U.S. patent application number 15/783388 was filed with the patent office on 2018-02-08 for capillary electrophoresis-electrospray ionization-mass spectrometry system.
The applicant listed for this patent is Beckman Coulter, Inc.. Invention is credited to Jean-Marc Rene Lucien Busnel, Clive Cheung, Sunil S. Deliwala, Craig A. Hudson, Peter S. Kotowski, Anna X. Lou, Jane Luo, Dale Alan Owens, Brian D. Peterson, Chitra K. Ratnayake, James H. Reyes, Tom Tran.
Application Number | 20180038829 15/783388 |
Document ID | / |
Family ID | 47221552 |
Filed Date | 2018-02-08 |
United States Patent
Application |
20180038829 |
Kind Code |
A1 |
Peterson; Brian D. ; et
al. |
February 8, 2018 |
CAPILLARY ELECTROPHORESIS-ELECTROSPRAY IONIZATION-MASS SPECTROMETRY
SYSTEM
Abstract
Aspects of the innovations presented herein relate to improved
systems that in some embodiments perform capillary electrophoresis
(CE) and CE in conjunction with electrospray ionization (ESI) as an
input to a mass spectrometry system (MS). Some embodiments use a
high voltage isolated CE power supply that is configured to float
on the high voltage output of an ESI-MS power supply, with a
protective resistance in the ESI-MS path, as well as DC/DC
converter isolation and communication system isolation for the
isolated CE power supply. Some embodiments additionally use a
cartridge assembly integrating separation and conductive fluid
capillaries with fluid cooling and protective retractable housings
for the capillary end portions and for the ESI output. The
protective housing may further be used with an adapter for
interfacing with different MS systems.
Inventors: |
Peterson; Brian D.;
(Ontario, CA) ; Owens; Dale Alan; (Corona, CA)
; Kotowski; Peter S.; (Yorba Linda, CA) ;
Deliwala; Sunil S.; (Placentia, CA) ; Hudson; Craig
A.; (Brownsburg, IN) ; Reyes; James H.;
(Victoville, CA) ; Cheung; Clive; (Norco, CA)
; Tran; Tom; (Irvine, CA) ; Lou; Anna X.;
(Arcadia, CA) ; Luo; Jane; (Irvine, CA) ;
Busnel; Jean-Marc Rene Lucien; (Marseille, FR) ;
Ratnayake; Chitra K.; (Yorba Linda, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Beckman Coulter, Inc. |
Brea |
CA |
US |
|
|
Family ID: |
47221552 |
Appl. No.: |
15/783388 |
Filed: |
October 13, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14354489 |
Apr 25, 2014 |
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PCT/US2012/062270 |
Oct 26, 2012 |
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15783388 |
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61552411 |
Oct 27, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N 27/44717 20130101;
Y10T 307/313 20150401; H01J 49/165 20130101; G01N 30/7266 20130101;
H01J 49/022 20130101; G01N 27/44743 20130101 |
International
Class: |
G01N 27/447 20060101
G01N027/447; H01J 49/02 20060101 H01J049/02; G01N 30/72 20060101
G01N030/72; H01J 49/16 20060101 H01J049/16 |
Claims
1. An electrical circuit comprising: a first dc power supply having
a first output and a first input; a first resistive electrical path
connected to a ground that provides a first dc power supply return
from the first output to the first input; a second dc power supply
having a second output and a second input; a second resistive
electrical path that provides a second dc power supply return from
the second output to the second input, wherein the second resistive
electrical path is isolated from the ground, and wherein the first
output is electrically coupled with the second input; an isolated
control circuit that is electrically coupled with the second dc
power supply and is isolated from the ground, wherein the isolated
control circuit is communicatively coupled with an interface board
via a communication link, and wherein the communication link
maintains isolation from the ground; and a DC/DC converter that
provides isolated input power to the second dc power supply and the
isolated control circuit.
2. The electrical circuit of claim 1 wherein the second resistive
electrical path is electrically coupled to an electro-spray (ES)
assembly.
3. The electrical circuit of claim 2 wherein the ES assembly is
electrically coupled to an adapter, and wherein the ES assembly
comprises a sprayer housing, and wherein the sprayer housing
comprises a needle, a spring wound around the needle, and a
retracting protective sheath coupled to the spring.
4. The electrical circuit of claim 3 wherein the ES assembly is
coupled to a mass spectrometer via the adapter.
5. The electrical circuit of claim 2 wherein the ES assembly
comprises a conductive slug portion that provides a resistive
electrical ES assembly path from an external surface of the ES
assembly to a conductive fluid contact area inside the ES assembly;
and wherein the second resistive electrical path comprises the
resistive electrical ES assembly path.
