EP0982757A1 - Trägergas-Separator für Massenspektrometrie - Google Patents

Trägergas-Separator für Massenspektrometrie Download PDF

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Publication number
EP0982757A1
EP0982757A1 EP98116015A EP98116015A EP0982757A1 EP 0982757 A1 EP0982757 A1 EP 0982757A1 EP 98116015 A EP98116015 A EP 98116015A EP 98116015 A EP98116015 A EP 98116015A EP 0982757 A1 EP0982757 A1 EP 0982757A1
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EP
European Patent Office
Prior art keywords
ions
ion beam
field
ion
mass
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.)
Withdrawn
Application number
EP98116015A
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English (en)
French (fr)
Inventor
Dar Bahatt
David G. Welkie
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.)
Applied Biosystems Inc
Original Assignee
Perkin Elmer Corp
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 Perkin Elmer Corp filed Critical Perkin Elmer Corp
Priority to JP10238790A priority Critical patent/JP2000067807A/ja
Priority to EP98116015A priority patent/EP0982757A1/de
Publication of EP0982757A1 publication Critical patent/EP0982757A1/de
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/02—Details
    • H01J49/04—Arrangements for introducing or extracting samples to be analysed, e.g. vacuum locks; Arrangements for external adjustment of electron- or ion-optical components

