U.S. patent application number 14/528917 was filed with the patent office on 2015-03-19 for ion manipulation device to prevent loss of ions.
This patent application is currently assigned to BATTELLE MEMORIAL INSTITUTE. The applicant listed for this patent is Gordon A. Anderson, Erin M. Baker, Yehia M. Ibrahim, Richard D. Smith, Aleksey Tolmachev. Invention is credited to Gordon A. Anderson, Erin M. Baker, Yehia M. Ibrahim, Richard D. Smith, Aleksey Tolmachev.
Application Number | 20150076343 14/528917 |
Document ID | / |
Family ID | 51493351 |
Filed Date | 2015-03-19 |
United States Patent
Application |
20150076343 |
Kind Code |
A1 |
Tolmachev; Aleksey ; et
al. |
March 19, 2015 |
ION MANIPULATION DEVICE TO PREVENT LOSS OF IONS
Abstract
An ion manipulation method and device to prevent loss of ions is
disclosed. The device includes a pair of surfaces. An inner array
of electrodes is coupled to the surfaces. A RF voltage and a DC
voltage are alternately applied to the inner array of electrodes.
The applied RF voltage is alternately positive and negative so that
immediately adjacent or nearest neighbor RF applied electrodes are
supplied with RF signals that are approximately 180 degrees out of
phase.
Inventors: |
Tolmachev; Aleksey;
(Richland, WA) ; Smith; Richard D.; (Richland,
WA) ; Ibrahim; Yehia M.; (Richland, WA) ;
Anderson; Gordon A.; (Benton City, WA) ; Baker; Erin
M.; (West Richland, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tolmachev; Aleksey
Smith; Richard D.
Ibrahim; Yehia M.
Anderson; Gordon A.
Baker; Erin M. |
Richland
Richland
Richland
Benton City
West Richland |
WA
WA
WA
WA
WA |
US
US
US
US
US |
|
|
Assignee: |
BATTELLE MEMORIAL INSTITUTE
Richland
WA
|
Family ID: |
51493351 |
Appl. No.: |
14/528917 |
Filed: |
October 30, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14292448 |
May 30, 2014 |
8901490 |
|
|
14528917 |
|
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|
14146922 |
Jan 3, 2014 |
8835839 |
|
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14292448 |
|
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61809660 |
Apr 8, 2013 |
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Current U.S.
Class: |
250/290 ;
250/200; 250/396R |
Current CPC
Class: |
G01N 27/622 20130101;
H01J 49/062 20130101; H01J 49/06 20130101 |
Class at
Publication: |
250/290 ;
250/396.R; 250/200 |
International
Class: |
H01J 49/06 20060101
H01J049/06 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] The invention was made with Government support under
Contract DE-AC05-76RLO1830, awarded by the U.S. Department of
Energy. The Government has certain rights in the invention.
Claims
1. An ion manipulation device to prevent loss of ions comprising:
a. a pair of surfaces; b. an inner array of electrodes coupled to
the surfaces; and c. a RF voltage and a DC voltage being
alternately applied to the inner array of electrodes, wherein the
applied RF voltage is alternately positive and negative so that
immediately adjacent or nearest neighbor RF applied electrodes are
supplied with RF signals that are approximately 180 degrees out of
phase.
2. The device of claim 1 further comprising a first outer electrode
array coupled to the surface and positioned on one side of the
inner array of electrodes, and a second outer electrode array
coupled to the surface and positioned on the other side of the
inner array of electrodes.
3. The device of claim 2 wherein a second DC voltage is applied to
the first and second outer electrode arrays.
4. The device of claim 1 further comprising multiple pairs of
surfaces, wherein transfer of the ions is allowed through an
aperture and guided by a series of electrodes to move between
different pairs of surfaces of the multiple pairs of surfaces.
5. The device of claim 1 wherein the device is coupled to at least
one of the following: a charge detector, an optical detector, and a
mass spectrometer.
6. The device of claim 1 wherein the device is used to perform ion
mobility separations.
7. The device of claim 1 wherein the DC voltage is a static or
time-varying DC voltage.
8. The device of claim 7 wherein the time-varying DC voltage is a
traveling wave voltage.
9. The device of claim 1 wherein the surfaces are one of the
following: substantially planar, substantially parallel, and not
flat.
10. An ion manipulation device comprising: a. a pair of
substantially parallel surfaces; b. an array of inner electrodes
contained within, and extending substantially along the length of,
each parallel surface; c. a first outer array of electrodes and a
second outer array of electrodes, each positioned on either side of
the inner electrodes, contained within, and extending substantially
along the length of each parallel surface; and d. a RF voltage and
a first DC voltage being alternately applied to the inner array of
electrodes, wherein the applied RF voltage is alternately positive
and negative so that immediately adjacent or nearest neighbor RF
applied electrodes are supplied with RF signals that are
approximately 180 degrees out of phase; and e. a second DC voltage
applied to the first and second outer electrode arrays.
11. The device of claim 10 further comprising multiple pairs of
surfaces, wherein transfer of the ions is allowed through an
aperture and guided by a series of electrodes to move between
different pairs of surfaces of the multiple pairs of surfaces.
12. The device of claim 10 wherein the device is coupled to at
least one of the following: a charge detector, an optical detector,
and a mass spectrometer.
13. The device of claim 10 wherein the device is used to perform
ion mobility separations.
14. The device of claim 10 wherein the first DC voltage is a static
or time-varying DC voltage.
15. The device of claim 14 wherein the time-varying DC voltage is a
traveling wave voltage.
16. The device of claim 11 wherein the surfaces are one of the
following: substantially planar, substantially parallel, and not
flat.
17. A method of manipulating ions comprising: a. injecting ions
between a pair of surfaces, wherein each pair of surfaces contains
an array of inner electrodes; and b. applying a RF voltage and a DC
voltage alternately to the inner array of electrodes, wherein the
applied RF voltage is alternately positive and negative so that
immediately adjacent or nearest neighbor RF applied electrodes are
supplied with RF signals that are approximately 180 degrees out of
phase.
18. The method of claim 17 wherein each pair of surfaces further
contains a first outer electrode array coupled to the surface and
positioned on one side of the inner array of electrodes, and a
second outer electrode array coupled to the surface and positioned
on the other side of the inner array of electrodes.
19. The method of claim 18 further comprising applying a second DC
voltage to the first and second outer electrode arrays.
20. The method of claim 17 wherein the DC voltage is a static or
time-varying DC voltage.
21. The method of claim 20 wherein the time-varying DC voltage is a
traveling wave voltage.
22. An ion manipulation device to prevent loss of ions comprising:
a. a pair of surfaces; b. an inner array of electrodes coupled to
the surfaces; and c. a RF voltage applied to only one of the
surfaces, and a DC voltage applied to only the other surface.
23. The device of claim 22 further comprising a first outer
electrode array coupled to the surface and positioned on one side
of the inner array of electrodes, and a second outer electrode
array coupled to the surface and positioned on the other side of
the inner array of electrodes, wherein a second DC voltage source
is applied to the first and second outer electrode arrays.
24. The device of claim 22 wherein the DC voltage is a static or
time-varying DC voltage.
25. The device of claim 24 wherein the time-varying DC voltage is a
traveling wave voltage.
26. A method of manipulating ions comprising: a. injecting ions
between a pair of surfaces, wherein each pair of surfaces contains
an array of inner electrodes; b. applying a RF voltage to only one
of the surfaces; and c. applying a DC voltage to only the other
surface.
