Compact mass spectrometer

Patent metadata

Field	Value
Publication number	US-10755906-B2
Application number	US-201916238072-A
Country	US
Kind code	B2
Filing date	Jan 2, 2019
Priority date	May 31, 2013
Publication date	Aug 25, 2020
Grant date	Aug 25, 2020

Abstract

A miniature mass spectrometer is disclosed comprising an atmospheric pressure ionization source and a first vacuum chamber having an atmospheric pressure sampling orifice or capillary, a second vacuum chamber located downstream of the first vacuum chamber and a third vacuum chamber located downstream of the second vacuum chamber. An ion detector is located in the third vacuum chamber. A first RF ion guide is located within the first vacuum chamber and a second RF ion guide is located within the second vacuum chamber. The ion path length from the atmospheric pressure sampling orifice or capillary to an ion detecting surface of the ion detector is ≤400 mm. The mass spectrometer further comprises a tandem quadrupole mass analyzer, a 3D ion trap mass analyzer, a 2D or linear ion trap mass analyzer, a Time of Flight mass analyzer, a quadrupole-Time of Flight mass analyzer or an electrostatic mass analyzer arranged in the third vacuum chamber. The product of the pressure P 1 in the vicinity of the first RF ion guide and the length L 1 of the first RF ion guide is in the range 10-100 mbar-cm and the product of the pressure P 2 in the vicinity of the second RF ion guide and the length L 2 of the second RF ion guide is in the range 0.05-0.3 mbar-cm.

First claim

The invention claimed is:

1. A mass spectrometer comprising:
an atmospheric pressure ionisation source;
a first vacuum chamber having an atmospheric pressure sampling orifice or capillary, a second vacuum chamber located downstream of said first vacuum chamber and a third vacuum chamber located downstream of said second vacuum chamber;
a first RF ion guide located within said first vacuum chamber;
a first vacuum pump arranged and adapted to pump said first vacuum chamber; and
an ion detector located in said third vacuum chamber;
wherein the product of the pressure P 1 in the vicinity of said first RF ion guide and said length L 1 of said first RF ion guide is in the range 10-100 mbar-cm;
wherein said first vacuum pump has a maxum pumping speed ≤10 m 3 /hr (2.78 L/s); and
wherein the ion path length from said atmospheric pressure sampling orifice or capillary to an ion detecting surface of said ion detector is ≤400 mm.

2. A mass spectrometer comprising:
an atmospheric pressure ionization source;
a first vacuum chamber having atmospheric pressure sampling orifice or capillary, a second vacuum chamber located downstream of said first vacuum chamber and a third vacuum chamber located downstream of said second vacuum chamber;
a first RF ion guid located within said first vacuum chamber, wherein the product of the pressure P 1 in the vicinity of said first RF ion guide and said length L 1 of said first RF ion guide is in the range 10-100 mbar-cm;
a second RF ion guide located within said second vacuum chamber, wherein the product of the pressure P 2 in the vicinity of said second RF ion guide and said length L 2 of said second RF ion guide is in the range 0.05-0.3 mbar-cm; and
an ion detector located in said third vacuum chamber, wherein the ion path length from said atmospheric pressure sampling orifice or capillary to an ion detecting surface of said ion detector is <400 mm.

3. A mass spectrometer comprising:
an atmospheric pressure ionisation source;
a first vacuum chamber having an atmospheric pressure sampling orifice or capillary, a second vacuum chamber located downstream of said first vacuum chamber and a third vacuum chamber located downstream of said second vacuum chamber;
an RF ion guide located within said second vacuum chamber; and
and ion detector located in said third vacuum chamber;
wherein the product of the pressure P 2 in the vicinity of said RF ion guide and said length L 2 of said RF ion guide is in the range 0.05-0.3 mbar-cm;
wherein the product of the pressure P 1 in the said first vacuum chamber and the length L 1 of said first vacuum chamber is in the range 10-100 mbar-cm; and
wherein the ion path length from said atmospheric pressure sampling orifice or capillary to an ion detecting surface of said ion detector is <400 mm.

4. A mass spectrometer as claimed in claim 1 , further comprising a fourth vacuum chamber located downstream of said third vacuum chamber.

