106 results about "Collision-induced dissociation" patented technology

A mass spectrometer is configured with individual multipole ion guides, configured in an assembly in alignment along a common centerline wherein at least a portion of at least one multipole ion guide mounted in the assembly resides in a vacuum region with higher background pressure, and the other portion resides in a vacuum region with lower background pressure. Said multipole ion guides are operated in mass to charge selection and ion fragmentation modes, in either a high or low pressure region, said region being selected according to the optimum pressure or pressure gradient for the function performed. The diameter, lengths and applied frequencies and phases on these contiguous ion guides may be the same or may differ. A variety of MS and MS/MSⁿ analysis functions can be achieved using a series of contiguous multipole ion guides operating in either higher background vacuum pressures, or along pressure gradients in the region where the pressure drops from high to low pressure, or in low pressure regions. Individual sets of RF, +/−DC and resonant frequency waveform voltage supplies provide potentials to the rods of each multipole ion guide allowing the operation of ion transmission, ion trapping, mass to charge selection and ion fragmentation functions independently in each ion guide. The presence of background pressure maintained sufficiently high to cause ion to neutral gas collisions along a portion of each multiple ion guide linear assembly allows the conducting of Collisional Induced Dissociation (CID) fragmentation of ions by axially accelerating ions from one multipole ion guide into an adjacent ion guide. Alternatively ions can be fragmented in one or more multipole ion guides using resonant frequency excitation CID. A multiple multipole ion guide assembly can be configured as the primary mass analyzer in single or triple quadrupole mass analyzers with or without mass selective axial ejection. Alternatively, the multiple multipole ion guide linear assembly can be configured as part of a hybrid Time-Of-Flight, Magnetic Sector, Ion Trap or Fourier Transform mass analyzer.

Multipole ion guides configured with one or mote segments and positioned in a higher pressure vacuum region, are operated in mass to charge selection and ion fragmentation modes. Individual multipole ion guides are mounted in a linear assembly with no electrodes configured in between each multipole ion guide. At least a portion of each multipole ion guide mounted in a linear assembly resides in a vacuum region with higher background pressure. At least one ion guide can be configured to extend continuously from one vacuum stage into another. Individual sets of RF, +/− DC and secular frequency voltage supplies provide potentials to the rods of each multipole ion guide allowing the operation of ion transmission, ion trapping, mass to charge selection and ion fragmentation functions independently in each ion guide. The presence of higher background pressure along a portion of the multiple ion guide linear assembly allows the Collisional Induced Dissociation (CID) fragmentation of ions by axially accelerating ions from one multipole ion guide to an adjacent ion guide, analogous to a triple quadrupole function. A variety of MS and MS/MSⁿ analysis functions can be achieved with a mass analyzer configured with multiple ion guide linear assembly operated in a higher background pressure.

The content of the invention comprises a concept of multi-beam ion pre-selection from a single sample, coordinated mobility (against the gas flow) separation, cooling ions in supersonic gas flow and mass separation of thus low divergent ions by single or plural compact high-resolution orthogonal time-of-flight mass spectrometers both linear or reflectron type with controlled collision-induced dissociation (CID) and multi-channel data recording for the optimization of sample use in the analysis, and obtaining as much useful information about the sample as possible in a reasonably short time.

Multipole ion guides configured with one or more segments and positioned in a higher pressure vacuum region, are operated in mass to charge selection and ion fragmentation modes. Individual multipole ion guides are mounted in a linear assembly with no electrodes configured in between each multipole ion guide. At least a portion of each multipole ion guide mounted in a linear assembly resides in a vacuum region with higher background pressure. At least one ion guide can be configured to extend continuously from one vacuum stage into another. Individual sets of RF, +/−DC and secular frequency voltage supplies provide potentials to the rods of each multipole ion guide allowing the operation of ion transmission, ion trapping, mass to charge selection and ion fragmentation functions independently in each ion guide. The presence of higher background pressure along a portion of the multiple ion guide linear assembly allows the Collisional Induced Dissociation (CID) fragmentation of ions by axially accelerating ions from one multipole ion guide to an adjacent ion guide, analogous to a triple quadrupole function. A variety of MS and MS/MSⁿ analysis functions can be achieved with a mass analyzer configured with multiple ion guide linear assembly operated in a higher background pressure.

