High Duty Cycle Ion Storage/Ion Mobility Separation Mass Spectrometer

• US 20120256083A1
• Filed: 04/11/2011
• Published: 10/11/2012
• Est. Priority Date: 04/11/2011
• Status: Active Grant

• Current Assignee: Thermo Finnigan LLC (Thermo Fisher Scientific Incorporated)
• Original Assignee: Thermo Finnigan LLC (Thermo Fisher Scientific Incorporated)
• Inventors: KOVTOUN, Viatcheslav V.
• Granted Patent: US 8,581,177 B2
• Time in Patent Office: Days
• US Class Current: 250/282
• CPC Class Codes: G01N 27/623 combined with mass spectrometry
• CPC Class Codes: H01J 49/004 Combinations of spectrometers, tandem spectrometers, e.g. MS/MS, MSn
• CPC Class Codes: H01J 49/06 Electron- or ion-optical arrangements

Abstract

A novel high ion storage/ ion mobility separation mass spectrometer that provides for a high duty cycle of operation is presented herein. In particular, the example embodiments, as disclosed herein, provides for a high ion storage/ion mobility instrument that beneficially includes a two-dimensional (2D) plurality of adjacently arranged ion confinement channels to provide a high storage bank of a desired mass range of ions. Such ions, via ion mobility transport, are separated into smaller fractions of an overall mass window into desired confinement regions of the disclosed 2D confinement channels and thereafter transferred out in a manner so as to enable the aforementioned novel high-duty cycle of sequential operation.

Claims

1. ) A high duty cycle ion storage/ion mobility mass spectrometer, comprising:

an ion source;

a first ion interface instrument partitioned into one or more confinement channels having predetermined spatial locations provided by desired DC and RF potentials, wherein a first confinement channel of said first ion interface instrument is configured to receive ions of a predetermined mass window from said ion source and adjacent one or more confinement channels (N₁) configured within said first ion interface instrument is designed, via ion mobility transport, to receive and thereafter confine selected ions of a smaller fraction of the mass range of said predetermined mass window;

a second ion interface instrument additionally partitioned into one or more confinement channels (N₂) also having predetermined spatial locations provided by desired DC and RF potentials, wherein any of said one or more confinement channels (N₂) is configured to receive from said one or more confinement channels (N₁) configured within said first ion interface instrument, said selected ions of a smaller fraction of the mass range of said predetermined mass window, said second ion interface instrument being additionally configured to transfer such selected ions to successive ion confinement channels; and

one or more mass analyzers having an entrance configured to receive ions transferred from one or more predetermined confinement channels of said second ion interface instrument to enable high throughput mass analysis.

2. ) The mass spectrometer of claim 1, wherein said subsequent one or more confinement channels (N₁) of said first ion interface instrument and said one or more confinement channels (N₂) of said second ion interface instrument comprises about 12 confinement channels up to about 20 confinement channels.

3. ) The mass spectrometer of claim 1, wherein said mass spectrometer is configured with electrodes selected from:

one or more auxiliary electrodes, plate electrodes, and predetermined multipole electrodes to provide DC confining potentials and DC axial gradients.

4. ) The mass spectrometer of claim 3, wherein said one or more auxiliary electrodes, plate electrodes, and predetermined multipole electrodes are configured to provide a DC gradient of about 1 V/cm up to about 10 V/cm to aid ion mobility transport and separation.

5. ) The mass spectrometer of claim 3, wherein said one or more auxiliary electrodes are configured within said first ion interface instrument to provide transfer to said second ion transfer instrument.

6. ) The mass spectrometer of claim 1, wherein said confinement channels of said mass spectrometer are configured with gas pressures of about 20 mtorr up to about 100 mtorr.

7. ) The mass spectrometer of claim 1, wherein said mass spectrometer comprises a controller coupled to said ion source and said first and said second ion interface instruments to apply predetermined confining voltages and sufficient gradient voltages to aid ion mobility transfer and separation.

8. ) The mass spectrometer of claim 1, wherein said ion source comprises at least one source selected from:

an Electrospray Ionization (ESI) source, an Atmospheric Pressure Ionization (API) source, an Atmospheric Pressure Chemical Ionization (APCI) source, a Nanoelectrospray Ionization (NanoESI) source, a thermospray ionization source, an electron impact (EI) ionization source, a chemical ionization (CI) source, and an EI/CI source.

