1343results about "Electron/ion optical arrangements" patented technology

A micromechanical field asymmetric ion mobility filter for a detection system includes a pair of spaced substrates defining between them a flow path between a sample inlet and an outlet; an ion filter disposed in the path and including a pair of spaced filter electrodes, one electrode associated with each substrate; and an electrical controller for applying a bias voltage and an asymmetric periodic voltage across the ion filter electrodes for controlling the paths of ions through the filter.

An asymmetric field ion mobility spectrometer with an ionization source for ionizing a sample media and creating ions. An ion filter is disposed in the analytical gap downstream from the ionization source for creating an asymmetric electric field to filter the ions. An ion flow generator for creating an electric field in a direction transverse to the asymmetric electric field and which propels the ions through the asymmetric electric field towards a detector.

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.

An improved tube for accepting gas-phase ions and particles contained in a gas by allowing substantially all the gas-phase ions and gas from an ion source at or greater than atmospheric pressure to flow into the tube and be transferred to a lower pressure region. Transport and motion of the ions through the tube is determined by a combination of viscous forces exerted on the ions by the flowing gas molecules and electrostatic forces causing the motion of the ions through the tube and away from the walls of the tube. More specifically, the tube is made up of stratified elements, wherein DC potentials are applied to the elements so that the DC voltage on any element determines the electric potential experience by the ions as they pass through the tube. A precise electrical gradient is maintained along the length of the stratified tube to insure the transport of the ions. Embodiments of this invention are methods and devices for improving the sensitivity of mass spectrometry or ion mobility spectrometers when coupled to atmospheric and above atmospheric pressure ionization sources. An alternate embodiment of this invention applies an AC voltage to one or more of the conducting elements in the laminate.

Atmospheric pressure, intermediate pressure and vacuum laser desorption ionization methods and ion sources are configured to increase ionization efficiency and the efficiency of transmitting ions to a mass to charge analyzer or ion mobility analyzer. An electric field is applied in the region of a sample target to accumulate ions generated from a local ion source on a solid or liquid phase sample prior to applying a laser desorption pulse. The electric field is changed just prior to or during the desorption laser pulse to promote the desorption of charged species and improve the ionization efficiency of desorbed sample species. After a delay, the electric field may be further changed to optimize focusing and transmission of ions into a mass spectrometer or ion mobility analyzer. Charged species may also be added to the region of the laser desorbed sample plume to promote ion-molecule reactions between the added ions and desorbed neutral sample species, increasing desorbed sample ionization efficiency and / or creating desired product ion species. The cycling of electric field changes is repeated in a timed sequence with one or more desorption laser pulse occurring per electric field change cycle. Embodiments of the invention comprise atmospheric pressure, intermediate pressure and vacuum pressure laser desorption ionization source methods and devices for increasing the analytical flexibility and improving the sensitivity of mass spectrometric analysis.

An improved lens for collecting and focusing dispersed charged particles or ions having a stratified array of elements at atmospheric or near-atmospheric pressure, each element having successively smaller apertures forming a tapered terminus, wherein the electrostatic DC potentials are applied to each element necessary for focusing ions through the stratified array for introducing charged particles and ions into the vacuum system of a mass spectrometer. Embodiments of this invention are methods and devices for improving sensitivity of mass spectrometry when coupled to both high and low electrostatic field atmospheric pressure ionization sources.

An ion manipulation method and device is disclosed. The device includes a pair of substantially parallel surfaces. An array of inner electrodes is contained within, and extends substantially along the length of, each parallel surface. The device includes a first outer array of electrodes and a second outer array of electrodes. Each outer array of electrodes is positioned on either side of the inner electrodes, and is contained within and extends substantially along the length of each parallel surface. A DC voltage is applied to the first and second outer array of electrodes. A RF voltage, with a superimposed electric field, is applied to the inner electrodes by applying the DC voltages to each electrode. Ions either move between the parallel surfaces within an ion confinement area or along paths in the direction of the electric field, or can be trapped in the ion confinement area.

A method for introducing ions generated in a region of relatively high pressure into a region of relatively low pressure by providing at least two electrospray ion sources, providing at least two capillary inlets configured to direct ions generated by the electrospray sources into and through each of the capillary inlets, providing at least two sets of primary elements having apertures, each set of elements having a receiving end and an emitting end, the primary sets of elements configured to receive a ions from the capillary inlets at the receiving ends, and providing a secondary set of elements having apertures having a receiving end and an emitting end, the secondary set of elements configured to receive said ions from the emitting end of the primary sets of elements and emit said ions from said emitting end of the secondary set of elements. The method may further include the step of providing at least one jet disturber positioned within at least one of the sets of primary elements, providing a voltage, such as a dc voltage, in the jet disturber, thereby adjusting the transmission of ions through at least one of the sets of primary elements.

