Ion mobility analyzer, combination device thereof, and ion mobility analysis method

Patent metadata

Field	Value
Publication number	US-9429543-B2
Application number	US-201514735876-A
Country	US
Kind code	B2
Filing date	Jun 10, 2015
Priority date	Dec 10, 2012
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

An ion mobility analyzer, combination device thereof, and ion mobility analysis method. The ion mobility analyzer comprises an electrode system that surrounds the analytical space and a power device that attaches to the electrode system an ion mobility electric potential field that moves along one space axis. During the process of analyzing mobility of ions to be measured, by always placing the ions to be measured in the moving ion mobility electric potential field, and keeping the movement direction of the ion mobility electric potential field consistent with the direction of the electric field on the ions to be measured within the ion mobility electric potential field, theoretically a mobility path of an infinite length can be formed so as to distinguish ions having mobility or ion cross sections that have very small differences.

First claim

What is claimed is:

1. An ion mobility analyzer, comprising:
an electrode system around an analytical space; and
a first power supply adapted to apply voltages to the electrode system for forming a moving drift electric field in at least a portion of the analytical space along an axis, such that specific analyte ions are always in and have the same moving direction as that of the drift electric field during ion mobility analysis, wherein radio frequency voltages for radial ion confinement are not applied for at least one portion of the analysis time in order to avoid damage on resolution of ion mobility separation through heating by the radio frequency voltages.

2. The ion mobility analyzer according to claim 1 , further comprising a group of ion confining electrodes and a second electric power supply for applying voltage(s) to the ion confining electrodes to restrict the ion motion in at least one direction substantially perpendicular to the axis.

3. The ion mobility analyzer according to claim 1 , wherein the axis is a curved axis.

4. The ion mobility analyzer according to claim 3 , wherein the curved axis includes at least one enclosed part.

5. The ion mobility analyzer according to claim 3 , further comprising a third electric power supply for applying different voltages to the ion confining electrodes in order to split the axis of ion trajectories during a specific period of the analysis time.

6. The ion mobility analyzer according to claim 1 , wherein the moving speed of the moving drift electric field generated by the first power supply keeps same as the balanced drift speed of at least one specific ion species in the moving drift electric field.

7. The ion mobility analyzer according to claim 2 , wherein the moving speed of the moving drift electric field keeps same as the balanced drift speed of at least one specified ion species in the moving drift electric field, wherein the trajectory of the ion species is restricted in the analytical space.

8. The ion mobility analyzer according to claim 1 , wherein the strength of the moving drift electric field changes along the axis.

9. The ion mobility analyzer according to claim 8 , wherein there are at least two ion species with different mobility drifting at different positions of the axis, wherein the balanced drifting speed of the ion species are the same as the moving speed of the moving drift electric field.

10. The ion mobility analyzer according to claim 9 , wherein the gradient of the drift electric field gradually decreases in the drift direction of a specific ion specie with certain polarity.

11. The ion mobility analyzer according to claim 2 , wherein the voltage applied to the ion confining electrodes changes periodically along the axis.

12. The ion mobility analyzer according to claim 2 , wherein the second power supply generates AC voltage with frequency from 10 Hz to 10 MHz.

13. The ion mobility analyzer according to claim 1 , wherein the first power supply is a digital switching power supply switching output between at least two voltage levels and having frequency from 1 to 10 MHz.

14. The ion mobility analyzer according to claim 13 , wherein the drift electric field is formed by applying waveforms with at least two different duty cycle ratios switching between high and low voltage level.

15. The ion mobility analyzer according to claim 1 further comprising a upstream and/or downstream ion analyzer of mass-to-charge ratio tandem to the ion mobility analyzer to form an ion mobility—mass spectrometer tandem analytical device for improving the capability of analyzing complex analyte samples.

16. The ion mobility analyzer according to claim 15 further comprising an ion guiding device between the ion mobility analyzer and the ion analyzer of mass-to-charge ratio for keeping the region of different pressure away from the ion mobility analyzer.

17. The ion source for the ion mobility analyzer according to claim 1 , which stabilizes the performance of the ion mobility analyzer with at least one of the following methods,
(a) operated at the similar pressure range as that of the ion mobility analyzer;
(b) Inserted with an ion guiding device between the ion mobility analyzer and ion analyzer of mass-to-charge ratio to keep the region of different pressure and gas flow turbulence away from the ion mobility analyzer.

18. A method of ion mobility analysis comprising the following operation steps: injecting ions with at least one mobility into the ion mobility analyzer continuously or discontinuously, accumulating said ions with specific mobility at the corresponding positions in the analysis regions for a period of time, ejecting the ions while they arrive at a specified position, and then detecting the ions.

19. A method of ion mobility analysis comprising the following operation steps: injecting ions with at least one mobility into the ion mobility analyzer according to claim 1 , removing chemical noises from matrix ions while establishing the drift electric filed in the ion mobility analyzer with at least one of the following methods:
(a) eliminating the matrix ions through destabilizing their axial motion while they move with the moving drift electric field; and
(b) ejecting the matrix ions radially by applying additional radial deflection or excitation AC electric field in the rest of the moving drift electric field region.

20. The ion mobility analyzer according to claim 1 for simultaneously analyzing positive and negative ions, wherein a voltage gradient distribution with its polarity varying alternatively is built in the moving drift electric field along its moving direction, which makes the positive and negative ions with specific mobility confined in the regions in which the voltage gradient direction is same with or opposite to the direction of the moving drift electric field, wherein the positive and negative ions are separately analyzed based on ion mobility.

21. A method of extracting analyte ions from the ion mobility analyzer according to claim 1 , comprising the following operation steps: applying a high radial deflection field on at least one part of the ion confining electrodes and extracting the mobility separated ions radially with high speed, while they move to the corresponding positions of the said ion confining electrodes.

22. A method of extracting analyte ions from the ion mobility analyzer according to claim 1 , comprising the following operation steps: applying a high radial deflection field or AC excitation field on at least one part or all of the ion confining electrodes, extracting the ions of different mobility radially at their corresponding moving position and detecting them or their fragments by a position sensitive detector to form an ion mobility spectrum or tandem ion mobility-mass spectrum, wherein the position sensitive detector is at least one of the following ones:
(a) single position sensitive detector with large area;
(b) an array of ion detectors;
(c) an array of mass analyzers.

23. A chromatography analysis method using the ion mobility analyzer according to claim 1 , wherein the ion mobility analyzer is used as the subsequent detector of chromatography analyzer.

24. A mass analysis method using the ion mobility analyzer according to claim 1 , wherein the ion mobility analyzer is used as a tandem analyzer of at least a kind of mass analyzers.

25. The ion mobility analyzer according to claim 1 , wherein during a diffe

Assignees

• Shimadzu Corp

Inventors

• Jiang Gongyu
• Cheng Yupeng
• Zhang Xiaoqiang
• Sun Wenjian

Classifications

• G01N27/624

  Differential mobility spectrometry [DMS]; Field asymmetric-waveform ion mobility spectrometry [FAIMS] · CPC title

• H01J49/004

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

• G01N27/622 Primary

  Ion mobility spectrometry · CPC title

• H01J49/22

  Electrostatic deflection · CPC title

• G01N27/623 Primary

  combined with mass spectrometry · CPC title