EP1704578B1 - Dispositifs d'extraction d'ions et procedes d'extraction selective d'ions - Google Patents

Dispositifs d'extraction d'ions et procedes d'extraction selective d'ions Download PDF

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EP1704578B1
EP1704578B1 EP05701820A EP05701820A EP1704578B1 EP 1704578 B1 EP1704578 B1 EP 1704578B1 EP 05701820 A EP05701820 A EP 05701820A EP 05701820 A EP05701820 A EP 05701820A EP 1704578 B1 EP1704578 B1 EP 1704578B1
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Prior art keywords
ions
ion
potential
ion extraction
electrodes
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EP1704578A2 (fr
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John Brian Hoyes
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Micromass UK Ltd
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Micromass UK Ltd
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Priority claimed from GB0408628A external-priority patent/GB0408628D0/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/26—Mass spectrometers or separator tubes
    • H01J49/34—Dynamic spectrometers
    • H01J49/42—Stability-of-path spectrometers, e.g. monopole, quadrupole, multipole, farvitrons
    • H01J49/4205—Device types
    • H01J49/422—Two-dimensional RF ion traps
    • H01J49/4235—Stacked rings or stacked plates

Definitions

  • This invention relates to ion extraction devices, analytical devices incorporating same, methods of extracting ions and methods of analysing ions or physical phenomena associated with ions, with particular, but by no means exclusive, reference to mass spectrometry and to selective extraction of ions of different mass (m) to charge (z) ratios (henceforth termed "m/z" ratios) and/or of different ion mobilities.
  • US 4,283, 626 describes the use of a"leaky dielectric"inserted inside the multipol to allow for the provision of a drift field to speed the ions through a collision cell.
  • This leaky dielectric is transparent to the RF field (thus maintaining a potential well) but has enough resistivity to allow a potential gradient to be applied axially along its length.
  • US 4,283, 626 recognises that such a drift field in the presence of gas may be used to separate ions for analytical purposes.
  • US 5,847, 386 describes a number of different methods to induce a smooth axial field along the length of the linear guides to speed the transmission of ions through them.
  • Such methods include segmenting of the rods themselves, or using external ring electrodes, or tapering the rods themselves or using different pitch circle diameters for opposite phased rod sets at either end of the guide.
  • US patent publication 2002/0070338 describes the use of segmented rods to provide an axial D. C. field and to give separation of the ion species according to their ion mobility. Again, RF confinement is combined with a drift field in the presence of gas. This combination is versatile since ions may be manipulated in a wide variety of ways using D. C travelling waves in the axial direction to create moving potential wells while maintaining radial confinement with the ponderomotive force from the RF supply.
  • Related techniques are described in US 5,206, 506 and US 6483109 .
  • Gerlich With the exception of Gerlich, all of the above techniques describe devices using RF ponderomotive confinement in both dimensions, i. e. they confine ions radially simultaneously but provide little or no radial spatial separation of ions. Gerlich describes a stacked rf plate ion guide with DC top and bottom plates which is employed as a storage ion source, but no theoretical treatment of this device is presented.
  • the present invention provides ion extraction devices which, at least in some embodiments, satisfy the above described needs and overcomes the above described problems and disadvantages associated with the prior art.
  • the present invention provides new ion separation and storage devices capable of separating ions according to their mass, charge and/or ion mobility.
  • the present invention recognises that the effective potential well created by the juxtaposition of an RF potential and an electrostatic potential is dependent on the charge on an ion in the potential in a way that permits spatial separation of ions of different m/z ratio, eg, ions of similar mass but differing charge.
  • the present invention exploits this phenomenon to provide selective extraction of ions.
  • the present invention recognises that the effective potential is dependent on ion mobility, and exploits this phenomenon to provide ion mobility dependent selective extraction of ions.
  • the present invention is not dependent on the space charge effect to achieve spatial separation: in fact, space charge effects can be reduced through appropriate design of the ion trapping environment.
  • the present invention provides a way of separating ions in a predictive manner, and enables efficient coupling to further stages such as mass spectrometer stages. Methods of ion separation, storage (trapping) and fragmentation are provided.
  • the ions may be entrained in a flow of gas.
  • the ponderomotive ion trapping potential and the electrostatic ion trapping potential may be generated generally along single axes which are orthogonal to the direction of the flow of gas.
  • the electrostatic ion trapping potential well may be generated by applying potentials to at least one pair of electrodes, the at least one pair of electrodes being spaced apart across the body of gas.
  • the pondermotive ion trapping potential is generated by an RF electrode set, such as a multipol or ring set.
  • DC electrostatic potentials may be applied to the RF electrode set to assist in the generation of the electrostatic ion trapping potential well.
  • a population of ions may be extracted from a predetermined spatial location. Selective extraction of a population of ions may be achieved by causing a selected population of ions to move to the predetermined spatial location, and thereafter extracting said population of ions from said predetermined spatial location. A selected population of ions may be caused to move to the predetermined spatial location by varying the effective potential. The effective potential may be varied by varying the pondermotive ion trapping potential and/or the electrostatic ion trapping potential well.
  • the effective potential may be varied by varying the pressure of the body of gas.
  • a population of ions may be extracted from a predetermined spatial location by way of providing an ion barrier across the body of gas, the ion barrier having an aperture located therein, and extracting ions through the aperture.
  • selected populations of ions can be extracted by "tuning" the effective potential so that the spatial position occupied by a population of ions is adjusted to coincide with the predetermined spatial location from which ions can be extracted through the aperture.
  • a drift potential may be applied along the body of gas.
  • a flexible, sensitive and accurate way of trapping and extracting ions is provided.
  • High duty cycles approaching or actually achieving 100% duty cycle across the entire mass range are possible.
  • An additional advantage is that bunching of ions into intense packets is achieved, lessening noise in ADC systems.
  • the RF electrode set comprises subsets of RF electrodes disposed along the ion extraction pathway, in which instance the at least one potential barrier is caused by a periodicity in the oscillatory RF potential applied to subsets of RF electrodes disposed along the ion extraction pathway.
  • the effective potential may comprise a drift potential applied along the ion extraction pathway, in which instance ions may be selectively extracted by varying the magnitude of the drift potential. Alternatively, or additionally, ions may be selectively extracted by varying the magnitude of the oscillatory RF potential.
  • the ions may be entrained in a flow of gas, in which instance the ponderomotive ion trapping potential may be generated generally along at least one axis which is orthogonal to the direction of the flow of gas.
  • the method further comprises the step of generating an electrostatic ion trapping potential well generally along an axis which is orthogonal to an axis along which the ponderomotive ion trapping potential is generated, and orthogonal to the ion extraction pathway.