Improvements have been made for collecting, focusing, and directing of ions and / or charged particles generated at atmospheric or near atmospheric pressure sources, such as but not limited to, electrospray; atmospheric pressure discharge ionization, chemical ionization, photoionization, and matrix assisted laser desorption ionization; and inductively coupled plasma ionization. A multiple-aperture laminated structure is place at the interface of two pressure regions. Electric fields geometries and strengths across the laminated structure and diameters of the apertures; all of which act to optimize the transfer of the ions from the higher pressure region into the lower pressure region while reducing the gas-load on the lower pressure region. Embodiments of this invention are methods and devices for improving sensitivity of mass spectrometry when coupled to atmospheric, near atmospheric, or higher pressure ionization sources by reducing the gas-load on the vacuum system.

A novel high ion storage / ion mobility separation mass spectrometer that provides for a high duty cycle of operation is presented herein. In particular, the example embodiments, as disclosed herein, provides for a high ion storage / ion mobility instrument that beneficially includes a two-dimensional (2D) plurality of adjacently arranged ion confinement channels to provide a high storage bank of a desired mass range of ions. Such ions, via ion mobility transport, are separated into smaller fractions of an overall mass window into desired confinement regions of the disclosed 2D confinement channels and thereafter transferred out in a manner so as to enable the aforementioned novel high-duty cycle of sequential operation.

The invention relates to a time-of-flight mass spectrometer for injection of the ions orthogonally to the time-resolving axis-of-flight component, with a pulser for acceleration of the ions of the beam in the axis-of-flight direction, preferredly with a velocity-focusing reflector for reflecting the ion beam and with a flat detector at the end of the flight section. The invention consists of using, both for acceleration in the pulser and for reflection in the reflectors, a gridless optical system made up of slit diaphragms which can spatially focus the ions onto the detector in the direction vertical to the directions of injection and flight axis, but which does not have any focusing or deflecting effect on the other directions. For some reflector geometries it is essential to use an additional cylindrical lens for focusing, and for other reflector geometries the use of such a lens may be advantageous.

An apparatus and method for performing mass spectroscopy uses an ion interface to provide the function of removing undesirable particulates from an ion stream from an atmospheric pressure ion source, such as an electrospray source or a MALDI source, before the ion stream enters a vacuum chamber containing the mass spectrometer. The ion interface includes an entrance cell with a bore that may be heated for desolvating charged droplets when the ion source is an electrospray source, and a particle discrimination cell with a bore disposed downstream of the bore of the entrance cell and before an aperture leading to the vacuum chamber. The particle discrimination cell creates gas dynamic and electric field conditions that enables separation of undesirable charged particulates from the ion stream.

The invention provides devices, device configurations and methods for improved sensitivity, resolution and efficiency in mass spectrometry, particularly as applied to biological molecules, including biological polymers, such as proteins and nucleic acids. More particularly, the invention provides methods and devices for analyzing and detecting electrically charged particles, especially suitable for gas phase ions generated from high molecular weight compounds. In one aspect, the invention provides devices and methods for determining the velocity, charged state or both of electrically charged particles and packets of electrically charged particles. In another aspect, the invention provides methods and devices for the time-of-flight analysis of electrically charged particles comprising spatially collimated sources. In another aspect, the invention relates to multiple detection using inductive detectors, improved methods of signal averaging and charged particle detection in coincidence.

In some embodiments, a method of optimizing operating parameters of an analytical instrument (e.g. lens voltages of a mass spectrometer) includes steps taken to minimize the method duration in the presence of substantial instrument noise and / or drift. Some methods include selecting a best point between a default instrument parameter set (vector) and a most-recent optimum parameter set; building a starting simplex at the selected best point location in parameter-space; and advancing the simplex to find an optimal parameter vector. The best simplex points are periodically re-measured, and the resulting readings are used to replace and / or average previous readings. The algorithm convergence speed may be adjusted by reducing simplex contractions gradually. The method may operate using all-integer parameter values, recognize parameter values that are out of an instrument range, and operate under the control of the instrument itself rather than an associated control computer.

Improvements have been made for collecting, focusing, and directing of ions and / or charged particles generated at atmospheric or near atmospheric pressure sources, such as but not limited to, electrospray; atmospheric pressure discharge ionization, chemical ionization, photoionization, and matrix assisted laser desorption ionization; and inductively coupled plasma ionization. A multiple-aperture laminated structure is place at the interface of two pressure regions. Electric fields geometries and strengths across the laminated structure and diameters of the apertures; all of which act to optimize the transfer of the ions from the higher pressure region into the lower pressure region while reducing the gas-load on the lower pressure region. Embodiments of this invention are methods and devices for improving sensitivity of mass spectrometry when coupled to atmospheric, near atmospheric, or higher pressure ionization sources by reducing the gas-load on the vacuum system.

