Efficient Atmospheric Pressure Interface for Mass Spectrometers and Method

• US 20090283674A1
• Filed: 08/02/2007
• Published: 11/19/2009
• Est. Priority Date: 11/07/2006
• Status: Abandoned Application

• Current Assignee: Thermo Fisher Scientific (Bremen) GmbH (Thermo Fisher Scientific Incorporated)
• Original Assignee: Thermo Fisher Scientific (Bremen) GmbH (Thermo Fisher Scientific Incorporated)
• Inventors: Pesch, Reinhold
• Application Number:
  US11/833,209
• Publication Number:
  US 20090283674A1
• Time in Patent Office: Days
• US Class Current: 250/288
• CPC Class Codes: H01J 3/14 Arrangements for focusing or reflecting ray or beam H01J3/02, H01J3/04 take precedence
• CPC Class Codes: H01J 49/062 Ion guides linear ion traps performing mass selection H01J49/4225, mass filters H01J49/421

Abstract

An interface for atmospheric pressure ionization sources has an ion transfer tube with a plurality of passageways through a sidewall such that background gas can be pumped away before it reaches an exit end of the ion transfer tube. A flow of the background gas out the exit end is reduced, and a proportion of laminar flow in the ion transfer tube may be increased. Pressure in the ion transfer tube is also reduced and desolvation is increased. In one embodiment, an enclosure surrounds an inner tube of the ion transfer tube within a first vacuum chamber such that the enclosure provides a reduced pressure region within the first vacuum chamber. Overall, transport efficiency is increased.

Claims

1. An interface for a mass spectrometer, comprising:

an ion transfer tube having an inlet end opening to an atmospheric pressure chamber, an outlet end opening to a low pressure chamber, and at least one sidewall surrounding an interior region through which is directed a flow of gas and ions, the sidewall extending along a central axis between the inlet end and the outlet end;

at least a portion of the sidewall being fabricated from a porous material to permit the flow of gas from the interior region through the sidewall to a reduced-pressure region exterior to the sidewall.

2. The interface of claim 1, wherein the atmospheric pressure chamber comprises an ion source chamber, and the low pressure chamber comprises a first vacuum chamber.

3. The interface of claim 2, wherein the ion source chamber is configured as an electrospray ionization source.

4. The interface of claim 2, wherein the ion source chamber is configured as a chemical ionization source.

5. The interface of claim 2, wherein the reduced-pressure region is located within an enclosure extending around the sidewall, the enclosure being disposed within the first vacuum chamber and communicating with a pump.

6. The interface of claim 1, further comprising a heater in thermal contact with the ion transfer tube.

7. The interface of claim 1, wherein the porous material is at least one of a a permeable ceramic, or a permeable polymer.

8. The interface of claim 1, wherein the porous material is a porous metal.

9. The interface of claim 1, further comprising a skimmer lens having an aperture positioned proximate to the outlet end.

10-17. -17. (canceled)