Abstract: 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 adjusted to be proportional to the voltages on the main electrodes. The adjustment(s) may be done to optimize the RF field for different modes of operation such as ion ejection and ion dissociation. For dissociation, a supplemental RF dipole may be applied, or two mutually orthogonal dipoles may be applied in phase quadrature to form a circularly polarized field. Electrode structures may include main trapping electrodes, one or more compensation electrodes, one or more ion exit apertures, and means for applying the various desired voltages.

Abstract: An ion spectrometer apparatus is disclosed having an ion source, an ion mobility spectrometer device such as a FAIMS cell, and a capillary for transporting ions from the ion source to the entrance of the FAIMS cell. The capillary is heated to promote evaporation of solvent from incompletely desolvated droplets entering the capillary inlet, thereby preventing or minimizing operational problems associated with the presence of wet material in the FAIMS cell. The FAIMS cell may be used to selectively transmit ions to a mass analyzer.

Abstract: An object of the present invention is to provide a mass spectrometer that uses a time-of-flight mass spectrometer for performing mass spectrometry on the basis of the difference in flight time based on mass of desired ions, and that is suitable for improving the sensitivity and analysis precision of the mass spectrometer. A gate electrode is located at a stage before an acceleration region that is located before an emitter for emitting ions. This gate electrode is capable of applying the voltage that is set on a mass-number region basis, and is also capable of separating desired ions to be measured on the basis of the mass number by switching the gate electrode at high speed. Therefore, it is possible to improve the resolution.

Abstract: A mass spectrometer includes: an ion source for ionizing a specimen to generate ions, an ion transport portion for transporting the ions, a linear ion trap portion for accumulating the transported ions by a potential formed axially, and a control portion of ejecting the ions within a second m/z range different from a first m/z range, from the linear ion trap portion, and substantially at the same timing as the timing of accumulating the ions within the first m/z range from the transport portion into the linear ion trap portion. The ion transportation portion having a mass selection means for selecting the ions in the first m/z range.

Abstract: The invention provides a two-dimensional ion trap, comprising a plurality of elongate electrodes positioned between first and second end electrodes, the plurality of electrodes and first and second end electrodes defining a trapping volume. A controller in electrical communication with the plurality of elongate electrodes and the first and second end electrodes is configured to progressively vary a periodic voltage applied to at least one of the plurality of elongate electrodes to cause ions to be radially ejected from the ion trap in order of their mass to charge ratios. Concurrently, the controller is configured to progressively vary a DC offset of least one of the first and second end electrodes with respect to the plurality of elongate electrodes.

Abstract: The present invention is a device to restrict the sampling of analyte ions and neutral molecules from surfaces with mass spectrometry and thereby sample from a defined area or volume. In various embodiments of the present invention, a tube is used to sample ions formed with a defined spatial resolution from desorption ionization at or near atmospheric pressures. In an embodiment of the present invention, electrostatic fields are used to direct ions to either individual tubes or a plurality of tubes positioned in close proximity to the surface of the sample being analyzed. In an embodiment of the present invention, wide diameter sampling tubes can be used in combination with a vacuum inlet to draw ions and neutrals into the spectrometer for analysis. In an embodiment of the present invention, wide diameter sampling tubes in combination with electrostatic fields improve the efficiency of ion collection.

Abstract: The present invention is a device to restrict the sampling of analyte ions and neutral molecules from surfaces with mass spectrometry and thereby sample from a defined area or volume. In various embodiments of the present invention, a tube is used to sample ions formed with a defined spatial resolution from desorption ionization at or near atmospheric pressures. In an embodiment of the present invention, electrostatic fields are used to direct ions to either individual tubes or a plurality of tubes positioned in close proximity to the surface of the sample being analyzed. In an embodiment of the present invention, wide diameter sampling tubes can be used in combination with a vacuum inlet to draw ions and neutrals into the spectrometer for analysis. In an embodiment of the present invention, wide diameter sampling tubes in combination with electrostatic fields improve the efficiency of ion collection.

