Mass spectrometry probes and systems for ionizing a sample
The invention generally relates to mass spectrometry probes and systems for ionizing a sample. In certain embodiments, the invention provides a mass spectrometry probe including a substrate in which a portion of the substrate is coated with a material, a portion of which protrudes from the substrate.
1. A method for analyzing a sample, the method comprising:
providing a mass spectrometry probe comprising a paper substrate in which a portion of the paper substrate is coated with an electrically conductive material that is not a sample or a solvent, in a manner that a plurality of nanoscale features protrude from the paper substrate, the plurality of nanoscale features configured to act as a plurality of electrodes and upon application of a voltage of 3 volts or less, providing a field strength high enough to cause field emission of microscale solution droplets at the plurality of nanoscale features at a voltage that does not cause fragmentation of the analyte;
connecting the mass spectrometry probe to a voltage source, wherein the voltage source is configured to generate a voltage of 3 volts or less;
contacting the mass spectrometry probe with a sample;
ionizing the sample that has contacted the mass spectrometry probe; and
analyzing the ionized sample in a mass spectrometer.
2. The method according to claim 1 , wherein the electrically conductive material comprises one or more electrically conductive nanotubes.
3. The method according to claim 2 , wherein the electrically conductive nanotubes are carbon nanotubes.
4. The method according to claim 3 , wherein the carbon nanotubes coat an external surface of the paper substrate.
5. The method according to claim 1 , wherein prior to the ionizing step, the method further comprises applying a solvent to the mass spectrometry probe.
6. The method according to claim 5 , wherein the solvent is continuously supplied to the mass spectrometry probe.
7. The method according to claim 5 , wherein the mass spectrometry probe is separate from the solvent.
8. The method according to claim 5 , wherein the solvent assists in at least one of separation, extraction, and ionization of the sample.
9. The method according to claim 1 , wherein pneumatic assistance is not required to transport the sample through the mass spectrometry probe.
10. The method according to claim 1 , wherein the paper is filter paper.
11. A method for analyzing a sample, the method comprising:
providing a mass spectrometry probe comprising a paper substrate and a plurality of carbon nanotubes, the mass spectrometry probe configured such that a portion of each of the plurality of carbon nanotubes protrudes from the paper substrate forming a plurality of nanoscale features that extend from the paper substrate, the plurality of nanoscale features configured to act as a plurality of electrodes and upon application of a voltage of 3 volts or less, providing a filed strength high enough to cause field emission of microscale solution droplets at a voltage that does not cause fragmentation of the analyte;
connecting the mass spectrometry probe to a voltage source, wherein the voltage source is configured to generate a voltage of 3 volts or less;
contacting the mass spectrometry probe with a sample;
ionizing the sample that has contacted the mass spectrometry probe; and
analyzing the ionized sample in a mass spectrometer.
12. The method according to claim 11 , wherein the carbon nanotubes coat an external surface of the paper substrate.
13. The method according to claim 11 , wherein prior to the ionizing step, the method further comprises applying a solvent to the mass spectrometry probe.
14. The method according to claim 13 , wherein the solvent is continuously supplied to the mass spectrometry probe.
15. The method according to claim 13 , wherein the mass spectrometry probe is separate from the solvent.
16. The method according to claim 13 , wherein the solvent assists in at least one of separation, extraction, and ionization of the sample.
17. The method according to claim 11 , wherein pneumatic assistance is not required to transport the sample through the mass spectrometry probe.
18. The method according to claim 11 , wherein the paper is filter paper.
19. The method according to claim 18 , wherein the filter paper comprises a pointed tip.
20. The method according to claim 18 , wherein the filter paper does not comprise a pointed tip.