Ion transfer method and device

• US 10,236,168 B1
• Filed: 11/21/2017
• Issued: 03/19/2019
• Est. Priority Date: 11/21/2017
• Status: Active Grant

• Current Assignee: Thermo Finnigan LLC (Thermo Fisher Scientific Incorporated)
• Original Assignee: Thermo Finnigan LLC (Thermo Fisher Scientific Incorporated)
• Inventors: Kovtoun, Viatcheslav V.
• Primary Examiner(s): Ippolito, Nicole M
• Application Number:
  US15/820,267
• Time in Patent Office: 483 Days
• Field of Search: 250281, 250282, 250283
• CPC Class Codes: H01J 49/0031 Step by step routines describing the use of the apparatus H01J49/0081 takes precedence
• CPC Class Codes: H01J 49/0404 Capillaries used for transferring samples or ions electrospray nozzles H01J49/167
• CPC Class Codes: H01J 49/0468 with means for heating or cooling the sample
• CPC Class Codes: H01J 49/0481 with means for collisional cooling
• CPC Class Codes: H01J 49/065 having stacked electrodes, e.g. ring stack, plate stack

Abstract

An ion transport device of a mass spectrometer includes a plurality of pole rod arranged in first and second parallel rows and a controller. The controller is configured to apply voltages in a repeating voltage pattern to the pole rods of the first row and apply a common voltage to the pole rods of the second row thereby creating a plurality of potential wells capable of capturing ions, wherein each ion transport cell receives the same pattern of voltages; move the repeating voltage pattern along the pole rods of the first row to move captured ions within and between the plurality of ion transport cells along the ion transport device; and apply at least one ejection voltage to one or more electrodes to cause ions to be ejected from the ion transport device.

Claims

1. An ion transport device of a mass spectrometer, comprising:

a plurality of pole rod arranged in first and second rows, the second row parallel to the first row, each pole rod of the first row forming a pole rod pair with a corresponding pole rod of the second row, the pole rod pairs defining a plurality of ion transport cells, each ion transport cell uniquely corresponding to a contiguous group of a fixed number of pole rod pairs, such that no two ion transport cells share a common pole rod pair; and

a controller configured to

apply voltages in a repeating voltage pattern to the pole rods of the first row and apply a common voltage to the pole rods of the second row thereby creating a plurality of potential wells capable of capturing ions, wherein each ion transport cell receives the same pattern of voltages;

move the repeating voltage pattern along the pole rods of the first row to move captured ions within and between the plurality of ion transport cells along the ion transport device; and

apply at least one ejection voltage to one or more electrodes to cause ions to be ejected from the ion transport device.

2. The ion transport device of claim 1, wherein the ions are ejected from the ion transport device in a direction parallel to the pole rods.

3. The ion transport device of claim 1, wherein the ions are ejected from the ion transport device in a direction of travel along the ion transport device.

4. The ion transport device of claim 1, wherein the controller is configured to apply at least one ejection voltage to one or more electrodes to generate a DC potential gradient that causes ions to be ejected from the ion transport device.

5. The ion transport device of claim 4, wherein adjacent pole rod pairs have opposite RF pole rod polarities.

6. The ion transport device of claim 1, wherein each pole rod pair includes a pole rod having a RF+ polarity and a pole rod having an RF−

pole rod polarity.

7. The ion transport device of claim 1, wherein the spacing between pole rods of a pole rod pair is greater than the spacing between pole rod pairs.

8. The ion transport device of claim 1, wherein the spacing between pole rod pairs is substantially equal along the length of the ion transport device.

9. The ion transport device of claim 1, wherein the spacing between pole rods of a pole rod pair is between two and four times greater than the spacing between pole rod pairs.

10. The ion transport device of claim 1, wherein the repeating voltage pattern is a stepped voltage pattern.

11. The ion transport device of claim 1, wherein the repeating voltage pattern is a pattern of continuously varying voltage levels.

12. The ion transport device of claim 11, wherein the pattern of continuously varying voltage levels is applied across three pole rod pairs and is defined by V1(t)=+V*cos(Pi/4−

ω

*t), V2(t)=−

V*cos(Pi/4−

ω

*t), V3(t)=+V*cos(Pi/4−

ω

*t).

13. The ion transport device of claim 11, wherein the pattern of continuously varying voltage levels is applied across four pole rod pairs and is defined by V1(t)=V*cos(ω

*t−

Pi/4), V2(t)=V*sin(ω

*t−

Pi/4), V3(t)=−

V*cos(ω

*t−

Pi/4), V4(t)=−

V*sin(ω

*t−

Pi/4).