Abstract: 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.

Abstract: A two-dimensional ion trap comprises a first and second trapping plate located in a first and second terminals of the ion trap device, a set of four predetermined surface-shaped rods located in the center, a set of electrodes located between the set of four predetermined surface-shaped rods, and a control circuitry for applying a predetermined voltage to said first and second trapping plates.

Abstract: A method for obtaining high accuracy mass spectra using an ion trap mass analyzer includes adjusting operating parameters of the analyser to enable a reverse mass scan in a mass selective resonance ejection mode and setting the trapping field to trap ions in a mass-to-charge ratio which has a lower limit close to the mass-to-charge ratio of an ion of interest. A method of determining chemical shift includes adjusting operating parameters of the analyzer to enable forward and reverse mass scans and calibrating the spectra obtained from the forward and reverse mass scans.

Abstract: A method for manipulating ions in an ion trap includes storing ions, spatially compressing, and ejecting selected ions according to mass-to-charge ratio. An ion trap includes an injection port, an arm having a first and a second end for confining and spatially compressing the ions, and an ejection port for ejecting the ions from the second end. The arm includes two pairs of opposing electrodes, which provide a quadrupole electric field potential at any cross-section of the ion trap. The distance between opposing electrodes and the cross-sectional area of the electrodes increases from the first to second end. The electrodes may be tapered cylindrical rods or of hyperbolic cross-section. Ions selected for ejection are spatially compressed into a region at the second (wider) end. The ion trap may include one arm, with either orthogonal or axial ejection, or two arms with a central insert for orthogonal ejection.

Abstract: The present invention relates to an apparatus and method for focusing, separating, and detecting gas-phase ions using the principles of electrohydrodynamic quadrupole fields at high pressures, at or near atmospheric pressure. Ions are entrained in a concentric flow of gas and travel through a high-transmission element into a RF/DC quadrupole, exiting out of the RF/DC quadrupole, and then impacting on an ion detector, such as a faraday plate; or through an aperture or capillary tube with subsequent identification by a mass spectrometer. Ions with stable trajectories pass through the RF/DC quadrupole while ions with unstable trajectories drift off-axis collide with the rods and are lost. Alternatively, detection of ions with unstable trajectories can be accomplished by allowing the ions to pass through the rods and be detected by an off-axis detector.

Abstract: A mass spectrometer is disclosed comprising a guide wire ion guide 1 having an outer cylindrical electrode 2 and an inner guide wire electrode 3. AC and DC potential differences are maintained between the outer electrode 2 and the inner electrode 3 so that ions are radially confined within the ion guide 1 in an annular potential well. The outer electrode 2 may be segmented and axial potential wells created along the length of the ion guide 1 may be translated along the length of the ion guide 1 by applying additional transient DC potentials to the segments forming the outer electrode 2.

Abstract: The invention provides a multipole ion trap. The trap has a longitudinal axis. An oscillating on-axis potential is set up along the longitudinal axis, providing a potential well in which ions are trapped. In some embodiments, rods forming the poles are symmetrically and equidistantly positioned about the longitudinal axis and RF signal with different magnitudes are applied to the poles. In other embodiments, the rods are not positioned symmetrically about the longitudinal axis and the RF signals applied to the poles may have the same or different magnitudes. Poles used in the invention may include two or more rods. An ion trap according to the invention may include more than two poles, and in some embodiments, a third or additional pole may be added to provide the oscillating on-axis potential. The ion trap may be used mass selectively scan ions, fragment ions and to trap and separate differently charged ions, among other uses.

