Abstract: A method and apparatus are provided for operating a linear ion trap. A linear ion trap configuration is provided that allows for increased versatility in functions compared to a conventional three-sectioned linear ion trap. In operation, the linear ion trap provides multiple segments, the segments spatially portioning an initial population of ions into at least a first and a second ion population. Each segment is effectively independent and ions corresponding to the first ion population are able to be manipulated independently from ions corresponding to ions corresponding to the second ion population; the ions having been generated by an ion source under the same conditions. The ions can then be expelled from the ion trap.

Abstract: A device for transporting and focusing ions in a low vacuum or atmospheric-pressure region of a mass spectrometer is constructed from a plurality of longitudinally spaced apart electrodes to which oscillatory (e.g., radio-frequency) voltages are applied. In order to create a tapered field that focuses ions to a narrow beam near the device exit, the inter-electrode spacing or the oscillatory voltage amplitude is increased in the direction of ion travel.

Abstract: Systems and methods of the invention include a branched radio frequency multipole configured to act, for example, as an ion guide. The branched radio frequency multipole comprises multiple ion channels through which ions can be alternatively directed. The branched radio frequency multipole is configured to control which of the multiple ion channels ions are directed, through the application of appropriate potentials.

Abstract: A device for transporting and focusing ions in a low vacuum or atmospheric-pressure region of a mass spectrometer is constructed from a plurality of longitudinally spaced apart electrodes to which oscillatory (e.g., radio-frequency) voltages are applied. In order to create a tapered field that focuses ions to a narrow beam near the device exit, the inter-electrode spacing or the oscillatory voltage amplitude is increased in the direction of ion travel.

Abstract: A MALDI/LDI source includes an ion collection device, e.g., a skimmer, orifice, mass analyzer, ion transfer optics and/or ion guide, configured for use with a short focal length lens with a large aperture. In some embodiments, the ion collection device includes an outer edge that can be disposed approximately parallel to a beam envelope between a lens and a focal point positioned at a MALDI/LDI sample. This configuration of the outer edge allows the ion collection device to be placed in close proximity to the focal point. This placement results in favorable collection efficiencies of laser desorbed analyte from the MALDI/LDI sample.

Abstract: A method and apparatus are provided for operating a linear ion trap. A linear ion trap configuration is provided that allows for increased versatility in functions compared to a conventional three-sectioned linear ion trap. In operation, the linear ion trap provides multiple segments, the segments spatially portioning an initial population of ions into at least a first and a second ion population. Each segment is effectively independent and ions corresponding to the first ion population are able to be manipulated independently from ions corresponding to ions corresponding to the second ion population; the ions having been generated by an ion source under the same conditions. The ions can then be expelled from the ion trap.

Abstract: An ion source is disclosed for forming multiply-charged analyte ions from a solid sample. A beam of pulsed radiation is directed onto a portion of the sample to desorb analyte molecules. A retaining structure holding a solvent volume is positioned proximate the sample. Desorbed analyte molecules contact a free surface of the solvent and pass into solution. The solution is then conveyed through an outlet passageway to an electrospray apparatus, which introduces a spray of charged solvent droplets into an ionization chamber.

Abstract: A method and apparatus are provided for operating a linear ion trap. A linear ion trap configuration is provided that allows for increased versatility in functions compared to a conventional three-sectioned linear ion trap. In operation, the linear ion trap provides multiple segments, the segments spatially partitioning an initial ion population into at least a first and a second ion population, and enabling the ions corresponding to the first ion population to be expelled from the linear ion trap substantially simultaneously with the ions corresponding to the second ion population. Each segment is effectively independent and ions corresponding to the first ion population are able to be manipulated independently from ions corresponding to ions corresponding to the second ion population; the ions having been generated by an ion source under the same conditions.

Abstract: A mass spectrometer includes a multipole having a main RF field for radially containing ions generally on a central axis. The multipole has first and second axial DC fields in opposite first and second direction along a length of the multipole. The first and second axial DC fields approach or add substantially to zero on the central axis. The multipole has an excitation voltage applied thereto for selectively exciting the ions of desired m/z ratios off the central axis. The excitation voltage thus causes excursion of the ions into a region where either the first or second axial DC field is strong. Thus, excitation of the ions and the DC fields cause ion drift toward a front end or a back end of the multipole. Further excitation moves the ions into regions of the DC fields that overcome barriers and causes axial ejection of the ions from the multipole.

Abstract: An ion trap is provided with at least two discrete trapping regions or segments. Both segments are located in a vacuum chamber of a mass spectrometer system. An entrance of the ion trap is disposed downstream to a laser based ionization source to receive the ions with a wide range of kinetic energies that have been generated by the laser-based ionization source. Once sufficient ions have been accumulated in the first segment and sufficient time has passed to cool the ions, they are transferred to the second segment and ultimately ejected through an aperture or slot to a detector arrangement to produce a mass spectrum.

