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CN-122029637-A - Time-of-flight mass spectrometer

CN122029637ACN 122029637 ACN122029637 ACN 122029637ACN-122029637-A

Abstract

In one aspect, a time-of-flight (TOF) mass analyzer is disclosed that includes an inlet for receiving ions, a first ion acceleration region in which at least a portion of the received ions are accelerated to a first energy, a first field-free ion drift region positioned downstream of the first ion acceleration region for receiving the accelerated ions, a second ion acceleration region positioned downstream of the first field-free ion drift region for receiving ions exiting the first field-free ion drift region and accelerating ions to a second energy, a second field-free ion drift region positioned downstream of the second ion acceleration region for receiving ions exiting the second ion acceleration region, and an ion detector for receiving ions passing through the second field-free ion drift region and generating ion detection data. The ion detection data may be analyzed to generate a mass spectrum of the detected ions.

Inventors

  • Robert Hofler
  • Aaron Boi

Assignees

  • DH科技发展私人贸易有限公司

Dates

Publication Date
20260512
Application Date
20241015
Priority Date
20231016

Claims (20)

  1. 1.A time of flight (TOF) mass analyzer, comprising: an inlet for receiving ions and a device for receiving ions, A first ion acceleration region in which at least a portion of ions received are accelerated to a first energy, A first field-free ion drift region positioned downstream of the first ion acceleration region for receiving the accelerated ions, A second ion acceleration region positioned downstream of the first field-free ion drift region for receiving ions exiting the first field-free ion drift region and accelerating the ions to a second energy, A second field-free ion drift region positioned downstream of the second ion acceleration region for receiving the ions exiting the second ion acceleration region, and An ion detector for receiving ions passing through the second field-free ion drift region and generating ion detection data.
  2. 2. The TOF mass analyzer of claim 1, further comprising a first pair of electrodes across which a first voltage difference (V1) is applied to generate an electric field (E1) in the first ion acceleration region.
  3. 3. The TOF mass analyzer according to claim 2, further comprising a second pair of electrodes across which a second voltage difference (V3) is applied to generate an electric field (E3) in the second ion acceleration region.
  4. 4. A TOF mass analyser according to claim 3 wherein the first and second voltage differences applied across the first and second pairs of electrodes result in an electric field approaching zero in the first field-free ion drift region.
  5. 5. The TOF mass analyzer according to any one of claims 1 to 4, wherein said TOF mass analyzer exhibits a mass resolution of at least 3000, and wherein optionally said mass resolution is in the range of about 3000 to about 20000.
  6. 6. The TOF mass analyser of any one of claims 1 to 4, wherein the length of the mass analyser is equal to or less than about 2 meters, and wherein optionally the length is in the range of about 200 mm to about 2 meters.
  7. 7. The TOF mass analyser according to claim 2, wherein the first voltage difference (V1) is in the range of about 500 volts to about 3000 volts.
  8. 8. The TOF mass analyzer of claim 6, wherein the first acceleration region has a length (d 1) such that the voltage difference (V1) generates an electric field in the first ion acceleration region in the range of about 10V/mm to about 250V/mm.
  9. 9. A TOF mass analyser according to claim 3, wherein the second voltage difference (V3) is in the range of about 1000 volts to about 20000 volts.
  10. 10. The TOF mass analyzer of claim 7, wherein the second ion acceleration region has a length (d 2) such that the second voltage difference (V3) generates an electric field in the range of about 100V/mm to 850V/mm.
  11. 11. A TOF mass analyser according to claim 3 further comprising at least one voltage source for applying any one of the first and second voltage differences to the first and second pairs of electrodes, respectively.
  12. 12. The TOF mass analyzer of claim 11, wherein said at least one voltage source is configured to apply said first voltage as a plurality of temporally separated voltage pulses.
  13. 13. The TOF mass analyzer of claim 12, wherein said at least one voltage source is configured to apply said voltage pulses at a frequency in the range of about 1000 Hz to about 200 kHz, and wherein optionally said frequency is greater than about 20 kHz, or greater than about 50 kHz, or greater than about 75 kHz.
  14. 14. A TOF mass analyser according to claim 3, wherein the length (d 2) of the first field-free ion drift region and the length (d 4) of the second field-free ion drift region simultaneously satisfy the following relationship: And Wherein, the D1 represents the effective length of the first ion acceleration region, D2 denotes the effective length of the first field-free ion drift region, D3 denotes the effective length of the second ion acceleration region, D4 denotes the effective length of the second field-free ion drift region, V1 represents the voltage across the first ion acceleration region, and V3 represents the voltage across the second ion acceleration region, an Wherein, the D2 and d4 have real numbers (not imaginary numbers) and positive values.
  15. 15. The TOF mass analyzer of claim 1, wherein said first ion acceleration has a length in the range of about 2mm to 25 mm, said first field-free ion drift region has a length in the range of about 0.5 mm to 20 mm, said second ion acceleration region has a length in the range of about 2mm to 100mm, and said second field-free ion drift region has a length in the range of about 200 mm to 2 meters.
  16. 16. A linear time of flight (TOF) mass analyzer comprising: an inlet for receiving ions and a device for receiving ions, At least two of the ion acceleration regions, At least two field-free ion drift regions, and The ion detector is configured to detect the ions, Wherein one of the field-free ion drift regions is positioned between the two acceleration regions and the other of the field-free ion drift regions is positioned between one of the acceleration regions and the ion detector.
  17. 17. The linear TOF mass analyzer of claim 16, wherein said TOF mass analyzer provides a mass resolution of at least 3000.
  18. 18. The linear TOF mass analyzer of any of claims 16 and 17, wherein the field-free region positioned between one of the ion acceleration regions and the ion detector has a length equal to or less than 2 meters, and wherein optionally a combined length associated with the at least two ion acceleration regions and the at least two field-free ion drift regions is equal to or less than about 2 meters, and wherein optionally the combined length is in the range of about 200 mm to about 2 meters.
  19. 19. The linear TOF mass analyzer of claim 16, further comprising a first pair of electrodes and a second pair of electrodes, a first differential voltage being applicable across said first pair of electrodes to generate one of said at least two ion acceleration regions, and a second differential voltage being applicable across said second pair of electrodes to generate the other of said at least two ion acceleration regions.
  20. 20. A mass spectrometer, comprising: a mass filter for receiving a plurality of ions and allowing ions having an m/z ratio within its bandpass window to pass, An ion dissociation device for receiving the ions passing through the mass filter and dissociating at least a portion thereof to generate a plurality of product ions, A linear time of flight (TOF) mass analyzer positioned downstream of the ion dissociation device for receiving the product ions and having an ion detector for detecting at least a portion of the product ions to generate ion detection data, Wherein the TOF mass analyser comprises: A first ion acceleration region and a second ion acceleration region, A first field-free ion drift region and a second field-free ion drift region, Wherein the first field-free ion drift region is positioned between the first ion acceleration region and the second ion acceleration region, and the second field-free ion drift region is positioned between a detector of the TOF mass analyzer and the second ion acceleration region.