27. The method of claim 26 wherein each pair of surfaces further
contains a first outer electrode array coupled to the surface and
positioned on one side of the inner array of electrodes, and a
second outer electrode array coupled to the surface and positioned
on the other side of the inner array of electrodes, wherein a
second DC voltage is applied to the first and second outer
electrode arrays.
28. The method of claim 27 wherein the DC voltage is a static or
time-varying DC voltage.
29. The method of claim 28 wherein the time-varying DC voltage is a
traveling wave voltage.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 14/292,448, filed May 30, 2014, which is a
continuation-in-part of U.S. application Ser. No. 14/146,922, filed
Jan. 3, 2014, now issued as U.S. Pat. No. 8,835,839, which claims
the benefit of U.S. Provisional Application No. 61/809,660, filed
Apr. 8, 2013, the disclosures of which are hereby incorporated by
reference herein.
TECHNICAL FIELD
[0003] This invention relates to ion manipulations in gases. More
specifically, this invention relates to the use of RF and/or DC
fields to manipulate ions through electrodes, and building complex
sequences of such manipulations in devices that include one or more
such surfaces and structures built upon the surfaces.
BACKGROUND OF THE INVENTION
[0004] As the roles for mass spectrometry and other technologies
that involve the use, manipulation or analysis of ions continue to
expand, new opportunities can become limited by approaches
currently used for extended sequences of ion manipulations,
including their transport through regions of elevated pressure,
reaction (both ion-molecule and ion-ion), and ion mobility
separations. As such manipulations become more sophisticated,
conventional instrument designs and ion optic approaches become
increasingly impractical, expensive and/or inefficient.
SUMMARY OF THE INVENTION
[0005] The present invention is directed to devices and methods of
manipulating ions in gases. In one embodiment, an ion manipulation
device is disclosed that is essentially lossless and allows
extended sequences of ion manipulations. The device includes a pair
of surfaces and in which a pseudopotential is formed that inhibits
charged particles from approaching either of the surfaces, and the
simultaneous application of DC potentials to control and restrict
movement of ions between the surfaces.
[0006] In one implementation this involves two substantially or
identical surfaces that have an inner array of electrodes,
surrounded by a first outer array of electrodes and a second outer
array of electrodes. Each outer array of electrodes is positioned
on either side of the inner electrodes and contained within--and
extending substantially along the length of--each parallel surface
in a fashion similar to the inner array of electrodes. The DC
potentials are applied to the first and second outer array of
electrodes. The RF potentials, with a superimposed electric field,
are applied to the array of inner electrodes.
[0007] The superimposed electric field may be a static or dynamic
electric field. The static electric field may be, but is not
limited to, a DC gradient. The dynamic electric field may be, but
is not limited to, a traveling wave.
[0008] In one embodiment, the electrode arrangements on the two
surfaces are identical, such that similar or identical voltages are
applied to both. However, the exact arrangement of electrodes can
differ, and the precise voltages applied to the two facing surfaces
can also differ.
[0009] The pair of surfaces may be substantially planar,
substantially parallel or parallel, or not flat.
[0010] In one embodiment, the RF potentials are applied along with
the DC potentials on the first and second outer electrode arrays.
In another embodiment, the RF potentials are applied to only one of
the two surfaces. In another embodiment, the RF potentials are
applied to both of the surfaces.
[0011] In one embodiment, the electric field in all or a portion of
the device may be replaced with a gas flow to move ions in the
direction of the gas flow.
[0012] In one embodiment, the RF on at least one inner electrode is
out of phase with its neighboring inner electrode. In one
embodiment the RF on each electrode is phase shifted with its
neighboring inner electrode to form a repulsive pseudopotential. In
one embodiment, the RF on each electrode is approximately 180
degrees out of phase with its neighboring inner electrode to form
the pseudopotential.
[0013] In one embodiment, the array of inner electrodes comprises
at least two electrodes on the pair of surfaces. In another
embodiment, the first outer array of electrodes and the second
outer array of electrodes each comprise at least two electrodes on
the pair of surfaces. The device can include insulating material or
resistive material between the electrodes.
[0014] The RF voltage applied to the electrodes is between 0.1 kHz
and 50 MHz, the electric field is between 0 and 5000 volts/mm, and
operating pressures from less than 10.sup.-3 torr to approximately
atmospheric pressure or higher.
[0015] In one embodiment, the electrodes are perpendicular to at
least one of the surfaces. In an alternative embodiment, the
electrodes are parallel to at least one of the surfaces. The
electrodes may comprise a thin conductive layer on the
surfaces.
[0016] In certain embodiments, the device comprises multiple pairs
of surfaces and allows transfer of the ions through an aperture to
move between different pairs of surfaces.
[0017] The electrodes on the pair of surfaces may form one or more
different configurations. These configurations include, but are not
limited to, the following: a substantially T-shaped configuration,
allowing ions to be switched at a junction of the T-shaped
configuration; a substantially Y-shaped configuration, allowing
ions to be switched at a junction of the Y-shaped configuration; a
substantially X-shaped or cross-shaped configuration, allowing ions
to be switched at a junction of one or more sides of the X-shaped
or cross-shaped configuration; and/or a substantially
multidirectional shape, such as an asterisk (*)--shaped
configuration, with multiple junction points, allowing ions to be
switched at a junction to one or more sides of the
configuration.
[0018] In one embodiment, the electric field allows the ions to
move in a circular-shaped path, rectangular-shaped path, or other
irregular path, to allow the ions to make more than one transit
and, as one example, achieve higher resolution ion mobility
separations.
[0019] The space between the surfaces may be filled with an inert
gas or a gas that ions react with ions.
[0020] Stacks of cyclotron stages may be used with the device to,
for example, allow different ranges of ion mobilities to be
separated in different cyclotron stages, and in sum cover the
entire range of ions in a mixture.
[0021] The electric fields can be increased to cause ions to react
or dissociate.
[0022] The device may be coupled to at least one of the following:
a charge detector, an optical detector, and/or a mass
spectrometer.
[0023] In one embodiment, the device can be fabricated and
assembled using printed circuit board technology and interfaced
with a mass spectrometer.
[0024] The device can be used to perform ion mobility separations
and/or differential ion mobility separations (e.g., FAIMS).
[0025] Ions may be formed outside or inside the device using
photoionization, Corona discharge, laser ionization, electron
impact, field ionization, electrospray, or any other ionization
technique that generates ions to be used with the device.
[0026] In another embodiment of the present invention, an ion
manipulation device is disclosed. The device includes a pair of
substantially parallel surfaces. The device further includes an
array of inner electrodes contained within, and extending
substantially along the length of, each parallel surface. The
device also includes a first outer array of electrodes and a second
outer array of electrodes, each positioned on either side of the
inner electrodes, contained within, and extending substantially
along the length of, each parallel surface, wherein a
pseudopotential is formed that inhibits charged particles from
approaching either of the parallel surfaces. The device also
includes a RF voltage source and DC voltage sources, wherein a
first DC voltage source is applied to the first and second outer
array of electrodes and wherein a RF frequency, with a superimposed
electric field, is applied to the inner electrodes by applying a
second DC voltage to each electrode, such that ions move between
the parallel surfaces within an ion confinement area in the
direction of the electric field or can be trapped in the ion
confinement area.
[0027] In one embodiment, the RF frequency applied to the
electrodes is between 0.1 kHz and 50 MHz. The RF peak-to-peak
voltage is approximately 10 to 2000 volts. The electric field is
between about 0 and about 5000 volts/mm, and the pressure is
between 10.sup.-3 torr and atmospheric pressure.