  • the electrostatic ion trapping potential well may be generated by applying potentials to at least one pair of electrodes, the at least one pair of electrodes being spaced apart cross the body of gas.
  • DC electrostatic potentials may be applied to the RF electrode set to assist in the generation of the electrostatic ion trapping potential well.
  • the ponderomotive ion trapping potential is generated generally along two axes which are mutually orthogonal and orthogonal to the ion extraction pathway.
  • an expanded RF electrode set is employed, preferably having additional subsets of RF electrodes disposed along the ion extraction pathway.
  • the RF electrodes in the additional subsets are thinner than the RF electrodes in the other subsets of RF electrodes.
  • the effective potential may be varied by varying the pressure of the body of gas.
  • the analysis means comprises mass spectrometry means.
  • Other forms of analysis means such as a spectroscopic technique, may be employed instead.
  • Phenomena associated with ions such as ion-molecule, ion-radical or ion-ion reactions, might be analysed using techniques to analyse reaction products, measure reaction rates and study reaction dynamics.
  • the mass spectrometry means may comprise a time of flight (TOF) mass spectrometer. Improvements in duty cycle and signal to noise ratio are possible when the present invention is coupled to a TOF mass spectrometer.
  • TOF time of flight
  • the mass spectrometry means may comprise a multipol mass spectrometer, such as a quadruple mass spectrometer.
  • Other types of mass spectrometry means such as a Fourier Transform mass spectrometer (FTMS), magnetic sector and ion- trap devices may be used.
  • FTMS Fourier Transform mass spectrometer
  • the method according to the first aspect of the invention may be used to separate ions of different ion mobilities, and the mass spectrometry means may operate as a mass filter for said ions, ie, may select ions of desired m/z ratio. In this way, selection of a desired charge state can be accomplished.
  • First and second analysis means for analysing ions or phenomena associated with ions may be provided, and ions emanating from the first analysis means may be introduced into the second analysis means by selective ion extraction using a method according to the first aspect of the invention.
  • the first and second analysis means comprise mass spectrometry means.
  • the first analysis means may comprise a multipole mass spectrometer, and the second analysis means may comprise a TOF mass spectrometer.
  • the method according to the first aspect of the invention may selectively extract populations of ions of selected ion mobilities.
  • the analysis means may operate by way of pulsed acquisition of ions and the timing of the selective extraction of ions may be synchronised with the pulsed acquisition of ions by the analysis means so as to improve the efficiency with which extracted ions are analysed.
  • the analysis means may comprise a detector and data acquisition means to acquire data relating to events detected by the detector.
  • the data acquisition means may acquire data over a selected time period which is correlated with the period of time during which events which are associated with the selectively extracted ions are detected by the detector. In this way improved signal to noise ratios may be obtained, since the data acquisition means only acquires data when "true" signal is arriving at the detector, and does not acquire data in time periods where the detector is not detecting events associated with the selectively extracted ions.
  • the data acquisition means may comprise analogue to digital converter acquisition means.
  • the analysis means may comprise mass spectrometry means, preferably a TOF mass spectrometer, most preferably an oa-TOF mass spectrometer.
  • An ion trap may be utilised to control the supply of ions for use in the method of the first aspect of the invention.
  • an ion extraction device as claimed in claim 12.
  • the ion extraction device may be an ion separation, ion storage or ion fragmentation device.
  • At least a portion of the gas cell may comprise a gas flow conduit through which ions entrained in a flow of gas can be transported, the conduit having a direction of gas flow.
  • the device may further comprise gas flow means for providing said flow of gas.
  • the means for generating a ponderomotive ion trapping potential may generate said potential across the direction of flow, and the means for generating an electrostatic ion trapping potential well may generate said potential well across the direction of flow.
  • the means for generating a ponderomotive ion trapping potential comprises an RF electrode set.
  • the RF electrode set may comprise at least one pair of RF electrode stacks, the stacks in each pair of RF electrode stacks being spaced apart across the gas cell.
  • RF electrodes in the RF electrode stacks extend along substantially the entire length of the gas cell.
  • the RF electrodes in each stack are stacked along the length of the gas cell.
  • the RF electrode set may comprise a series of pairs of RF electrode stacks spaced apart across the gas cell.
  • the electrodes in each stack may be stacked in a direction orthogonal to a longitudinal axis of the gas cell.
  • the means for generating an electrostatic ion trapping potential well may comprise at least one pair of electrodes, the electrodes in the at least one pair of electrodes being spaced apart across the gas cell.
  • the means for generating an electrostatic ion trapping potential well may comprise a series of pairs of electrodes disposed along the gas cell.
  • the means for generating an electrostatic ion trapping potential well may comprise a single pair of electrodes spaced apart across the gas cell. The single pair of electrodes may be inclined with respect to the direction of flow. Potentials may be applied to the series of pairs of electrodes so as to apply a drift field along at least a portion of the gas cell.
  • the means for generating a ponderomotive ion trapping potential comprises an RF electrode set
  • the means for generating an electrostatic ion trapping potential well comprises a series of pairs of electrodes disposed along the gas cell
  • the device comprises a plurality of segmented RF electrode/electrode units, in which each unit comprises a coplanar arrangement of two opposed RF electrodes and two opposed electrodes.
  • DC electrostatic potentials may be applied to the means for generating a pondermotive ion trapping potential so as to assist in the generation of the electrostatic ion trapping potential well.
  • the ion extraction means may comprise an ion barrier disposed across the gas flow conduit having an aperture formed therein.
  • the ion barrier prevents ions from crossing the barrier and hence leaving the ion extraction device.
  • the ion barrier may be a physical barrier, such as an end cap, and/or may comprise means for applying an ion retarding electric field.
  • the ion extraction device may further comprise means for applying an extraction field to extract ions through the aperture.
  • the ion extraction means may comprise an inwardly extending tube formed of a leaky dielectric material which is in communication with the aperture.
  • At least one of the means for generating a pondermotive ion trapping potential, the means for generating an electrostatic ion trapping potential well, and the pressure of the body of gas may be variable so as to cause a selected population of ions to move to a predetermined spatial location.
  • the ion extraction device may be used as a gas collision cell.
  • the RF electrode set comprises subsets of RF electrodes disposed along the ion extraction pathway, in which the at least one potential barrier is caused by a periodicity in the oscillatory RF potential applied to subsets of RF electrodes disposed along the ion extraction pathway.
  • the ion guiding means may further comprise means for applying a drift potential along the ion extraction pathway.
  • the means for varying the effective potential may vary the magnitude of the drift potential applied by the means for applying a drift potential so as to selectively extract ions.
  • the means for varying the effective potential may vary the oscillatory RF potential so as to selectively extract ions.
  • At least one portion of the gas cell may comprise a gas flow conduit through which ions entrained in a flow of gas can be transported, the conduit having a direction of gas flow.
