Atmospheric pressure plasma mass spectrometer

• US 8,481,923 B1
• Filed: 06/29/2012
• Issued: 07/09/2013
• Est. Priority Date: 06/29/2012
• Status: Active Grant

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Kitamoto, Jun
• Primary Examiner(s): NGUYEN, KIET TUAN
• Application Number:
  US13/537,285
• Time in Patent Office: 375 Days
• Field of Search: 250/281, 250/289
• US Class Current: 250/281
• CPC Class Codes: B01D 59/44 Separation by mass spectrography particle spectrometers or separator tubes H01J49/00
• CPC Class Codes: F04D 19/04 specially adapted to the production of a high vacuum, e.g. molecular pumps
• CPC Class Codes: H01J 49/24 Vacuum systems, e.g. maintaining desired pressures

Abstract

A mass spectrometer includes first to fifth vacuum chambers and a single split-flow turbo molecular pump. The first vacuum chamber draws an ionized sample from atmospheric pressure plasma. The second vacuum chamber includes means for extracting and guiding an ion beam from ions from the first vacuum chamber. The third vacuum chamber includes first ion-optical separator means. The fourth vacuum includes a collision/reaction cell into which collision/reaction gas is introduced. The fifth vacuum chamber includes second ion-optical separator means and a detector. The split-flow turbo molecular pump has multiple inlets for differentially evacuating the second, third, fourth and fifth vacuum chambers. The fourth vacuum chamber is connected to an inlet of the split-flow turbo molecular pump providing a pressure higher than a pressure of an inlet of the split-flow turbo molecular pump to which the third vacuum chamber is connected.

Claims

1. A mass spectrometer, comprising:

a first vacuum chamber configured to draw an ionized sample from atmospheric pressure plasma;

a second vacuum chamber connected to the first vacuum chamber;

a third vacuum chamber connected to the second vacuum;

a fourth vacuum chamber connected to the third vacuum chamber;

a fifth vacuum chamber connected to the fourth vacuum chamber; and

a single split-flow turbo molecular pump having a plurality of inlets for differentially evacuating the second, third, fourth and fifth vacuum chambers,

wherein the fourth vacuum chamber is connected to an inlet of the split-flow pump providing a pressure higher than a pressure of an inlet of the split-flow pump to which the third vacuum chamber is connected.

2. The mass spectrometer of claim 1, wherein split-flow pump is a split-flow turbo molecular pump.

3. The mass spectrometer of claim 1, wherein the first vacuum chamber is evacuated by a rotary pump, and the split-flow pump is a split-flow molecular pump.

4. The mass spectrometer of claim 3, wherein the split-flow turbo molecular pump is backed by the rotary pump.

5. The mass spectrometer of claim 1, wherein the third vacuum chamber is evacuated to a pressure in a range of about 1×

10<sup>−

4</sup> Pa to about 2×

10<sup>−

2</sup> Pa.

6. The mass spectrometer of claim 5, wherein the fourth vacuum chamber is evacuated to a pressure in a range of about 1×

10<sup>−

3</sup> Pa to about 5×

10<sup>−

2</sup> Pa.

7. The mass spectrometer of claim 1, wherein the second vacuum chamber is connected to an inlet of the split-flow pump providing a lowest vacuum.

8. The mass spectrometer of claim 7, wherein the fifth vacuum chamber is connected to an inlet of the split-flow pump providing a highest vacuum.

9. The mass spectrometer of claim 1, wherein the third vacuum chamber and the fifth vacuum chamber are connected with each other.

10. The mass spectrometer of claim 1, wherein the split-flow pump comprises first to fourth inlets providing first to fourth vacuum levels, respectively, that decrease in order from the first inlet to the fourth inlet, and

wherein the first inlet is connected to the fifth vacuum chamber, the second inlet is connected to the third vacuum chamber, the third inlet is connected to the fourth vacuum chamber, and the fourth inlet is connected to the second vacuum chamber.