[0028] In one embodiment, one or more of the electrodes has 0.5 to
10 mm relief from the surface, so that degradation of device
performance due to charging of the surfaces between electrodes is
prevented.
[0029] In another embodiment of the present invention, a method of
manipulating ions is disclosed. The method includes injecting ions
between a pair of substantially parallel surfaces, wherein each
pair of parallel surfaces contains an array of inner electrodes and
a first and second array of outer electrodes on either side of the
inner electrodes. The method further includes applying RF fields to
confine the ions between the surfaces. The method also includes
applying a first DC field to the outer electrodes equal to or
higher than a second DC field applied to the inner electrodes to
confine ions laterally. The method also includes superimposing the
second DC field on the RF field to further confine and move the
ions along in a direction set by the electric field.
[0030] In one embodiment, the method further includes transferring
the ions through an aperture in at least one of the pairs of
parallel surfaces, wherein the ions travel to between another pair
of parallel surfaces.
[0031] In another embodiment of the present invention, an ion
manipulation device is disclosed. The device includes multiple
pairs of substantially parallel surfaces. The device further
includes an array of inner electrodes contained within, and
extending substantially along the length of, each parallel surface.
The device also includes a plurality of outer arrays of electrodes,
wherein at least one outer array of electrodes is positioned on
either side of the inner electrodes. Each outer array is contained
within and extends substantially along the length of each parallel
surface, forming a potential that can inhibit ions moving in the
direction of the outer array of electrodes, and which works in
conjunction with a pseudopotential created by potentials applied to
the inner array of electrodes that inhibits charged particles from
approaching either of the parallel surfaces. The device also
includes a RF voltage source and a DC voltage source. A DC voltage
is applied to the plurality of outer arrays of electrodes. The RF
voltage, with a DC superimposed electric field, is applied to the
inner electrodes by applying the DC voltage to each electrode, such
that ions will move between the parallel surfaces within an ion
confinement area in the direction of the electric field or have
their motion confined to a specific area such that they are trapped
in the ion confinement area. Transfer of the ions to another pair
of parallel surfaces or through multiple pairs of parallel surfaces
is allowed through an aperture in one or more of the surfaces.
[0032] In another embodiment of the present invention, the
electrodes have significant relief from the surfaces. Regions of
such relief can be used to alter the electric fields, or also to
prevent effects due to charging of nonconductive regions between
electrodes. Such designs have particular value in regions where ion
confinement is imperfect, such as in reaction regions where
ion-molecule or ion-ion reactions result in ion products that have
m/z values either too high or too low for effective ion
confinement. In such cases just the reaction regions may require
electrodes that extend from the surfaces, and in such cases these
regions may have different, often larger, spacing between the two
surfaces.
[0033] In another embodiment of the present invention RF potentials
having two or more distinct frequencies and different electric
fields are co-applied to the arrays of electrodes on the two
surfaces and with a pattern of application that creates a
pseudopotential that inhibits charged particles from approaching
one or both of the substantially parallel surfaces over a
substantially greater m/z range than would be feasible with RF
potentials of a single frequency.
[0034] In another embodiment of the present invention, each central
or inner electrode is replaced by two or more electrodes with
adjacent electrodes having different phase of the RF applied such
that the traps formed for ions close to one of the surfaces are
substantially reduced, resulting in improved performance such as a
reduction of possible trapping effects or reduction in the m/z
range that can be transmitted, particularly when ion currents near
the upper limit are being transmitted.
[0035] In another embodiment of the present invention, an ion
manipulation device with electrical breakdown protection is
disclosed. The device includes a pair of surfaces including an ion
inlet and an ion outlet. The device also includes arrays of
electrodes coupled to the surfaces to which RF potentials are
applied to at least one of the surfaces in order to create a
pseudopotential that inhibits charged particles from approaching
the surfaces. The device further includes simultaneous application
of DC potentials to control and restrict movement of ions in
between each pair of surfaces, wherein the surfaces are housed in a
chamber. At least one electrically insulative shield is coupled to
an inner surface of the chamber for increasing a mean-free path
between two adjacent electrodes in the chamber. The ion
manipulation device can be, but is not limited to, an ion mobility
cyclotron device.
[0036] In one embodiment, the at least one insulative shield
includes a first insulative shield enclosing at least a part of the
inlet and a second insulative shield enclosing at least a part of
the outlet. The first insulative and the second insulative shield
may be made of, but not limited, to Teflon, polyether ether ketone
(PEEK), or polycarbonate.
[0037] In another embodiment, the inner surface is a side plate,
and the at least one insulative shield is coupled to the plate via
a sealing member.
[0038] The sealing member is, but not limited to, an O-ring,
adhesive, or sealant, and the at least one insulative shield
includes electrical feedthrough housing.
[0039] In one embodiment, the device includes a plurality of ion
manipulation devices.
[0040] The device with electrical breakdown protection can include
a first insulation plate between each ion device inside of the
chamber. The first insulation plate is made of, but not limited to,
ceramic, Teflon, fiberglass, PEEK, or polycarbonate.
[0041] The device with electrical breakdown protection can include
a top cover located above a top ion device in the chamber, and a
bottom cover located below a bottom ion device. The top cover may
include bolt holes for sealing purposes, and the bottom lid may
include a metal plate with an insulation plate embedded on the
metal plate.
[0042] In one embodiment, an inlet of each device is coupled to an
ion source, and an outlet of each device is coupled to a mass
spectrometer. The ion source may be, but is not limited to, an ion
funnel or a dual ion funnel.
[0043] In another embodiment of the present invention, an ion
manipulation device with electrical breakdown protection is
disclosed. The device includes a pair of surfaces including an ion
inlet and an ion outlet. The device also includes arrays of
electrodes coupled to the surfaces to which RF potentials are
applied to at least one of the surfaces in order to create a
pseudopotential that inhibits charged particles from approaching
the surfaces. The device further includes simultaneous application
of DC potentials to control and restrict movement of ions in
between each pair of surfaces, wherein the surfaces are housed in a
chamber. At least one electrically insulative shield is coupled to
a side plate of the chamber via a sealing member for increasing a
mean-free-path between two adjacent electrodes in the chamber.
[0044] In another embodiment of the present invention, an ion
manipulation device with electrical breakdown protection is
disclosed. The device includes a pair of surfaces including an ion
inlet and an ion outlet. The device also includes arrays of
electrodes coupled to the surfaces to which RF potentials are
applied to at least one of the surfaces in order to create a
pseudopotential that inhibits charged particles from approaching
the surfaces. The device further includes simultaneous application
of DC potentials to control and restrict movement of ions in
between each pair of surfaces, wherein the surfaces are housed in a
chamber. A first insulative shield encloses at least part of the
inlet and a second insulative shield encloses at least a part of
the outlet.
[0045] In another embodiment of the present invention, an ion
manipulation device with electrical breakdown protection is
disclosed. The device includes a pair of surfaces including an ion
inlet and an ion outlet. The device also includes arrays of
electrodes coupled to the surfaces to which RF potentials are
applied to at least one of the surfaces in order to create a
pseudopotential that inhibits charged particles from approaching
the surfaces. The device further includes simultaneous application
of DC potentials to control and restrict movement of ions in
between each pair of surfaces, wherein the surfaces are housed in a
chamber. The device also includes a plurality of insulative shields
for increasing a mean-free-path between two adjacent electrodes in
the chamber, wherein the plurality of shields includes: i. one or
more inner surface insulative shields coupled to one or more side
plates of the chamber; and one or more inlet and outlet insulative
shields, wherein the inlet insulative shield encloses at least a
part of the inlet, and the outlet insulative shield encloses at
least a part of the outlet.