  • the device may further comprise gas flow means for providing said flow of gas.
  • the RF electrode set may generate the ponderomotive ion trapping potential across the direction of flow.
  • the ion guiding means further comprises means for generating an electrostatic ion trapping potential well generally along an axis which is orthogonal to an axis along which the ponderomotive ion trapping potential is generated and orthogonal to the ion extraction pathway.
  • the means for generating an electrostatic ion trapping potential well may comprise at least one pair of electrodes, the electrodes in the at least one pair of electrodes being spaced apart across the gas cell.
  • the means for generating an electrostatic ion trapping potential well may comprise a series of pairs of electrodes disposed along the gas cell. Potentials may be applied to the series of pairs of electrodes so as to apply a drift field along the ion extraction pathway.
  • DC electrostatic potentials may be applied to the RF electrode set so as to assist in the generation of the electrostatic ion trapping potential well.
  • the ion extraction volume is a cuboid having a width, height and length. It is understood that a cuboid is of rectangular cross section, ie, the width is different from the height.
  • the ponderomotive ion trapping potential should be generated generally along an axis corresponding to the width of the cuboid.
  • the ratio of the width to the height of the cuboid is at least 1: 1.5, preferably greater than 1: 1.7.
  • the device may comprise an entrance end plate at one end of the device having at least one ion inlet.
  • the device may comprise an exit end plate at one end of the device having at least one ion exit.
  • a drift potential may be applied along the ion extraction pathway by way of applying voltages to the end plates.
  • Devices of the invention may be cascaded together to produce arrays of devices in x, y or z directions, or in combinations of directions. Ions can be transferred between adjacent devices by using electrodes with slots, holes, meshes or other apertures. Preferably, these electrodes are common to the adjacent devices.
  • the RF electrode set may comprise at least one pair of RF electrode stacks; wherein the stacks in each pair of RF electrode stacks are spaced apart across the gas cell and the RF electrodes in each stack are stacked along the ion extraction pathway.
  • the means for applying an oscillatory RF potential may apply oscillatory RF potential of a common phase to a plurality of adjacent RF electrodes in a subset of RF electrodes, so that the periodicity in the oscillatory RF potential is established between groups of RF electrodes in the subsets.
  • Ion extraction devices of the invention may further comprise ion supply means for generating a supply of ions to the gas cell.
  • Ions may be created using a suitable ionisation technique such as electrospray ionisation, MALDI (Matrix Assisted Laser Desorption lonisation), electron impact, chemical ionisation, fast atom bombardment, field ionisation, field desorption and soft ionisation techniques employing vacuum ultraviolet or soft x-ray radiation produced by a convenient light source such as a laser.
  • a suitable ionisation technique such as electrospray ionisation, MALDI (Matrix Assisted Laser Desorption lonisation), electron impact, chemical ionisation, fast atom bombardment, field ionisation, field desorption and soft ionisation techniques employing vacuum ultraviolet or soft x-ray radiation produced by a convenient light source such as a laser.
  • the ions are generated externally of the gas cell, but in principle might be generated inside the gas cell.
  • the mass spectrometry means may comprise a time of flight (TOF) mass spectrometer or a multipol mass spectrometer or other types of mass spectrometry means, such as described above.
  • TOF time of flight
  • An analytical device comprising at least two analysis means may be provided.
  • an ion extraction device may be disposed between two analysis means.
  • Advantageous embodiments employ an ion extraction device disposed between two mass spectrometry means.
  • Devices in accordance with the preferred embodiment of the invention are advantageous in complex analyses such as proteomics and/or applications which give rise to cluster ions which have the same mass to charge ratio but which have different masses and charges. Separation of such clusters can be achieved using the present invention.
  • a tandem ion separation device comprising a first ion extraction device coupled to an ion separation stage.
  • the upstream ion extraction device may operate as an ion mobility separator, and the downstream ion extraction device may separate ions according to their m/z ratio.
  • the upstream ion extractor device can then operate at relatively high pressures.
  • the ion separation stage may comprise mass spectrometry means.
  • the mass spectrometry means may comprise a multipol mass spectrometer.
  • the mass spectrometry means may operate as a mass filter, and the first ion extraction device may operate as an ion mobility separator.
  • the ion separation stage may supply ions to the first ion extraction device.
  • the equation also includes the classical electrostatic potential q ⁇ s where ⁇ s is a voltage created by DC potentials applied to electrodes in any general system. It can be seen that the potential due to the oscillatory field is proportional to charge squared while the electrostatic potential is proportional to charge. The present invention exploits this relationship to separate ions of similar mass but differing charge.
  • these ion guides are all to some degree cylindrically symmetric and all exhibit a radial dependence on effective potential with steeper sided potential wells for higher order multiples and ring sets.
  • Gerlich also describes a stacked rf plate ion guide with DC top and bottom plates which is employed as a storage ion source.
  • the use of such a source as a mass discriminating device operating in the space charge limit is described by applying a weak dc difference but no analytical treatment of this geometry is presented.
  • a linear stacked rf plate device is used to select desired combinations of mass and charge state, the use of a long linear geometry allows for operation not compromised (or affected) by space charge due to its large charge capacity.
  • it is necessary to obtain an-analytical solution to the form of the effective potential at any point in the guide i. e. a solution , to Equation (1) for the general geometry chosen.
  • Such a solution can be obtained by solving for the rf and electrostatic elements separately and then adding the two solutions, a process known as superposition.
  • a general two dimensional solution has been found for the guide whose form and notation is set out in Figure 1 and which comprises :- an rf parallel rod set (shown generally at 10) which consists of a plurality of RF rods 12 and a pair of DC electrodes 14.
  • the guide gives electrostatic trapping in the Y direction and ponderomotive effective potential trapping in the X direction. Due to the nature of Laplace's equation the electrostatic potential well which traps in Y is a saddle point causing ions to move away from the centre of the device in the X direction. The ponderomotive effective potential well must be great enough to overcome this negative dispersion if complete X-Y trapping is to be achieved
  • Figures 2 , 3 and 5 to 8 illustrate embodiments of the present invention, solutions of which are satisfied by the two dimensional solution shown above within the body of the device.
  • Different means are employed to give additional axial fields of varying complexities ranging from simple linear driving fields to polynomials applied to electrode sets for trapping and extraction purposes.
  • Various features are shared between the embodiments depicted in Figures 2 to 8 , and like numerals are used to depict such common features.
  • Figure 2 (a) shows an X-Y slice through the centre of a first embodiment showing DC only trapping electrodes 22 at voltage Vp and RF electrodes 20.
