HIGH SPATIAL RESOLUTION MATRIX ASSISTED LASER DESORPTION/IONIZATION (MALDI)

• US 20030222212A1
• Filed: 05/31/2002
• Published: 12/04/2003
• Est. Priority Date: 05/31/2002
• Status: Active Grant

• Current Assignee: Battelle Memorial Institute
• Original Assignee: Battelle Memorial Institute
• Inventors: Wunschel, David S., Beck, Kenneth M.
• Granted Patent: US 6,680,477 B2
• Time in Patent Office: Days
• US Class Current: 250/288
• CPC Class Codes: H01J 49/164 Laser desorption/ionisation, e.g. matrix-assisted laser desorption/ionisation [MALDI] sample holders H01J49/0418
• CPC Class Codes: Y10T 436/24 Nuclear magnetic resonance, electron spin resonance or other spin effects or mass spectrometry

Abstract

Disclosed is an invention that provides a system and process for focusing light to micron and submicron spot sizes for matrix assisted laser desorption/ionization (MALDI). Moreover, the present invention features a second process and system for creating a correlated optical image of the ion desorption region of a sample substrate.

Claims

1. A system for matrix assisted laser desorption/ionization (MALDI) comprising:

a. a coherent light source to generate light;

b. at least one confocal microscopic objective to create a desorption/ionization source at the surface of a MALDI sample plate adapted to receive a sample substrate within the focal working distance of the microscopic objective;

c. at least one fiber optic cable to transport the light to said at least one confocal microscopic objective;

d. at least one collimating fiber optic coupler to collimate the light to an aperature of said at least one fiber optic cable;

e. a insulating microscopic objective holder to hold said at least one confocal microscopic objective and insulate said at least one confocal microscopic objective from the electrical fields of the MALDI;

f. at least one adapter to secure the said objective holder;

g. at least one X, Y positioner to move said confocal microscopic objective in X and Y co-ordinates;

h. a Z positioner to move said confocal microscopic objective in the Z co-ordinate; and

i. a mass analyzer to analyze said sample substrate.

2. A system as described in claim 1, wherein said at least one confocal microscopic objective is positioned above said sample plate.

3. A system as described in claim 1, wherein said sample plate is transparent.

4. A system as described in claim 3, wherein said at least one confocal microscopic objective is positioned below said transparent sample plate.

5. A system as described in claim 4, wherein said mass analyzer comprises at least one ion mobility spectrometer.

6. A system as described in claim 4, wherein said mass analyzer comprises at least one evacuated internal chamber.

7. A system as described in claim 1, wherein said mass analyzer comprises at least one ion mobility spectrometer.

8. A system as described in claim 1, wherein said mass analyzer comprises at least one evacuated internal chamber.

9. A system as described in claim 1, wherein said confocal microscopic objective and said slide are positioned outside of a vacuum chamber.

10. A system for focusing light to a sub-micron spot size area for matrix assisted laser desorption/ionization (MALDI) comprising:

a. a coherent light source to generate ultra-violet light;

b. at least one confocal microscopic objective to create a desorption/ionization source of sub-micron spatial resolution at the surface of a MALDI sample plate adapted to receive a sample substrate within the focal working distance of the microscopic objective;

c. at least one fiber optic cable to transport the ultra-violet light to said at least one confocal microscopic objective;

d. at least one collimating fiber optic coupler to collimate the light to the aperture of said at least one fiber optic cable;

e. at least one insulating microscopic objective holder to hold said at least one confocal microscopic objective and insulate said at least one confocal microscopic objective from electrical fields of the MALDI;

f. at least one adapter to secure the said objective holder;

g. at least one X, Y positioner to move said confocal microscopic objective in X and Y co-ordinates;

h. a Z positioner to move said confocal microscopic objective in the Z co-ordinate; and

i. a mass analyzer to analyze ions desorbed from said sample substrate.

11. A system as described in claim 10, wherein said at least one confocal microscopic objective is positioned above said sample plate.

12. A system as described in claim 10, wherein said sample plate is transparent.

13. A system as described in claim 12, wherein said at least one confocal microscopic objective is positioned below said transparent sample plate.

14. A system as described in claim 13, wherein said mass analyzer comprises at least one ion mobility spectrometer.

15. A system as described in claim 13, wherein said mass analyzer comprises at least one evacuated internal chamber.

16. A system as described in claim 10, wherein said mass analyzer comprises at least one ion mobility spectrometer.

17. A system as described in claim 10, wherein said mass analyzer comprises at least one evacuated internal chamber.

18. A system as described in claim 10, wherein said confocal microscopic objective and said sample plate are positioned outside of a vacuum chamber.

19. A process for focusing a light source to a sub-micron spot size for matrix assisted laser desorption/ionization (MALDI), comprising the steps of:

a. depositing a sample substrate containing analyte and an appropriately absorbing matrix on a sample plate;

b. generating a coherent light source;

c. positioning said sample plate within the focal working distance of at least one confocal microscopic objective;

d. coupling said at least one confocal microscopic objective to said coherent light source with at least one fiber optic cable;

e. positioning said at least one confocal microscopic objective in a geometry that does not interfere with the path of desorbed sample ions;

f. focusing said coherent light source through said at least one microscopic objective to create a desorption/ionization ultra-violet light source of submicron spatial resolution directed at said sample substrate;

g. ionizing said sample substrate; and

h. separating and detecting ions from said ionized sample substrate in one or more stages using an appropriate mass separation and analysis method.

20. A process as described in claim 19, further comprising positioning said at least one confocal microscopic objective above said sample plate.

21. A process as described in claim 19, further comprising providing said sample plate as a transparent member.

22. A process as described in claim 21, further comprising positioning said at least one confocal microscopic objective below said transparent member.

