Probe for extraction of molecules of interest from a sample
A device is described for generating ionized molecules for analysis in a mass spectrometer. The device includes: a solid substrate having one or more edges and a coated area that is coated with an extraction phase comprising an extraction polymer. The solid substrate may have at least two edges that meet at an angle from about 8° to about 180°. Mass spectrometry systems that include such a device are also described. Methods of analyzing a molecule previously extracted from a sample onto the device are also described.
1. A device for generating ionized molecules for analysis in a mass spectrometer, the device comprising:
a solid substrate having one or more edges and a coated area that is coated with an extraction phase comprising an extraction polymer, the extraction phase coating the solid substrate over an area from about 0.1 mm 2 to about 100 mm 2 .
2. The device according to claim 1 , wherein the extraction polymer is a biocompatible polymer.
3. The device according to claim 1 , wherein the solid substrate has at least two edges that meet at an angle from about 8° to about 90°.
4. The device according to claim 1 , wherein the solid substrate has a plurality of edges that meet to form a plurality of points.
5. The device according to claim 1 , wherein the solid substrate has a homogeneous thickness from about 0.01 mm to about 2 mm.
6. The device according to claim 1 , wherein the solid substrate has:
a. a length from about 1 to about 10 cm;
b. a width from about 0.1 to about 5 mm; and
c. a thickness from about 0.1 mm to about 2 mm.
7. The device according to claim 1 , wherein the solid substrate comprises a metal, a metal alloy, or a polymer.
8. The device according to claim 1 , wherein the extraction phase coating the solid substrate comprises solid phase micro-extraction (SPME) porous particles having a surface able to absorb a molecule from a sample.
9. The device according to claim 1 wherein the extraction phase is homogeneous in thickness and composition over the coated area.
10. The device according to claim 1 wherein the extraction phase is inhomogeneous along the length of the mass spectrometry probe.
11. The device according to claim 10 , wherein the extraction phase is inhomogeneous along the length of the solid substrate due to variations in the composition of the extraction phase along the length of the solid substrate, or due to variations in the thickness of the extraction phase along the length of the solid substrate.
12. The device according to claim 1 , wherein the extraction phase has a thickness from about 0.2 μm to about 100 μm.
13. The device according to claim 8 , wherein the extraction phase has a thickness sufficient to include one or two layers of particles.
14. The device according to claim 1 , wherein the coated solid substrate has a first side coated with a first extraction phase, and a second side coated with a second extraction phase that is different from the first extraction phase.
15. The device according to claim 14 , wherein the first extraction phase comprises extractive particles that provide hydrophobic interactions, and the second extraction phase comprises extractive particles that provide hydrophilic interactions.
16. The device according to claim 1 , wherein the extraction phase is loaded with an internal standard.
17. The device according to claim 1 , wherein the solid substrate is square or rectangular in cross-section.
18. A mass spectrometry system comprising:
a device according to claim 1 ;
a desorption solvent covering at least a portion of the extraction phase;
a high voltage source; and
a mass analyzer;
wherein the device is connected to the high voltage source, and no solvent is applied to the device during ionization.
19. A method for analyzing a molecule previously extracted from a sample onto the extraction phase of a device according to claim 1 , the method comprising:
applying a voltage to the device that is sufficiently high to desorb and expel ions of molecules from the extraction phase, while keeping the coated solid substrate separate from a flow of solvent; and
analyzing the expelled ions by mass spectrometry.