[0046] In another embodiment of the present invention, an ion
manipulation device to prevent loss of ions is disclosed. The
device includes a pair of surfaces and an inner array of electrodes
coupled to the surfaces. The device also includes a RF voltage and
a DC voltage. The RF and DC voltages are alternately applied to the
inner array of electrodes. The applied RF voltage is alternately
positive and negative so that immediately adjacent or nearest
neighbor RF applied electrodes are supplied with RF signals that
are approximately 180 degrees out of phase.
[0047] In one embodiment, the device includes a first outer
electrode array coupled to the surface and positioned on one side
of the inner array of electrodes, and a second outer electrode
array coupled to the surface and positioned on the other side of
the inner array of electrodes. A second DC voltage is applied to
the first and second outer electrode arrays.
[0048] The device can include multiple pairs of surfaces, wherein
transfer of the ions is allowed through an aperture and guided by a
series of electrodes to move between different pairs of surfaces of
the multiple pairs of surfaces.
[0049] The DC voltage may be a static or a time-varying DC voltage.
In one embodiment, the time-varying DC voltage is a traveling wave
voltage.
[0050] In one embodiment, the pair of surfaces is a pair of
substantially parallel surfaces.
[0051] In one embodiment, the array of inner electrodes is
contained within and extends substantially along the length of each
surface. In one embodiment, the arrays of outer electrodes are
contained within and extend substantially along the length of each
surface.
[0052] In another embodiment of the present invention, a method of
manipulating ions is disclosed. The method includes injecting ions
between a pair of surfaces. Each pair of surfaces contains an array
of inner electrodes. The method also includes applying a RF voltage
and a DC voltage alternately to the inner array of electrodes. The
applied RF voltage is alternately positive and negative so that
immediately adjacent or nearest neighbor RF applied electrodes are
supplied with RF signals that are approximately 180 degrees out of
phase.
[0053] In another embodiment of the present invention, an ion
manipulation device to prevent loss of ions is disclosed. The
device includes a pair of surfaces and an inner array of electrodes
coupled to the surfaces. The device also includes a RF voltage
applied to only one of the surfaces and a DC voltage applied to
only the other surface. In one embodiment, the device includes
first outer electrode array coupled to the surface and positioned
on one side of the inner array of electrodes, and a second outer
electrode array coupled to the surface and positioned on the other
side of the inner array of electrodes, wherein a second DC voltage
is applied to the first and second outer electrode arrays.
[0054] In another embodiment of the present invention, a method of
manipulating ions is disclosed. The method includes injecting ions
between a pair of surfaces, wherein each pair of surfaces contains
an array of inner electrodes. The method also includes applying a
RF voltage to only one of the surfaces and a DC voltage to only the
other surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0055] FIG. 1A is a schematic of a portion of an individual
parallel surface containing an arrangement of electrodes for an ion
manipulation device, in accordance with one embodiment of the
present invention.
[0056] FIG. 1B is a schematic of a portion of an ion manipulation
device, in accordance with one embodiment of the present
invention.
[0057] FIG. 2 is a schematic of a portion of an individual parallel
surface containing an arrangement of electrodes, and also showing
an ion confinement area, for an ion manipulation device, in
accordance with one embodiment of the present invention.
[0058] FIG. 3A is a schematic of an individual parallel surface
containing an arrangement of electrodes for an ion manipulation
device, in accordance with one embodiment of the present
invention.
[0059] FIG. 3B is a schematic of an ion manipulation device, in
accordance with one embodiment of the present invention.
[0060] FIG. 4A is a schematic of an ion manipulation device, in
accordance with one embodiment of the present invention.
[0061] FIG. 4B shows where the ions will be confined when DC and RF
potentials are applied to the device of FIG. 4A, in accordance with
one embodiment of the present invention.
[0062] FIGS. 5A, 5B, and 5C show simulations for an ion switch in a
T-shaped configuration of an ion manipulation device, in accordance
with one embodiment of the present invention.
[0063] FIG. 6 shows dual polarity trapping regions for ion-ion
reactions in an ion manipulation device, in accordance with one
embodiment of the present invention.
[0064] FIG. 7 shows simulations of an ion switch in an "elevator"
configuration where ions are transferred through one or more
apertures to move between different pairs of parallel surfaces in
an ion manipulation device, in accordance with one embodiment of
the present invention.
[0065] FIG. 8 shows simulations of an ion switch in an "elevator"
configuration having multiple levels where ions are transferred
through one or more apertures to move between different pairs of
parallel surfaces in an ion manipulation device, in accordance with
one embodiment of the present invention.
[0066] FIG. 9 shows an ion manipulation device implemented as an
ion mobility cyclotron for high resolution separations, in
accordance with one embodiment of the present invention.
[0067] FIG. 10 shows an ion mobility device coupled between an
array of ion sources and an array of mass spectrometer devices, in
accordance with one embodiment of the present invention.
[0068] FIG. 11 shows one example of an electrical interface for an
ion manipulation device in a chamber, including a side lid,
electrical insulation housings and electrical feedthroughs, in
accordance with one embodiment of the present invention.
[0069] FIG. 12 shows one example of an insulation shield coupled to
inlet and outlet openings of an ion manipulation device inside of a
chamber, in accordance with one embodiment of the present
invention.
[0070] FIG. 13 shows a plurality of vacuum chambers arranged in a
stack for housing one or more ion manipulation devices, in
accordance with one embodiment of the present invention.
[0071] FIG. 14A is a schematic of one surface of an ion
manipulation device with RF inner electrodes having widths of
approximately 0.9 mm and the gap between the electrodes is
approximately 0.7 mm, in accordance with one embodiment of the
present invention.
[0072] FIG. 14B is a schematic of one surface of an ion
manipulation device with RF inner electrodes, similar to FIG. 14A,
having larger widths and a narrower gap between the electrodes, in
accordance with one embodiment of the present invention.
[0073] FIG. 15A is a schematic of one surface of an ion
manipulation device with alternating RF and DC inner electrodes
having similar widths and a gap of approximately 0.3 mm between the
electrodes, in accordance with one embodiment of the present
invention.
[0074] FIG. 15B is a schematic of one surface of an ion
manipulation device with alternating RF and DC inner electrodes,
similar to FIG. 15A, with the RF electrodes having widths larger
than the widths of the DC electrodes and a gap of approximately 0.2
mm between the electrodes, in accordance with one embodiment of the
present invention.
[0075] FIG. 15C is a schematic of one surface of an ion
manipulation device with alternating RF and DC inner electrodes,
similar to FIGS. 15A and 15B, with the RF electrodes having widths
smaller than the widths of the DC electrodes and a gap of
approximately 0.2 mm between the electrodes, in accordance with one
embodiment of the present invention.
[0076] FIG. 16 shows the effective field, calculated for a range of
distances from the midplane (Y=0 mm) to the surface of the device
(Y=2.2), with f=1 MHz, V.sub.RF=100 V.sub.0p, and m/z=1000, using
the ion manipulation devices of FIG. 14A (denoted as `c1` on the
figure), FIG. 14B (denoted as `c2` on the figure), FIG. 15A
(denoted as `c3` on the figure), FIG. 15B (denoted as `c4` on the
figure), and FIG. 15C (denoted as `c5` on the figure).
[0077] FIGS. 17A and 17B show the effective potential z-profiles
for various off-board distances `h` using the ion manipulation
device of FIG. 14A, with f=1 MHz, V.sub.RF=100 V.sub.0p, and
m/z=1000.
