CA2689084A1 - Mass spectrometry method and apparatus - Google Patents

Mass spectrometry method and apparatus Download PDF

Info

Publication number
CA2689084A1
CA2689084A1 CA2689084A CA2689084A CA2689084A1 CA 2689084 A1 CA2689084 A1 CA 2689084A1 CA 2689084 A CA2689084 A CA 2689084A CA 2689084 A CA2689084 A CA 2689084A CA 2689084 A1 CA2689084 A1 CA 2689084A1
Authority
CA
Canada
Prior art keywords
storage device
ions
voltage
trapping
electrostatic trap
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CA2689084A
Other languages
French (fr)
Other versions
CA2689084C (en
Inventor
Alexander Makarov
Mark E. Hardman
Jae C. Schwartz
Michael W. Senko
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Thermo Finnigan LLC
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority claimed from CA2441589A external-priority patent/CA2441589C/en
Publication of CA2689084A1 publication Critical patent/CA2689084A1/en
Application granted granted Critical
Publication of CA2689084C publication Critical patent/CA2689084C/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00Particle spectrometers or separator tubes
    • H01J49/26Mass spectrometers or separator tubes
    • H01J49/34Dynamic spectrometers
    • H01J49/42Stability-of-path spectrometers, e.g. monopole, quadrupole, multipole, farvitrons
    • H01J49/4205Device types
    • H01J49/422Two-dimensional RF ion traps
    • H01J49/4225Multipole linear ion traps, e.g. quadrupoles, hexapoles
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00Particle spectrometers or separator tubes
    • H01J49/26Mass spectrometers or separator tubes
    • H01J49/34Dynamic spectrometers
    • H01J49/42Stability-of-path spectrometers, e.g. monopole, quadrupole, multipole, farvitrons
    • H01J49/4205Device types
    • H01J49/4245Electrostatic ion traps
    • H01J49/425Electrostatic ion traps with a logarithmic radial electric potential, e.g. orbitraps

Landscapes

  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
  • Electron Tubes For Measurement (AREA)

Abstract

A mass spectrometer comprises an ion source for supplying sample ions for analysis, an ion trap and a voltage source. The ion trap has an entrance for receiving sample ions and an exit through which the sample ions are released.
The voltage source is configured to apply a first set of trapping voltages to the ion trap to confine the sample ions within the ion trap. The first set of trapping voltages are selected to cause a center of an ion cloud defined by the sample ion contained within the ion trap to be positioned closer to the exit than to the entrance. The voltage source is configured to apply a release voltage to the ion trap to release the sample ions from the ion trap through the exit.

Claims (46)

1. A method of injection of sample ions into an electrostatic trap, comprising the steps of:
(a) generating a plurality of sample ions to be analysed, each of which has a mass-to-charge ratio m/z;
(b) receiving the sample ions through a storage device entrance in an ion storage device having a plurality of storage device poles;
(c) supplying a trapping voltage to the storage device so as to trap at least a proportion of the received sample ions within a volume .rho. in the storage device, during at least a part of a trapping period, the thus trapped ions each having a kinetic energy E k such that there is an average kinetic energy ~k of the ions in the volume .rho. during the trapping period or the said part thereof;
(d) supplying a release voltage to the storage device so as to controllably release at least some of the said sample ions contained within the said volume of the storage device from a storage device exit, the release voltage being of a magnitude such that the potential difference then experienced by the ions across the volume .rho. is greater than the said average kinetic energy ~k during the trapping period or said part thereof, and further wherein the release voltage is such that the strength of the electric field generated thereby at any first point across the volume .rho., upon application of the said release voltage, is no more than 50% greater or smaller than the strength of the electric field generated thereby at any other second point across the volume .rho.;