5. A mass spectrometer as claimed in claim 1 , further comprising a tandem quadrupole mass analyser, a 3D ion trap mass analyser, a 2D or linear ion trap mass analyser, a Time of Flight mass analyser, a quadrupole-Time of Flight mass analyser or an electrostatic mass analyser arranged in said third vacuum chamber and/or said fourth vacuum chamber.

6. A mass spectrometer as claimed in claim 1 , wherein a quadrupole mass filter is arranged in said third vacuum chamber.

7. A mass spectrometer as claimed in claim 1 , further comprising one or more collision, fragmentation or reaction cells arranged in said second, third and/or fourth vacuum chamber.

8. A mass spectrometer as claimed in claim 1 , wherein said first vacuum pump comprises a rotary vane vacuum pump or a diaphragm vacuum pump.

9. A mass spectrometer as claimed in claim 1 , wherein said first vacuum pump is arranged and adapted to maintain said first vacuum chamber at a pressure <10 mbar.

10. A mass spectrometer as claimed in claim 1 , wherein said first RF ion guide and/or said second RF ion guide comprise a dual conjoined stacked ring ion guide, a multipole ion guide, a stacked ring ion guide or an ion funnel ion guide.

11. A mass spectrometer as claimed in claim 1 , wherein said first RF ion guide and/or said second RF ion guide has a length <100 mm.

12. A mass spectrometer as claimed in claim 1 , wherein said second vacuum chamber is arranged to be maintained at a pressure in the range 0.001-0.1 mbar.

13. A mass spectrometer as claimed in claim 1 , wherein said third vacuum chamber is arranged to be maintained at a pressure <0.0003 mbar.

14. A mass spectrometer as claimed in claim 1 , further comprising a second vacuum pump arranged and adapted to pump said second vacuum chamber and said third vacuum chamber.

15. A mass spectrometer as claimed in claim 14 , wherein said second vacuum pump comprises a split flow turbomolecular vacuum pump.

16. A mass spectrometer as claimed in claim 14 , wherein said first vacuum pump is arranged and adapted to act as a backing vacuum pump to said second vacuum pump.

17. A mass spectrometer as claimed in claim 14 , wherein said second vacuum pump comprises an intermediate or interstage port connected to said second vacuum chamber and a high vacuum (“HV”) port connected to said third vacuum chamber.

18. A method of mass spectrometry comprising:
providing a mass spectrometer comprising an atmospheric pressure ionisation source, a first vacuum chamber having an atmospheric pressure sampling orifice or capillary, a second vacuum chamber located downstream of said first vacuum chamber, a third vacuum chamber located downstream of said second vacuum chamber, and an ion detector located in said third vacuum chamber, wherein the ion path length from said atmospheric pressure sampling orifice or capillary to an ion detecting surface of said ion detector is <400 mm;
providing a first RF ion guide located within said first vacuum chamber, maintaining the product of the pressure P 1 in the vicinity of said first RF ion guide and said length L 1 of said first RF ion guide in the range 10-100 mbar-cm, and passing analyte ions through said first RF ion guide; and/or
providing a second RF ion guide located within said second vacuum chamber, maintaining the product of the pressure P 2 in the vicinity of the second RF ion guide and the length L 2 of the second RF ion guide in the range 0.05-0.3 mbar-cm, and passing analyte ions through said second RF ion guide.

19. A mass spectrometer as claimed in claim 17 , wherein said second vacuum pump is arranged to pump said second vacuum chamber via said intermediate or interstage port at a maximum pumping speed <70 L/s.

20. A mass spectrometer as claimed in claims 17 , wherein said second vacuum pump is arranged to pump said third vacuum chamber via said high vacuum port at a maximum pumping speed in the range 40-80 L/s.

21. A mass spectrometer as claimed in claim 1 , wherein the total internal volume of said first, second and third vacuum chambers is <2000 cm 3 .

Assignees

• Micromass Ltd

Inventors

• Gordon David
• Kenny Daniel James

Classifications

• H01J49/062

  Ion guides (linear ion traps performing mass selection H01J49/4225, mass filters H01J49/421) · CPC title

• H01J49/24

  Vacuum systems, e.g. maintaining desired pressures · CPC title

• H01J49/0031

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

• H01J49/0013 Primary

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

• H01J49/145

  using chemical ionisation · CPC title