[0078] FIGS. 18A and 18B show the effective potential profiles
along the ion path, z axis, for various off-board distances using
the ion manipulation device of FIG. 14B, with f=1 MHZ, V.sub.RF=100
V.sub.0p, and m/z=1000.
[0079] FIGS. 19A and 19B show the effective potential z-profiles
for various off-board distances using the ion manipulation device
of FIG. 15A, with f=1 MHZ, V.sub.RF=100 V.sub.0p, and m/z=1000.
[0080] FIGS. 20A and 20B show the effective potential z-profiles
for various off-board distances using the ion manipulation device
of FIG. 15B, with f=1 MHZ, V.sub.RF=100 V.sub.0p, and m/z=1000.
[0081] FIGS. 21A and 21B show the effective potential z-profiles
for various off-board distances using the ion manipulation device
of FIG. 15C, with f=1 MHZ, V.sub.RF=100 V.sub.0p, and m/z=1000.
[0082] FIGS. 22A and 22B show the DC potential z-profiles for
various off-board distances using the ion manipulation device of
FIG. 15A, with potential 100 V applied to DC inserts or
electrodes.
[0083] FIGS. 23A and 23B show the DC potential z-profiles for
various off-board distances using the ion manipulation device of
FIG. 15B, with DC potential 100 V applied to DC inserts or
electrodes.
[0084] FIGS. 24A and 24B show the DC potential z-profiles for
various off-board distances using the ion manipulation device of
FIG. 15C, with DC potential 100 V applied to DC inserts or
electrodes.
[0085] FIG. 25 is a schematic of a top and bottom surface of an ion
manipulation device with DC only inner electrodes on the top
surface and RF only inner electrodes on the bottom surface, in
accordance with one embodiment of the present invention.
[0086] FIG. 26A is a schematic of the RF only inner electrode
surface, similar to the bottom surface of FIG. 25, with wider RF
electrodes.
[0087] FIG. 26B is a schematic of the RF only inner electrode
surface, similar to FIG. 26A, with narrower RF electrodes.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0088] The present invention is directed to devices, apparatuses,
and method of manipulating ions. The present invention uses
electric fields to create field-defined pathways, traps, and
switches to manipulate ions in the gas phase, and with minimal or
no losses. Embodiments of the device enable complex sequences of
ion separations, transfers, path switching, and trapping to occur
in the space between two surfaces positioned apart and each
patterned with conductive electrodes. In one embodiment, the
present invention uses the inhomogeneous electric fields created by
arrays of closely spaced electrodes to which readily generated
peak-to-peak RF voltages (V.sub.p-p .about.100 V; .about.1 MHz) are
applied with opposite polarity on adjacent electrodes to create
effective potential or pseudopotential fields that prevent ions
from approaching the surfaces. These ion confining fields result
from the combination of RF and DC potentials, with the RF
potentials among other roles creating a pseudopotential that
prevents loss of ions and charged particles over certain m/z ranges
to a surface, and the DC potentials among other roles being used to
confine ions to particular defined paths of regions between the two
surfaces, or to move ions parallel to the surfaces. The confinement
functions over a range of pressures (<0.001 torr to .about.1000
torr), and over a useful, broad, and adjustable mass to charge
(m/z) range. Of particular interest is the ability to manipulate
ions that can be analyzed by mass spectrometers, and where
pressures of <0.1 to .about.50 torr can be used to readily
manipulate ions over a useful m/z range, e.g., m/z 20 to >5,000.
This effective potential works in conjunction with DC potentials
applied to side electrodes to prevent ion losses, and allows the
creation of ion traps and/or conduits in the gap between the two
surfaces for the effectively lossless storage and/or movement of
ions as a result of any gradient in the applied DC fields.
[0089] In one embodiment, the invention discloses the use of RF and
DC fields to manipulate ions. The manipulation includes, but is not
limited to, controlling the ion paths, separating ions, reacting
ions, as well as trapping and accumulating the ions by the addition
of ions to the trapping region(s). The ion manipulation device,
which may be referred to as an "ion conveyor" or Structure for
Lossless Ion Manipulation (SLIM), uses arrays of electrodes on
substantially parallel surfaces to control ion motion. Combinations
of RF and DC potentials are applied to the electrodes to create
paths for ion transfer and ion trapping. The parallel surfaces may
be fabricated using, but not limited to, printed circuit board
technologies or 3D printing.
[0090] FIG. 1A is a schematic of a portion of an individual
parallel surface 100 containing a first and second array of outer
electrodes 120 and an array of inner electrodes 130 for an ion
manipulation device, in accordance with one embodiment of the
present invention. The array of inner electrodes 130 is contained
within and extends substantially along the length of the surface
100. The array of outer electrodes 120, positioned on either side
of the inner electrodes 130, is also contained within and extends
substantially along the length of the surface 100.
[0091] FIG. 1B is a schematic of a portion of an ion manipulation
device 200, in accordance with one embodiment of the present
invention. The device 200 includes a pair of substantially parallel
surfaces 210 and 215. Each surface contains an array of inner
electrodes 230 and a first and second array of outer electrodes
220. The arrays of outer electrodes 220 are positioned on either
side of the array of inner electrodes 230. The arrays of electrodes
220 and 230 are contained within and extend substantially along the
length of each parallel surface 210 and 215. The arrangement of
electrodes on the opposing surfaces can be identical as well as the
electric field applied. Alternately, either the detailed electrode
arrangements or the electric fields applied can be different in
order to affect ion motion and trapping between the device.
[0092] The portion of the device 200 also includes a RF voltage
source and DC voltage sources (not shown). In one embodiment, the
DC voltages are applied to the first and second outer array of
electrodes 220. The RF voltage, of opposite polarity upon adjacent
electrodes, with a superimposed DC electric field, is applied to
the inner array of electrodes 220. In the arrangement of FIG. 2,
with the RF and DC fields applied as such, ions either move between
the parallel surfaces 210 and 215 within an ion confinement area in
the direction of the electric field or can be trapped in the ion
confinement area depending on the DC voltages applied.
[0093] In one embodiment, the RF on at least one inner electrode is
out of phase with its neighboring inner electrode. In another
embodiment, each inner electrode is 180 degrees out of phase with
its neighboring inner electrode to form a pseudopotential that
inhibits charged particles from approaching either of the parallel
surfaces. In another embodiment each inner electrode is replaced by
two or more electrodes to which RF is applied to each and with one
or more the electrodes being out of phase with its neighboring
inner electrodes.
[0094] The electric field also allows the ions to move in a
circular-shaped or a rectangular-shaped path, to allow the ions to
make more than one transit. Stacks of cyclotron stages can be used
with the device 200. Arrangements with cyclotrons, where the ions
traverse a circular path, will allow very high-resolution mobility
separations with small physical size.
[0095] In one embodiment, the array of inner electrodes 220
comprises at least two electrodes on the pair of parallel surfaces
210 and 215. The first outer array of electrodes and the second
outer array of electrodes 220 may each comprise at least two
electrodes on the pair of parallel surfaces 210 and 215.
[0096] In one embodiment the RF is simultaneously applied with DC
potentials to the electrodes 220, and in another embodiment the RF
applied to adjacent outer electrodes has opposite polarity.
[0097] In one embodiment the space between the surfaces 210 and 215
may include a gas or otherwise vaporized or dispersed species that
ions react with.