6. The electrical circuit of claim 5 wherein the second resistive
electrical path further comprises a resistive electrical adapter
path as part of an adapter that couples the ES assembly to a mass
spectrometer.
7. The electrical circuit of claim 5 wherein the first output is
electrically coupled with the second input via the resistive
electrical ES assembly path.
8. The electrical circuit of claim 1 wherein the second resistive
electrical path comprises a sample capillary path that is part of a
capillary electrophoresis (CE) analysis system.
9. The electrical circuit of claim 8 wherein the interface board is
part of the CE analysis system, and wherein the CE analysis system
communicates with the isolated control circuit via the interface
board to control the second DC power supply.
10. The electrical circuit of claim 1 wherein the interface board
is part of the CE analysis system; wherein the communications link
is an optical communications link; wherein the interface board
receives an analog control signal, converts the analog control
signal to a digital logic pulse stream which is routed to the
isolated control circuit; and wherein the isolated control circuit
converts the digital logic pulse stream back into the analog
control signal and controls the second DC power supply using the
analog control signal.
11. The electrical circuit of claim 1 further comprising a voltage
limit resistor coupled directly with the first dc power supply,
wherein said voltage limit resistor is in the first resistive
electrical path and is not in the second resistive electrical
path.
12. The electrical circuit of claim 11 wherein the communication
link and the DC/DC converter each is able to withstand a voltage
greater than or equal to a maximum output voltage of the first dc
power supply, a maximum output voltage of the second dc power
supply, or a voltage that is a sum of said maximum output
voltages.
13. The electrical circuit of claim 12 wherein the maximum output
voltage of the first dc power supply is a value between -10 kV and
+10 kV, inclusive.
14. The electrical circuit of claim 12 wherein the maximum output
voltage of the second dc power supply is a value between -30 kV and
+30 kV, inclusive.
15. The electrical circuit of claim 11 wherein the voltage limit
resistor has a resistive value between 10 megaOhms and 500
megaOhms, inclusive.
16. The electrical circuit of claim 11 further comprising a leakage
detection circuit operably coupled with the voltage limit resistor
that measures leakage current.
17. The electrical circuit of claim 16 wherein the leakage
detection circuit comprises: a sense resistor coupled directly to
the voltage limit resistor; and an amplifier coupled with the sense
resistor and the voltage limit resistor; wherein the sense resistor
and the amplifier are disposed in the first resistive electrical
path and are not disposed in the second resistive electrical
path.
18. The electrical circuit of claim 16 wherein the leakage
detection circuit comprises: a sense resistor coupled indirectly
with the voltage limit resistor; and an amplifier coupled directly
with the sense resistor, wherein the amplifier is indirectly
coupled with a first side of the voltage limit resistor via the
first DC power supply and is indirectly coupled with a second side
of the voltage limit resistor via a mass spectrometer load and the
sense resistor; and wherein the sense resistor and the amplifier
are disposed in the first resistive electrical path and are not
disposed in the second resistive electrical path.
19. The electrical circuit of claim 17 wherein the resistive value
of the sense resistor is a value between 1 kOhm and 503 kOhms,
inclusive.
20. The electrical circuit of claim 18 wherein the resistive value
of the sense resistor is a value between 1 kOhm and 503 kOhms,
inclusivey.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 14/354,489, filed on Apr. 25, 2014, which claims the benefit of
priority from U.S. Provisional Application No. 61/552,411, filed on
Oct. 27, 2011, the contents of all of which are hereby incorporated
by reference.
BACKGROUND
[0002] This invention relates to electrophoresis and to capillary
electrophoresis used in conjunction with electrospray ionization
mass spectrometry.
[0003] Electrophoresis is fundamentally the movement of charged
particles within an applied electric field. Capillary
electrophoresis (CE) is a known process. In capillary
electrophoresis, a sample is injected at one end of the capillary.
A detector is attached on the capillary at the other end of the
capillary distant from the sample. A voltage is applied along the
length of the capillary.
[0004] With the electric potential applied, two separate flow
effects occur. The first of these flow effects is a gross sample
flow effect. The sample moves as a mass into the capillary. The
second of these flow effects is the electrophoretic flow. This
causes the constituents of the sample having differing electric
charge to move relative to the main stream of fluid within the
capillary. The portions of the sample having differing electric
charges are thereby separated in the capillary.
