Method and apparatus for desorption and ionization of analytes

• US 5,719,060 A
• Filed: 06/07/1995
• Issued: 02/17/1998
• Est. Priority Date: 05/28/1993
• Status: Expired due to Term

• Current Assignee: Baylor College of Medicine (Baylor College)
• Original Assignee: Baylor College of Medicine (Baylor College)
• Inventors: Hutchens, T. William, Yip, Tai-Tung
• Primary Examiner(s): ALEXANDER, LYLE
• Application Number:
  US08/483,357
• Time in Patent Office: 986 Days
• Field of Search: 436/173, 436/178, 436/63, 436/155, 436/174, 250/287-88, 250/423
• US Class Current: 436/174
• CPC Class Codes: G01N 1/405 by adsorption or absorption
• CPC Class Codes: G01N 33/6851 Methods of protein analysis involving laser desorption ionisation mass spectrometry
• CPC Class Codes: H01J 49/0418 for laser desorption, e.g. matrix-assisted laser desorption/ionisation [MALDI] plates or surface enhanced laser desorption/ionisation [SELDI] plates
• CPC Class Codes: Y10T 436/24 Nuclear magnetic resonance, electron spin resonance or other spin effects or mass spectrometry
• CPC Class Codes: Y10T 436/25 including sample preparation
• CPC Class Codes: Y10T 436/255 including use of a solid sorbent, semipermeable membrane, or liquid extraction

Abstract

This invention relates generally to methods and apparatus for desorption and ionization of analytes for the purpose of subsequent scientific analysis by such methods, for example, as mass spectrometry or biosensors. More specifically, this invention relates to the field of mass spectrometry, especially to the type of matrix-assisted laser desorption/ionization, time-of-flight mass spectrometry used to analyze macromolecules, such as proteins or biomolecules. Most specifically, this invention relates to the sample probe geometry, sample probe composition, and sample probe surface chemistries that enable the selective capture and desorption of analytes, including intact macromolecules, directly from the probe surface into the gas (vapor) phase without added chemical matrix.

Claims

1. A method for desorbing analyte molecules from a sample presenting surface, comprising:

providing a sample presenting surface derivitized with an affinity capture device having means for binding with said analyte molecules;

exposing said derivitized sample presenting surface to a sample containing said analyte molecules;

capturing said analyte molecules on said derivitized sample presenting surface by means of said affinity capture device; and

exposing said analyte molecules, while bound to said derivitized sample presenting surface by means of said affinity capture device, to an energy or light source to desorb, without substantial combustion at least a portion of said analyte molecules from said surface.

2. The method of claim 1, further comprising, depositing a desorption/ionization assisting material to said sample presenting surface in association with said affinity capture device.

3. The method of claim 1 wherein said energy source comprises a laser.

4. The method of claim 1, wherein said energy source comprises an ion source.

5. The method according to claim 1, wherein the binding is selective.

7. The method of claim 1 wherein the affinity capture device comprises an enzyme.

8. The method of claim 1 wherein a portion of said analyte molecules remain bound to said sample presenting surface after exposure to said energy source.

9. The method of claim 8, further comprising the steps of:

converting at least a portion of the analyte molecules remaining bound on said derivitized sample presenting surface to modified analyte molecules by a chemical, biological or physical reaction, wherein said analyte molecules remain bound to said derivitized sample presenting surface by means of said affinity capture device or photolabile attachment molecule; and

exposing said modified analyte molecules to an energy source so as to desorb at least a portion of said modified analyte molecules from said surface.

6. The method according to claim or 1, wherein the binding is non-selective.

10. A method for preparing a sample probe for mass spectrometry for presenting analyte molecules for analysis, said method comprising:

providing a substrate on said surface for supporting said analyte;

derivitizing said substrate with an affinity capture device having means for selectively binding with said analyte.

11. A sample probe for promoting desorption of intact analytes into the gas phase comprising:

a sample presenting surface; and

an affinity capture device associated with said sample presenting surface;

wherein, when said sample probe is impinged by an energy source, said sample probe promotes the transition of an intact analyte molecule into the gas phase.

12. The sample probe of claim 11, wherein the affinity capture device is selected from the group consisting of metal ions, proteins, peptides, immunoglobulins, nucleic acids, carbohydrates, lectins, dyes, reducing agents and combination thereof.

13. The sample probe of claim 11, wherein the sample presenting surface is selected from the group consisting of glass, ceramics, teflon coated magnetic materials;

organic polymers and native biopolymers.

14. The sample probe of claim 11 wherein the affinity capture device comprises an enzyme.

19. The sample probe according to claims 11, 12 or 15, wherein the binding is non-selective.

20. The sample probe according to claims 11, 12, or 15, wherein the binding is selective.

15. A sample probe for promoting differential desorption of intact analyte into the gas phase, comprising:

a sample presentation surface; and

at least two different affinity capture devices associated with said sample presentation surface;

wherein, when said sample probe is impinged by an energy source, said sample probe promotes the transition of an analyte molecule into the gas phase at different rates depending on the affinity capture device associated with said analyte molecule.

16. The sample probe of claim 15, wherein the affinity devices are arranged in predetermined arrays.

17. The sample probe of claim 16, wherein the arrays selectively absorb a plurality of different analytes.

18. A sample probe for presenting an analyte to an energy source capable of desorbing the analyte from the probe, comprising:

a sample presentation surface; and

a surface associated molecule associated with said sample presenting surface, wherein said surface associated molecule can function both as an energy absorbing molecule and as an affinity capture device.