Ion traps that apply an inverse Mathieu q scan

Patent metadata

Field	Value
Publication number	US-10622202-B2
Application number	US-201715789688-A
Country	US
Kind code	B2
Filing date	Oct 20, 2017
Priority date	Oct 21, 2016
Publication date	Apr 14, 2020
Grant date	Apr 14, 2020

Abstract

The invention generally relates to ion traps that operate by applying an inverse Mathieu q scan. In certain embodiments, the invention provides systems that include a mass spectrometer having an ion trap and a central processing unit (CPU). The CPU includes storage coupled to the CPU for storing instructions that when executed by the CPU cause the system to apply an inverse Mathieu q scan to the ion trap.

First claim

What is claimed:

1. A system, the system comprising:
a mass spectrometer comprising an ion trap; 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 an inverse Mathieu q scan to the ion trap,
wherein the instructions that when executed by the CPU further cause the system to: apply a constant radio frequency (RF) signal to the ion trap and vary a frequency of the AC signal as a function of time, wherein the frequency of the AC signal is swept nonlinearly while the RF signal is held constant for an entire scan cycle such that a plurality of ejected ions have a mass to charge ratio proportional to an ejection time, wherein the ejection time is of a plurality of ejected ions.

2. The system according to claim 1 , wherein the inverse Mathieu q scan comprises nonlinearly applying an alternating current (AC) signal to the ion trap that varies as a function of time.

3. The system according to claim 1 , wherein the AC signal is in resonance with a secular frequency of ions of different mass-to-charge ratios trapped within the ion trap.

4. The system according to claim 1 , wherein the ion trap is selected from the group consisting of: a hyperbolic ion trap, a cylindrical ion trap, a linear ion trap, a rectilinear ion trap.

5. The system according to claim 1 , wherein the mass spectrometer is a miniature mass spectrometer.

6. The system according to claim 1 , further comprising an ionization source.

7. A method for operating an ion trap of a mass spectrometer, the method comprising apply an inverse Mathieu q scan to the ion trap, wherein applying the inverse Mathieu q scan comprises applying the inverse Mathieu q scan further comprises applying a constant radio frequency (RF) signal to the ion trap and nonlinearly applying an alternating current (AC) signal to the ion trap that varies as a function of time, wherein a frequency of the AC signal varies as a function of time, wherein the frequency of the AC signal is swept nonlinearly while the RF signal is held constant for an entire scan cycle such that a plurality of ejected ions have a mass to charge ratio proportional to an ejection time, wherein the ejection time is of a plurality of ejected ions.

8. The method according to claim 7 , wherein the AC signal is in resonance with a secular frequency of ions od different mass-to-charge ratios trapped within the ion trap.

9. The method according to claim 7 , wherein applying the inverse Mathieu q scan extends a mass range of the mass spectrometer without instrumental modification.

10. The method according to claim 7 , wherein the inverse Mathieu q scan is applied in a manner that excites a precursor ion while a second AC signal ejects a product ion from the ion trap.

11. The method according to claim 10 , wherein both the excitation of the precursor ion and the ejection of the product ion occur simultaneously.

12. The method according to claim 7 , wherein the method further comprises ejecting one or more target ions at a target mass-to-charge ratio from the ion trap while non-target ions at a higher or lower mass-to-charge ratio remain in the ion trap.

13. The method according to claim 7 , wherein the method further comprises simultaneously monitoring multiple ions.

14. The method according to claim 7 , wherein the method further comprises simultaneously monitoring multiple precursor ion to product ion transitions.

15. The method according to claim 7 , wherein the inverse Mathieu q scan is applied in a manner that ion injection, ion cooling, and mass scanning occur in a single step.

16. A system, the system comprising:
a mass spectrometer comprising an ion trap; 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 an inverse Mathieu q scan to the ion trap,
wherein the instructions that when executed by the CPU further cause the system to: apply a constant radio frequency (RF) signal to the ion trap and vary a frequency of the AC signal, wherein the frequency of the AC signal is swept nonlinearly while the RF signal is held constant for an entire scan cycle such that a plurality of ejected ions have a mass to charge ratio proportional to an ejection time, wherein the ejection time is of a plurality of ejected ions.

Assignees

• Purdue Research Foundation

Inventors

• Cooks Robert Graham
• Snyder Dalton

Classifications

• H01J49/0013

  Miniaturised spectrometers, e.g. having smaller than usual scale, integrated conventional components · CPC title

• H01J49/0031

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

• H01J49/429 Primary

  Scanning an electric parameter, e.g. voltage amplitude or frequency · CPC title

• H01J49/422 Primary

  Two-dimensional RF ion traps (ion guides without mass selection H01J49/062) · CPC title