Compact mass spectrometer

Patent metadata

Field	Value
Publication number	US-9530631-B2
Application number	US-201414892360-A
Country	US
Kind code	B2
Filing date	May 29, 2014
Priority date	May 31, 2013
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

A miniature mass spectrometer is disclosed comprising an atmospheric pressure ionisation 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 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 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 miniature 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 ion detector located in said third vacuum chamber;
a first RF ion guide located within said first vacuum chamber;
a second RF ion guide located within said second 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;
wherein the mass spectrometer further comprises:
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;
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; and
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.

2. A miniature 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 a fourth vacuum chamber located downstream of said third vacuum chamber;
an ion detector located in said fourth vacuum chamber;
a first RF ion guide located within said first vacuum chamber;
a second RF ion guide located within said second 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;
wherein the mass spectrometer further comprises:
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;
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; and
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.

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

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

5. A miniature 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.

6. A miniature mass spectrometer as claimed in claim 1 , wherein said atmospheric pressure sampling orifice or capillary has a diameter ≦0.3 mm.

7. A miniature mass spectrometer as claimed in claim 1 , further comprising a differential pumping aperture or orifice between said first vacuum chamber and said second vacuum chamber;
wherein said differential pumping aperture or orifice between said first vacuum chamber and said second vacuum chamber has a diameter ≦1.5 mm.

8. A miniature 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.

9. A miniature mass spectrometer as claimed in claim 1 , further comprising a differential pumping aperture or orifice between said second vacuum chamber and said third vacuum chamber;
wherein said differential pumping aperture or orifice between said second vacuum chamber and said third vacuum chamber has a diameter ≦2.0 mm.

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

11. A miniature 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;
wherein said second vacuum pump comprises a split flow turbomolecular vacuum pump; and
wherein said first vacuum pump is arranged and adapted to act as a backing vacuum pump to said second vacuum pump.

12. A miniature mass spectrometer as claimed in claim 11 , 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.

13. A miniature mass spectrometer as claimed in claim 1 , further comprising a second vacuum pump arranged and adapted to pump said second vacuum chamber;
wherein said second vacuum pump comprises a first turbomolecular vacuum pump.

14. A miniature mass spectrometer as claimed claim 13 , further comprising a third vacuum pump arranged and adapted to pump said third vacuum chamber;
wherein said third vacuum pump comprises a second turbomolecular vacuum pump; and
wherein said first vacuum pump is arranged and adapted to act as a backing vacuum pump to said second vacuum pump and/or said third vacuum pump.

15. A method of mass spectrometry comprising:
providing a miniature 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, an ion detector located in said third vacuum chamber, a first RF ion guide located within said first vacuum chamber, a second RF ion guide located within said second 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 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;
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;
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.

16. A method of mass spectrometry comprising:
providing a miniature 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, a fourth vacuum chamber located downstream of said third vacuum chamber, an ion detector located in said fourth vacuum chamber, a first RF ion guide located within said first vacuum chamber, a second RF ion guide located within said second

Assignees

• Micromass Ltd

Inventors

• Gordon David
• Kenny Daniel James

Classifications

• H01J49/10

  Ion sources; Ion guns · CPC title

• H01J49/40

  Time-of-flight spectrometers (H01J49/36 takes precedence) · CPC title

• H01J49/062

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

• H01J49/0013 Primary

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

• H01J49/24

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