[0005] Different detectors may be used to analyze the sample after
the separation has occurred. In a system that combines capillary
electrophoresis with electrospray ionization (ESI), and mass
spectrometry (MS), the output of the capillary is input to an
electrospray assembly. The electrospray ionization is accomplished
by placing a high voltage potential at the outlet of the separation
capillary with respect to the capillary inlet to the mass
spectrometer. The separation capillary also requires a high voltage
potential placed between its inlet and outlet. The separated
portions of the sample are dispersed by the electrospray into a
fine aerosol as they exit the capillary. The droplets of the
aerosol then are observed by mass spectrometry.
[0006] Capillary electrophoresis coupled with electrospray
ionization and mass spectrometry is a relatively difficult
procedure. The capillary must be mechanically connected to the rest
of the system and positioned with respect to a detector. The
capillaries are small and fragile, and the alignment process with
the electrospray ionization assembly into the mass spectrometer may
be difficult, time consuming, and may damage the capillary.
[0007] The system is further complicated by the need to cool the
capillary. This cooling is required because the small capillary is
subject to electrical resistance heating during the period of time
electrophoresis potential voltage is applied. A small current under
high voltage flowing in the capillary generates heat. The cooling
is required to prevent damage to the capillary and to prevent
variations in temperature during analysis of the sample from
impacting the results of the analysis. Excess heat may cause
diffusion of the separated portions of the sample that migrate
through the capillary at different speeds. The heat and its
resultant diffusion degrade separation and following classification
result that is the purpose of using electrophoresis.
[0008] FIG. 2A describes a known CE-MS system using a CE power
supply 220a that is not isolated. This configuration may also be
considered a non-floating configuration, where the high voltage
from CE power supply 220a used to create separation in the sample
capillary 242a has the same ground as the ESI-MS power supply 254
that is used by mass spectrometer 250. Using non-isolated
(non-floating) power supplies requires that the return path, which
is the path that the current from the DC power supply output
follows to return to the power supply input, for both separation
and electrospray power supplies are ground referenced. This
presents a problem in that the separation power supply return
creates an electrical short circuit for the electrospray power
supply. This is seen in FIG. 2A in the connection from electrospray
(ES) High Voltage Output 226 through Conductive Fluid Capillary
244a to CE High Voltage (HV) return 224a.
[0009] To alleviate this problem, one known approach is to have the
high voltage return for the separation power supply disconnected.
In FIG. 2A, this may be shown as disconnecting the direct path from
conductive fluid vial 234a to CE Power Supply 220a. This changes
the return path for CE Power Supply 220a, and then requires that
current generated by the separation supply not only pass through
the sample capillary 242a but also the electrospray assembly 252a,
the mass spectrometer ESI-MS Power Supply 254, and the instrument
chassis ground before finding its return to CE power supply 220a at
CE HV return 224a. Although such a method provides the
functionality for CE-ESI-MS, if the separation power supply
requires current to return through a dedicated pin rather than
chassis ground, a false current leakage reading may be induced.
Furthermore, current measurements for the electrospray power supply
will reflect the sum of both ESI and separation current. Because
the separation current is typically one to two orders of magnitude
greater than the electrospray current, the electrospray current
cannot be determined for system diagnostic purposes.
[0010] Another alternative solution involves placing the
electrospray needle or separation capillary outlet at ground
potential. This may work with the operation of the CE-ESI-MS system
but requires the inlet of the mass spectrometer to be at high
voltage potentials. This complicates the design of the mass
spectrometer.
[0011] Therefore, other alternative solutions to the problems
presented by a non-isolated power supply may avoid the drawbacks of
the known alternatives. Additionally, while systems and methods of
using capillary electrophoresis with electrospray ionization and
mass spectrometry are known, as described above, modifications to
current systems as presented herein improve the ease of use,
performance, and electrical functionality of these systems.
SUMMARY
[0012] The innovations presented herein relate to an improved
system where capillary electrophoresis is used in conjunction with
electrospray ionization mass spectrometry. In one potential
implementation, a capillary electrophoresis electrospray ionization
mass spectrometry (CE-ESI-MS) system is disclosed that comprises a
mass spectrometry (MS) dc power supply having a first output and a
first input and an isolated capillary electrophoresis (CE) dc power
supply having a second output and a second input. A MS electrical
path connected to a ground provides a mass spectrometry dc power
supply return from the first output to the first input via a mass
spectrometry load, and a CE electrical path provides a CE dc power
supply return from the second output to the second input via a
separation capillary. The second resistive electrical path in this
system is isolated from ground and the first output is electrically
coupled with the second input. The system finally includes a
control circuit that is electrically coupled with the isolated CE
dc power supply and is isolated from ground and a DC/DC converter
that provides isolated input power to the second dc power supply
and the isolated control circuit.