A means and method are disclosed whereby ions from an ion source can be selected and transferred to a time-of-flight mass analyzer via an arrangement of multipoles in such a way that fragmented ions may be generated by collision-induced dissociation or surface-induced dissociation. First, ions from the source are collisionally cooled by a first multipole. Second, the m/z range of the ions is then selected by a second multipole (preferably a quadrupole). Third, the selected ions are allowed to collide with a "collision surface" capable of producing fragment ions. Fourth, these fragment ions are collisionally cooled in a third multipole and delivered into a TOF mass analyzer for subsequent analysis of the fragmented ions.

Systems and methods of generating ions at atmospheric pressure are presented. These systems and methods include spatially dependent analysis of a sample using an effusive ionization source. Systems and methods of isolating samples at atmospheric pressure are presented. These systems and methods include using a barrier to prevent metastables or electrons from an effusive ion source from reaching a sample unless the sample is in an analysis position. Systems and methods of using metastables in collisionally induced dissociation are presented.

The invention provides a system apparatus and methods for fragmenting various molecules. In particular, the invention may be employed for fragmenting biomolecules like peptides to determine sequence information. The invention provides a mass spectrometry system for photo-activated collision induced dissociation. The mass spectrometry system or device includes an ion source for producing ions, a photon source adjacent to the ion source for photo-activating ions produced by the ion source, an electrical element adjacent to the photon source for creating an electric field for accelerating ions produced by the ion source and photo-activated by the photon source; wherein ions are produced by the ion source, photo-activated by the photon source and accelerated into a surface to cause dissociation of the activated ions; and a detector downstream from the ion source for detecting the collision induced and dissociated ions.

Methods for molecule and/or peptide fragmentation are also disclosed.

A mass analysis of a standard sample having a known mass-to-charge ratio is carried out by performing a mass scan at a first-stage quadrupole (13) over a predetermined mass range, under the condition that a collision induced dissociation (CID) gas is introduced into a collision cell (14) and a voltage applied to a third-stage quadrupole (17) is set so that no substantial mass separation occurs in this quadrupole. Various kinds of product ions originating from a precursor ion selected by the first-stage quadrupole (13) arrive at and are detected by a detector (18) without being mass separated. Accordingly, based on the detection data, a data processor (25) can obtain a relationship between the voltage applied to the first-stage quadrupole (13) and the mass-to-charge ratio of the selected ions, with a time delay in the collision cell (14) reflected in that relationship. This relationship is stored in a calibration data memory (26), to be utilized in a neutral loss scan measurement or the like. By using this relationship, a mass shift due to the time delay in the collision cell (14) can be cancelled, so that the product ions can be detected with high sensitivity over the entire mass range. Furthermore, a mass spectrum having an accurate mass axis can be created.

The invention relates to a mass spectrum analyzer, in particular to a mass spectrum VUV (Vacuum Ultraviolet) photoionization source device for in-source collision induced dissociation, which comprises a sample injecting capillary tube, an ion repelling electrode, an ion accelerating electrode, a vacuum ultraviolet lamp, a side pumping valve and an ionization source cavity, wherein the ion repelling electrode and the ion accelerating electrode are placed in the ionization source cavity at interval in parallel, the sample injecting capillary tube passes through the outer wall of the ionization source cavity, and one end of the sample injecting capillary tube is arranged in a central small hole of the ion repelling electrodes; a light emitting window of the vacuum ultraviolet lamp is placed opposite to a gap between the ion repelling electrode and the ion accelerating electrode; and an air outlet is arranged on the side wall of the ionization source cavity, and the side pumping valve is connected with the air outlet through a pipeline. The mass spectrum VUV photoionization source device can be used together with any types of quality analyzers, can simultaneously obtain the molecular weight and the structural information of a matter to be analyzed and also be used for rapidly distinguishing isomerides by utilizing in-source collision induced dissociation.

In a method for exciting a precursor ion in an ion trap, the ion is trapped in a nonlinear trapping field that includes a quadrupolar field and a multipole field. The quadrupolar field is generated by applying a radio-frequency (RF) trapping voltage to the ion trap at a trapping amplitude and trapping frequency. A supplemental alternating-current (AC) voltage is applied to the ion trap at a supplemental amplitude and supplemental frequency. The supplemental amplitude is low enough to prevent ejection of the ion from the ion trap, and the supplemental frequency differs from the secular frequency of the ion by an offset amount. One or more operating parameters of the ion trap are adjusted, such that the ion absorbs energy from the supplemental field sufficient to undergo collision-induced dissociation (CID) without being in resonance with the supplemental field.