(e) receiving those sample ions released from the storage device exit according to the criteria of step (d) through an entrance of an electrostatic trap having a plurality of trapping electrodes, the ions arriving as a convolution of bunched time of flight distributions for each m/z, each distribution having a full width at half maximum (FWHM); and (f) trapping the received sample ions within the electrostatic trap by applying a potential to the electrodes such that the sample ions describe movement having periodic oscillations in at least one direction.
2. The method of claim 1, in which the potential applied to the electrodes of the electrostatic trap is ramped towards the trapping voltage at the same time as the release voltage is applied to the storage device to cause the said controllable release of the sample ions therefrom.
3. The method of claim 2, in which the potential applied to the electrodes of the electrostatic trap commences ramping towards the trapping voltage prior to application of the said release voltage, and continues to be applied until after the release voltage stops being applied.
4. The method of claim 1, 2 or 3, in which the trapping voltage includes an AC component to trap the ions in a radial direction of the storage device.
5. The method of claim 4, in which the trapping voltage further comprises a DC component, the trapping voltage being selected so as to create a potential well in the storage device defining the said volume .rho., the base of which potential well is adjacent to the storage device exit during at least a part of that trapping period.
6. The method of any preceding claim, in which the release voltage includes at least one DC pulse.
7. The method of any of claims 1, 2, 3 or 4, in which each of the storage device poles is axially segmented into at least two separate pole elements, the step of supplying a trapping voltage to the storage device further comprising supplying a differential DC voltage between at least two separate pole elements so as to cause the sample ions to be trapped in a potential well having a base adjacent to the storage device exit.
8. The method of any of claims 1 to 7, in which the said period of oscillation of those sample ions in the electrostatic trap is shorter than the said FWHM
of the time of flight of those sample ions between ejection from the storage device exit and arrival at the electrostatic trap entrance.
9. The method of any preceding claim, in which, during the step (d), the storage device is arranged to release ions stored therein along an axis generally parallel with a major axis of the storage device when said release voltage is applied.
10. The method of claim 9, in which the storage device is a linear trap whose poles together define an inscribed diameter, and in which the trapping potential is applied so that the base of the potential well is located not more than a distance equal to twice the inscribed diameter from the storage device exit.
11. The method of claim 8, claim 9 or claim 10, in which the release voltage is a differential voltage applied across the axial segment adjacent the storage device exit, and wherein the magnitude of the release voltage is greater than the magnitude of the trapping voltage.
12. The method of any of claims 1, 2 or 3, in which, during the step (d), the storage device is arranged to release ions stored therein along an axis generally orthogonal with a major axis of the storage device when said release voltage is applied.
13. The method of claim 12, further comprising trapping the ions in a storage device which is curved along its major axis.
14. The method of any preceding claim, further comprising applying a voltage to an energy lifter downstream.of the storage device, so as to increase the ion energies as they pass through the said energy lifter.
15. The method of any preceding claim, further comprising cooling the sample ions to reduce their kinetic energies E k.
16. The method of claim 15, in which the cooling is carried out in an ion cooler prior to receipt through the said storage device entrance.
17. The method of claim 15 or claim 16 in which the cooling is carried out within the storage device by forcing sample ions to collide with a collision gas.
18. The method of any preceding claim, in which the release voltage is of a magnitude such that the potential difference then experienced by the ions across the volume .rho. is at least an order of magnitude greater than the said average kinetic energy E k.
19. The method of any preceding claim, in which the release potential is applied so as to release the ions trapped within the volume .rho. such that they focus in time of flight upon the entrance to the electrostatic trap.
20. The method of claim 19, further comprising directing the ions towards the entrance of the electrostatic trap so that they arrive there at an angle which is tangential to a central plane of the electrostatic trap.
21. The method of any of claims 1 to 18, in which the release potential is applied so as to release the ions trapped within the volume .rho. such that they focus in time of flight upon a collision surface located downstream of the electrostatic trap, the method further comprising accelerating fragment ions, created by the impact of the said sample ions upon the collision surface, back towards the electrostatic trap.
22. The method of any one of the preceding claims, further comprising deflecting the sample ions between their exit from the storage device and their entrance to the electrostatic trap such that the said ions do not travel along a line of sight between the storage device exit and the electrostatic trap entrance.
23. The method of any preceding claim, further comprising: applying time dependent voltages to the trapping electrodes of the electrostatic trap so as to increase the electric field within the electrostatic trap until the arrival of the FWHM of the highest m/z to be analysed.
24. The method of any preceding claim, in which the electrostatic trap is of the orbitrap type having a central electrode and an outer electrode split into two sections, the method further comprising ramping to an electrostatic trapping potential on the said central electrode, and detecting an image current induced by the said trapped ions in the said split outer electrode.
25. The method of claim 24, in which the ions are confined in the axial direction and constrained to move around the central electrode by a hyper-logarithmic field having a potential distribution of the form:

where: r and z are cylindrical coordinate, z=0 being the plane of symmetry of the field; C, k, R m(>0) are constants, and k>0 for positive ions.
26. The method of claim 24 or claim 25, further comprising compensating the field within the orbitrap so as to minimise field perturbation within a volume occupied by the sample ions therein.
27. The method of claim 26, in which the field is compensated by applying a time dependent voltage to a field compensator in the orbitrap.
28. The method of any preceding claim, further comprising determining the optimum duration of trapping within the said storage device.
29. The method of any preceding claim, further comprising filtering out a proportion of the sample ions prior to their introduction into the storage device, in accordance with their m/z ratio.
30. A mass spectrometer comprising:
(a) an ion source arranged to supply a plurality of sample ions to be analysed, each of which has a mass-to-charge ratio m/z;
(b) an ion storage device comprising a plurality of storage device poles and having a storage device entrance end through which the said sample ions are received and a storage device exit end through which the said sample ions may exit;
(c) a voltage source arranged to supply a trapping voltage to the storage device poles so as to contain at least a proportion of the sample ions received through the storage device entrance end of the storage device within a volume .rho. of the storage device in a trapping mode during at least a part of a trapping period, the thus trapped ions each having a kinetic energy E k such that there is an average kinetic energy ~k of the ions in the volume .rho. during the trapping period or the said part thereof, and to supply a release voltage to the storage device in an ion ejection mode so as to controllably release at least some of the said sample ions contained within the said volume .rho. of the storage device through the storage device exit end, the release voltage being of a magnitude such that the potential difference then experienced by the ions across the volume .rho. is greater than the said average kinetic energy ~k during the trapping period or said part thereof, and further wherein the release voltage is such that the electric field generated thereby at any first point across the volume .rho., upon application of the said release voltage, is no more than 50% greater or smaller than the electric field generated thereby at any other second point across the volume .rho.; and (d) an electrostatic trap having an electrostatic trap entrance arranged to receive those ions released through the storage device exit end and meeting the criteria imposed by the applied trapping and release potentials, as a convolution of bunched time of flight distributions for each m/z, each distribution having a full width at half maximum (FWHM); the electrostatic trap further comprising a plurality of electrodes arranged to trap ions received through the electrostatic trap entrance therebetween so that the said trapped ions describe movement having periodic oscillations in at least one direction.
31. The mass spectrometer of claim 30, in which the storage device poles are each segmented into two or more axially separate segments, the voltage source being arranged to supply a differential DC voltage between a one of the axially separated segments and the other or another of the axially separated segments.
32. The mass spectrometer of claim 31, in which the segments of the storage device poles are radially spaced from one another to define a trapping volume including the volume of therebetween, the axial length of the segment of each end pole most adjacent to the storage device exit being no greater than twice the inscribed diameter defined by the radial spacing of those end pole segments.
33. The mass spectrometer of claim 32, in which the storage device further comprises an end cap defining therein a storage device exit, the axial distance between the end cap and a point mid-way along the end pole segments being no less than the said inscribed diameter.
34. The mass spectrometer of any of claims 30 to 33, further comprising a lens arrangement between the storage device exit and the electrostatic trap entrance, the lens arrangement being arranged to deflect the path of ions between the storage device and electrostatic trap such that they do not travel along a direct line of sight between the interior of the said storage device and the interior of the said electrostatic trap.
35. The mass spectrometer of claim 34, in which the lens arrangement is arranged to focus the ions into the electrostatic trap at an angle tangential to a central plane thereof.
36. The mass spectrometer of any of claims 30 to 35, in which the electrostatic trap is an orbitrap comprising a first, central electrode and a second, outer electrode, the second, outer electrode being split into two sections, the mass spectrometer further comprising means for detecting ions constrained within the orbitrap.
37. The mass spectrometer of claim 36, in which the voltage source is further arranged to supply a potential to the said central electrode, the mass spectrometer further comprising a voltage supply controller which is arranged to control the ramping of the potential on the central electrode in the electrostatic trap so that it occurs over a period of time which encompasses the duration of application of the release voltage to the storage device to cause the said controlled ejection of ions therefrom.
38. The mass spectrometer of claim 37, in which the voltage supply controller is arranged to apply the said release voltage to the storage device so that the ions arrive at the electrostatic trap whilst the potential on the central electrode is between (D1/D2)1/2 V and V, where V is the final static voltage applied to the central electrode, D1, is the outer diameter of that central electrode, and D2 is the inner diameter thereof.
39. The mass spectrometer of any of claims 30 to 38, further comprising field compensation means, the voltage supply being further arranged to supply a compensation voltage to the field compensation means so as to minimize field perturbation within the electrostatic trap.
40. The mass spectrometer of any of claims 30 to 39 further comprising a collision surface located downstream of the electrostatic trap, the ions exiting the storage device being focussed in time of flight onto the said collision surface so as to generate fragment ions for capture by the electrostatic trap.
41. The mass spectrometer of any of claims 30 to 40, further comprising ion cooling means arranged upstream of the said storage device.
42. The mass spectrometer of any of claims 30 to 41, further comprising a mass filter arranged upstream of the said storage device.
43. The mass spectrometer of claim 30, in which the storage device is arranged to receive ions substantially along a first longitudinal axis, and to release the said ions along a second, substantially orthogonal axis.
44. The mass spectrometer of claim 43, in which the storage device is curved.
45. The mass spectrometer of any one of claims 30 to 44, further comprising an ion deflector downstream of the storage device.
46. The mass spectrometer of any one of claims 30 to 45, further comprising an ion energy booster upstream of the electrostatic trap.
CA2689084A 2001-03-23 2002-03-20 Mass spectrometry method and apparatus Expired - Lifetime CA2689084C (en)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
GB0107380A GB0107380D0 (en) 2001-03-23 2001-03-23 Mass spectrometry method and apparatus
GB0107380.8 2001-03-23
GB0126764.0 2001-11-07
GB0126764A GB2378312B (en) 2001-03-23 2001-11-07 Mass spectrometry method and apparatus
CA2441589A CA2441589C (en) 2001-03-23 2002-03-20 Mass spectrometry method and apparatus