  • FIG. 2 (b) also shows a typical end plate 24 of the device which has a hole 26 in the centre through which ions of desired characteristic are ejected. The end plate 24 can be used also as an entrance plate for an ion extraction device.
  • Figure 3 shows how segmented DC electrodes 30 provide an axial field of desired form by applying different voltages Vp1- Vp8 to each electrode.
  • Figure 4 shows how a simple axial field can be created by inclining top 40 and bottom 42 plates which act as DC electrodes.
  • Figure 5 shows an embodiment comprising segmented RF plates 52 and segmented DC plates 50, which permits greater flexibility to be had in creating trapping wells for purposes of upstream storage as explained
  • Figures 6 (a) and 6 (b) show an embodiment of the device which is analogous to that shown in Figure 2 (a) except that the RF plates 20 have been stacked in the Z direction rather than the Y direction.
  • Figures 7 (a) and 7 (b) show a sixth embodiment having inclined DC plates 70 (analogous to the third embodiment) and RF plates 72 stacked in the Z direction (analogous to the fifth embodiment).
  • Figures 8 (a) and 8 (b) show a seventh embodiment comprising segmented RF plates 80 stacked in the Z direction-and segmented DC plates 82 also in the Z direction.
  • the seventh embodiment is arranged so as to comprise a plurality of segmented RF/DC electrode units, wherein each RF/DC electrode unit comprises a coplanar arrangement of two opposed RF electrodes and two opposed RF electrodes.
  • each RF/DC electrode unit comprises a coplanar arrangement of two opposed RF electrodes and two opposed RF electrodes.
  • Typical, but non-limiting, dimensions of the ion extraction device are length 50 to 250mm, width 5 to 50mm and extraction aperture diameter 0.5 to 4mm, preferably about 2mm.
  • Figure 9 shows a typical electrostatic potential well along the Y axis of the device of the embodiment shown in Figure 2 (a)
  • Figure 10 shows a typical negative dispersion along the X axis. These plots are calculated from the 2nd term in equation (4).
  • Figure 11 shows the form of the effective potential well along the x axis, and is calculated from the 1 st term in equation (4).
  • Figure 12 shows a composite potential (electrostatic + ponderomotive) along the X axis for chosen device geometry. At the centre of the device near the Y axis it can be seen that the potential is at a local maximum.
  • the same voltage settings were used in the guide for these three Figures and they demonstrate how spatial separation of ions having similar mass but different z can be achieved. So far only the 2 dimensional behaviour of the device has been discussed and the extraction of the ions to further spectrometer stages has not been discussed. It is important to note that the device can be constructed of any desired length in order to increase the space charge capacity before degradation of performance.
  • an end plate 140 with an aperture 142 through which ions are extracted.
  • the end plate 140 In normal operation the end plate 140 is biased such as to trap ions in the body of the device.
  • An auxiliary electrode 144 situated behind the trapping end plate 140 causes a local extraction field in the centre of the device.
  • Figure 14 Also shown in Figure 14 are the end extremities of DC electrodes 146.
  • Figure 14 shows the cross section of this arrangement with the lines of equipotential showing the local extraction field. Ions which reside in the potential wells away from the optic axis remain trapped in the device whereas ions residing in the centre are extracted to subsequent stages of the spectrometer. Operation of the device then entails scanning the RF and/or electrostatic potential to sequentially bring those ions of desired M/z and z to its optic axis for subsequent ejection through the endplate hole.
  • FIG. 15 depicts an arrangement in which the end plate 140 has an inwardly extending leaky dielectric tube 150 through which to extract the ions.
  • the leaky dielectric tube 150 is positioned adjacent to aperture 142.
  • the trapping voltage applied to the end plate 140 keeps the ions in the device and the combination of gas flow and electric field in the tube 150 drives ions into the tube 150 and out of the device.
  • the RF fields are maintained through the leaky dielectric to keep ions to the centre of the tube 150 during their exit, eg, to subsequent spectrometer stages.
  • the extraction elements may be pulsed for optimum interfacing to the downstream elements of the instrumental arrangement.
  • a general three dimensional solution has been found for the guide whose form and notation is set out in Figure 19 and which comprises an RF parallel rod set which consists of a plurality of RF plates 212 and a plurality of DC electrodes 214, and a pair of end plates 216. Note that the coordinate system utilised for the guide shown in Figure 19 differs for the coordinate system utilised for the guide shown in Figure 1 .
  • the z axis to RF plate distance is 'a' (6mm)
  • RF plate width is 'b' (10mm)
  • half length of device in y direction is 'd' (20mm)
  • number of plates from x axis to DC plate is 'n' (5)
  • peak voltage is V0
  • insertion plate is Vent (1V)
  • extraction plate voltage is Vext (-1V unless otherwise stated)
  • trapping plate voltage is Vp (1V).
  • Figure 20 shows an embodiment of an ion extraction device of the present invention, the operation of which stems from the 3D solution discussed above.
  • Figure 20(a) shows an x-z slice through the centre of the device showing DC electrostatic trapping electrodes 220 and RF electrodes 222.
  • the RF electrodes 222 are plate electrodes.
  • the RF electrodes form a pair of RF electrode stacks, shown generally at 224a and 224b. Each RF electrode in a stack has a matching electrode in the other stack positioned across the ion extraction device in the x direction.
  • Figure 20(a) shows such a pair of RF electrodes 222a, 222b spaced apart in the x direction.
  • the DC electrodes 220 are segmented, and form a pair of DC electrode stacks extending axially of the device, shown generally at 225a and 225b. It can be seen that the device comprises a plurality of segmented RF/DC electrode units, wherein each RF/DC electrode unit comprises a co-planar arrangement of two opposed RF electrodes 222 and two opposed DC electrodes 224.
  • the device further comprises a first end plate 226 and a second end plate 228.
  • the first end plate 226 has an aperture 230 formed therein enabling ions to be supplied to the device.
  • the aperture 230 may be of any convenient shape, such as a square, as shown in Figure 20 , or a circle.
  • the second end plate 228 has an aperture 232 through which ions are extracted from the device.
  • the aperture 232 can be any suitable shape, such as a slot. Other suitable configurations for the aperture through which ions exit the device are discussed below.
  • Figure 21 is a plan view depicting the RF electrodes 222 in Figure 20 in the two stacks 224a, 224b.
  • Figure 21 shows the phases of the RF potential as applied to each RF electrode 222.
  • pairs of RF electrodes 222 spaced apart in the x direction are connected to the same phase of the RF potential.
  • adjacent electrodes in a stack of electrodes are connected to opposite phases of the RF potential.
  • Figure 23 shows a typical DC electrostatic potential well in the z direction generated by the application of a voltage V p to the DC electrostatic trapping electrodes 220. Again, the potential increases quite markedly as an ion approaches either of the electrodes 220.