Abstract: Disclosed is a high field asymmetric waveform ion mobility spectrometer (FAIMS) including a set of spaced-apart parallel rods, the space between the parallel rods having first and second ends and defining an analyzer region. The apparatus includes an electrical controller for electrically coupling to the set of parallel rods, for applying at least an rf-voltage between the parallel rods of the set of parallel rods in a first operating mode and for applying a combination of an asymmetric waveform voltage and a direct current voltage between the parallel rods of the set of parallel rods in a second operating mode.

Abstract: A quadrupole ion trap device has a field adjusting electrode located outside the trapping region adjacent the aperture in the entrance end cap electrode, and optionally adjacent the aperture in the exit end cap electrode. The field adjusting electrode(s) controls field distortion in the vicinity of the apertures. By appropriately setting the voltages on the field adjusting electrodes the efficiency and resolution of operational processes such as ion introduction, precursor ion isolation and mass scanning can be improved.

Abstract: A system is provided for processing data values in a data set to create a data value representation having a signal side. The data set contains valid data values and noise data values where the number of the valid data values is statistically insignificant with respect to the number of noise data values. The system determines a statistically significant portion of the signal side and fits a curve to the statistically significant portion which extends beyond the statistically significant portion of the signal side. Once the curve is determined, the system can determine a data-validity confidence value for one of the data values responsive to the curve. The data-validity confidence value can be used determine that a data value in a set of spectral data is not a noise data value.

Abstract: Apparatus and method for trapping uncharged multi-pole particles comprises a bound cavity for receiving the particles, and a multiplicity of electrodes coupled to the cavity for producing an electric field in the cavity. In a preferred embodiment, the electrodes are configured to produce in the electric field potential both a multi-pole (e.g., dipole) component that aligns the particles predominantly along an axis of the cavity and a higher order multi-pole (e.g., hexapole) component that forms a trapping region along the axis. In one embodiment, the electrodes and/or the particles are cooled to a cryogenic temperature.

Abstract: A mass spectrometer 10 comprises an ion source 12 which generates nebulized ions which enter an ion cooler 20 via an ion source block 16. Ions within a window of m/z of interest are extracted via a quadrupole mass filter 24 and passed to a linear trap 30. Ions are trapped in a potential well in the linear trap 30 and are bunched at the bottom of the potential well adjacent an exit segment 50. Ions are gated out of the linear trap 30 into an electrostatic ion trap 130 and are detected by a secondary electron multiplier 10. By bunching the ions in the linear trap 30 prior to ejection, and by focussing the ions in time of flight (TOF) upon the entrance of the electrostatic trap 130, the ions arrive at the electrostatic trap 130 as a convolution of short, energetic packets of similar m/z. Such packets are particularly suited to an electrostatic trap because the FWHM of each packet's TOF distribution is less than the period of oscillation of those ions in the electrostatic trap.

Abstract: In a mass spectrometer in which a high ion dissociation efficiency is possible, inserted electrodes are arranged with a form divided into two or more in the axial direction of the ion trap, an electric static harmonic potential is formed from a DC voltage applied to the inserted electrodes, and with an Supplemental AC voltage applied, ions in the ion trap are oscillated between the divided inserted electrodes in the axial direction of the ion trap by resonance excitation, and the ion with a mass/charge ratio within a specific range is mass-selectively dissociated. Thus, a high ion dissociation efficiency is realized by the use of ion trap of the present invention.

Abstract: A mass spectrometer comprises an ion source which provides a beam of ions; a mass filter comprising a pair of electrodes and a drive circuit, the drive circuit operable to apply a time varying voltage to the electrodes having a profile that accelerates the ions to equal velocities irrespective of their mass: charge ratios; and an ion detector for detecting the proportions of ions according to their mass-to-charge ratios. In one embodiment, the voltage profile is exponential. In another embodiment, the voltage profile is a sequence of constant amplitude and increasing repetition frequency pulses. The novel mass filter thus imparts equal velocities to all ion species irrespective of their mass. This allows the ion species to be discriminated at the detector by energy, enabling simple and compact detection schemes to be used.