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
CA2441589A Division CA2441589C (en) 2001-03-23 2002-03-20 Mass spectrometry method and apparatus

Publications (2)

Publication Number Publication Date
CA2689084A1 true CA2689084A1 (en) 2002-10-03
CA2689084C CA2689084C (en) 2012-05-15

Family

ID=9911464

Family Applications (4)

Application Number Title Priority Date Filing Date
CA2689091A Expired - Lifetime CA2689091C (en) 2001-03-23 2002-03-20 Mass spectrometry method and apparatus
CA2689094A Expired - Lifetime CA2689094C (en) 2001-03-23 2002-03-20 Mass spectrometry method and apparatus
CA2689088A Expired - Lifetime CA2689088C (en) 2001-03-23 2002-03-20 Mass spectrometry method and apparatus
CA2689084A Expired - Lifetime CA2689084C (en) 2001-03-23 2002-03-20 Mass spectrometry method and apparatus

Family Applications Before (3)

Application Number Title Priority Date Filing Date
CA2689091A Expired - Lifetime CA2689091C (en) 2001-03-23 2002-03-20 Mass spectrometry method and apparatus
CA2689094A Expired - Lifetime CA2689094C (en) 2001-03-23 2002-03-20 Mass spectrometry method and apparatus
CA2689088A Expired - Lifetime CA2689088C (en) 2001-03-23 2002-03-20 Mass spectrometry method and apparatus

Country Status (2)