Definitions

  • This invention generally relates to a mass spectrometer with an ion source, where the ion source is producing an ion beam containing both carrier ions and analyte ions.
  • This invention specifically comprises a separation system for removing the carrier ions from the ion beam.
  • a gas chromatography-mass spectroscopy (GC-MS) instrument gas chromatography is usually performed first and the resulting gas stream is then introduced into the mass spectrometer.
  • both the carrier gas used during gas chromatography and the analytes become ionized and are directed as an ion beam into the mass spectrometer detector.
  • the carrier gas concentration is orders of magnitude greater than the analytes.
  • the carrier gas ion concentration in the ion beam is many times more intense than the analyte ions.
  • the divergent beam may cause signal loss during detection if some of the beam falls outside the detector entrance.
  • Another adverse consequence of the high carrier ion concentration is detector distortion or saturation. If the concentration causes the detector to exceed its linear range, its output will be distorted and the system may report erroneous results. In the event that the detector becomes saturated, those erroneous results will continue until the detector overcomes any inherent hysteresis.
  • One solution has been to gate the detector off during the arrival of the carrier gas ions, but this has the disadvantage of burdening the system with additional circuitry.
  • Another solution has been to include an electrostatic deflection gate in the flight region that is activated during the passage of carrier ions, thereby preventing them from reaching the detector. This solution requires additional circuitry, additional mechanisms, precise timing and critical placement in the flight region.
  • the present invention is based on the realization that it would be more advantageous to remove the carrier gas ions from the beam as soon as possible after the ion source, in order to prevent space charge effects and to minimize detector saturation problems. It is the object of this invention to provide for the removal of carrier ions from the ion beam after the ion source but before entering the mass spectrometer detector. In accordance with the invention this is achieved by applying a magnetic or electrostatic field to the ion beam soon after it emerges from the ion source which causes the constituents of the ion beam to disperse according to their mass to charge ratios.
  • the amount of dispersion is related to the individual ion's mass charge ratio and the strength of the applied magnetic or electrostatic field, the location of ions in the plane perpendicular to the ion stream can be accurately predicted. A mechanical stop can then be placed to block ions from the stream as desired.
  • FIG. 1 shows a schematic of a mass spectrometer utilizing the invention.
  • Carrier gas containing analytes is introduced into the mass spectrometer through a sample inlet 10 . From there it travels into the ion source 20 where the gas stream is ionized.
  • the resulting ion stream 30 may be subjected to optionally either electrostatic or magnetic fields in a first region 40 .
  • the ion stream then passes through a separator 50 in accordance with the present invention and specific ions are blocked from the stream.
  • the ion stream may again be optionally subjected to additional electrostatic or magnetic fields in a second region 60 and is then directed into a mass analyzer 70 .
  • a typical mass analyzer might consist of a quadrapole, ion trap, or time of flight system including a detector.
  • a vacuum system 80 keeps the main components of the mass spectrometer at negative pressure.
  • Figure 2 shows a diagram of the first field according to the invention, in this embodiment a magnetic field.
  • the ion stream 30 is previously accelerated and collimated so that the ions are brought to a homogeneous potential of 300 eV and the stream is approximately 1mm wide.
  • the carrier gas might be helium, hydrogen or nitrogen or any other typical GC carrier gas.
  • the beam is then subjected to a first magnetic field 90 approximately 6 mm long along its axis of travel, having a strength and polarity of +4400 gauss, applied perpendicular to the beam.
  • the ions disperse, following circular paths defined by the following equation:
  • helium ions in the stream with a mass of 4 follow a path having a 29 mm radius
  • hydrogen ions with a mass of 2 follow a 20 mm radius
  • nitrogen ions with a mass of 28 follow a 76 mm radius.
  • a magnetic field width of 6 mm at approximately 25 mm past the magnetic field, helium diverges approximately 6.5 mm to follow path 100 from the beam, hydrogen approximately 9.3 mm to follow path 120 and nitrogen approximately 2.4 mm to follow path 130 .
  • a physical stop 140 is constructed and placed to block particular ions and remove them from the stream.
  • the stop is positioned anywhere along the beam as long as the beam has diverged enough so the stop blocks those particular ions and effectively removes them from the stream.
  • Figure 3 shows an embodiment where a second magnetic field 150 of equal magnitude, reverse polarity and double the length of magnetic field 90 in the direction of ion travel is then applied to the stream causing it to reconverge.
  • the stream is then subjected to a third magnetic field 160 having the same magnitude and polarity as the first, in order to re-collimate and direct the beam.
  • Figure 4 shows an embodiment using two magnetic fields of opposite polarity.
  • the ion stream 30 is accelerated and collimated so that the ions are brought to a homogeneous potential of 300 eV and the stream is approximately 1mm wide.
  • the first magnetic field 90 is applied, causing the ions to disperse according to Equation 2.
  • the physical stop 140 is positioned to block the ions of interest and subsequently a second magnetic field 150 is applied, causing the beam to reconverge. Because there is no third magnetic field, the beam will converge in an area 170 and then begin to disperse, however, the detector can be located effectively in the region 180 around the convergence point where the beam is condensed enough to meet detection requirements.
  • the actual strengths and lengths of the magnetic fields in the embodiments of figures 2, 3 and 4 may vary according to the dispersion and reconvergence required in order to achieve acceptable detection and the available area in which to achieve separation.
  • the angle at which the magnetic fields are applied with respect to the direction of the ion stream and the beam energy also may vary depending on the desired location of the stop.
  • x o L(tan A) where L is the length the ion has traveled along the ion beam's axis of travel after the magnetic field, and
  • A is the angle of deflection from the beam outside the field
  • the tangent of the angle of deflection outside the field is determined by v x /v where v x is the velocity attained by the ion in the direction of the electrostatic field and v is the initial velocity in the direction of travel.
  • Figure 5 shows an embodiment where three electrostatic fields are applied to the stream.
  • the ion stream 30 is previously accelerated and collimated so that the ions are brought to a homogeneous velocity and the stream is approximately 1mm wide.
  • the beam is then subjected to a first electrostatic field 190 along its axis of travel, applied perpendicular to the beam. Calculations similar to those performed for the magnetic field example above are performed using equation 8 to determine the deflection for specific ions and the ideal location for the stop.
  • the physical stop 140 is constructed and placed to block particular ions and remove them from the stream. As stated previously, the stop is positioned anywhere along the beam as long as the beam has diverged enough so the stop blocks those particular ions and effectively removes them from the stream.
  • a second electrostatic field 200 of equal magnitude, reverse polarity and double the length of electrostatic field 190 in the direction of ion travel is then applied to the stream causing it to reconverge.
  • the stream is then subjected to a third electrostatic field 210 having the same magnitude and polarity as the first, in order to re-collimate and direct the beam.
  • Figure 6 shows an embodiment using only two electrostatic fields of opposite polarity.
  • the ion stream 30 is accelerated and collimated so that the ions are brought to a homogeneous velocity and the stream is approximately 1mm wide.
  • the first electrostatic field 190 is applied, causing the ions to disperse according to Equation 8.
  • the physical stop 140 is positioned to block the ions of interest and subsequently a second electrostatic field 150 is applied, causing the beam to reconverge. Because there is no third electrostatic field, the beam will converge in an area 170 and then begin to disperse, however, the detector can be located effectively in the region 180 around the convergence point where the beam is condensed enough to meet detection requirements.
  • the actual strengths and lengths of the electrostatic fields in the embodiments of figures 5 and 6 may vary according to the dispersion and reconvergence required in order to achieve acceptable detection and the available area in which to achieve separation.
  • the angle at which the electrostatic fields are applied with respect to the direction of the ion stream and the beam energy also may vary depending on the desired location of the stop.