The invention belongs to the technical field of mass analysis, in particular to a tandem mass spectrometry analysis method performed in ion traps. The method comprises ion selective isolation, collision induced dissociation and quality scanning analysis. Dipole excitation voltages with asymmetric wave shapes are imposed on a pair of electrodes to generate dipole direct voltages, so that isolated parent ions obtain energy to be excited, collided with neutral molecules in the ion traps and dissociated, and tandem mass spectrometry analysis is achieved. The tandem mass spectrometry analysis method performed in ion traps has the advantages that additional direct current power supplies are not needed, and the dipole direct voltages can be obtained only through the control of software, and experiment devices and methods can be simplified apparently. Simultaneously, the parent ions are subjected to a non-resonance excited dissociation mode under the action of the dipole direct voltages, and abundant ion fragment information can be given through the non-resonance excitation of collision and dissociation.

Objects of the present invention is to provide a quadrupole mass filter that can be fabricated at low cost and has a high transmission efficiency even under a high pressure (0.5 mTorr or more), and to provide a mass spectrometer or mass spectrometry method that reduces crosstalk in a wide mass range. Now, in a mass spectrometer, an ion separating unit is configured to include quadrupole rod electrodes that form a quadrupole radio-frequency electric field, electrodes that form a quadrupole electrostatic field, and a power supply that allows the voltage of the electrodes to form a quadrupole electrostatic field to change. In a collision cell configured to perform collision induced dissociation, harmonic potentials in a plurality of stages are produced to resonance excite ions in the axial direction, so that the ions obtain kinetic energy to move in the direction of the detector. This energy allows a time period to shorten for which ions stay in the collision cell.

Methods for applying an RF field in a two-dimensional electrode structure include applying RF voltages to main electrodes and to compensation electrodes. The voltages on the compensation electrodes may be proportional to the voltages on the main electrodes so as to optimize the RF field for processes involving ion excitation, including collision-induced dissociation. Electrode structures may include main trapping electrodes, one or more compensation electrodes, one or more ion exit apertures, and a device or circuitry for applying the various desired voltages.

In a method for increasing the kinetic energy of an ion in a linear electrode structure, axial motion of the ion is constrained substantially to a selected axial end the electrode structure. The ion is driven to move axially from the selected end toward the other end and to reflect back toward the selected end. Constraining may be effected by adjusting one or more DC voltages applied to the ends and a central region of the electrode structure to create an axial potential well in the selected end. Driving may be affected by adjusting the DC voltage applied to the selected end to a magnitude greater than the value applied during the constraining step. The constraining and driving steps may be repeated a number of times. The method may be performed in connection with collision-induced dissociation.

The invention discloses a method for evaluating a traditional Chinese medicine preparation making technology based on a metabonomics technology, which comprises the following steps: 1, an orthogonal experiment design or a parallel contrast experiment design are used for acquiring traditional Chinese medicine preparation products with different preparation technologies; 2, the prepared products are subjected to sample pre-treatment; 3, a liquid phase series high resolution mass spectrometer is used for acquiring a chromatogram of the traditional Chinese medicine preparation product; 4, the belongingness components of the traditional Chinese medicine are found in the chromatogram according to mass loss strategy; 5, each component structure can be deducted according to fragment information obtained by determined accurate mass number and collision induced dissociation; 6, all belongingness components content in each product are subjected to quantitative analysis; and 7) the influence of the preparation technology on the preparation can be evaluated through multivariable data statistics analysis method. The method of the invention has the advantages of accuracy and sensitivity, and is not depend on standard compounds, and the change of belongingness components of the traditional Chinese medicine in the preparation product can be integrally traced.

A cloud of ions captured in an ion trap (2) is irradiated with a stream of hydrogen radicals cast through a radical particle introduction hole (26) bored in a ring electrode (21) at a flow rate of 4×10¹⁰ [atoms/s]. As a result, a radical induced dissociation which does not rely on the transfer or capture of electrons occurs within the ion trap (2), whereby c/z-type fragment ions are efficiently generated. After the irradiation with the hydrogen radicals, a supplemental collision-induced dissociation process may performed by introducing inert gas into the ion trap (2) and resonantly exciting the ions, in order to further promote the generation of the c/z-type fragment ions. In this manner, according to the present invention, it is possible to achieve radical induced dissociation of singly-charged ions derived from a peptide and use the thereby generated c/z-type fragment ions for mass spectrometry.