  • Figure 24 shows the effective potential in the y direction, ie, along the length of the ion extraction device. It can be seen that the effective potential shows ripples along the y axis. The magnitude of the ripple, which is caused by the periodicity in the RF potential along the y axis, is dependent on the m/z ratio of an ion in the ion extraction device. Very surprisingly, it has been found that the magnitude of the ripple in the effective potential along the y axis is independent of the proximity to the RF electrodes 222 and the DC electrodes 220.
  • Figure 25 shows the mass dependent effective potential in the y direction in a number of different instances.
  • Figures 25(a) and (b) show the effective potential for a singly charged ion of mass 2900.
  • Figure 25(b) shows the effective potential at an RF electrode 222.
  • the potential at an RF electrode 222 is higher than at the centre of the device.
  • the magnitude of the ripple is 0.3 V.
  • Figures 25(c) and 25(d) show the effective potential in the y direction for a singly charged ion of mass 200.
  • Figure 25(c) shows the effective potential at the centre of the device and Figure 25(d) shows the effective potential at an RF electrode 222.
  • the potential at RF electrode 222 is higher than in the centre of the device, but the magnitude of the ripple observed is the same in both instances.
  • the magnitude of the ripple is in this case 3V, illustrating that the magnitude of the ripple is dependent on the m/z ratio of the ion in the device.
  • Figures 26 to 32 show a variety of two dimensional effective potentials in a number of planes through the ion extraction device of Figure 20 .
  • the ripples in the effective potential described above represent a mass dependent potential barrier. This phenomena can be utilised to trap ions (either fragment or parent).
  • an axial field is applied to the device (such as, for example, by applying appropriate potentials to the end plates 226, 228 of the device shown in Figure 20 ) thereby permitting transport of ions of relatively high mass along the length of the device whereas ions of relatively low mass, which encounter a deeper potential well in the y direction, remain trapped in the body of the device.
  • This approach permits easy interfacing with further spectrometer stages, such as an oa-TOF whereby an enhanced duty cycle can be achieved.
  • ions of a chosen m/z ratio may be selectively extracted from the device.
  • Figure 33 shows how mass selective extraction of ions may be achieved through the application of a drift field along the device.
  • Figure 33(a) shows the effective potential experienced by ion in the instance in which the drift field is large enough to overcome the potential maxima created by the RF potential. In this instance, there is no axial energy barrier in the effective, potential, and the drift field is sufficient to enable the ion to be transmitted along the device.
  • Figure 33(b) depicts the effective potential in the instance in which the applied drift field reduces, but does not eliminate, the potential maxima created by the RF potential. In this instance, the ion is trapped behind the potential maxima in the effective potential.
  • the applied RF potential may be swept in order to selectively transmit ions from high to low mass.
  • the magnitude of the applied drift field may be swept in order to selectively transmit ions.
  • Figure 34 shows an alternative way in which the periodicity in the axial effective potential can be generated.
  • a plurality of adjacent RF electrodes 222 are connected to a common phase of the applied oscillatory RF potential.
  • groups of three adjacent RF electrodes 360 are connected to a common phase of the applied RF potential.
  • the phase of the applied RF potential changes every third electrode. The effect of this arrangement is that, for a given set of RF electrodes, the spacing of the periodicity in the applied RF potential is increased.
  • groups of three adjacent RF electrodes are connected to a common phase of the applied RF potential.
  • the number of electrodes in a group of adjacent electrodes connected to a common RF potential is not limited to three, but rather can be any number, for example, between two and five adjacent RF electrodes may be connected together in this way.
  • adjacent RF electrodes in a stack may be connected to opposite plates of the applied RF potential, as shown in Figure 21 In these instances, it is advantageous if relatively thick RF electrodes are employed, since this results in ripples in the axial potential of greater magnitude.
  • Figure 35 shows a preferred embodiment of an end plate 370 for use at the exit of a device of the present invention.
  • the end plate 370 has a slotted aperture 372 through which ions may be extracted from the device.
  • the effective potential along the x axis ie, between spaced apart pairs of RF electrodes across the device
  • the position of the potential minima is dependent on the m/z ratio of the ion in the effective potential.
  • Figure 37 shows other possible types of end plates which may be used in the present invention.
  • Figure 37(a) shows an end plate 390 having a grid or mesh 392 defining a plurality of exit apertures.
  • Figure 37(b) shows an end plate 390 having a vertically slotted aperture 394.
  • Figure 37(c) shows an end plate 390 having circular aperture 396.
  • Figure 37(d) shows an end plate 390 having a cross shaped aperture 398 formed from vertical and horizontal slots.
  • Figure 37(e) shows an end plate 390 having a plurality of vertically slotted apertures 400.
  • the methodologies described in respect of Figures 14 and 15 might be used in order to extract ions from devices of the type shown in Figure 20 .
  • a further embodiment has a pair of spaced apart DC plates which act as DC electrodes.
  • the DC plates extend axially along the device.
  • a further embodiment still has a pair of inclined, spaced apart DC plates which act as DC electrodes. In this way a simple axial field along the device can be created.
  • Typical, but non-limiting, dimensions of an ion extraction device utilising axial potential barriers are length 50 to 250 mm, width 5 to 50 mm with around 140 RF electrodes in each stack.
  • Figure 38 shows an arrangement comprising a fragmentation thermalisation and trap stage 420, a mass selective transmission stage 422, a trap-TOF stage 424 and a beam shaper stage 426.
  • the mass selective transmission stage 422 is an ion extraction device of the type discussed above.
  • Each of the stages 420, 422, 424, 426 comprise spaced apart stacks of RF electrodes 428 and spaced apart stacks of DC electrodes 430.
  • the fragmentation thermalisation and trap 420 is operated so as to produce a negligible ripple in the effective axial potential.
  • the device has a relatively gentle drive field, and accumulates and fragments ions, sending populations of fragments to the mass selective transmission stage 422.
  • the fragmentation thermalisation and trap stage 420 accumulates incoming signal whilst mass selective ejection occurs.
  • the mass selective transmission stage 422 operates generally in the manner described above, having a relatively large mass dependent ripple in the effective axial potential.
  • the trap-TOF stage 424 has a negligible ripple in the axial effective potential.
  • the device accumulates ions and sends packets of ions to the beam shaper stage 426.
  • the trap-TOF stage 424 has a relatively gentle drive field. Extraction from the trap may be synchronised with a pusher by a variable mass dependent delay such as shown in Figure 39 .
  • the beam shaper stage 426 is an RF only device.
  • the beam shaper stage 426 has a negligible ripple in the axial effective potential, and, as shown in Figure 40 , has a plurality of different plates 440 of varying internal aspect ratio which prepares the ion beam for introduction into a subsequent analysis stage.