9. ) The mass spectrometer of claim 1, wherein said one or more mass analyzers comprises at least one analyzer selected from:

quadrupole mass analyzers, a two-dimensional ion trap, a three dimensional ion trap, an electrostatic trap, a time-of-flight (TOF) device, and a Fourier Transform Ion Cyclotron Resonance analyzer.

10. ) A method of mass spectrometric analysis, comprising:

a) providing an ion interface instrument partitioned into a first confinement channel and adjacent one or more confinement channels (N₁), each of which has predetermined fixed spatial locations configured from desired DC and RF potentials,

b) providing a packet of ions of a predetermined mass window into said first confinement channel;

c) releasing ions of said predetermined mass window from said first confinement channel and locking fractions of said ions into predetermined said adjacent one or more confinement channels (N₁) after urging, via ion mobility separation and transport, into said predetermined adjacent one or more confinement channels (N₁);

d) providing a subsequent packet of ions of said predetermined mass window into said first confinement channel after the transfer of said fractions of said ions of said predetermined mass window into said adjacent one or more confinement channels (N₁) configured within said ion interface instrument;

e) transferring one or more of more of said fractions of ions of said predetermined mass window to an entrance of one or more mass analyzers;

f) mass analyzing said ions of said predetermined mass window;

g) repeating steps c) to f);

for any number of a plurality of said subsequent packet of ions of a predetermined mass window, wherein said packet of ions have a mass-to-charge window similar to a mass-to-charge window of any of said subsequent packet of ions.

11. ) The method of claim 10, wherein the transferring step e) further comprises:

e1) providing a second ion interface instrument additionally partitioned into one or more confinement channels (N₂) also having predetermined fixed spatial locations provided by desired DC and RF potentials; and

e2) receiving into any of one or more confinement channels (N₂) of said second ion interface instrument, one or more of said fractions of said ions of said predetermined mass window from said adjacent one or more confinement channels (N₁) of said ion interface instrument;

wherein said one or more of more of said fractions of said predetermined mass window are thereafter transferred to an entrance of said one or more mass analyzers.

12. ) The method of claim 11, wherein said receiving step e2) further comprises:

fragmenting said fractions of said ions of said predetermined mass window undergo prior to being received by any of said one or more confinement channels (N₂) of said second ion interface instrument.

13. ) The method of claim 11, wherein the maximum ion mobility transfer period of ions across the length of said partitioned one or more confinement channels (N₁) of said first ion interface instrument and the length of said partitioned one or more confinement channels (N₂) of said second ion interface instrument is set to a time frame that is less than the difference between the fill time for said first confinement channel of said first ion interface instrument and the scanning time for said predetermined mass window using a beneficial mass analyzer.

14. ) The method of claim 13, wherein an applied electric field (E) gradient and ion mobility separation time t are adjusted to provide said ion mobility transfer period.

15. ) The method of claim 14, wherein said applied electric field (E) gradient is enabled by a controller to provide DC pulses from about 1 microsecond (μ

sec) up to about 10 microseconds (μ

secs), and from about in the tens of micro seconds.

16. ) The method of claim 14, wherein said applied electric field (E) gradient is enabled by a controller to provide DC pulses from about 10 microseconds (μ

sec) up to about 40 microseconds (μ

secs).

17. ) The method of claim 14, wherein electrodes to provide a DC gradient of about 1 V/cm up to about 10 V/cm so as to aid said ion mobility transport and separation are selected from:

one or more auxiliary electrodes, a plate electrode, and multipole electrodes.

18. ) The method of claim 10, further comprises:

providing gas pressures of about 20 mtorr up to about 100 motor to aid said ion mobility transport and separation.

19. ) The method of claim 10, wherein said method further comprises:

providing a mobility resolution of down to about 10.

20. ) The method of claim 10, wherein the step of transferring one or more of more of said fractions of ions of said predetermined mass window to an entrance of one or more mass analyzers further comprises Automatic Gain Control (AGC).