Description

Time-of-flight mass spectrometer RELATED APPLICATIONS The present application claims priority from U.S. provisional application No. 63/590,600 entitled "Time of FLIGHT MASS Spectrometer," filed on 10/16 of 2023, the contents of which are incorporated herein by reference in their entirety. Technical Field The present disclosure relates generally to systems and methods for performing mass spectrometry, and more particularly to such systems and methods utilizing a time-of-flight (ToF) mass analyzer. Background The present disclosure provides systems and methods for performing mass spectrometry, and in particular, such systems and methods that allow for faster data acquisition with sufficient mass resolution. Mass Spectrometry (MS) is an analytical technique used to determine the structure of a test chemical as well as both qualitative and quantitative applications. MS can be used to identify unknown compounds, determine the composition of atomic elements in a molecule, determine the structure of a compound by observing its fragmentation, and quantify the amount of a particular chemical compound in a mixed sample. Mass spectrometers detect chemical entities as ions so that conversion of analytes to charged ions must occur. Time-of-flight mass spectrometry relies on different detection times to separate ions with different m/z ratios. In such systems, the mass analyser accelerates ions via the ions through a region in which an electric field imparts kinetic energy to the ions. The accelerated ions enter a field-free ion drift region where they travel to an ion detector that detects the ions. The time required for ions to reach the detector through the drift region depends on their m/z ratio, allowing separation of ions based on their m/z ratio. The longer the ions need to pass through the drift region to reach the ion detector, the higher the resolution of the mass measurement. However, the longer time for each measurement means that fewer mass spectra are obtained per unit time, e.g., fewer mass spectra per second. In other words, higher mass resolution results in a lower duty cycle. Disclosure of Invention In one aspect, a time-of-flight (TOF) mass analyzer is disclosed that includes an inlet for receiving ions, a first ion acceleration region in which at least a portion of the received ions are accelerated to a first energy, a first field-free ion drift region positioned downstream of the first ion acceleration region for receiving the accelerated ions, a second ion acceleration region positioned downstream of the first field-free ion drift region for receiving ions exiting the first field-free ion drift region and accelerating ions to a second energy, a second field-free ion drift region positioned downstream of the second ion acceleration region for receiving ions exiting the first field-free ion drift region and accelerating ions to a second energy, and an ion detector for receiving ions passing through the second field-free ion drift region and generating ion detection data. The TOF mass analyzer may include a first pair of electrodes across which a first voltage difference (V1) is applied to generate an electric field (E1) in a first ion acceleration region. Further, the TOF mass analyzer may include a second pair of electrodes across which a second voltage difference (V3) is applied to generate an electric field (E2) in a second ion acceleration region. Further, voltages applied to at least one of the first pair of electrodes and at least one of the second pair of electrodes are selected to result in an electric field approaching zero in the first field-free ion drift region. In other words, there is no electric field in the first field-free ion drift region. Similarly, there is no electric field in the second field-free ion drift region. In some embodiments, the electric field may be present in either of the first and second field-free ion drift regions, but at such a low level that it does not cause any substantial change in the trajectories of ions passing through those field-free ion drift regions. For example, in various embodiments, the magnitude of such an electric field may be less than about 10V/mm. In some embodiments, the TOF mass analyzer exhibits a mass resolution of at least about 3000. By way of example, TOF mass analyzers may exhibit mass resolutions in the range of about 3000 to about 20000. In some embodiments, the first voltage difference (V1) may be in a range of about 500 volts to about 3000 volts. Further, the second voltage difference (V3) may be in a range of about 100 volts to about 20 kilovolts. In some embodiments, the mass analyzer may have an effective length equal to or less than about 2 meters. By way of example, the effective length of the mass analyzer may be in the range of about 200 mm to about 2 meters. In some embodiments, the first acceleration region may have an effective length (d 1) such that the first voltage difference (V1) generates an electric field in the fi