The present invention provides a time of flight mass spectrometer having a spiral flight path, whose mass resolution can be appropriately changed with respect to the analysis object or other factor without any complicated alteration or addition of the mechanical construction. In a specific form of the invention, the mass spectrometer includes deflecting electrodes 20-23 located between semi-cylindrical electrodes 11 and 12 for making ions fly along a spiral path. The deflecting electrodes 20-23 generate deflecting electric fields for shifting the ions in the axial direction of the semi-cylindrical electrodes 11 and 12. The voltage applied to the deflecting electrodes 20-23 is changed according to the mass resolution required. The deflecting electric fields are generated or removed with the change of the voltage, which makes the ions fly either along a spiral path or in the same loop orbit. The flight distance of the ions can be controlled as desired by regulating the voltage so that the ions fly in the loop orbit an appropriate number of times. Thus, the mass resolution can be arbitrarily controlled.

The invention relates to a time-of-flight mass spectrometer for injection of the ions orthogonally to the time-resolving axis-of-flight component, with a pulser for acceleration of the ions of the beam in the axis-of-flight direction, preferably with a velocity-focusing reflector for reflecting the ion beam and with a flat detector at the end of the flight section. The invention consists of using, both for acceleration in the pulser and for reflection in the reflectors, a gridless optical system made up of slit diaphragms which can spatially focus the ions onto the detector in the direction vertical to the directions of injection and flight axis, but which does not have any focusing or deflecting effect on the other directions. For some reflector geometries it is essential to use an additional cylindrical lens for focusing, and for other reflector geometries the use of such a lens may be advantageous.

The invention relates to a reaction cell for reactions between different types of ion species and a related mass spectrometer to analyze the ion products. The invention consists in an RF-operated straight ion guide with a side inlet, particularly suitable for reactions between positive and negative ion species, one ion species being fed in through the side inlet. Particularly favorable is an ion guide made up of a set of coaxial apertured diaphragms with a slight axial potential gradient. The reactions can be used for a fragmentation of multiply charged protein or peptide ions by electron transfer, or for the removal of excess charges of multiply charged biopolymer ions, for example.

In the mass spectrometer of the present invention, a flight space is provided before the mass analyzer, and the flight space includes a loop orbit on which ions fly repeatedly. While ions fly on the loop orbit repeatedly, ion selecting electrodes placed on the loop orbit selects object ions having a specific mass to charge ratio in such a manner that, for a limited time period when the object ions are flying through the ion selecting electrodes, an appropriate voltage is applied to the ion selecting electrodes to make them continue to fly on the loop orbit, but otherwise to make or let other ions deflect from the loop orbit. If ions having various mass to charge ratios are introduced in the loop orbit almost at the same time, the object ions having the same mass to charge ratio continue to fly on the loop orbit in a band, but ions having mass to charge ratios different from that are separated from the object ions while flying on the loop orbit repeatedly. Even if the difference in the mass to charge ratio is small, the separation becomes large when the number of turns of the flight becomes large. After such a separation is adequately achieved, the ion selecting electrodes can select the object ions with high selectivity, or at high mass resolution. By adding dissociating means, fragment ions originated only from the selected object ions can be analyzed, which enables the identification and structural analysis of the sample at high accuracy.

A multi-reflection mass spectrometer is provided comprising two ion-optical mirrors, each mirror elongated generally along a drift direction (Y), each mirror opposing the other in an X direction, the X direction being orthogonal to Y, characterized in that the mirrors are not a constant distance from each other in the X direction along at least a portion of their lengths in the drift direction. In use, ions are reflected from one opposing mirror to the other a plurality of times while drifting along the drift direction so as to follow a generally zigzag path within the mass spectrometer. The motion of ions along the drift direction is opposed by an electric field resulting from the non-constant distance of the mirrors from each other along at least a portion of their lengths in the drift direction that causes the ions to reverse their direction.

A multi-device interface for use in mass spectrometry for interfacing one or more ion sources to one or more downstream devices. The multi-device interface comprises three or more multipole rod sets configured as either an input rod set or an output rod set depending on potentials applied to the multipole rod sets. The multipole rod sets configured as an input rod set are connectable to the one or more ion sources for receiving generated ions therefrom and sending the ions to at least one multipole rod set configured as an output multipole rod set. The output multipole rod sets are connectable to a downstream device for sending the generated ions thereto. At least two of the multipole rod sets are configured as input rod sets or at least two of the multipole rod sets are configured as output rod sets.