  • the subsequent analysis stage may be a mass spectrometer stage such as a multipole device or, preferably, a TOF device.
  • FIG 41 is an end view of a device, shown generally at 450, comprising a plurality of RF electrodes 452 and DC electrodes 454.
  • the RF electrodes 452, which may be RF plates, are directly mounted onto PCBs 456, 458.
  • One stack of RF electrodes is mounted on first PCB 456, and a second stack of RF electrodes is mounted on a second PCB 458.
  • the DC electrodes 454 are mounted on members 460 which themselves are mounted on the PCBs 456, 458 via edge connectors 462.
  • the passageway defined by the spaced apart DC electrodes 454 and RF electrodes 452 represents an ion extraction volume having an ion extraction pathway.
  • the ion extraction volume is a cuboid having a rectangular face defined by the spacings of the DC electrodes 454 and RF electrodes 452. In the non-limiting example, these spacings are 14mm and 8mm respectively, providing an aspect ratio of 1.75. Other dimensions and/or aspect ratios are within the scope of the invention.
  • the device shown in Figure 41 further comprises a top plate 463 and bottom plate 464.
  • the top and bottom plates 463, 464 may be formed from a convenient material such as metal, and may be positioned against the PCBs 456, 458 with gaskets 466, and fixed in place with suitable fixing means such as screws 268.
  • a gas inlet 470 is provided on the top plate 462.
  • the RF electrodes 452 have tabs 452a which protrude through the PCBs 456, 458 thereby permitting convenient wiring.
  • the DC electrodes 454 have tabs 454a which protrude through the members 460 enabling convenient wiring of the DC electrodes too.
  • Each DC electrode 454 may be attached to a separate member 460, with each DC electrode 454/member 460 unit being spaced apart from each other. In this way, apertures are provided between DC electrodes 454/member 460 units permitting the entry of gas into the cell from the gas inlet. Entrance and exit plate assemblies including suitably shaped entrance and exit apertures can be fixed to the edges of the PCBs 456, 458 and top and bottom plates 462, 464 using gaskets.
  • Figure 42 shows possible designs of hollow RF plates 480, 482. Hollow plates result in a reduced capacitance, and thus a reduced loading on the RF power supply. It is possible to provide adjacent plates that have a different shape.
  • the plates can be chemically etched, and might be gold plated.
  • the constructional approach depicted in Figure 41 is convenient, cost effective and permits easy manufacture of devices of the present invention.
  • the device may be constructed by soldering, which may require use of a construction jig to hold the plates in place.
  • Figure 16(a) (reproduced from EP 1,271,138 ) shows how ions of different mass to charge ratio become temporally and spatially separated in an axial drift region, whilst Figure 16(b) shows how the duty cycle is increased to up to 100% for the chosen ion species but reduced to zero for ions outside a certain range. This is compared to a typical maximum duty cycle of 25% obtained by operating the TOF in a conventional manner.
  • US Application 2003/0132377 describes duty cycle improvements across the entire mass range using either a 3D ion trap, a magnetic Penning trap or a linear quadrupole ion trap.
  • Okumua et al (51 st ASMS THPJ2 170) also describes the use of a 3D ion trap coupled to an oa-TOF with improved duty cycle. It is envisaged that the current invention will also provide 100% duty cycle for all ions, ie, both parents and fragments when coupled to a TOF mass spectrometer.
  • desired ions are pulsed out of the device, for example by varying the RF potential, by an auxiliary extraction electrode or by an end plate, and the pulsing of the pusher electrode is timed to coincide with the ejection of the M/z packet from the device.
  • the extract-pulse cycle may be repeated until all the ions have been extracted and then the device adjusted to eject ions of the next desired M/z value.
  • the simplicity of operation and mono-energetic nature of the extracted ions offer a significant advantage over the 3D Quadrupole Ion Trap (QIT) embodiments.
  • QIT 3D Quadrupole Ion Trap
  • 100% duty cycle depends upon the ion extraction device accumulating with 100% efficiency and being isolated by 100% efficient TRAP upstream of the ion extraction device while it is ejecting ions sequentially to the TOF.
  • the upstream TRAP could be another ion extraction device of the present invention which has been appropriately biased to prevent ions entering the downstream stage.
  • an ion extraction device of the invention with an oa-TOF can improve signal to noise ratio particularly when coupled to analogue to digital converter acquisition electronic (ADC's).
  • ADC converters offer significant dynamic range advantages over time-to-digital converters (TDC's) for high ion currents, however at low ion currents their poorer noise characteristics may obscure weak signals particularly over long integration periods.
  • TDC's time-to-digital converters
  • concentration of ion signals into shorter timepackets and concentration into smaller discrete mass ranges.
  • Figure 17 shows the steady implementation (ie, constant ion signal into the device) of an accumulating ion trap 170 with extract pulse wide "W” and trapping time "T” split into n discrete and equal mass ranges. If the trap is 100% efficient and emits ions of all mass equally then the intensity of the ion packet is n(W+T)/W times more intense during its extraction phase (and emitted in a factor of W/n(W+T) shorter time) than the equivalent continuous experiment for any particular mass. Signal to noise is dramatically improved as the ADC need not be acquiring data while there is no signal, the mass range of acquisition set on the ADC being correlated to that being emitted by the trap of the present invention at that point in time.
  • the trap of the present invention may be set to emit over ten separate discrete mass ranges to cover the whole mass range of interest with data only being recorded into those mass channels corresponding to that being emitted by the trap.
  • the trap to extract ratio is limited only by the space charge capacity of the device as the overall charge contained within the device increases by the ratio (W+T)/W.
  • a tandem ion mobility spectrometer may be scanned in tandem with a quadrupole mass filter to select a chosen charge state (see, for example, European Patent Application EP 1 271 138 A2 ).
  • the output of the ion extraction device of the present invention when operating as a mobility separator may also be filtered by mass spectrometry means such as a quadrupole mass filter or axial time-of-flight (or other MS) to give complete selection of desired charge state so improving the signal to noise ratio in, for example, Proteomics experiments.
  • the principle of operation of the ion extraction device of the present invention as a mobility separation device should be considered ion the light of the added consideration that the magnitude of effective potential will vary with gas pressure and ion cross, section.
  • Tolmachev A.V. Tolmachev et a/: Nuclear Instruments and Methods in Physics Research B 124 (1997) 112-119 ) utilises the hard sphere model to predict how the magnitude of the effective potential varies with gas pressure and ion cross section.
  • a multiple attenuation factor ⁇ should be incorporated in the effective potential and is given by:- where ⁇ is the angular frequency of the RF driving field, m the mass of the background gas molecules, M the mass of the ion, n the number density of the buffer gas, v the average Maxwellian gas velocity and ⁇ the collision cross section of the ion.