Abstract: A mass spectrometer adopting a differential pumping system includes an ionization chamber with substantially atmospheric pressure, two intermediate vacuum chambers, and a mass analyzing chamber with a very low pressure (or a very high vacuum), where the pressures of these chambers are in the order of higher to lower. A hole is provided in every wall between two adjoining chambers for allowing ions to be mass analyzed to pass through. An auxiliary electrode with an aperture is placed near the hole, and an AC voltage is applied to the auxiliary electrode. Owing to an AC electric field generated by the AC voltage around the hole, an ion coming near the hole is exerted with such a force that confines the ion to the ion optical axis C. Under these circumstances, even when the ion collides with a residual gas molecule or atom and is deflected away from the ion optical axis, the confining force exerted by the electric field pulls the ion back toward the ion optical axis.

Abstract: A virtual ion trap that uses electric focusing fields instead of machined metal electrodes that normally surround the trapping volume, wherein two opposing surfaces include a plurality of uniquely designed and coated electrodes, and wherein the electrodes can be disposed on the two opposing surfaces using plating techniques that enable much higher tolerances to be met than existing machining techniques.

Abstract: In the field of mass spectrometry, a method and apparatus for fragmenting ions with a relatively high degree of resolution and efficiency. The technique includes trapping the ions in a linear ion trap, in which the background or neutral gas pressure is preferably on the order of 10-5 Torr. The trapped ions are resonantly excited for a relatively extended period of time, e.g., exceeding 50 ms, at relatively low excitation levels, e.g., less than 1 Volt (0-pk). The technique allows selective dissociation of ions with a high discrimination. High fragmentation efficiency may be achieved by superimposing a higher order multipole field onto the quadrupolar RF field used to trap the ions. The multipole field, preferably an octopole field, dampens the radial oscillatory motion of resonantly excited ions at the periphery of the trap. This reduces the probability that ions will eject radially from the trap thus increasing the probability of collision induced dissociation.

Abstract: A mass spectrometer and a method of operating same is provided. The mass spectrometer has an elongated rod set. The rod set has an entrance end and an exit end. An RF drive voltage is applied to the rod set to radially confine a first group of ions and a second group of ions of opposite polarity in the rod set. An entrance auxiliary RF voltage is applied to the entrance end and an exit auxiliary RF voltage to the exit end relative to the RF drive voltage, to trap both the first group of ions and the second group of ions in the rod set.

Abstract: Improved ion focusing for an ion mobility drift cell allows for improved throughput for subsequent detection such as mass detection. Improved focusing is realized by the use of alternating regions of high and low electric fields in the ion mobility drift cell.

Abstract: The invention, in various embodiments, is directed to a solid-state flow generator and related systems, methods and applications.

Abstract: A method/apparatus for multiplexing plural ion beams to a mass spectrometer. At least two ion sources are provided with means of transporting the ions from the ion sources to separate two-dimensional ion traps. Each ion trap is used for storage and transmission of the ions and operates between the ion sources and the mass analyzer. Each ion trap has a set of equally spaced, parallel multipole rods, as well as entrance and exit sections into which and from which ions enter and exit the trap, respectively. For each ion trap, the entrance section is placed in a region where background gas pressure is at viscous flow. The pressure at the exit section drops to molecular flow pressure regimes without a break in the structure of the ion trap. Each trap alternately stores and transmits ions by way of a fast voltage switch applied to the ion trap exit lens.

Abstract: A method of constructing a micro-engineered mass spectrometer from bonded silicon-on-insulator (BSOI) wafers is described with reference to a quadrupole spectrometer. The quadrupole geometry is achieved using two BSOI wafers (200), which are bonded together to form a monolithic block (410). Deep etched features and springs formed in the outer silicon layers are used to locate cylindrical metallic electrode rods (300). The precision of the assembly is determined by a combination of lithography and deep etching, and by the mechanical definition of the bonded silicon layers. Deep etched features formed in the inner silicon layers are used to define ion entrance and ion collection optics. Other features such as fluidic channels may be incorporated.

