APPARATUS FOR HOLDING SOLIDS FOR USE WITH SURFACE IONIZATION TECHNOLOGY

• US 20100140468A1
• Filed: 02/19/2010
• Published: 06/10/2010
• 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 8,421,005 B2
• Time in Patent Office: Days
• US Class Current: 250/282
• 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 on a first surface comprising:

a component for generating a plurality of ionizing species, wherein the plurality of ionizing species are directed at the analyte to form analyte ions, wherein the analyte is at approximately atmospheric pressure;

a tube with a proximal end and a distal end, wherein the distal end of the tube is positioned to transfer analyte ions into a spectrometer; and

a light source affixed to the tube, wherein the proximal end of the tube is positioned based on the light source illuminating the first surface, wherein when the proximal end of the tube is positioned one or more analyte ions pass through the tube into the spectrometer.

2. The device of claim 1, wherein the proximal end of the tube is positioned based on the light source illuminating a detector associated with the first surface.

3. The device of claim 1, 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.

4. The device of claim 1, 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.

5. The device of claim 1, 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.

6. The device of claim 1, wherein the diameter of the tube is between:

a lower limit of approximately 10<sup>−

4</sup> m; and

an upper limit of approximately 10<sup>−

1</sup> m.

7. The device of claim 1, wherein the light source is a light emitting diode.

8. 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.

9. The device of claim 1, further comprising:

a second surface, wherein the second surface contacts at least part of the inside of the tube, wherein the second surface is conductive;

wherein a first potential is applied to the second surface.

10. The device of claim 9, wherein one or more sample analyte ions are attracted to the first potential applied to the second surface and thereby pass through the tube into the mass spectrometer

11. The device of claim 9, wherein the inside diameter of the second surface is between:

a lower limit of approximately 10<sup>−

4</sup> m; and

an upper limit of approximately 10<sup>−

1</sup> m.

12. The device of claim 9, wherein:

the inner tube is positioned relative to the first surface of between;

a lower limit of approximately 10 degrees; and

an upper limit of approximately 90 degrees.

13. The device of claim 9, wherein:

the second 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.

14. The device of claim 13, wherein:

the second surface 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 10<sup>−

1</sup> m.

15. The device of claim 1, wherein one or more reference position of the second surface relative to one or both the first surface and the analyte is determined by measuring the coincidence of the light source on two or more photo-detectors associated with the first surface.

16. The device of claim 9, wherein:

the second 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.

17. The device of claim 1, further comprising:

a third surface of the tube, wherein the third surface contacts at least part of the outside of the tube, wherein the third surface is conductive;

wherein a second potential is applied to the third surface.

18. The device of claim 1, wherein:

the tube is comprised of two or more segments;

wherein the segment which constitutes the proximal end of the tube is the proximal segment and the segment which constitutes the distal end of the tube is the distal segment;

wherein the proximal segment of the tube has a smaller inner diameter than the distal segment of between;

a lower limit of 1% of the inside diameter of the distal segment; and

an upper limit of approximately 50% of the inside diameter of the distal segment.

19. A method of analyzing an analyte on a surface at approximately atmospheric pressure comprising:

orienting a tube with a proximal end and a distal end, wherein the distal end of the tube is positioned to transfer analyte ions into a spectrometer; and

orienting a light source affixed to the tube to illuminate a photo-detector embedded in the surface, to position the proximal end of the tube such that analyte ions pass into the proximal end of the tube; and

directing a plurality of ionizing species at the analyte to form analyte ions, wherein the tube is positioned such that one or more analyte ions pass through the tube into the spectrometer.

20. A device for analyzing an analyte on a surface comprising:

a DART®

source for generating a plurality of ionizing species;

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 connected to a mass spectrometer; and

a detector affixed to the tube, wherein the detector detects a position on the surface, wherein the proximal end of the tube is positioned relative to the position and between;

a lower limit of approximately 1 mm; and

an upper limit of approximately 5 mm;

away from the surface such that one or more analyte ions pass through the tube into the mass spectrometer.