[0098] In one embodiment the electrodes 220 are augmented by an
additional set of electrodes further displaced from the central
electrodes that has DC potentials applied that are opposite in
polarity to allow the confinement or separation of ions of opposite
polarity.
[0099] The device 200 can be coupled to other devices, apparatuses
and systems. These include, but are not limited to, a charge
detector, an optical detector, and/or a mass spectrometer. The ion
mobility separation possible with the device 200 can be used for
enrichment, selection, collection and accumulation over multiple
separations of any mobility resolved species.
[0100] The device 200 may be used to perform ion mobility
separations.
[0101] In one embodiment, the RF frequency applied to the
electrodes 230 is between 0.1 kHz and 50 MHz, and the electric
field is between 0 and 5000 volts/mm.
[0102] In one embodiment, the electrodes 220 and 230 are
perpendicular to at least one of the surfaces and may comprise a
thin conductive layer on the surfaces 210 and 215.
[0103] The device 200 can include multiple pairs of substantially
parallel surfaces, allowing transfer of the ions through an
aperture to move between different pairs of parallel surfaces.
[0104] The electrodes on the pair of surfaces 210 and 215 can form
one of many different configurations. In one embodiment, the
surfaces 210 and 215 form a substantially T-shaped configuration,
allowing ions to be switched at a junction of the T-shaped
configuration. In another embodiment, the surfaces 210 and 215 form
a substantially Y-shaped configuration, allowing ions to be
switched at a junction of the Y-shaped configuration. In another
embodiment, the surfaces 210 and 215 form a substantially X-shaped
or cross-shaped configuration, allowing ions to be switched at a
junction or one or more sides of the X-shaped configuration. In
another embodiment, the surfaces 210 and 215 form a substantially
multidirectional shape, such as an asterisk (*)-shaped
configuration, with multiple junction points, allowing ions to be
switched at a junction to one or more sides of the configuration.
Devices may be constituted from any number of such elements.
[0105] The electrodes on the surfaces can have any shape, not being
limited to the rectangular shapes such as in FIG. 1. For example,
the electrodes can be round, have ellipse or oval shapes, or be
rectangles with rounded corners.
[0106] FIG. 2 is a schematic of an individual parallel surface 300
containing an arrangement of electrodes 320 and 330 with an ion
confinement area 340 for an ion manipulation device, in accordance
with one embodiment of the present invention. Static DC voltages
may be applied to the outer electrodes 320 with RF applied to the
inner electrodes 330. Each central electrode can have RF applied
out of phase with its neighboring electrode.
[0107] A DC or other electric field is superimposed on the RF and
applied to the inner electrodes 330 to move ions through the device
of FIG. 2, in addition to successively lower voltages applied on
each outer electrode 320--moving from left to right or
alternatively from right to left, depending on the polarity and the
desired direction of motion. This electric field forces ions to the
right, while the RF and DC fields also confine ions to a central
region of the device as shown. Voltage polarities can be changed to
allow manipulation of both negative and positive ions.
[0108] FIG. 3A is a schematic of an individual parallel surface 400
containing an arrangement of electrodes for an ion manipulation
device, in accordance with one embodiment of the present invention.
The surface 400 includes electrodes 450 that are individually
programmable by a DC voltage, electrodes 430 associated with a
negative RF voltage, and electrodes 435 associated with a positive
RF voltage--where negative and positive RF refers to the phase of
the RF waveform.
[0109] FIG. 3B is a schematic of an ion manipulation device 500, in
accordance with one embodiment of the present invention. The ion
manipulation device 500 includes substantially parallel surfaces
510 and 515 that are similar to the surface 400 of FIG. 3A. The
device 500 includes electrodes 550 that are individually
programmable by a DC voltage, electrodes 530 associated with a
negative RF voltage, and electrodes 535 associated with a positive
RF voltage. In this arrangement, ions are confined between the
surfaces 510 and 515. The ions move in the direction defined by an
electric field.
[0110] FIG. 4A is a schematic of an ion manipulation device, in
accordance with one embodiment of the present invention. The
central or inner electrodes have RF fields applied with opposite
polarity to adjacent electrodes to create fields that prevent ions
from closely approaching the surfaces. Ions are moved according to
their mobilities under DC fields applied to the outer
electrodes.
[0111] FIG. 4B shows the trapping volume of ions between the
surfaces containing electrodes of an ion manipulation device, in
accordance with one embodiment of the present invention. Both
positive and negative charged ion particles are confined in
overlapping areas of the ion manipulation device. This can be
accomplished using multiple arrays of outer electrodes and applying
both RF and DC potentials.
[0112] The devices of the present invention provide for at least
the following: lossless (a) linear ion transport and mobility
separation, (b) ion transport around a corner (e.g., a 90 degree
bend), (c) ion switches to direct ions to one of at least two
paths, (d) ion elevators for transporting ions between different
levels of multilevel ion manipulation devices, (e) ion traps for
trapping, accumulation, and reaction of ions of one polarity. These
devices can be combined to create a core module for more complex
ion manipulation devices such as an ion mobility cyclotron. In one
implementation, integrating several modules will allow fabrication
of a single level device that will enable the separation of ions
over periods on the order of 0.1 to 10 seconds while achieving
resolutions of up to approximately 1000 for species over a limited
range of mobilities. The range of mobilities, and the fractions of
the total biomolecule ion mixture that can be separated, decreases
as the resolution is increased. Thus, an ion mobility cyclotron
module can provide a useful and targeted separation/analysis
capability--where information is desired for a limited subset of
species.
[0113] The integrated device can consist of a stack of modules each
covering a different portion of the full mobility spectrum. In
combination, they provide separations that cover the full range of
ion mobilities needed for a sample, while at the same time making
efficient use of all the ions from the sample. The integrated
device can draw upon the ion switch, elevator, and trap components
to provide a low resolution separation that partitions ions from
the sample into fractions that are delivered to different
cyclotrons using the ion elevator.
[0114] FIGS. 5A, 5B, and 5C show simulations of an ion switch in a
T-shaped configuration of an ion manipulation device, in accordance
with one embodiment of the present invention. These ion paths can
be controlled using switch elements. As shown in FIGS. 5A, 5B, and
5C, the ion path can be dynamically or statically changed by
modifying the electrode arrangement of the device and/or varying
the RF and DC voltages. The ions can be switched at a junction as
shown in FIG. 5A, move in a straight path as shown in FIG. 5B,
and/or curve or bend around a corner at the junction as shown in
FIG. 5C. Alternatively, the pair of parallel surfaces of the device
can form other configurations such as, but not limited to, Y-shaped
configurations, X-shaped or cross-shaped configurations, and other
multidirectional shapes.
[0115] FIG. 6 shows dual polarity trapping regions for ion-ion
reactions in an ion manipulation device, in accordance with one
embodiment of the present invention. Different polarity of ions,
positive and negative, can be trapped at the same time in at least
partially overlapping physical volumes between the two surfaces of
the device using multiple sets of electrodes and applying both RF
and DC potentials. Additional RF or DC potentials can be applied to
heat and excite either the positive or negatively charged ions in
order to change the reaction rate or reaction products.
[0116] FIG. 7 shows simulations of an ion switch in an "elevator"
configuration where ions are transferred through one or more
apertures to move between different pairs of parallel surfaces in
an ion manipulation device, in accordance with one embodiment of
the present invention. This allows multi-dimensional ion
manipulation using the ion manipulation device. In some embodiments
additional electrodes are added to increase the efficiency of
transfer between different levels, including electrodes with DC
and/or RF potentials with different polarities on adjacent
electrodes.