Abstract: Systems and methods of the invention include a branched radio frequency multipole configured to act, for example, as an ion guide. The branched radio frequency multipole comprises multiple ion channels through which ions can be alternatively directed. The branched radio frequency multipole is configured to control which of the multiple ion channels ions are directed, through the application of appropriate potentials. Thus, ions can alternatively be directed down different ion channels without the use of a mechanical valve.

Abstract: A MALDI mass spectrometer includes a radiation source, such as a gas or solid state laser, that emits a beam of radiation (typically in the UV or IR wavelengths) directed along the central axis of a linear ion trap in which analyte ions and matrix cluster ions are confined. The radiation beam has a wavelength that is strongly absorbed by the matrix cluster ions. The absorption of radiation by the matrix cluster ions produces dissociation of the matrix cluster ion into fragments having mass-to-charge ratios that lie below a mass-to-charge ratio range of interest. Thus, chemical noise associated with matrix cluster ions is reduced or eliminated.

Abstract: A method and apparatus are provided for operating a linear ion trap. A linear ion trap configuration is provided that allows for increased versatility in functions compared to a conventional three-sectioned linear ion trap. In operation, the linear ion trap provides multiple segments, the segments spatially partitioning an initial ion population into at least a first and a second ion population, and enabling the ions corresponding to the first ion population to be expelled from the linear ion trap substantially simultaneously with the ions corresponding to the second ion population. Each segment is effectively independent and ions corresponding to the first ion population are able to be manipulated independently from ions corresponding to ions corresponding to the second ion population; the ions having been generated by an ion source under the same conditions.

Abstract: A method and apparatus are provided for operating a linear ion trap. A linear ion trap configuration is provided that allows for increased versatility in functions compared to a conventional three-sectioned linear ion trap. In operation, the linear ion trap provides multiple segments, the segments spatially portioning an initial population of ions into at least a first and a second ion population. Each segment is effectively independent and ions corresponding to the first ion population are able to be manipulated independently from ions corresponding to ions corresponding to the second ion population; the ions having been generated by an ion source under the same conditions. The ions can then be expelled from the ion trap.

Abstract: Systems and methods of the invention include a branched radio frequency multipole configured to act, for example, as an ion guide. The branched radio frequency multipole comprises multiple ion channels through which ions can be alternatively directed. The branched radio frequency multipole is configured to control which of the multiple ion channels ions are directed, through the application of appropriate potentials. Thus, ions can alternatively be directed down different ion channels without the use of a mechanical valve.

Abstract: An RF-only multipole includes a spiral resistive path formed around each multipole rod body. RF voltages are applied to the rod body and resistive path, and DC voltages are applied to the resistive path, to create a radially confining RF field and an axial DC field that assists in propelling ions through the multipole interior along the longitudinal axis thereof. In one implementation, the resistive path takes the form of a wire of resistive material, such as nichrome, which is laid down in the groove defined between threads formed on the rod body. The RF-only multipole of the invention avoids the need to use auxiliary rods or similar supplemental structures to generate the axial DC field.

Abstract: A three section linear or two-dimensional (2D) quadrupole ion trap as a high performance mass spectrometer is described. Mass analysis is performed by ejecting ions radically out slots formed in at least two of the rods using the mass selective instability mode of operation. The slot geometry is optimized to enable ions of different mass ranges to be scanned out of differently dimensioned slots. Multiple detectors arranged to receive ejected ions in multiple directions provide the ability to simultaneously or sequentially scan or perform mass analysis of ions of different natures.

Abstract: A mass spectrometer is operated by generating a test packet of ions from a pulsed ion source. A population of ions derived from the test packet of ions is detected. A number of ionization events of the pulsed ion source is determined that will be required to provide an analysis packet of ions expected to have a desired population of ions. An analysis packet of ions is produced by accumulating ions for the determined number of ionization events.

Abstract: Ion source assemblies for generating ions for laser desorption mass spectrometry. An ion source assembly includes a target for receiving analyte samples and a plurality of rods. The rods define an interior volume having an axis extending away from a surface of the target for transporting ions. One or more of the rods include an aperture defining an opening through a cross-section of the rod. The aperture is configured such that a laser beam can pass through the aperture to irradiate a location on the target surface to generate ions from an analyte sample deposited at the location.

Abstract: Ion source assemblies for generating ions for laser desorption mass spectrometry. An ion source assembly includes a target for receiving analyte samples and a plurality of rods. The rods define an interior volume having an axis extending away from a surface of the target for transporting ions. One or more of the rods include an aperture defining an opening through a cross-section of the rod. The aperture is configured such that a laser beam can pass through the aperture to irradiate a location on the target surface to generate ions from an analyte sample deposited at the location.