Abstract:
This invention relates to a method of trapping ions and to an ion trapping assembly. In particular, the present invention has application in gas-assisted trapping of ions in an ion trap prior to a mass analysis of the ions in a mass spectrometer. The invention provides a method of trapping ions in a target ion trap of an ion trapping assembly that comprises a series of volumes arranged such that ions can traverse from one volume to the next, the volumes including the target ion trap, whereby ions are allowed to pass repeatedly through the volumes such that they also pass into and out from the target ion trap without being trapped. Potentials may be used to reflect the ions from respective ends of the ion trapping assembly. Optionally, a potential well and/or gas-assisted cooling may be used to cause the ions to settle in the target ion trap.
Abstract:
This invention relates to a mass spectrometer including a reaction cell and to a method of using such a mass spectrometer. In particular, although not exclusively, this invention relates to a tandem mass spectrometer and to tandem mass spectrometry. The invention provides a method of mass spectrometry using a mass spectrometer having a longitudinal axis, comprising guiding ions to travel along the longitudinal axis of the mass spectrometer in a forwards direction to pass through an intermediate ion store and then to enter a reaction cell, to process the ions within the reaction cell, to eject the processed ions to travel back along the longitudinal axis to enter the intermediate ion store once more, and to eject one or more pulses of the processed ions in an off-axis direction to a mass analyser.
Abstract:
An electrostatic trap such as an orbitrap is disclosed, with an electrode structure. An electrostatic trapping field of the form U′(r,φ,z) is generated to trap ions within the trap so that they undergo isochronous oscillations. The trapping field U′(r, φ,z) is the result of a perturbation W to an ideal field U(r, φ,z) which, for example, is hyperlogarithmic in the case of an orbitrap. The perturbation W may be introduced in various ways, such as by distorting the geometry of the trap so that it no longer follows an equipotential of the ideal field U(r, φ,z), or by adding a distortion field (either electric or magnetic). The magnitude of the perturbation is such that at least some of the trapped ions have an absolute phase spread of more than zero but less than about 2π radians over an ion detection period Tm.
Abstract:
The invention concerns autoreactive peptides, peptide-MHC complexes, T cell subpopulations that react thereto as well as diagnostic and therapeutic applications of these compounds.
Abstract:
New HCV peptide antigens are described. These peptide antigens are suitable for the determination of HCV antibodies as immunogens for the preparation of antibodies to HCV and as immunogens for the preparation of vaccines to HCV.
Abstract:
A mass spectrometer includes an inductive coupled plasma source whose flame is near ground potential, an interface, a flight tube, and an analyzer that includes magnetic and electric sectors, and an ion detector, which detector is operated at high voltage for ion acceleration. The magnetic sector includes a magnet and pole pieces that are insulated electrically relative to the flight tube. The pressure within the interface preferably does not exceed 10.sup.-3 mbar. By varying the magnetic field and the acceleration potential, identification of a specified mass over defined time intervals is carried out. The disclosed mass spectrometer provides improved coupling between the plasma ion source and a double-focussing analyzer, while advantageously providing a low voltage regime for the plasma source.
Abstract:
A lens arrangement (30) for the focusing of a beam of electrically charged particles (24) in the beam path of imaging systems, more particularly in mass spectrometers (10), is indicated, the lens arrangement (30) being connected to an electrical voltage supply. The lens arrangement (30) is situated at the location or in the vicinity of the intermediate image (29) produced by the imaging system, and consists of a plurality of plates (32 to 35) disposed in succession, with aligned transmission apertures (38 to 41), the plates being connected to adjustable electrical voltages.
Abstract:
An electrostatic trap such as an orbitrap is disclosed, with an electrode structure. An electrostatic trapping field of the form U′ (r, Φ, z) is generated to trap ions within the trap so that they undergo isochronous oscillations. The trapping field U′(r, Φ, z) is the result of a perturbation W to an ideal field U(r, Φ, z) which, for example, is hypologarithmic in the case of an orbitrap. The perturbation W may be introduced in various ways, such as by distorting the geometry of the trap so that it no longer follows an equipotential of the ideal field U(r, Φ, z), or by adding a distortion field (either electric or magnetic). The magnitude of the perturbation is such that at least some of the trapped ions have an absolute phase spread of more than zero but less than 2 n radians over an ion detection period Tm.
Abstract:
This invention relates to a method of trapping ions and to an ion trapping assembly. In particular, the present invention has application in gas-assisted trapping of ions in an ion trap prior to a mass analysis of the ions in a mass spectrometer. The invention provides a method of trapping ions in a target ion trap of an ion trapping assembly that comprises a series of volumes arranged such that ions can traverse from one volume to the next, the volumes including the target ion trap, whereby ions are allowed to pass repeatedly through the volumes such that they also pass into and out from the target ion trap without being trapped. Potentials may be used to reflect the ions from respective ends of the ion trapping assembly. Optionally, a potential well and/or gas-assisted cooling may be used to cause the ions to settle in the target ion trap.
Abstract:
An electrostatic trap such as an orbitrap is disclosed, with an electrode structure. An electrostatic trapping field of the form U′(r, φ, z) is generated to trap ions within the trap so that they undergo isochronous oscillations. The trapping field U′(r, φ, z) is the result of a perturbation W to an ideal field U(r, φ, z) which, for example, is hyperlogarithmic in the case of an orbitrap. The perturbation W may be introduced in various ways, such as by distorting the geometry of the trap so that it no longer follows an equipotential of the ideal field U(r, φ, z), or by adding a distortion field (either electric or magnetic). The magnitude of the perturbation is such that at least some of the trapped ions have an absolute phase spread of more than zero but less than 2 π radians over an ion detection period Tm.