[0117] FIG. 8 shows simulations of an ion switch in an "elevator"
configuration having multiple levels where ions are transferred
through one or more apertures to move between different pairs of
parallel surfaces in an ion manipulation device, in accordance with
one embodiment of the present invention.
[0118] FIG. 9 is a schematic showing an ion manipulation device
implemented as an ion mobility cyclotron. Ions entering from the
ion source are initially trapped before a first low resolution
separation. Separated ions of interest are trapped and then
injected for cyclotron separations, potentially achieving
resolutions greater than 1000. The switching points direct ions to
one of at least two paths. All four points--the switching points
and the bends--are where changes in the rotating DC electric field
can be applied to create the cyclotron motions.
[0119] FIG. 10 shows an ion mobility device coupled between an
array of ion sources and an array of mass spectrometer devices, in
accordance with one embodiment of the present invention. As shown
in FIG. 10, the present invention also enables multiplexed sample
analyses using an array of ion sources and multiple ion separations
in parallel--separated during travel through the device--and
detected using an array of high speed, high dynamic range
time-of-flight (TOF) mass spectrometers (MS).
[0120] The pair of surfaces of the ion manipulation device can be
housed in a vacuum chamber. In one embodiment, at least one
electrically insulative shield is coupled to an inner surface of
the chamber for increasing a mean-free-path between two adjacent
electrodes in the chamber.
[0121] FIG. 11 shows one example of an electrical interface for an
ion manipulation device in a chamber, including a side lid 610,
electrical insulation housings 600 and electrical feedthroughs 620,
in accordance with one embodiment of the present invention. The
side lid is made of a nonconductive material. The bottom or flange
side 605 of the electrical insulation housing 600 includes a
sealing member to isolate the mean-free-path between adjacent
electrodes on the chamber side of the feedthroughs 620. The sealing
member is, but not limited to, an O-ring, an adhesive, or a
sealant. The flange 605 is coupled to the side lid 610 via the
sealing member.
[0122] FIG. 12 shows one example of an insulation shield 700
coupled to inlet and outlet openings of an ion manipulation device
inside of a chamber 710, in accordance with one embodiment of the
present invention. The insulation shield 700 is made of, but not
limited to, Teflon, PEEK, or polycarbonate.
[0123] FIG. 13 shows a plurality of vacuum chambers 810 arranged in
a stack 800 for housing one or more ion manipulation devices, in
accordance with one embodiment of the present invention. Although
six chambers are shown in FIG. 13, it should be noted that the
stack 800 is not limited to any specific number of chambers.
[0124] The chambers 810 include at least one inlet and at least one
outlet. The inlet may be coupled to an ion source interface such
as, but not limited to, an ion funnel or a dual ion funnel 820. The
outlet may be coupled to a mass spectrometer or analyzer directly
or indirectly via another ion device 830 for manipulating and/or
focusing ions. In the embodiment of FIG. 13, the bottom chamber of
the stack 800 is coupled through an ion funnel chamber 820 to a
mass spectrometer 830 at the outlet. In the inlet, two ion funnel
chambers 820 are connected as the ion source interface. One or more
of the chambers 810 can include a sensor such as, but not limited
to, a pressure sensor.
[0125] FIG. 14A is a schematic of one surface of an ion
manipulation device 1400 with RF inner electrodes 1420 having
widths of approximately 0.9 mm and the gap between the electrodes
is approximately 0.7 mm. The surface also includes DC outer
electrodes 1410. At least one RF voltage is applied to the RF inner
electrodes 1420 and at least one DC voltage is applied to the DC
outer electrodes 1410.
[0126] FIG. 14B is a schematic of one surface of an ion
manipulation device 1450 with RF inner electrodes 1470, similar to
FIG. 14A, having larger widths and a narrower gap between the
electrodes 1470. The surface also includes DC outer electrodes
1460. As with FIG. 14A, a RF voltage or voltages are applied to the
RF inner electrodes 1470 and a DC voltage or voltages are applied
to the DC outer electrodes 1460.
[0127] In another embodiment, as shown in FIGS. 15A-C, RF and DC
voltages are alternately applied to the inner array of electrodes,
and the applied RF voltage is alternately positive and negative so
that immediately adjacent or nearest neighbor RF applied electrodes
are supplied with RF signals that are approximately 180 degrees out
of phase.
[0128] FIG. 15A is a schematic of one surface of an ion
manipulation device 1500 with alternating RF inner electrodes 1520
and DC inner electrodes 1530. In this example, the electrodes 1520
and 1530 having similar widths of approximately 0.5 mm and a gap of
approximately 0.3 mm between the electrodes 1520 and 1530. The
surface also includes outer electrodes 1510 adjacent or positioned
on either side of the inner electrodes 1520 and 1530. DC voltages
are applied to the outer electrodes 1510. It should be noted that
the widths or diameters of the electrodes, as well as the gap
dimensions between each electrode, may vary by length.
[0129] FIG. 15B is a schematic of one surface of an ion
manipulation device with alternating RF inner electrodes 1570 and
DC inner electrodes 1575, similar to FIG. 15A, with the RF
electrodes having widths larger than the widths of the DC
electrodes and a gap of approximately 0.2 mm between the
electrodes. In this example, the RF electrodes have a width of
approximately 0.9 mm, and the DC electrodes have a width of
approximately 0.3 mm. The surface also includes outer electrodes
1560 adjacent or positioned on either side of the inner electrodes
1570 and 1575. DC voltages are applied to the outer electrodes
1560.
[0130] FIG. 15C is a schematic of one surface of an ion
manipulation device 1580 with alternating RF inner electrodes 1592
and DC inner electrodes 1595, similar to FIGS. 15A and 15B. In this
example, the RF electrodes 1592 have widths smaller than the widths
of the DC electrodes 1595. The width of the RF electrodes 1592 is
approximately 0.3 mm, and the width of the DC electrodes 1595 is
approximately 0.9 mm. The surface includes a gap of approximately
0.2 mm between each inner electrode 1592 and 1595.
[0131] The ion manipulation device of FIGS. 15A-15C may be coupled,
but not limited to, a charge detector, an optical detector, and a
mass spectrometer. In one embodiment, the ion manipulation device
is used to perform ion mobility separations.
[0132] The DC voltages on the inner electrodes of FIGS. 15A-15C is
a static or time-varying DC voltage. The time-varying voltage may
be a traveling wave voltage.
[0133] The ion manipulation device of FIGS. 15A-15C includes a pair
of surfaces. The pair of surfaces are substantially parallel or
substantially planar. In one embodiment, the surfaces are not
flat.
[0134] FIG. 16 shows the effective field, calculated for a range of
distances from the midplane (Y=0 mm) to the surface of the device
(Y=2.2 mm), with f=1 MHz, V.sub.RF=100 V.sub.0p, and m/z=1000,
using the ion manipulation devices of FIG. 14A (denoted as `c1` on
the figure), FIG. 14B (denoted as `c2` on the figure), FIG. 15A
(denoted as `c3` on the figure), FIG. 15B (denoted as `c4` on the
figure), and FIG. 15C (denoted as `c5` on the figure). An effective
field of E.sub.y.apprxeq.100 V/cm was achievable at approximately
1.6 mm or 0.6 mm from the surface of the ion manipulation device,
where y.sub.max is approximately 2.2 mm.
[0135] FIGS. 17A and 17B show the effective potential z-profiles
for various off-board distances `h` using the ion manipulation
device of FIG. 14A, with f=1 MHz, V.sub.RF=100 V.sub.0p, and
m/z=1000. Smooth profiles are obtained for h>0.5 mm.