Country Link
CA (4) CA2689091C (en)
GB (2) GB0107380D0 (en)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2402260B (en) 2003-05-30 2006-05-24 Thermo Finnigan Llc All mass MS/MS method and apparatus
US7385187B2 (en) 2003-06-21 2008-06-10 Leco Corporation Multi-reflecting time-of-flight mass spectrometer and method of use
US7026613B2 (en) 2004-01-23 2006-04-11 Thermo Finnigan Llc Confining positive and negative ions with fast oscillating electric potentials
DE102004014582B4 (en) 2004-03-25 2009-08-20 Bruker Daltonik Gmbh Ion optical phase volume compression
GB2415541B (en) * 2004-06-21 2009-09-23 Thermo Finnigan Llc RF power supply for a mass spectrometer
DE102007017236B4 (en) 2007-04-12 2011-03-31 Bruker Daltonik Gmbh Introduction of ions into a magnetic field
DE102009020886B4 (en) * 2009-05-12 2012-08-30 Bruker Daltonik Gmbh Storing ions in Kíngdon ion traps
GB2476844B (en) 2010-05-24 2011-12-07 Fasmatech Science And Technology Llc Improvements relating to the control of ions
EP3879559A1 (en) * 2020-03-10 2021-09-15 Thermo Fisher Scientific (Bremen) GmbH Method for determining a parameter to perform a mass analysis of sample ions with an ion trapping mass analyser

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5179278A (en) * 1991-08-23 1993-01-12 Mds Health Group Limited Multipole inlet system for ion traps
US5572022A (en) * 1995-03-03 1996-11-05 Finnigan Corporation Method and apparatus of increasing dynamic range and sensitivity of a mass spectrometer
GB9506695D0 (en) * 1995-03-31 1995-05-24 Hd Technologies Limited Improvements in or relating to a mass spectrometer
US5569917A (en) * 1995-05-19 1996-10-29 Varian Associates, Inc. Apparatus for and method of forming a parallel ion beam

Also Published As

Publication number Publication date
CA2689091A1 (en) 2002-10-03
GB0107380D0 (en) 2001-05-16
CA2689088C (en) 2012-11-27
CA2689094A1 (en) 2002-10-03
GB2378312A (en) 2003-02-05
GB2378312B (en) 2005-01-12
CA2689084C (en) 2012-05-15
CA2689091C (en) 2012-05-15
CA2689088A1 (en) 2002-10-03
GB0126764D0 (en) 2002-01-02
CA2689094C (en) 2012-05-15

Similar Documents

Publication Publication Date Title
CA2441589A1 (en) Mass spectrometry method and apparatus
KR101957808B1 (en) First and second order focusing using field free regions in time­of­flight
CN111742390B (en) charge detection mass spectrometry
JP2005500646A5 (en)
US7459679B2 (en) Method and apparatus for mass selective axial transport using pulsed axial field
US9064679B2 (en) High duty cycle ion spectrometer
EP3239705B1 (en) Ion storage for a mobility separator of a mass spectrometric system
US7858929B2 (en) Ion energy spread reduction for mass spectrometer
CN112514029A (en) Multi-pass mass spectrometer with high duty cycle
US20090272895A1 (en) Mass spectrometer with ion storage device
US8461521B2 (en) Linear time-of-flight mass spectrometry with simultaneous space and velocity focusing
US8981287B2 (en) Ion analysis apparatus and method
CA2689084A1 (en) Mass spectrometry method and apparatus
US9214321B2 (en) Methods and systems for applying end cap DC bias in ion traps
US8093555B2 (en) Mass spectrometer
CN110828286B (en) Quantitative flux enhancement by differential mobility based pre-separation
US11515138B2 (en) Ion trapping scheme with improved mass range
JP2005019209A (en) Flight time type mass spectrometry device
US20210313164A1 (en) Pulsed accelerator for time of flight mass spectrometers
JP2000268771A (en) Vertical acceleration and flying-time mass spectrometer

Legal Events

Date Code Title Description
EEER Examination request
MKEX Expiry

Effective date: 20220321