[0013] In further alternative embodiments, the CE-ESI-MS system
comprises a voltage limit resistor coupled directly to the MS dc
power supply and that is in the MS electrical path and is not in
the CE electrical path, or a system wherein the control circuit is
communicatively coupled with an interface board via a communication
link, wherein the communication link maintains the isolation from
the ground. In some of such additional embodiments, the
communication link is selected for being capable of withstanding a
voltage greater than or equal to the maximum output voltage of the
MS or CE dc power supplies. In some embodiments, the relevant
voltages include those whereby the maximum output voltage of the MS
dc power supply is a voltage value between -10 kV and +10 kV
(inclusive), and the maximum output voltage of the CE dc power
supply is a voltage value between -30 kV and +30 kV (inclusive). In
some embodiments, other voltage ranges are appropriate depending on
other variables in the system.
[0014] In certain embodiments the communication link comprises an
optical fiber link, while in other embodiments, the link comprises
a wireless link, such that the floating control circuit
communicates with another circuit that is operating referenced to a
ground potential without damaging either itself or the other
component.
[0015] In additional embodiments according to an improved CE-ESI-MS
system, a cartridge for use with a CE-ESI-MS system comprises both
a protective sheath, configured to be coupled with the cartridge
and capable of extending from and retracting with respect to a
housing of the cartridge, and a capillary coupled with the
protective sheath. In some embodiments, such a system is
additionally a system wherein the sheath is a first sheath, the
capillary is a first capillary, and wherein the cartridge comprises
both a second sheath, capable of extending from and retracting with
respect to the housing of the cartridge, and a second capillary
coupled with the second protective sheath. In some embodiments a
cartridge assembly further comprises first and second cooling tubes
respectively surrounding a portion of the first and second
capillaries, wherein the first and second cooling tubes are
configured to contain a cooling fluid, and some embodiments include
a system wherein the cooling fluid circulates in the first and
second tubes in a cooling circuit.
[0016] Additional embodiments include systems comprising a
cartridge assembly including a cartridge having a housing, a
protective sheath configured to be coupled with the cartridge and
capable of extending from and retracting with respect to the
housing of the cartridge, a capillary coupled with the protective
sheath, a sprayer housing comprising a first electrical contact
coupled with the capillary; an adapter comprising a second
electrical contact, wherein the first electrical contact is
configured to contact the second electrical contact.
[0017] In one potential alternative embodiment, a cartridge
assembly comprises a separation capillary, a first tube that
surrounds at least a middle portion of the separation capillary, a
cartridge having a first protective sheath that is adjustable from
an extended position to a retracted position; and a sprayer
housing. In some of such embodiments the first tube and the
separation capillary enter a first opening of the cartridge at a
first position along the separation capillary where the first tube
surrounds the at least a middle portion of the separation
capillary; in some of such embodiments, a first end portion of the
capillary that is not surrounded by the first tube is covered by
the first protective sheath when the first protective sheath is in
an extended position, and in some of such embodiments the first end
portion of the separation capillary extends through a first
capillary interface as the first protective sheath is adjusted from
the extended position to the retracted position such that the first
end portion of the separation capillary protrudes from the
cartridge to an extent sufficient to enter a CE vial. Additionally,
in some embodiments, a second end portion of the separation
capillary opposite the first end portion of the separation
capillary extends through an electrospray needle in the sprayer
housing, and the middle portion of the first capillary surrounded
by the tube ends at an entrance to the sprayer housing.
[0018] In some embodiments, the system further includes a
conductive fluid capillary and a second tube that surrounds at
least a middle portion of the conductive fluid capillary, where the
cartridge has a second protective sheath that is adjustable from an
extended position to a retracted position, and the second tube and
the conductive fluid capillary enter a second opening of the
cartridge at a second position along the conductive fluid capillary
where the second tube surrounds the at least a middle portion of
the conductive fluid capillary. Additionally, a first end portion
of the conductive fluid capillary that is not surrounded by the
second tube is covered by the second protective sheath when the
second protective sheath is in the extended position, and in some
embodiments the first end portion of the conductive fluid capillary
extends through a second capillary interface as the second
protective sheath is adjusted from the extended position to the
retracted position, such that the first end portion of the
conductive fluid capillary protrudes from the cartridge to an
extent sufficient to enter a conductive fluid vial. Finally, a
second end portion of the conductive fluid capillary opposite the
first end portion of the conductive fluid capillary extends into a
double lumen tube and the double lumen tube is positioned in a
central space in the sprayer housing and extends along a portion of
the separation capillary that extends through the sprayer
housing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 illustrates a diagram of one potential implementation
of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0020] FIG. 2A illustrates a prior art implementation of a CE-ESI
mass spectrometry system with a non-isolated power supply.