Abstract: The invention relates to an ion guide consisting of RF multipole segments to transfer ions from an ion source into a mass analyzer. The invention consists in having movable RF multipole segments in the ion guide which extend or electrically connect other RF multipole segments along the axis of the ion guide, in which spaces have arisen as a result of a change in configuration of the mass spectrometer, comprising ion source, ion guide and mass analyzer. The moved RF multipole segments bridge the spaces which have arisen between the components of the mass spectrometer and facilitate the transfer of the ions from the ion source to the mass analyzer.

Abstract: Ion separation in a FAIMS analyzer is affected by the presence of neutral species and solvent vapor. A diffuser element, which is fabricated from a porous material, is disposed within a curtain gas chamber adjacent to the FAIMS ion inlet, such that a flow of a curtain gas is blocked from flowing directly out through a curtain gas orifice. The porous material creates a pressure drop across the diffuser and results in the flow of curtain gas being provided out of the curtain gas orifice, along a direction that is approximately perpendicular to a plane containing the curtain gas orifice. The perpendicular gas flow opposes ions traveling toward the curtain gas orifice from an ionization source, thereby desolvating the ions. Providing a perpendicular curtain gas flow for desolvating ions reduces the ion losses that are normally associated with the curtain gas flow deflecting some of the ions away from the curtain gas orifice and toward a curtain plate electrode.

Abstract: A method and system for producing an ion beam from an ion guide. In the method, ions are introduced into the ion guide, a radio frequency trapping field is generated in the ion guide to confine ions in a direction transverse to a longitudinal axis of the ion guide, a DC potential is generated along the longitudinal axis to direct ion motion along the longitudinal axis, a strength of the radio frequency trapping field is reduced toward an ion guide exit of the ion guide, and the ions are transmitted from the ion guide exit to form the ion beam. In the system, an ion guide is configured to transmit ions in a longitudinal axis of the ion guide and configured to trap ions in a direction transverse to the longitudinal axis via a radio frequency trapping field. The ion guide includes a segmented set of electrodes spaced along the longitudinal axis and an ion guide exit at the last of the segmented set of electrodes.

Abstract: 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.

Abstract: The invention provides a method of design for a time-of-flight mass spectrometer that is compact and has high mass resolution over a broad range of ion masses. This method of design, for the high-resolution analysis of analyte ions in the time-of-flight mass spectrometer, includes decreasing the strength of the time-dependent extraction potential according to a predetermined continuous function so as to spread out the energy distribution of the ions and achieving high mass resolution over a broad range of masses without altering the time dependence or magnitude of the applied potentials, across the acceleration region and ion mirror, and the time-dependent extraction potential, and not changing the physical dimensions of the mass spectrometer. Using this method of design, mass resolution of approximately or greater than 10,000 can be achieved over approximately five orders of magnitude of mass for a time-of-flight mass spectrometer having a total overall length of less than 46 cm.

Abstract: A reflectron lens and method are provided. The reflectron lens comprises a tube having a continuous conductive surface along the length of the tube for providing an electric field interior to the tube that varies in strength along the length of the tube. The tube may comprise glass, and in particular, a glass comprising metal ions, such as lead, which may be reduced to form the conductive surface. The method includes a step of introducing a beam of ions into a first end of a dielectric tube having a continuous conductive surface along the length of the tube. The method further includes a step of applying an electric potential across the tube to create an electric field gradient that varies in strength along the length of the tube so the electric field deflects the ions to cause the ions to exit the tube through the first end of the tube.

