Ion source for mass spectrometry

Patent metadata

Field	Value
Publication number	US-9711338-B2
Application number	US-201113819084-A
Country	US
Kind code	B2
Filing date	Sep 1, 2011
Priority date	Sep 1, 2010
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

Systems and methods for delivering a sample to a mass spectrometer are provided. In one aspect, the system can include a sample source for generating a sample plume entrained in a primary gas stream in a first flow direction at a first flow rate, and a gas source for generating a secondary gas stream along a second flow direction different from the first flow direction and at a second flow rate greater than the first flow rate. The sample source and the gas source can be positioned relative to one another such that the primary gas stream intersects the secondary gas stream so as to generate a resultant gas stream propagating along a trajectory different from said first and second direction to bring the sample to proximity of a sampling orifice of the mass spectrometer.

First claim

The invention claimed is:

1. A system for directing a sample to a mass spectrometer comprising:
a sample source for generating an electrically neutral sample plume having a zero net velocity that is less than 1 cm/s,
a venturi chamber in fluid communication with a sampling orifice of said mass spectrometer, said venturi chamber having an inlet port and an outlet port,
said sample source being positioned relative to said inlet port of the venturi chamber so as to deposit the sample plume in proximity of said inlet port of the venturi chamber, and
a gas source arranged to generate a gas flow in a direction so as to pass in proximity of said outlet port of the venturi chamber so as to cause a lowering of pressure within the venturi chamber, thereby drawing at least a portion of the sample plume through said inlet port into the venturi chamber such that at least a portion of the sample plume drawn into the chamber enters said sampling orifice.

2. The system of claim 1 , wherein said gas flow has a flow rate in a range of about 0.2 L/min to about 20 L/min, and wherein said gas flow has an average flow velocity in a range of about 1 m/s to about 330 m/s.

3. A system for directing a sample to a mass spectrometer, comprising
a sample source housing defining a source chamber, the source chamber configured to be in fluid communication with a sampling orifice of a mass spectrometer,
a sample source for generating an electrically neutral sample plume having zero net velocity that is less than 1 cm/s along any particular direction, and
a gas source for generating a steering gas flow in a first flow direction at a first flow rate such that the gas interacts with the sample plume to confine the sample plume, and
a secondary gas source for generating a heated secondary gas flow along a second flow direction different from said first flow direction and at a second flow rate greater than said first flow rate,
wherein said steering gas source and said secondary gas source are positioned relative to one another such that said steering gas flow intersects said secondary gas flow so as to generate a resultant gas flow propagating with a shape and along a trajectory defined to balance the exposure of the sample plume to the secondary gas flow with dispersion of the sample plume in the resultant gas flow;
wherein a minimum distance between an outlet port of the sample source and a longitudinal axis of said mass spectrometer is in a range of about 3 mm to about 50 mm, wherein a minimum distance between a longitudinal axis of the sample source and the sampling orifice is about 3 mm to about 8 mm, wherein a minimum distance between an output port of the secondary gas source and a putative plane orthogonal to a longitudinal axis of the mass spectrometer and containing the sampling orifice is in a range of about 10 mm to about 80 mm, and wherein a minimum distance between a longitudinal axis of the secondary gas source and said sampling orifice is in a range of about 0 mm to about 40 mm.

4. The system of claim 3 , wherein said steering gas flow is directed substantially orthogonal to a longitudinal axis of the mass spectrometer.

5. The system of claim 4 , wherein said resultant gas flow is directed across the sampling orifice.

6. The system of claim 3 , wherein said sample source is configured to generate said sample plume via any one of a mechanical, an electromechanical, or a thermal evaporation mechanism.

7. The system of claim 6 , wherein said sample source comprises any of a piezoelectric and a thermal nebulizer.

8. The system of claim 3 , further comprising a pair of electrodes adjacent the sampling orifice, said pair of electrodes being configured to charge at least a portion of electrically neutral species contained in the portion of the sample plume that enters the sampling orifice.

9. The system of claim 3 , wherein the sampling orifice is positioned on a longitudinal axis of said mass spectrometer.

10. The system of claim 3 , wherein said secondary gas flow rate is at least about 5 times greater than said steering gas flow rate.

11. The system of claim 3 , wherein said steering gas stream exits the sample source at a first average velocity and said secondary gas stream exits said gas source at a second average velocity, wherein said first average velocity is greater than said second average velocity.

12. The system of claim 11 wherein said first average velocity is at least about 8 times greater than said second average velocity.

13. The system of claim 3 , wherein said resultant gas flow has a flow rate in a range of about 1 L/min to about 29 L/min.

Assignees

• Covey Thomas R
• Kovarik Peter
• Dh Technologies Dev Pte Ltd

Inventors

• Covey Thomas R
• Kovarik Peter

Classifications

• H01J49/04 Primary

  Arrangements for introducing or extracting samples to be analysed, e.g. vacuum locks; Arrangements for external adjustment of electron- or ion-optical components · CPC title

• H01J49/0422 Primary

  for gaseous samples (interfaces to gas chromatographs G01N30/7206) · CPC title