Pulsed ion beam source for electrospray mass spectrometry

Patent metadata

Field	Value
Publication number	US-9524859-B2
Application number	US-201414450267-A
Country	US
Kind code	B2
Filing date	Aug 3, 2014
Priority date	Aug 4, 2013
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

Apparatus and methods for creating a pulsed ion beam. The pulsed ion beam can be used for performing mass spectrometry. A pulsed solenoid valve can provide a pulsed ion beam from an electrospray in a pre-vacuum chamber. The pulsed ion beam can enter a high vacuum region and a mass analyzer for mass spectrometry.

First claim

What is claimed is:

1. A method for obtaining a mass spectrum, the method comprising:
providing analyte ions from an electrospray tip in a pre-vacuum chamber having an orifice;
operating a pulsed solenoid valve attached to the pre-vacuum chamber by opening and closing the orifice with a conductive tip of a poppet of the pulsed solenoid valve, thereby providing a pulsed analyte ion beam comprising pulses of analyte ions exiting the pre-vacuum chamber through the orifice and entering a high vacuum region containing a mass analyzer, wherein when the orifice is opened the pre-vacuum chamber is in fluid communication with the high vacuum region and the build up of electrical charges on the poppet and orifice are avoided;
operating the mass analyzer to collect the analyte ions in the pulsed analyte ion beam and separate the analyte ions by their mass to charge ratio;
detecting the separated analyte ions.

2. The method of claim 1 , wherein more than one pulse of the pulsed analyte ion beam is collected and separated by the mass analyzer.

3. The method of claim 1 , wherein the duration of the pulsed analyte ion beam is controlled by using a delay time function generator.

4. The method of claim 1 , wherein the analyte ions are formed from nonvolatile, thermally-labile organic molecules or biomolecules.

5. The method of claim 1 , further comprising heating the pre-vacuum chamber to a temperature of up to 130° C.

6. The method of claim 1 , further comprising heating the pre-vacuum chamber to a temperature of up to 105° C.

7. A mass spectrometer apparatus comprising:
a high vacuum region containing a mass analyzer, wherein the pressure in the high vacuum region is maintained by pumps;
a pre-vacuum chamber having an orifice formed by a wall of the pre-vacuum chamber;
an electrospray tip in the pre-vacuum chamber;
a pulsed solenoid valve attached to the pre-vacuum chamber that seals the orifice when the valve is closed, wherein the orifice provides fluid communication between the pre-vacuum chamber and the high vacuum region when the pulsed solenoid valve is opened;
a detector.

8. The apparatus of claim 7 , wherein the pulsed solenoid valve has a poppet with a conductive tip, wherein the tip of the poppet is arranged to close the orifice.

9. The apparatus of claim 8 , wherein the conductive tip is formed from a conductive rubber or conductive plastic.

10. The apparatus of claim 7 , wherein the pulsed solenoid valve has a response time of less than 2 ms.

11. The apparatus of claim 7 , wherein the wall of the pre-vacuum chamber containing the orifice is integrated with the mass analyzer.

12. The apparatus of claim 7 , wherein the mass analyzer is an ion trap.

13. The apparatus of claim 7 , wherein the mass analyzer is a quadrupole ion trap.

14. The apparatus of claim 7 , wherein the duration of the pulsed ion beam is controlled by using a delay time function generator.

15. The apparatus of claim 7 , wherein the mass of the pumps is less than about 6 kg.

16. The apparatus of claim 7 , wherein the mass of the apparatus is less than 40 kg.

17. An apparatus for creating a pulsed ion beam, the apparatus comprising:
a pre-vacuum chamber;
an orifice formed by a wall of the pre-vacuum chamber;
a pulsed solenoid valve attached to the pre-vacuum chamber;
a poppet of the pulsed solenoid valve having a tip, wherein the tip of the poppet is formed of conductive rubber and seals the orifice when the valve is closed, and wherein the pulsed solenoid valve can be opened by pulling the poppet back from the orifice.

18. The apparatus of claim 17 , wherein the pulsed solenoid valve has a response time of less than 2 ms.

19. The apparatus of claim 17 , wherein the duration of the pulsed ion beam is controlled by a delay time function generator to operate the pulsed solenoid valve.

20. The apparatus of claim 17 , wherein the pre-vacuum chamber is heated.

Assignees

• Academia Sinica
• Academia Sinica

Inventors

• Lin Jung-Lee
• Chen Chung-Hsuan
• Hsieh Chen-Yu

Classifications

• H01J49/165 Primary

  Electrospray ionisation · CPC title

• H01J49/0495

  Vacuum locks; Valves (valves per se F16K) · CPC title