Abstract: The invention relates to a device and a method for producing, from any previously configured ion beams, precisely localized small packages of ions which all fly at the same velocity. The invention consists of damping the ions in a damping-gas filled series of apertured diaphragms (which are firstly subjected alternately to the two phases of an RF voltage and secondly to a multiphase low-frequency travelling field voltage) into the axis of the apertured diaphragm arrangement and packaging the ions in bundles which are propelled axially at the same velocity for ions of different specific masses. These ion packages, which are restricted both in an axial and a radial direction, can be used to advantage for injection into different types of mass spectrometer, both storage ion-trap mass spectrometers, such as cyclotron resonance mass spectrometers or quadrupole ion traps and, especially, for time-of-flight mass spectrometers with orthogonal injection.

Abstract: One or more methods for multiplexed determination and deconvolution of complex mass spectra, using quadrupole ion trap mass spectrometry.

Abstract: A method and apparatus for manipulating ions using a two-dimensional substantially quadrupole field, and a method of manufacturing and operating an apparatus for manipulating ions using a two-dimensional substantially quadrupole field are described. The field has a quadrupole harmonic with amplitude A2 and a hexapole harmonic with amplitude A3. The amplitude A3 of the hexapole component of the field is selected to improve the performance of the field with respect to ion selection and ion fragmentation.

Abstract: Accurate mass measurement is carried out for product ions of a sample. A method for accurate mass determination of ions with Trap-TOF/?s includes steps of generating ions of an analyte sample and a standard material; introducing the ions of the analyte sample and the standard material together into an ion trap to trap them; selecting a precursor ion from the ions of the analyte sample to leave the precursor ion and a standard material ion in the ion trap and eliminate other ions; exciting and dissociating the precursor ion to generate product ions; ejecting the precursor ion, its product ions, and the standard material ion trapped in the ion trap to introduce these ions into the TOF mass spectrometer; and measuring a mass spectrum with the TOF mass spectrometer, where correction for accurate masses of the product ions is carried out based on the standard material ion measured.

Abstract: A method of separating ions comprises applying a spot of a sample material to a target plate. The target plate is mounted in fluid communication with an ion inlet orifice of a FAIMS analyzer region and externally to the FAIMS analyzer region. Using a laser light source that is disposed external to the FAIMS analyzer region, the target plate is irradiated with light of a predetermined wavelength, the light of a predetermined wavelength being selected to affect the sample material applied to the target plate so as to produce ions of the sample material. The ions of the sample material are directed along an ion flow path between the target plate and FAIMS analyzer region, via the ion inlet orifice. A flow of a gas is directed counter-current to the ion flow path and passing through the target plate. The flow of gas through the target plate assists in desolvation of ions and directs neutral molecules away from the FAIMS analyzer region.

Abstract: A mass spectrometer includes: an ion source; a mass separator for separating ions with respect to mass to charge ratios of the ions; an ion detector; an ion deflector including a pair of electrodes placed opposite each other across an ion optical axis, the ion deflector being placed between the ion source and the mass separator or between the mass separator and the ion detector; and a voltage generator for applying AC voltages of opposite polarities respectively to the pair of electrodes, where a frequency of the AC voltages is determined so that lighter ions are more deflected and prevented from entering the mass separator or the ion detector and heavier ions are less deflected and allowed to enter the mass separator or the ion detector. Only helium ions which are deleterious to the mass spectrometry can be efficiently eliminated while object sample ions are hardly affected.

Abstract: A mass spectrometer is provided for identifying mass and velocity distributions in a continuous ion beam is configured with a circular dispersive system creating a rotating electromagnetic field, which is capable of deflecting the ion beam from an initial direction, and a circular position-sensitive detector intercepting the deflected ion beam and providing information from which the ion mass-per-charge ratio is determined

Abstract: An apparatus for separating ions includes providing a FAIMS analyzer region defined by a space between a first electrode surface and a second electrode surface and extending between an ion inlet end and an ion outlet end. An asymmetric waveform is applied to the first electrode surface and a compensation voltage difference is applied between the first and second electrode surfaces. An output signal is provided from a temperature sensor, the output signal relating to a temperature within the FAIMS analyzer region. In dependence upon the output signal, the temperature within the FAIMS analyzer region is controllably affected. The apparatus supports operation of FAIMS at temperatures different from the temperature of other components in a tandem multi-stage system, and supports the stable operation of FAIMS at different temperatures which increases the separation capability of FAIMS.