11. The mass spectrometer of claim 1, wherein the split-flow pump comprises first to third inlets providing first to third vacuum levels, respectively, that decrease in order from the first inlet to the third inlet, and

wherein the first inlet is connected to the third vacuum chamber, the second inlet is connected to the fourth vacuum chamber, and the third inlet is connected to the second vacuum chamber, and wherein the fifth vacuum chamber is connected to the third vacuum chamber via a conduit.

12. The mass spectrometer of claim 1, wherein the split-flow pump comprises first to third inlets providing first to third vacuum levels, respectively, that decrease in order from the first inlet to the third inlet, and

wherein the first inlet is connected to the third vacuum chamber and the fifth vacuum chamber via converging conduits, the second inlet is connected to the fourth vacuum chamber, and the third inlet is connected to the second vacuum chamber.

13. The mass spectrometer of claim 1, wherein the fourth vacuum chamber is connected to the corresponding inlet of the split-flow pump via a first conduit and the third vacuum chamber is connected to the corresponding inlet of the split-flow pump via a second conduit.

14. The mass spectrometer of claim 13, wherein each of the first and second conduits is a flexible tube.

15. The mass spectrometer of claim 13, wherein each of the first and second conduits is a groove formed in at least one of a housing of the vacuum chambers and a housing of the split-flow pump.

16. An atmospheric pressure plasma mass spectrometer comprising:

a vacuum chamber housing comprising, sequentially, first to fifth vacuum chambers, wherein the third vacuum chamber contains a first mass analyzer and the fourth vacuum chamber contains a collision/reaction cell;

a rotary pump for evacuating the first vacuum chamber; and

a single split-flow turbo molecular pump for differentially evacuating the second to fifth vacuum chambers,

wherein the fourth vacuum chamber is connected to an inlet of the single split-flow turbo molecular pump providing a vacuum lower than a vacuum provided by an inlet of the split-flow turbo molecular pump to which the third vacuum chamber is connected.

17. The mass spectrometer of claim 16, wherein the split-flow turbo molecular pump comprises first to fourth inlets providing first to fourth vacuum levels, respectively, that decrease in order from the first inlet to the fourth inlet, and

wherein the first inlet is connected to the fifth vacuum chamber, the second inlet is connected to the third vacuum chamber, the third inlet is connected to the fourth vacuum chamber, and the fourth inlet is connected to the second vacuum chamber.

18. The mass spectrometer of claim 16, wherein the split-flow turbo molecular pump comprises first to third inlets providing first to third vacuum levels, respectively, that decrease in order from the first inlet to the third inlet, and

wherein the first inlet is connected to the third vacuum chamber, the second inlet is connected to the fourth vacuum chamber, and the third inlet is connected to the second vacuum chamber, and wherein the fifth vacuum chamber is connected to the third vacuum chamber via a conduit.

19. The mass spectrometer of claim 16, wherein the split-flow turbo molecular pump comprises first to third inlets providing first to third vacuum levels, respectively, that decrease in order from the first inlet to the third inlet, and

wherein the first inlet is connected to the third vacuum chamber and the fifth vacuum chamber via converging conduits, the second inlet is connected to the fourth vacuum chamber, and the third inlet is connected to the second vacuum chamber.

20. A mass spectrometer, comprising:

a plurality of vacuum chambers arranged in series for receiving sample ions from atmospheric pressure plasma, wherein one vacuum chamber of the plurality of vacuum chambers includes a quadrupole mass filter and receives an ion beam of the sample ions from a previous vacuum chamber, and an adjacent vacuum chamber of the plurality of vacuum chambers, downstream from the one vacuum chamber, includes a collision reaction cell for introducing collision/reaction gas and receives the ion beam from the quadrupole mass filter of the one vacuum chamber; and

a single split-flow turbo molecular pump having a plurality of inlets for differentially evacuating the plurality of vacuum chambers, respectively,

wherein the one vacuum chamber is connected to one inlet of the split-flow turbo molecular pump providing a vacuum higher than a vacuum provided by another inlet of the split-flow turbo molecular pump to which the adjacent vacuum chamber is connected.