HIGH RESOLUTION SAMPLING SYSTEM FOR USE WITH SURFACE IONIZATION TECHNOLOGY

• US 20080067348A1
• Filed: 05/25/2007
• Published: 03/20/2008
• Est. Priority Date: 05/26/2006
• Status: Active Grant

• Current Assignee: Bruker Scientific LLC (Bruker Corporation)
• Original Assignee: IonSense, Inc. (Bruker Corporation)
• Inventors: Musselman, Brian D.
• Granted Patent: US 7,777,181 B2
• Time in Patent Office: Days
• US Class Current: 250/284
• CPC Class Codes: H01J 49/0404 Capillaries used for transferring samples or ions electrospray nozzles H01J49/167
• CPC Class Codes: H01J 49/0409 Sample holders or containers containers for retaining a material to be analyzed, B01L3/50, for DNA, C12Q1/6834, for biological materials, G01N33/543
• CPC Class Codes: H01J 49/0459 for solid samples
• CPC Class Codes: H01J 49/16 using surface ionisation, e.g. field-, thermionic- or photo-emission

Abstract

The present invention is a device to restrict the sampling of analyte ions and neutral molecules from surfaces with mass spectrometry and thereby sample from a defined area or volume. In various embodiments of the present invention, a tube is used to sample ions formed with a defined spatial resolution from desorption ionization at or near atmospheric pressures. In an embodiment of the present invention, electrostatic fields are used to direct ions to either individual tubes or a plurality of tubes positioned in close proximity to the surface of the sample being analyzed. In an embodiment of the present invention, wide diameter sampling tubes can be used in combination with a vacuum inlet to draw ions and neutrals into the spectrometer for analysis. In an embodiment of the present invention, wide diameter sampling tubes in combination with electrostatic fields improve the efficiency of ion collection.

Claims

1. A device for analyzing an analyte comprising:

a tube with a proximal end and a distal end, wherein the distal end of the tube transfers one or more analyte ions into a mass spectrometer;

a component for generating a plurality of ionizing species, wherein the plurality of ionizing species are directed at the proximal end of the tube; and

a permeable barrier positioned inside the tube, wherein the permeable barrier has been in contact with the analyte.

2. The device of claim 1, wherein:

the tube is made from one or more materials chosen from the group consisting of metal, glass, plastic, conductively coated plastic, conductively coated fused silica, non conductively coated plastic, non conductively coated fused silica, glass lined metal tube and resistively coated glass.

3. The device of claim 1, wherein the component for generating a plurality of ionizing species is selected from the group consisting of a direct analysis real time (DART), a desorption electrospray ionization (DESI), an atmospheric laser desorption ionization, a Corona discharge, an inductively coupled plasma (ICP) and a glow discharge source.

4. The device of claim 1, wherein the permeable barrier is selected from the group consisting of a microchannel plate, a wire mesh grid, a variable width slit, a pinhole, a pinhole with a grid, multiple pinholes and multiple pinholes with a grid.

5. The device of claim 1, further comprising:

an inner surface of the tube;

wherein the inner conductive surface is conductive;

wherein a first potential is applied to the inner conductive surface of the tube.

6. The device of claim 5, wherein:

the tube is a length of between;

a lower limit of approximately 10<sup>−

2</sup> m; and

an upper limit of approximately 4 m.

7. The device of claim 5, wherein the inner conductive surface inside diameter is between:

a lower limit of approximately 10<sup>−

4</sup> m; and

an upper limit of approximately 10<sup>−

1</sup> m.

8. The device of claim 5, wherein:

the inner tube conductive surface is positioned relative to the analyte at an angle between;

a lower limit of approximately 10 degrees; and

an upper limit of approximately 90 degrees.

9. The device of claim 5, wherein:

the inner tube conductive surface protrudes from the proximal end of the tube by a distance of between;

a lower limit of approximately 10<sup>−

4</sup> m; and

an upper limit of approximately 10<sup>−

2</sup> m.

10. The device of claim 5, wherein:

the inner tube conductive surface is positioned a distance away from one or both the analyte and the plurality of ionizing species of between;

a lower limit of approximately 10<sup>−

5</sup> m; and

an upper limit of approximately 10<sup>−

1</sup> m.

11. The device of claim 5, wherein:

the inner tube conductive surface extends inside the tube from the proximal end of the tube by a distance of between;

a lower limit of approximately 10<sup>−

4</sup> m; and

an upper limit of approximately 10<sup>−

1</sup> m.

12. A method for analyzing an analyte comprising:

inserting a permeable barrier which has been in contact with the analyte into a tube with a proximal end and a distal end, wherein the distal end of the tube transfers analyte ions into a mass spectrometer; and

directing a plurality of ionizing species at the proximal end of the tube;

wherein ions formed from the analyte are transferred into the mass spectrometer.

13. A device for analyzing an analyte comprising:

a component for generating a plurality of ionizing species; and

a tube with a proximal end and a distal end, wherein the plurality of ionizing species are directed at the analyte;

wherein the analyte is at approximately atmospheric pressure;

wherein the distal end of the tube is positioned to transfer one or more analyte ions into a mass spectrometer;

wherein the proximal end of the tube is positioned a distance away from the position where the plurality of ionizing species are directed at the analyte such that one or more analyte ions pass through the tube into the mass spectrometer.

14. The device of claim 13, wherein:

the tube can be one or more of flexible, curved and coiled.

15. The device of claim 13, wherein:

the tube is a length of between;

a lower limit of approximately 10<sup>−

2</sup> m; and

an upper limit of approximately 3 m.

16. The device of claim 13, wherein:

the tube is positioned a distance away from the analyte of between;

a lower limit of approximately 10<sup>−

5</sup> m; and

an upper limit of approximately 2×

10<sup>−

1</sup> m.

17. The device of claim 13, wherein the component for generating a plurality of ionizing species is selected from the group of sources consisting of a direct analysis real time (DART), a desorption electrospray ionization (DESI), an atmospheric laser desorption ionization, a Corona discharge, an inductively coupled plasma (ICP) and a glow discharge source.

18. The device of claim 13, wherein:

the tube is made from one or more materials chosen from the group consisting of metal, glass, plastic, conductively coated plastic, conductively coated fused silica, non conductively coated plastic, non conductively coated fused silica, glass lined metal tube and resistively coated glass.

19. The device of claim 13, further comprising:

an inner surface of the tube;

wherein the inner conductive surface is conductive;

wherein a first potential is applied to the inner conductive surface of the tube.

20. The device of claim 19, wherein the inner conductive surface inside diameter is between:

a lower limit of approximately 10<sup>−

4</sup> m; and

an upper limit of approximately 10<sup>−

1</sup> m.