[0136] FIGS. 18A and 18B show the effective potential z-profiles
for various off-board distances from 0.1 mm to 1.2 mm using the ion
manipulation device of FIG. 14B, with f=1 MHZ, V.sub.RF=100
V.sub.0p, and m/z=1000.
[0137] FIGS. 19A and 19B show the effective potential z-profiles
for various off-board distances using the ion manipulation device
of FIG. 15A, with f=1 MHZ, V.sub.RF=100 V.sub.0p, and m/z=1000.
[0138] FIGS. 20A and 20B show the effective potential z-profiles
for various off-board distances using the ion manipulation device
of FIG. 15B, with f=1 MHZ, V.sub.RF=100 V.sub.0p, and m/z=1000. The
profiles are close to ideal when h>0.5 mm, where E.sub.y is
>approximately 100 V/cm.
[0139] FIGS. 21A and 21B show the effective potential z-profiles
for various off-board distances using the ion manipulation device
of FIG. 15C, with f=1 MHZ, V.sub.RF=100 V.sub.0p, and m/z=1000. In
this example, the profiles were less than ideal, as the effective
fields were weak.
[0140] FIGS. 22A and 22B show the DC potential z-profiles for
various off-board distances using the ion manipulation device of
FIG. 15A, with f=1 MHZ, V.sub.RF=100 V.sub.0p, and m/z=1000.
Uniform profiles were obtained at h>1.2 mm, with a penetration
of 43% of the DC potential into the central volume.
[0141] FIGS. 23A and 23B show the DC potential z-profiles for
various off-board distances using the ion manipulation device of
FIG. 15B, with f=1 MHZ, V.sub.RF=100 V.sub.0p, and m/z=1000. The
narrower DC electrodes in this example led to a reduced penetration
of approximately 27% to the center.
[0142] FIGS. 24A and 24B show the DC potential z-profiles for
various off-board distances using the ion manipulation device of
FIG. 15C, with f=1 MHZ, V.sub.RF=100 V.sub.0p, and m/z=1000. The
wider DC electrodes in this example led to an increased penetration
of approximately 55% to the center.
[0143] FIG. 25 is a schematic of a top surface 1600 and a bottom
surface 1650 of an ion manipulation device with DC only inner
electrodes 1620 on the top surface 1600 and RF only inner
electrodes 1670 on the bottom surface 1650. The top surface 1600
includes outer electrodes 1610 on either side of the inner
electrodes 1620. Similarly, the bottom surface 1650 also includes
outer electrodes 1660 on either side of the inner electrodes 1670.
In this embodiment or example, a RF voltage is applied to only the
inner electrodes 1670 of the bottom surface 1650, and only a DC
voltage is applied to the inner electrodes 1620 of the top surface
1600. It should be noted that the top surface can have "RF only"
inner electrodes, while the bottom surface has "DC only" inner
electrodes. A DC voltage is applied to the outer electrodes of each
surface 1600 and 1650. The DC voltage applied to the outer
electrodes may be different or the same voltage applied to the DC
only inner electrodes.
[0144] FIG. 26A is a schematic of the RF only inner electrode
surface 1700, similar to the bottom surface of FIG. 25, with wider
RF inner electrodes 1720. The surface 1700 also includes a first
and second array of outer electrodes 1710. In this example, the RF
electrodes or strips 1720 are approximately 0.8 mm wide with
approximately 0.4 mm spaces between the strips.
[0145] FIG. 26B is a schematic of the RF only inner electrode
surface 1750, similar to FIG. 26A, with narrower RF electrodes
1770. The surface 1750 also includes a first and second array of
outer electrodes 1760. In this example, the RF electrodes or strips
1770 are approximately 0.4 mm wide with approximately 0.4 mm spaces
between the strips.
[0146] The ion manipulation devices, particularly the embodiments
shown in FIGS. 15A-C, 25 and 26, address the need for reduced
complexity, control electronics, and expense of power supplies
needed to enable complex sequences of ion manipulations. This is
mainly due to the separation of electrodes to which RF and DC
voltages are applied.
[0147] The devices also enable the use of longer path length ion
mobility separations and/or other manipulations, providing much
higher resolutions, as large differences in electric fields are not
required--the potential needed for, for example, separations
typically increase in proportion with the length of the ion
manipulation path. The devices cover the full mobility range, which
does not require a limited mobility range as would be required for
separations in a cyclotron or other receptive path of limited
length.
EXAMPLE
[0148] The following examples serve to illustrate certain
embodiments and aspects of the present invention and are not to be
construed as limiting the scope thereof.
[0149] A device, as shown in FIG. 1B, was used to manipulate ions
injected from an external ESI source. Simulations were performed to
refine the design of the device; e.g. electrode sizes and spacing
between the planar surfaces were adjusted. Boards were fabricated
with electrode regions to test capabilities that included efficient
ion transportation, ion mobility separations, ion trapping, and ion
switching between alternative corridors or paths.
[0150] In one test, ions were introduced from the external ESI
source and injected into one of the ion corridors at a pressure of
.about.4 torr. RF frequencies of approximately 1.4 MHz and 140 Vp-p
were applied to create repulsive fields to confine ions within the
ion corridors between the opposing board surfaces. The RF fields
were combined with DC for further confinement to the corridors and
also to move the ions along the corridors based upon their ion
mobilities. Separate electrodes were used to measure ion currents
at various locations and evaluate ion transmission efficiency
through different areas of the device. Initial measurements showed
that ions can be efficiently introduced into such devices, as well
as transported through them with minimal losses.
[0151] The device of the present invention, including its various
embodiments, can be manufactured at very low cost and is very
flexible, allowing application to many different areas in mass
spectrometry. As one example, the device can be fabricated and
assembled using printed circuit board technology and interfaced
with a mass spectrometer. The device can also be lossless. Ion
mobility separation and complex ion manipulation strategies can be
easily implemented with the device.
[0152] The device of the present invention, including its various
embodiments, can be altered in its performance by the use of
electrodes that have significant thickness and thus substantial
relief from one or both of the surfaces. The thickness can vary
between electrodes, and individual electrodes can have variable
thickness. These electrodes can be used to create electric fields
not practical for very thin electrodes (e.g. surface deposited such
as on conventional printed circuit boards). Regions of devices with
such electrodes have particular value when incomplete or
inefficient ion confinement may occur, such as for very low or high
m/z ions created by reactions that can provide a well-controlled
electric field and prevent degraded performance from distorted
electric fields due to the charging of surfaces between
electrodes.
[0153] Embodiments of the present invention can improve and extend
analysis capabilities in, for example, proteomics, metabolomics,
lipidomics, glycomics, as well as their applications to a broad
range of biological and chemical measurements and applicable
research areas. Utilization of the ion manipulation device can lead
to faster, cheaper, and more sensitive measurements relevant to
understanding chemical, environmental, or biological systems. The
present invention enables MS-based approaches involving complex ion
manipulations in the gas phase capable of augmenting or completely
displacing conventional liquid phase approaches. The present
invention also enables separations and other ion manipulations over
extended periods in a nearly lossless fashion. These capabilities
lead to very fast and high resolution gas phase separations of
ions.
[0154] The present invention has been described in terms of
specific embodiments incorporating details to facilitate the
understanding of the principles of construction and operation of
the invention. As such, references herein to specific embodiments
and details thereof are not intended to limit the scope of the
claims appended hereto. It will be apparent to those skilled in the
art that modifications can be made in the embodiments chosen for
illustration without departing from the spirit and scope of the
invention.
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