Ion focusing
The invention generally relates to apparatuses for focusing ions at or above ambient pressure and methods of use thereof. In certain embodiments, the invention provides an apparatus for focusing ions that includes an electrode having a cavity, at least one inlet within the electrode configured to operatively couple with an ionization source, such that discharge generated by the ionization source is injected into the cavity of the electrode, and an outlet. The cavity in the electrode is shaped such that upon application of voltage to the electrode, ions within the cavity are focused and directed to the outlet, which is positioned such that a proximal end of the outlet receives the focused ions and a distal end of the outlet is open to ambient pressure.
1. An apparatus for focusing ions, the apparatus comprising:
an electrode comprising a cavity;
at least one inlet within the electrode configured to operatively couple with an ionization source, such that discharge generated by the source is injected into the cavity of the electrode; and
an outlet;
wherein the cavity in the electrode is shaped such that upon application of voltage to the electrode, ions within the cavity are focused and directed to the outlet, which is positioned such that a proximal end of the outlet receives the focused ions and a distal end of the outlet is open to ambient pressure.
2. The apparatus according to claim 1 , wherein the interior of the cavity comprises an ellipsoidal shape.
3. The apparatus according to claim 2 , wherein the cavity is pressurized.
4. The apparatus according to claim 2 , wherein the outlet is connected to the electrode.
5. The apparatus according to claim 2 , wherein the outlet is spaced from the electrode.
6. The apparatus according to claim 2 , wherein the outlet is grounded.
7. The apparatus according to claim 1 , further comprising a gas inlet.
8. The apparatus according to claim 1 , further comprising a plurality of ring electrodes positioned within an interior portion of the cavity such that they are aligned with the outlet, wherein the electrodes are arranged in order of decreasing inner diameter with respect to the outlet.
9. A system for analyzing a sample, the system comprising:
an ionization source;
an ion focusing apparatus comprising and outlet and one or more electrodes, wherein the focusing apparatus is configured to receive discharge from the ionization source, focus ions at or above ambient pressure, direct ions through use of the one or more electrodes toward the outlet, and expel the ions through the outlet at ambient pressure; and
a mass analyzer positioned to receive the focused ions expelled from the ion focusing apparatus.
10. The system according to claim 9 , wherein the ion focusing apparatus comprises:
an electrode comprising a cavity;
at least one inlet within the electrode configured to operatively couple with an ionization source, such that discharge generated by the ionization source is injected into the cavity of the electrode; and
an outlet;
wherein the cavity in the electrode is shaped such that upon application of voltage to the electrode, ions within the cavity are focused and directed to the outlet, which is positioned such that a proximal end of the outlet receives the focused ions and a distal end of the outlet is open to ambient pressure.
11. The system according to claim 9 , wherein the ionization source is an electrospray probe or a nano electrospray probe.
12. The system according to claim 9 , wherein the mass analyzer is for a mass spectrometer or a handheld mass spectrometer.
13. The system according to claim 9 , wherein the mass analyzer is selected from the group consisting of: a quadrupole ion trap, a rectalinear ion trap, a cylindrical ion trap, a ion cyclotron resonance trap, an orbitrap, a time of flight, a Fourier Transform ion cyclotron resonance, and sectors.
14. The system according to claim 10 , wherein the cavity comprises an ellipsoidal shape.
15. The system according to claim 10 , wherein the cavity is pressurized.
16. The system according to claim 14 , wherein the outlet is connected to the electrode.
17. The system according to claim 14 , wherein the outlet is spaced from the electrode.
18. The system according to claim 14 , wherein the outlet is grounded.
19. The system according to claim 10 , further comprising a gas inlet.
20. The system according to claim 10 , further comprising a plurality of ring electrodes positioned within an interior portion of the cavity such that they are aligned with the outlet, wherein the electrodes are arranged in order of decreasing inner diameter with respect to the outlet.