Two-dimensional mass spectrometry using ion micropacket detection

Patent metadata

Field	Value
Publication number	US-11804370-B2
Application number	US-201916972099-A
Country	US
Kind code	B2
Filing date	May 23, 2019
Priority date	Jun 4, 2018
Publication date	Oct 31, 2023
Grant date	Oct 31, 2023

Abstract

The invention generally relates to two-dimensional mass spectrometry using ion micropacket detection. In certain aspects, the invention provides systems including a mass spectrometer having an ion trap and one or more detectors. The system includes a central processing unit (CPU), and storage coupled to the CPU for storing instructions that when executed by the CPU cause the system to: apply one or more scan functions to the ion trap that excite a precursor ion and eject a product ion from the ion trap; and determine a secular frequency of the product ion by detecting micropackets of the product ion as the micropackets are ejected from the ion trap.

First claim

What is claimed is:

1. A system comprising:
a mass spectrometer comprising an ion trap and one or more detectors; and
a central processing unit (CPU), and storage coupled to the CPU for storing instructions that when executed by the CPU cause the system to:
apply one or more scan functions to the ion trap that excite a precursor ion and eject a product ion from the ion trap; and
determine a secular frequency of the product ion or a harmonic thereof by detecting micropackets of the product ion as the micropackets are ejected from the ion trap.

2. The system of claim 1 , wherein the one or more scan functions are applied in a manner that precursor and product ions are correlated without isolation of the precursor ions.

3. The system of claim 1 , wherein the one or more scan functions that excite the precursor ion comprise a nonlinear frequency sweep at a constant rf voltage or the one or more scan functions that excite the precursor ion comprise a fixed frequency excitation while the rf amplitude is ramped linearly.

4. The system of claim 3 , wherein the one or more scan functions that eject a product ion from the ion trap comprise a broadband waveform.

5. The system of claim 1 , wherein a fast Fourier transform of a mass spectral peak recovers the secular frequency of the product ion or a harmonic thereof.

6. The system of claim 1 , wherein the system comprises two detectors and a fast Fourier transform of a mass spectral peak recovers twice the secular frequency of the product ion.

7. The system of claim 1 , wherein a rate of appearance of the micropackets at the one or more detectors corresponds to an excitation frequency of the product ion.

8. The system of claim 1 , wherein the instructions that when executed by the CPU cause the system to eject the micropackets at regularly spaced intervals.

9. The system of claim 1 , wherein the ion trap is pressurized with helium, nitrogen, carbon dioxide, or air.

10. The system of claim 1 , wherein the ion trap is a quadrupole ion trap and excitation and ejection signals can be on a same pair of quadrupole electrodes or on orthogonal electrode pairs.

11. The system of claim 1 , further comprising an ionization source.

12. The system of claim 1 , wherein dissociation of the precursor ion is caused by a technique selected from the group consisting of: collision-induced dissociation, surface-induced dissociation, infrared multiphoton dissociation, ultraviolet photodissociation, electron capture dissociation, and electron transfer dissociation.

13. A method for operating a mass spectrometer, the method comprising:
applying one or more scan functions to an ion trap of a mass spectrometer that excite a precursor ion and eject a product ion from the ion trap; and
determining a secular frequency of the product ion by detecting micropackets of the product ion as the micropackets are ejected from the ion trap.

14. The method of claim 13 , wherein the one or more scan functions are applied in a manner that precursor and product ions are correlated without isolation of the precursor ions.

15. The method of claim 13 , wherein the one or more scan functions that excite the precursor ion comprise a nonlinear frequency sweep at a constant rf voltage or the one or more scan functions that excite the precursor ion comprise a fixed frequency excitation while the rf amplitude is ramped linearly.

16. The method of claim 15 , wherein the one or more scan functions that eject a product ion from the ion trap comprise a broadband waveform.

17. The method of claim 13 , wherein a fast Fourier transform of a mass spectral peak recovers the secular frequency of the product ion or a harmonic thereof.

18. The method of claim 13 , wherein the determining step utilizes two detectors and a fast Fourier transform of a mass spectral peak recovers twice the secular frequency of the product ion.

19. The method of claim 13 , wherein a rate of appearance of the micropackets at the one or more detectors corresponds to an excitation frequency of the product ion.

20. The method of claim 13 , wherein the micropackets are ejected at regularly spaced intervals.

Assignees

• Purdue Research Foundation

Inventors

• Cooks Robert Graham
• Snyder Dalton
• Szalwinski Lucas

Classifications

• H01J49/004 Primary

  Combinations of spectrometers, tandem spectrometers, e.g. MS/MS, MSn · CPC title

• H01J49/0031

  Step by step routines describing the use of the apparatus (H01J49/0081 takes precedence) · CPC title

• H01J49/0081

  Tandem in time, i.e. using a single spectrometer · CPC title

• H01J49/427

  Ejection and selection methods · CPC title