  • the model predicts attenuation of the effective potential field as gas pressure increases, in particular it is stated that if an ion undergoes a large number of collisions with residual gas molecules during the period of one RF cycle then the effective potential is reduced.
  • the mobility of an ion is related to its collision cross section by the following relationship ( Anal.Chem.
  • Devices of the present invention may be operated as a collision cell. To do so the whole device should be held at a potential such that ions are accelerated into the device as a desired ion energy. Ions collide with the gas present in the device with sufficient energy to fragment, but are generally thermalised as the ions traverse the length of the device. Thus, by the time the ions reach the exit of the device they can be separated according to their mass to charge ratios in the same way that a mixture of unfragmented ions, injected at low energy, can be separated.
  • Ions are generated in an ion source 180, typically an electrospray or MALDI source, and are passed through an ion guide 182 to a conventional quadrupole mass spectrometer 184, thence into an ion extraction device 186 of the present invention and on to a further MS stage 188 which may comprise a quadrupole, TOF, FTMS, magnetic sector, ion-trap or any other mass spectrometer.
  • ion source 180 typically an electrospray or MALDI source
  • MS stage 188 which may comprise a quadrupole, TOF, FTMS, magnetic sector, ion-trap or any other mass spectrometer.
  • Ions are allowed to enter the device 186 for a period of time preferably such that the space charge capacity of said device 186 is not exceeded, the device 186 is then isolated to prevent any more ions entering and, finally ions are extracted sequentially into further downstream stages of the spectrometer. It is necessary to isolate the ion extraction device 186 to prevent artefacts, ie, if the device starts by ejecting an ion of low M/z (denoted M L ) and progressively moves to eject ions of higher M/z (denoted M H ) then any ions of M L that arrive in the device 186 at that time will also be transmitted.
  • FIG. 18 also shows an upstream ion guide 182 which may also be an ion extraction device of the present invention.
  • electrospray ionisation a consequence of interfacing with the atmospheric ionisation process of electrospray is that differentially pumped upstream chambers may necessarily be at higher pressures than those required for optimum operation of quadrupole spectrometers.
  • ion mobility separation in accordance with the invention occurs upstream of the quadrupole 184 to improve signal to noise on, for example, multiply charged peptides and mass selective ejection downstream occurs to give up to 100% duty cycle to the TOF or other MS stage 188.

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Claims (21)

  1. Procédé d'extraction sélective d'ions, comprenant les étapes qui consistent à :
    fournir une alimentation en ions dans un corps gazeux dans un volume d'extraction d'ions, ledit volume d'extraction d'ions définissant une voie d'extraction d'ions ;
    fournir des électrodes RF (222) disposées le long de ladite voie d'extraction d'ions ;
    appliquer un potentiel RF oscillatoire auxdites électrodes RF (222) pour générer un potentiel de piégeage d'ions pondéromoteur le long d'un premier axe qui est orthogonal à ladite voie d'extraction d'ions ;
    générer un puits de potentiel de piégeage d'ions électrostatique le long d'un deuxième axe qui est orthogonal audit premier axe et qui est orthogonal à ladite voie d'extraction d'ions ;
    dans lequel un potentiel efficace est fourni le long de ladite voie d'extraction d'ions, ledit potentiel efficace comprenant au moins une barrière de potentiel dont la grandeur dépend du rapport masse contre charge d'un ion dans ladite alimentation en ions, dans lequel ledit potentiel efficace le long de ladite voie d'extraction d'ions est généré au moins en partie par ledit potentiel RF oscillatoire appliqué auxdites électrodes RF (222), et dans lequel ladite au moins une barrière de potentiel est causée par une périodicité dans le potentiel RF oscillatoire appliqué auxdites électrodes RF (222) ;
    dans lequel ledit potentiel efficace empêche des ions d'être extraits d'une région d'extraction et cause une séparation spatiale d'ions ayant différents rapports masse contre charge et/ou d'ions ayant différentes mobilités ioniques, produisant ainsi une pluralité de populations d'ions séparées spatialement ayant différents rapports masse contre charge et/ou une pluralité de populations d'ions séparées spatialement ayant différentes mobilités ioniques ;
    ledit procédé comprenant en outre :
    le piégeage d'ions dans ledit potentiel efficace ; et
    l'extraction sélective d'une population d'ions ayant un rapport masse contre charge prédéterminé ou une mobilité ionique prédéterminée à partir de ladite région d'extraction en faisant varier ledit potentiel efficace de façon à permettre à des ions ayant un rapport masse contre charge prédéterminé ou une mobilité ionique prédéterminée d'être extraits sélectivement.
  2. Procédé selon la revendication 1, dans lequel l'étape d'extraction sélective d'une population d'ions comprend l'extraction d'une population d'ions à partir d'un emplacement spatial prédéterminé.
  3. Procédé selon la revendication 2, comprenant en outre le fait de causer le déplacement d'une population d'ions sélectionnée jusqu'audit emplacement spatial prédéterminé et ensuite l'extraction de ladite population d'ions à partir dudit emplacement spatial prédéterminé.
  4. Procédé selon la revendication 1, 2 ou 3, dans lequel ladite étape d'extraction sélective d'ions comprend le fait de faire varier ledit potentiel RF oscillatoire.
  5. Procédé selon l'une quelconque des revendications précédentes, dans lequel ladite étape d'extraction sélective d'ions comprend le fait de faire varier la grandeur d'un champ axial ou d'un potentiel de dérive appliqué le long de ladite voie d'extraction d'ions.
  6. Procédé selon l'une quelconque des revendications précédentes, dans lequel ladite étape d'extraction sélective d'ions comprend le fait de faire varier la pression dudit corps gazeux.
  7. Procédé selon l'une quelconque des revendications précédentes, comprenant en outre la fourniture d'au moins une paire d'électrodes de piégeage électrostatique en courant continu (220) espacées à travers ledit corps gazeux, dans lequel ledit puits de potentiel de piégeage d'ions électrostatique est généré par application de potentiels à ladite au moins une paire d'électrodes de piégeage électrostatique en courant continu (220).
  8. Procédé selon la revendication 7, comprenant en outre la fourniture d'une série de paires d'électrodes de piégeage électrostatique en courant continu (220) disposées le long de ladite voie d'extraction d'ions.
  9. Procédé d'analyse d'ions ou de phénomènes associés à des ions, comprenant les étapes qui consistent à :
    fournir un moyen d'analyse pour l'analyse d'ions ou de phénomènes associés à des ions ;
    introduire des ions dans ledit moyen d'analyse par extraction sélective d'ions en utilisant un procédé selon l'une quelconque des revendications précédentes ; et
    analyser lesdits ions extraits ou phénomènes associés auxdits ions extraits.