Abstract: A method of mass spectrometry is disclosed wherein a gas collision cell is repeatedly switched between a fragmentation and a non-fragmentation mode. Parent ions from a first sample are passed through the collision cell and parent ion mass spectra and fragmentation ion mass spectra are obtained. Parent ions from a second sample are then passed through the collision cell and a second set of parent ion mass spectra and fragmentation ion mass spectra are obtained. The mass spectra are then compared and if either certain parent ions or certain fragmentation ions in the two samples are expressed differently then further analysis is performed to seek to identify the ions which are expressed differently in the two different samples.

Abstract: For generation and delivery of ions from an ionization chamber through an ion entrance orifice to a mass analyzer operating at high vacuum, high pass ion filtration is effected within the ionization chamber by application of electrical potentials to an electrode associated with the ion entrance orifice and to an electrode between the ionization region and the ion entrance orifice to create a retarding electric field upstream from the ion entrance orifice. The retarding electric field hinders the movement to the ion entrance orifice of ions having drift velocities below a lower limit, and as the retarding voltage gradient is made steeper, the lower limit increases.

Abstract: Rapid and efficient fragmentation of ions in an ion trap for MS/MS analysis is achieved by a pulsed fragmentation technique. Ions of interest are placed at an elevated value of Q and subjected to a relatively high amplitude, short-duration resonance excitation pulse to cause the ions to undergo collision-induced fragmentation. The Q value of the ions of interest is then rapidly reduced, thereby decreasing the low-mass cutoff and allowing retention and subsequent analysis of low-mass ion fragments.

Abstract: Method and apparatus for high field asymmetric waveform ion mobility spectrometry in an electronic chip assembly,, including an input section, an ion filter and detection section and a control section, in which ion filtering proceeds in a planar chamber under influence of high field asymmetric periodic signals, with detection integrated into the flow path, for producing accurate, real-time, data for identification of a broad range of chemical compounds.

Abstract: A mass spectrometer is disclosed wherein ions having a particular desired charge state are selected by operating an ion mobility spectrometer in combination with a quadrupole mass filter. Precursor ions are fragmented or reacted to form product ions in a collision cell ion trap and sent back upstream to an upstream ion trap. The fragment or product ions are then passed through the ion mobility spectrometer wherein they become temporally separated according to their ion mobility. Fragment or product ions are then re-trapped in the collision cell ion trap before being released therefrom in packets. A pusher electrode of a time of flight mass analyser is energised a predetermined period of time after a packet of ions is released from the collision cell ion trap. Accordingly, it is possible to select multiply charged precursor ions from a background of singly charged ions, fragment them, and mass analyse the fragment ions with a near 100% duty cycle across the whole mass range.

Abstract: A mass spectrometer is disclosed having an ion guide which receives ions from either a pulsed ion source or an ion trap, or a continuous ion source. The ion guide emits packets of ions. The pulses of ions emitted from the ion guide may be synchronised with another device such as an ion detector, an orthogonal acceleration Time of Flight mass analyser, an ion trap or a mass filter.

Abstract: A mass spectrometer system and a method of operating a mass spectrometer having an elongated rod set, the rod set having an entrance end, an exit end, a plurality of rods and a longitudinal axis, involving (a) admitting ions into the entrance end of the rod set; (b) producing an RF field between the plurality of rods to radially confine the ions in the rod set; (c) providing a static axial electric field within the rod set; and (d) separating the ions into a first group of ions and a second group of ions by providing an oscillating axial electric field within the rod set to counteract the static axial electric field, wherein the oscillating axial electric field varies along the longitudinal axis of the rod se.