy of isomer identification.

A mass spectrometer including: a reaction chamber into which a precursor ion derived from a sample molecule is introduced; a collision gas supply part configured to supply collision gas to the reaction chamber; a radical supply part configured to supply hydrogen radicals, oxygen radicals, nitrogen radicals, or hydroxyl radicals to the reaction chamber; a dissociation operation control part configured to control operations of the collision gas supply part and the radical supply part to generate the product ions by collision-induced dissociation and radical attachment dissociation of the precursor ion inside the reaction chamber, an ion detection part configured to mass-separate and detect ions ejected from the reaction chamber, and a spectrum data generation part configured to generate spectrum data based on a detection result by the ion detection part.

The invention relates to the technical field of analytical chemistry mass spectrum imaging, in particular to a P-B reaction online detection system and method, and the system comprises a sample fixing unit, a multi-dimensional control platform, a fluid transmission unit, an auxiliary catalysis unit and a mass spectrum acquisition unit. According to the present invention, the P-B reaction and the mass spectrometry imaging technology are combined, the P-B reaction is adopted to generate the oxetane structure at the double bond through the ultraviolet light induced [2 + 2] cycloaddition reaction, and the characteristic fragment is generated after the collision induced dissociation so as to achieve the accurate positioning of the double bond position, and solve the problem of the lipid isomer spatial distribution analysis; meanwhile, accurate positioning and analysis of lipid carbon-carbon double bond positions in a complex biological sample are realized by utilizing high sensitivity and spatial resolution capability of a mass spectrum imaging technology; the method can be applied to the fields of biomedical research, metabonomics and drug development, and an innovative analysis method is provided for lipid molecular structure analysis and function research.

The present invention discloses a collision-induced dissociation method for an ion trap mass spectrometer. In a continuous-injection ion trap mass spectrometer, the electric field at the ion trap entrance is altered by varying the DC voltages on the x and y electrodes of the ion trap, thereby increasing the radial displacement of ions within the trap. This energy is then converted from the radio frequency field into internal energy through collisions, leading to collision-induced dissociation. This method can rapidly switch between collision-induced dissociation and fragmentation by regulating the DC voltages on the ion trap electrodes, controlling the degree of fragmentation and obtaining information on multiple characteristic fragment ions simultaneously, thereby improving qualitative accuracy.

The invention relates to the field of mass spectrometry and ion mobility spectrometry, and more particularly to the fragmentation of ions in collision cells. An ion fragmentation device is characterized in that it comprises an ion transport channel which has an inlet end and an outlet end and is delimited by surfaces on which are arranged radiofrequency and / or DC electrodes which generate a travelling wave field that guides ions toward the outlet end of the channel, wherein the middle part of the device is provided with electrodes that perform the function of fragmenting and thermalizing ions, said electrodes differing from the other electrodes on the rest of the device in terms of their power supply mode and / or geometry. The technical result of the invention consists in increased fragmentation efficiency, efficient ion transport through all of the component parts of CID cells, reduced ion loss in CID cells and greater analytical sensitivity, less blurring of ion packets over time, and a decrease in the pressure in adjacent chambers of the mass spectrometer, which permits the use of pumps with a lower pumping speed.

The present invention discloses a method for eliminating space charge effects in an ion trap based on selective collision-induced dissociation. This method uses a rectangular ion trap mass spectrometer equipped with a reagent-assisted photochemical ionization source and a continuous atmospheric pressure interface as a detection instrument. A major advantage of a continuous sampling ion trap mass spectrometer is that it can accumulate target ions and improve sensitivity by extending the injection time, but in practical applications, the presence of interfering ions will occupy the charge capacity in the ion trap. When the injection time is too long, a space charge effect will be introduced, resulting in peak broadening and peak position shift. Selective collision-induced dissociation can be achieved by utilizing the different voltages required for collision-induced dissociation of target ions and interfering ions, breaking up the interfering ions and making it impossible for the fragmented ions to be stabilized in the ion trap, thereby eliminating the space charge effect caused by the interfering ions.

The application belongs to the field of light industry grease, and discloses a method for detecting and analyzing the content of positional isomer of same-acid glyceride by high performance liquid chromatography tandem mass spectrometry. Based on the derivatization treatment of same-acid glyceride, the hydroxyl group in the glyceride not combined with the fatty acid is connected with a new group (isocyanate), and the corresponding 1,2-DAG isocyanate derivative or 1,3-DAG isocyanate derivative is generated. The same-acid glyceride derivative is analyzed by using a liquid chromatograph-mass spectrometer, and the content of the positional isomer of same-acid glyceride is quantitatively analyzed by the relative content difference of two daughter ions generated under collision-induced dissociation of the derivative. The method can realize the quantification of the positional isomer of glyceride without separating the positional isomer of glyceride by chromatography, and only the conventional C18 chromatography is used, so that the development of special chiral chromatographic column or specific chromatographic separation technology is reduced.