Periodic field differential mobility analyzer

Patent metadata

Field	Value
Publication number	US-9324552-B2
Application number	US-201213713792-A
Country	US
Kind code	B2
Filing date	Dec 13, 2012
Priority date	Dec 15, 2011
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

A periodic field differential mobility analyzer apparatus for separating and identifying ionic analytes employs a series of elongated parallel channels, a pump, a first voltage providing an electric field E x in a direction opposing the gas flow, a second voltage providing an electric field E y in a direction perpendicular to the gas flow, an ion source, and a detector. The periodic field differential mobility analyzer provides high resolution and sensitivity.

First claim

What is claimed is:

1. A periodic field differential mobility analyzer apparatus for separating and identifying ionic analytes, comprising:
a series of elongated parallel channels, each channel having an inlet at a first end and an outlet at a second end, each channel enclosed between first and second parallel walls, each first wall being formed from first and second electrode plates arranged to provide a slit opening in the first wall, each second wall being formed from third and fourth electrode plates arranged to provide a slit opening in the second wall, wherein the first and third electrode plates enclosing a channel oppose each other and the second and fourth electrode plates enclosing a channel oppose each other, wherein adjacent channels share electrode plates of one wall in common, wherein the channels are in fluid communication through the slit openings in each wall, and wherein the slit openings in each of the channels are aligned;
a pump operable to force gas in laminar flow along each of the series of parallel channels, wherein the gas flows through and exits each channel separately and is not recirculated;
a first voltage drop applied between the first and second electrode plates of the first wall of each channel providing an electric field E x in a direction opposing the gas flow, wherein the first voltage drop is also applied between the third and fourth electrode plates of the second wall;
a second voltage drop applied between the first and third electrode plates of each channel providing an electric field E y in a direction perpendicular to the gas flow, wherein the second voltage drop is also applied between the second and fourth electrode plates of each channel, wherein the electric fields E x and E y form a periodic arrangement of their combined electric field and a retarding potential wall;
an ion source arranged exterior to the channels for directing ionic analytes into an ion source slit of the wall of the channel farthest upstream with respect to the electric field E y , wherein the path of the ionic analytes is linear along the channels until they reach the retarding potential wall; and
a detector slit, wherein the detector slit is upstream from the ion source slit with respect to the direction of gas flow, and wherein the slit openings in each of the channels are aligned in a predetermined angle relative to the direction perpendicular to the walls of the channels so that the detector slit and the ion source slit are at opposite ends of the retarding potential wall.

2. The analyzer of claim 1 , further comprising an exit slit in the wall of the channel farthest downstream with respect to the electric field E y .

3. The analyzer of claim 1 , further comprising maintaining the first and third electrode plates of each channel at ground potential so that the voltage drop applied between the first and third electrode plates is zero.

4. The analyzer of claim 1 , wherein the number of channels in the series of elongated parallel channels is from two to fifty.

5. The analyzer of claim 1 , wherein the first voltage drop can be swept from zero to 2000 volts.

6. The analyzer of claim 1 , wherein the pump is operable to adjust the gas flow rate.

7. The analyzer of claim 1 , wherein the pump is operable to adjust the gas flow rate from 0.1 to 2500 L/min.

8. The analyzer of claim 1 , wherein the gas flow rates in each of the channels are equal.

9. The analyzer of claim 1 , wherein the ion source generates ions by MALDI, electrospray ionization, laser ionization, thermospray ionization, thermal ionization, electron ionization, chemical ionization, inductively coupled plasma ionization, glow discharge ionization, field desorption ionization, fast atom bombardment ionization, spark ionization, or ion attachment ionization.

10. The analyzer of claim 1 , wherein the ion source is a voltage biased tungsten wire.

11. The analyzer of claim 1 , wherein the detector is a current to voltage converter, a gas amplification detector, a Daly detector, or a charge detector.

12. The analyzer of claim 1 , wherein the analyzer achieves a resolution of greater than 100 with a transmission of greater than 90%.

13. The analyzer of claim 1 , wherein the analyzer achieves a resolution of greater than 200 with a transmission of greater than 40%.

14. The analyzer of claim 1 , wherein the analyzer achieves a resolution of greater than 50.

15. The analyzer of claim 1 , wherein the analyzer achieves a resolution of greater than 75.

16. The analyzer of claim 1 , wherein the analyzer achieves a resolution of greater than 100.

17. The analyzer of claim 1 , wherein the analyzer achieves a resolution of greater than 200.

18. A mass spectrometer comprising an analyzer according to claim 1 .

19. A periodic field differential mobility analyzer apparatus for separating and identifying ionic analytes, comprising:
a series of differential mobility analyzers having channels arranged in parallel, wherein adjacent differential mobility analyzers share a common wall;
a pump operable to force gas in laminar flow along the channels, wherein the gas flows through and exits each channel separately and is not recirculated;
a first voltage drop applied to each differential mobility analyzer to provide an electric field E x in a direction opposing the gas flow;
a second voltage drop applied to each differential mobility analyzer to provide an electric field E y in a direction perpendicular to the gas flow, wherein the electric fields E x and E y form a periodic arrangement of their combined electric field and a retarding potential wall;
an ion source arranged exterior to the channels for directing ionic analytes through a slit of the wall of the channel farthest upstream with respect to the electric field E y , wherein the path of the ionic analytes is linear along the channels until they reach the retarding potential wall; and
a detector slit, wherein the detector slit is upstream from the ion source slit with respect to the direction of gas flow, and wherein the slit openings in each of the channels are aligned in a predetermined angle relative to the direction perpendicular to the walls of the channels so that the detector slit and the ion source slit are at opposite ends of the retarding potential wall.

20. The analyzer of claim 19 , further comprising an exit slit in the channel farthest downstream with respect to the electric field E y .

21. The analyzer of claim 19 , wherein the number of channels is from two to twenty.

22. The analyzer of claim 19 , wherein the first voltage drop can be swept from zero to 2000 volts.

23. The analyzer of claim 19 , wherein the pump is operable to adjust the gas flow rate.

24. The analyzer of claim 19 , wherein the pump is operable to adjust the gas flow rate from 0.1 to 2500 L/min.

25. The analyzer of claim 19 , wherein the gas flow rates in each of the channels are equal.

26. The analyzer of claim 19 , wherein the ion source generates ions by MALDI, electrospray ionization, laser ionization, thermospray ionization, thermal ionization, electron ionization, chemical ionization, inductively coupled plasma ionization, glow discharge ionization, field desorption ionization, fast atom bombardment ionization, spark ionization, or ion attachment ionization.

27. The analyzer of claim 19 , wherein the ion source is a voltage biased tungsten wire.

28. The

Assignees

• Academia Sinica

Inventors

• Gillig Kent J
• Chen Chung-Hsuan

Classifications

• G01N27/624 Primary

  Differential mobility spectrometry [DMS]; Field asymmetric-waveform ion mobility spectrometry [FAIMS] · CPC title

• H01J49/26 Primary

  Mass spectrometers or separator tubes · CPC title

• H01J49/0031

  Step by step routines describing the use of the apparatus (H01J49/0081 takes precedence) · CPC title

• H01J49/22

  Electrostatic deflection · CPC title