  10. Procédé selon la revendication 9, dans lequel ledit moyen d'analyse comprend un moyen de spectrométrie de masse.
  11. Procédé selon la revendication 10, dans lequel ledit moyen de spectrométrie de masse comprend un spectromètre de masse à temps de vol ou un spectromètre de masse multipolaire.
  12. Dispositif d'extraction d'ions, comprenant :
    une pile à gaz comprenant un volume d'extraction d'ions dans laquelle, en cours d'utilisation, des ions présents dans un corps gazeux sont apportés dans ledit volume d'extraction d'ions, ledit volume d'extraction d'ions définissant une voie d'extraction d'ions ;
    des électrodes RF (222) disposées le long de ladite voie d'extraction d'ions ;
    un moyen d'application d'un potentiel RF oscillatoire auxdites électrodes RF (222) pour générer un potentiel de piégeage d'ions pondéromoteur le long d'un premier axe qui est orthogonal à ladite voie d'extraction d'ions ; caractérisé par :
    un moyen de génération d'un puits de potentiel de piégeage d'ions électrostatique le long d'un deuxième axe qui est orthogonal audit premier axe et qui est orthogonal à ladite voie d'extraction d'ions ;
    dans lequel, en cours d'utilisation, un potentiel efficace est fourni le long de ladite voie d'extraction d'ions, ledit potentiel efficace comprenant au moins une barrière de potentiel dont la grandeur dépend du rapport masse contre charge d'un ion dans ladite alimentation en ions, dans lequel ledit potentiel efficace le long de ladite voie d'extraction d'ions est généré au moins en partie par ledit potentiel RF oscillatoire appliqué auxdites électrodes RF (222), et dans lequel ladite au moins une barrière de potentiel est causée par une périodicité dans le potentiel RF oscillatoire appliqué auxdites électrodes RF (222) ;
    dans lequel ledit potentiel efficace empêche des ions d'être extraits d'une région d'extraction et cause une séparation spatiale d'ions ayant différents rapports masse contre charge et/ou d'ions ayant différentes mobilités ioniques, produisant ainsi une pluralité de populations d'ions séparées spatialement ayant différents rapports masse contre charge et/ou une pluralité de populations d'ions séparées spatialement ayant différentes mobilités ioniques ;
    ledit dispositif d'extraction d'ions comprenant en outre :
    un moyen de piégeage d'ions dans ledit potentiel efficace ; et
    un moyen d'extraction sélective d'une population d'ions ayant un rapport masse contre charge prédéterminé ou une mobilité ionique prédéterminée à partir de ladite région d'extraction en faisant varier ledit potentiel efficace de façon à permettre à des ions ayant un rapport masse contre charge prédéterminé ou une mobilité ionique prédéterminée d'être extraits sélectivement.
  13. Dispositif d'extraction d'ions selon la revendication 12, comprenant en outre un moyen pour causer le déplacement d'une population d'ions sélectionnée jusqu'à un emplacement spatial prédéterminé.
  14. Dispositif d'extraction d'ions selon la revendication 12 ou 13, dans lequel ledit moyen d'extraction sélective d'une population d'ions comprend un moyen pour faire varier ledit potentiel RF oscillatoire.
  15. Dispositif d'extraction d'ions selon la revendication 12, 13 ou 14, dans lequel ledit moyen d'extraction sélective d'une population d'ions comprend
    un moyen pour faire varier la grandeur d'un champ axial ou d'un potentiel de dérive appliqué le long de ladite voie d'extraction d'ions.
  16. Dispositif d'extraction d'ions selon l'une quelconque des revendications 12 à 15, dans lequel ledit moyen d'extraction sélective d'une population d'ions comprend un moyen pour faire varier la pression dudit corps gazeux.
  17. Dispositif d'extraction d'ions selon l'une quelconque des revendications 12 à 16, comprenant en outre au moins une paire d'électrodes de piégeage électrostatique en courant continu (220) espacées à travers ledit corps gazeux, dans lequel ledit puits de potentiel de piégeage d'ions électrostatique est généré par application de potentiels à ladite au moins une paire d'électrodes de piégeage électrostatique en courant continu (220).
  18. Dispositif d'extraction d'ions selon la revendication 17, comprenant en outre une série de paires d'électrodes de piégeage électrostatique en courant continu (220) disposées le long de ladite voie d'extraction d'ions.
  19. Dispositif d'extraction d'ions selon l'une quelconque des revendications 12 à 18, dans lequel ledit volume d'extraction d'ions comprend un cuboïde ayant une largeur, une hauteur et une longueur et dans lequel le rapport de la largeur contre la hauteur du cuboïde est d'au moins 1:1,5.
  20. Spectromètre de masse comprenant un dispositif d'extraction d'ions selon l'une quelconque des revendications 12 à 19.
  21. Spectromètre de masse selon la revendication 20, comprenant en outre un spectromètre de masse
    multipolaire ou un spectromètre de masse à temps de vol couplé audit dispositif d'extraction d'ions.
EP05701820A 2004-01-09 2005-01-10 Dispositifs d'extraction d'ions et procedes d'extraction selective d'ions Active EP1704578B1 (fr)

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GB0400420A GB0400420D0 (en) 2004-01-09 2004-01-09 Ion extraction devices and methods of selectively extracting ions
GB0408628A GB0408628D0 (en) 2004-04-17 2004-04-17 Ion extraction devices and methods of selectively extracting ions
PCT/GB2005/000050 WO2005067000A2 (fr) 2004-01-09 2005-01-10 Dispositifs d'extraction d'ions et procedes d'extraction selective d'ions

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DE10324839B4 (de) * 2002-05-31 2007-09-13 Micromass Uk Ltd. Massenspektrometer
US7045797B2 (en) * 2002-08-05 2006-05-16 The University Of British Columbia Axial ejection with improved geometry for generating a two-dimensional substantially quadrupole field

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8299443B1 (en) 2011-04-14 2012-10-30 Battelle Memorial Institute Microchip and wedge ion funnels and planar ion beam analyzers using same
WO2016149658A1 (fr) * 2015-03-16 2016-09-22 Sri International Spectromètre de masse d'identification avancé tout-terrain
US9589776B2 (en) 2015-03-16 2017-03-07 Sri International Ruggedized advanced identification mass spectrometer
US10861687B2 (en) 2015-04-23 2020-12-08 Micromass Uk Limited Separating ions in an ion trap

Also Published As

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EP1704578A2 (fr) 2006-09-27
ATE507576T1 (de) 2011-05-15
WO2005067000A2 (fr) 2005-07-21
DE602005027656D1 (de) 2011-06-09
WO2005067000A3 (fr) 2006-06-01

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