The invention relates to RF voltage-operated ion guides based on stacked apertured diaphragms. The invention provides ion guides consisting of diaphragm stacks that permit the ion beam to be shaped in cross-section so that it corresponds to the acceptance profile of the subsequent section of the device, therefore yielding optimal ion transmission. For this purpose, at least some of the diaphragms in the diaphragm stacks do not have circular openings, but instead have openings which shape the cross section of the emerging ion beam in the desired manner. It is possible, for instance, to obtain elliptical beam cross sections, divided beams or beams focused to the shape of a fine thread at the output of the diaphragm stacks.

This invention is generally in the field of improved ion mobility spectrometry. The improvement lies in the use of periodic focusing electric fields that minimize the spatial spread of the migrating ions by keeping them in a tight radius about the axis of travel. The resulting enhancement in sensitivity is accomplished without a concomitant loss in resolution as would normally be expected when non-linear fields are used.

A method and apparatus for manipulating ions using a two-dimensional substantially quadrupole field, and a method of manufacturing an apparatus for manipulating ions using a two-dimensional substantially quadrupole field are described. The field has a quadrupole harmonic with amplitude A2, an octopole harmonic with amplitude A4, and higher order harmonics with amplitudes A6 and A8. The amplitude A8 is less than A4. The A4 component of the field is selected to improve the performance of the field with respect to ion selection and ion fragmentation. The selected A4 component can be added by selecting a degree of asymmetry under a 90° rotation about a central axis of the quadrupole. The degree of asymmetry is selected to be sufficient to provide the selected A4 component.

The invention covers a method for detecting ions in high resolution time-of-flight mass spectrometers which operate with secondary electron multiplier multichannel plates and in which many single spectra are acquired and added to produce a sum spectrum. The invention involves (a) using an analog digital converter (ADC) for converting electron currents from secondary electron multipliers, instead of a time-to-digital converter (TDC) which was previously used for highest possible signal resolution, (b) performing a separate rapid peak recognition procedure for the ion signals of each spectrum by a fast calculation method, thereby collecting flight time and intensity value pairs for the ion peaks, and (c) constructing a time-of-flight / intensity histogram, which is further processed as a composite time-of-flight spectrum. The invention retains the significantly higher measurement dynamics of an ADC and achieves the improved resolution capability of a TDC, but without showing the latter's known signal distortion due to dead times.

A mass spectrometer comprises an ion source which produces an ion beam from a substance to be analysed and a detector to detect a quantity of ions incident thereon. The detector includes two elements (16, 18) each of which detect a part of the quantity of ions and an attenuation device attenuates the quantity of ions reaching one of the detector elements. At least one of the detector elements (16, 18) is connected to a time to digital converter (TDC) to allow counting of the ions and at least one of the detector elements is connected in parallel to both a time to digital converter (TDC) and an analogue to digital converter (ADC).

A method and apparatus for time-of-flight (TOF) mass spectrometry. The apparatus improves the ion focusing properties in an orthogonal direction and permits connection with an orthogonal-acceleration ion source for improvement of sensitivity. The apparatus comprises an ion source for emitting ions in a pulsed manner, an analyzer for realizing a helical trajectory, and a detector for detecting the ions. The analyzer is composed of plural laminated toroidal electric fields to realize the helical trajectory.

To provide comprehensive (i.e. rapid and sensitive) MS-MS analysis, the inventor employs a time-nested separation, using two time-of-flight (TOF) mass spectrometers. Parent ions are separated in a slow and long TOF1, operating at low ion energy (1 to l00eV), and fragment ions are mass analyzed in a fast and short TOF2, operating at much higher keV energy. Low energy fragmentation cell between TOF1 and TOF2 is tailored to accelerate fragmentation and dampening steps, mostly by shortening the cell and employing higher gas pressure. Since separation in TOF1 takes milliseconds and mass analysis in TOF2- microseconds, the invention provides comprehensive MS-MS analysis of multiple precursor ions per single ion pulse. Slow separation in TOF1 becomes possible with an introduction of novel TOF1 analyzers. The TOF-TOF could be implemented using a static TOF1, here described on the examples of spiratron, planar and cylindrical multi-pass separators with griddles spatial focusing ion mirrors. Higher performance is expected with the use of novel hybrid TOF 1 analyzers, combining radio frequency (RF) and quadratic DC fields. RF field retains low-energy ions within TOF 1 analyzer, while quadratic DC field improves resolution by compensate for large relative energy spread.

A novel method and mass spectrometer apparatus is introduced to enable the simultaneous isolation of cations and anions (i.e., precursor and reagent ions) in a linear multipole ion trap via the application of an additional axial DC gradient in combination with coupled RF potential(s). Thus, the combination of the RF and DC voltages in such an arrangement forms a pseudopotential designed to provide for minima for the trapped positively and negatively charged particles that result in the overlap of the ion clouds so as to provide for beneficial ion / ion reactions.