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  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
  • Electron Tubes For Measurement (AREA)
EP98116015A 1998-08-25 1998-08-25 Trägergas-Separator für Massenspektrometrie Withdrawn EP0982757A1 (de)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP10238790A JP2000067807A (ja) 1998-08-25 1998-08-25 イオンビームからイオンを分離するための方法及び装置
EP98116015A EP0982757A1 (de) 1998-08-25 1998-08-25 Trägergas-Separator für Massenspektrometrie

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP10238790A JP2000067807A (ja) 1998-08-25 1998-08-25 イオンビームからイオンを分離するための方法及び装置
EP98116015A EP0982757A1 (de) 1998-08-25 1998-08-25 Trägergas-Separator für Massenspektrometrie

Publications (1)

Publication Number Publication Date
EP0982757A1 true EP0982757A1 (de) 2000-03-01

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP98116015A Withdrawn EP0982757A1 (de) 1998-08-25 1998-08-25 Trägergas-Separator für Massenspektrometrie

Country Status (2)

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EP (1) EP0982757A1 (de)
JP (1) JP2000067807A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2404080A (en) * 2003-06-26 2005-01-19 Jeol Ltd Time-of-flight mass spectrometer
CN102714127A (zh) * 2010-02-22 2012-10-03 爱利卡技术有限公司 质谱仪和离子分离和检测的方法
WO2019195896A1 (en) * 2018-04-13 2019-10-17 ETP Ion Detect Pty Ltd Sample analysis apparatus having improved input optics and component arrangement

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4645424B2 (ja) * 2005-11-24 2011-03-09 株式会社島津製作所 飛行時間型質量分析装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3641339A (en) * 1968-07-05 1972-02-08 Atomic Energy Authority Uk Gas chromatography- mass spectrometry
US4047030A (en) * 1974-09-30 1977-09-06 Balzers Patent-Und Beteiligungs-Aktiengesellschaft Arrangement for the mass-spectrometric detection of ions
US4066895A (en) * 1975-09-12 1978-01-03 Shimadzu Seisakusho Ltd. Scanning mass spectrometer having constant magnetic field
US4649316A (en) * 1982-09-17 1987-03-10 Dubilier Scientific Limited Ion beam species filter and blanker
US5534699A (en) * 1995-07-26 1996-07-09 National Electrostatics Corp. Device for separating and recombining charged particle beams
US5767512A (en) * 1996-01-05 1998-06-16 Battelle Memorial Institute Method for reduction of selected ion intensities in confined ion beams

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3641339A (en) * 1968-07-05 1972-02-08 Atomic Energy Authority Uk Gas chromatography- mass spectrometry
US4047030A (en) * 1974-09-30 1977-09-06 Balzers Patent-Und Beteiligungs-Aktiengesellschaft Arrangement for the mass-spectrometric detection of ions
US4066895A (en) * 1975-09-12 1978-01-03 Shimadzu Seisakusho Ltd. Scanning mass spectrometer having constant magnetic field
US4649316A (en) * 1982-09-17 1987-03-10 Dubilier Scientific Limited Ion beam species filter and blanker
US5534699A (en) * 1995-07-26 1996-07-09 National Electrostatics Corp. Device for separating and recombining charged particle beams
US5767512A (en) * 1996-01-05 1998-06-16 Battelle Memorial Institute Method for reduction of selected ion intensities in confined ion beams

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
REINSFELDER R. E. AND DENTON M. B.: "Theory and characterizationnof a separator analyzer mass spectrometer", INT. J. MASS SPECTROM. ION PHYS., vol. 37, no. 2, February 1981 (1981-02-01), netherlands, pages 241 - 250, XP002093208 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2404080A (en) * 2003-06-26 2005-01-19 Jeol Ltd Time-of-flight mass spectrometer
GB2404080B (en) * 2003-06-26 2006-03-22 Jeol Ltd Time-of-flight mass spectrometer
CN102714127A (zh) * 2010-02-22 2012-10-03 爱利卡技术有限公司 质谱仪和离子分离和检测的方法
CN102714127B (zh) * 2010-02-22 2015-11-25 爱利卡技术有限公司 质谱仪和离子分离和检测的方法
WO2019195896A1 (en) * 2018-04-13 2019-10-17 ETP Ion Detect Pty Ltd Sample analysis apparatus having improved input optics and component arrangement
CN112106171A (zh) * 2018-04-13 2020-12-18 艾德特斯解决方案有限公司 具有改进的输入光学器件和组件布置的样品分析设备

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