23. A process as described in claim 22, further comprising separating and detecting ions from said ionized sample substrate using at least one ion mobility spectrometer.

24. A process as described in claim 22, further comprising further comprising separating and detecting ions from said ionized sample substrate using mass analyzer with at least one evacuated internal chamber.

25. A process as described in claim 19, further comprising separating and detecting ions from said ionized sample substrate using at least one ion mobility spectrometer.

26. A process as described in claim 19, further comprising separating and detecting ions from said ionized sample substrate using a mass analyzer with at least one evacuated internal chamber.

27. A process as described in claim 19, wherein said confocal microscopic objective and said sample plate are positioned outside of a vacuum chamber.

28. A process for creating a correlated optical image of the ion desorption region of a sample substrate comprising the steps of:

a. depositing a sample substrate containing analyte and an appropriately absorbing matrix on a sample plate;

b. generating a coherent light source;

c. positioning said sample plate within the focal working distance of at least one confocal microscopic objective;

d. coupling said at least one confocal microscopic objective to said coherent light source with at least one fiber optic cable;

e. positioning said at least one confocal microscopic objective in a geometry that does not interfere with the path of desorbed sample ions;

f. focusing said coherent light source through said at least one microscopic objective to create a desorption/ionization ultra-violet light source of submicron spatial resolution directed at said sample substrate;

g. ionizing said sample substrate; and

h. separating and detecting ions from said ionized sample substrate in one or more stages using an appropriate mass separation and analysis method;

i. illuminating the sample;

j. transferring an optical image of the ionized sample substrate using said at least one fiber optic cable; and

k. capturing an optical image of said ionized sample substrate.

29. A process as described in claim 28, further comprising providing at least one confocal microscopic objective positioned above said sample plate.

30. A process as described in claim 28, further comprising providing said sample plate as a transparent member.

31. A process as described in claim 30, further comprising providing said at least one confocal microscopic objective positioned below said transparent member.

32. A process as described in claim 31 further comprising providing said mass separation and analysis method is with at least one ion mobility spectrometer.

33. A process as described in claim 31, further comprising providing said mass separation and analysis method is within at least one evacuated internal chamber.

34. A process as described in claim 28, further comprising providing said mass separation and analysis method is with at least one ion mobility spectrometer.

35. A process as described in claim 28, further comprising providing said mass separation and analysis method is within at least one evacuated internal chamber.

36. A system for creating a correlated optical image of a ion desorption region of a sample substrate comprising the steps of:

a. a coherent light source to generate ultra-violet light;

b. at least one confocal microscopic objective to create a desorption/ionization source of sub-micron spatial resolution at the surface of a MALDI sample plate adapted to receive a sample substrate within the focal working distance of the microscopic objective;

c. at least one fiber optic cable to transport said light from said light source to said confocal microscopic objective and to transport optical images from the ion desorption region of said sample substrate to a camera;

d. at least one collimating fiber optic coupler to collimate the light to the aperture of said at least one fiber optic cable;

e. at least one insulating microscopic holder to hold said at least one confocal microscopic objective and insulate said at least one confocal microscopic objective from electrical fields of the MALDI;

f. at least one adapter to secure the said objective holder;

g. at least one X, Y positioner to move said confocal microscopic objective in X and Y co-ordinates;

h. a Z positioner to move said confocal microscopic objective in the Z co-ordinate;

i. a mass analyzer to separate and detect desorbed ions; and

j. at least one camera to capture images of said ion desorption region of said sample substrate.

37. A system as described in claim 36, wherein said at least one confocal microscopic objective is positioned above said sample plate.

38. A system as described in claim 36, wherein said sample plate is transparent.

39. A system as described in claim 38, wherein at least one confocal microscopic objective is positioned below said transparent sample plate.

40. A system as described in claim 39, wherein said mass analyzer comprises of at least one ion mobility spectrometer.

41. A system as described in claim 39, wherein said mass analyzer comprises of at least one evacuated internal chamber.

42. A system as described in claim 36, wherein said mass analyzer comprises of at least one ion mobility spectrometer.

43. A system as described in claim 36, wherein said mass analyzer comprises of at least one evacuated internal chamber.

44. A system for creating an optical image of the ion desorption region of a sample substrate comprising the steps of:

a. a coherent light source to generate light;

b. at least one confocal microscopic objective to create a desorption/ionization source at the surface of a MALDI sample plate adapted to receive a sample substrate within the focal working distance of the microscopic objective;

c. at least one fiber optic cable to transport said light from said light source to said confocal microscopic objective and to transport optical images from the ion desorption region of said sample substrate to a camera;

d. at least one collimating fiber optic coupler to collimate the light to the aperture of said at least one fiber optic cable;

e. at least one insulating microscopic holder to hold said at least one confocal microscopic objective and insulate said at least one confocal microscopic objective from electrical fields of the MALDI;

f. a mass analyzer to separate and detect desorbed ions; and

g. at least one camera to capture images of said ion desorption region of said sample substrate.

45. A system as described in claim 44, wherein said at least one confocal microscopic objective is positioned above said sample plate.

46. A system as described in claim 44, wherein said sample plate is transparent.

47. A system as described in claim 46, wherein at least one confocal microscopic objective is positioned below said transparent sample plate.

48. A system as described in claim 47, wherein said mass analyzer comprises at least one ion mobility spectrometer.

49. A system as described in claim 47, wherein said mass analyzer comprises at least one evacuated internal chamber.

50. A system as described in claim 44, wherein said mass analyzer comprises at least one ion mobility spectrometer.

51. A system as described in claim 44, wherein said mass analyzer comprises at least one evacuated internal chamber.