14. The ion transport device of claim 11, wherein the pattern of continuously varying voltage levels is applied across five pole rod pairs and is defined by V1(t)=V*cos(ω

*t−

Pi/5), V2(t)=−

V*cos(ω

*t+(2/5)*Pi), V3(t)=−

V*cos(ω

*t), V4(t)=−

V*cos(ω

*t−

(2/5)*Pi), V5(t)=V*cos(ω

*t+Pi/5).

15. A mass spectrometer, comprising:

an ion source;

a plurality of pole rod arranged in first and second rows, the second row parallel to the first row, each pole rod of the first row forming a pole rod pair with a corresponding pole rod of the second row, the pole rod pairs defining a plurality of ion transport cells, each ion transport cell uniquely corresponding to a contiguous group of a fixed number of pole rod pairs, such that no two ion transport cells share a common pole rod pair;

one or more mass analyzers; and

a controller configured to

apply voltages in a repeating voltage pattern to the pole rods of the first row and a common voltage to the pole rods of the second row thereby creating a plurality of potential wells capable of capturing ions, wherein each ion transport cell receives the same pattern of voltages; and

move the repeating voltage pattern along the pole rods of the first row to move captured ions within and between the plurality of ion transport cells along the ion transport device.

16. The mass spectrometer of claim 15, wherein the ions are transported along the ion transport device in a direction perpendicular to the pole rods.

17. The mass spectrometer of claim 15, wherein the controller is configured to apply at least one ejection voltage to one or more electrodes to cause ions to be ejected from the ion transport device in a direction parallel to the pole rods.

18. The mass spectrometer of claim 17, wherein the pole rods are divided into a plurality of segments and the controller is configured to apply a DC potential gradient across the segmented rods to eject the ions from the ion transport device.

19. The mass spectrometer of claim 15, wherein the spacing between pole rods of a pole rod pair is greater than the spacing between pole rod pairs.

20. The mass spectrometer of claim 15, wherein the spacing between pole rods of a pole rod pair is reduced near the ion ejection point of ion transport device.

21. The mass spectrometer of claim 20, wherein the RF voltage is reduced near the ion ejection point of ion transport device.

22. The mass spectrometer of claim 15, wherein the spacing between pole rod pairs is substantially equal along the length of the ion transport device.

23. A method of transporting ions along an ion transport device, the ion transport device including a plurality of ion transport cells arranged in parallel, the ion transport cells including a contiguous group of a fixed number of pole rods arranged in parallel and in first and second rows of pole rods, each pole rod of the first row forming a pole rod pair with a corresponding pole rod of the second row, no two ion transport cells share a common pole rod pair, the plurality of ion transport cells including first and second ion transport cells, the method comprising:

applying an initial voltage pattern to the pole rods of the first row and a common voltage to the pole rods of the second row of the ion transport cells to create a plurality of potential wells within the ion transport cells, wherein each ion transport cell receives the same pattern of voltages;

injecting a first plurality of ions into the first ion transport cell traveling in a direction parallel to the primary axes of the pole rods and capturing the first plurality of ions in the potential well of the first ion transport cell;

altering the voltage pattern applied to the pole rods of the ion transport cells to move the potential well and the first plurality of ions to the second ion transport cell; and

injecting a second plurality of ions into the first ion transport cell traveling in a direction parallel to the primary axes of the pole rods and capturing the second plurality of ions in the potential well of the first ion transport cell when a first cycle of the altering the voltage pattern is complete.

24. An multi-layer ion transport device of a mass spectrometer, comprising:

a plurality of pole rod arranged in a rectangular grid having at least a first row, a second row, and a third row, the first, second, and third rows parallel to one another, each pole rod of the first row forming a pole rod pair with a corresponding pole rod of the second row and each pole rod of the third row forming a pole rod pair with a corresponding pole rod of the second row such that the pole rods of the second row are shared between a pole rod pair of the first row and a pole rod pair of the third row, the pole rod pairs defining a plurality of ion transport cells, each ion transport cell uniquely corresponding to a contiguous group of a fixed number of pole rod pairs from the same row such that no two ion transport cells share a common pole rod pair, pole rods of the second row are shared between the ion transport cells of the first row and ion transport cells of the third row; and

a controller configured to

apply a common voltage to the pole rods of the second row;

apply voltages in a repeating voltage pattern to the pole rods of the first row thereby creating a first plurality of potential wells capable of capturing ions, wherein each ion transport cell of the first row receives the same pattern of voltages;

apply voltages in a repeating voltage pattern to the pole rods of the third row thereby creating a second plurality of potential wells capable of capturing ions, wherein each ion transport cell of the third row receives the same pattern of voltages;

move the repeating voltage pattern along the pole rods of the first row to move captured ions within and between the plurality of ion transport cells of the first row along the ion transport device;

move the repeating voltage pattern along the pole rods of the third row to move captured ions within and between the plurality of ion transport cells of the third row along the ion transport device; and

apply at least one ejection voltage to one or more electrodes to cause ions to be ejected from the ion transport device.