[0021] FIG. 2B illustrates a diagram of one potential
implementation of a CE-ESI mass spectrometry system with an
isolated power supply in accordance with one potential embodiment
of the innovations presented herein.
[0022] FIG. 3 illustrates a diagram of one potential implementation
of a CE-ESI mass spectrometry system with an isolated power supply
in accordance with one potential embodiment of the innovations
presented herein.
[0023] FIG. 4 illustrates a diagram of one potential implementation
of a CE-ESI mass spectrometry system with an isolated power supply
in accordance with one potential embodiment of the innovations
presented herein.
[0024] FIG. 5 illustrates a diagram of one potential implementation
of a CE-ESI mass spectrometry system with an isolated power supply
in accordance with one potential embodiment of the innovations
presented herein.
[0025] FIG. 6 illustrates a diagram of one potential implementation
of a CE-ESI mass spectrometry system with an isolated power supply
in accordance with one potential embodiment of the innovations
presented herein.
[0026] FIG. 7 illustrates a cartridge assembly and an adapter as
part of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0027] FIG. 8 illustrates a cartridge assembly that is used as part
of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0028] FIG. 9A illustrates a cartridge assembly that is used as
part of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0029] FIG. 9B illustrates a cartridge assembly that is used as
part of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0030] FIG. 10A illustrates a portion of a cartridge assembly
including a capillary protection cover (sheath in extended
position) that is used as part of a CE-ESI mass spectrometry system
in accordance with one potential embodiment of the innovations
presented herein.
[0031] FIG. 10B illustrates a portion of a cartridge assembly
including a capillary protection cover (sheath in retracted
position) that is used as part of a CE-ESI mass spectrometry system
in accordance with one potential embodiment of the innovations
presented herein.
[0032] FIG. 10C illustrates a portion of a cartridge assembly
including a capillary protection cover (sheath in extended position
and including a guide pass through) that is used as part of a
CE-ESI mass spectrometry system in accordance with one potential
embodiment of the innovations presented herein.
[0033] FIG. 10D illustrates a portion of a cartridge assembly
including a capillary protection cover including a locking portion
that is used as part of a CE-ESI mass spectrometry system in
accordance with one potential embodiment of the innovations
presented herein.
[0034] FIG. 11A illustrates a portion of a cartridge assembly
including a capillary protection cover (sheath) that is used as
part of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0035] FIG. 11B illustrates a portion of a cartridge assembly
including a seal that is used as part of a CE-ESI mass spectrometry
system in accordance with one potential embodiment of the
innovations presented herein.
[0036] FIG. 11C illustrates a portion of a cartridge assembly
including a seal that is used as part of a CE-ESI mass spectrometry
system in accordance with one potential embodiment of the
innovations presented herein.
[0037] FIG. 11D illustrates a portion of a cartridge assembly
including a seal that is used as part of a CE-ESI mass spectrometry
system in accordance with one potential embodiment of the
innovations presented herein.
[0038] FIG. 11E illustrates a portion of a cartridge assembly
including a seal that is used as part of a CE-ESI mass spectrometry
system in accordance with one potential embodiment of the
innovations presented herein.
[0039] FIG. 11F illustrates a portion of a cartridge assembly
including a capillary protection cover (sheath) that is used as
part of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0040] FIG. 11G illustrates a portion of a cartridge assembly
including a capillary protection cover (sheath) that is used as
part of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0041] FIG. 12 illustrates a cartridge assembly that is used as
part of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0042] FIG. 13 illustrates a cartridge assembly that is used as
part of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0043] FIG. 14 illustrates a cartridge assembly that is used as
part of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0044] FIG. 15 illustrates an electrospray assembly that is used as
part of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0045] FIG. 16A illustrates an electrospray assembly that is used
as part of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0046] FIG. 16B illustrates an electrospray assembly that is used
as part of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0047] FIG. 16C illustrates an electrospray assembly that is used
as part of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0048] FIG. 17 illustrates an electrospray assembly that is used as
part of a CE-ESI mass spectrometry system in accordance with one
potential embodiment of the innovations presented herein.
[0049] FIG. 18 illustrates an electrospray assembly including an
adapter for a specific mass spectrometer that is used as part of a
CE-ESI mass spectrometry system in accordance with one potential
embodiment of the innovations presented herein.
[0050] FIG. 19 illustrates an electrospray assembly including an
adapter for a specific mass spectrometer that is used as part of a
CE-ESI mass spectrometry system in accordance with one potential
embodiment of the innovations presented herein.
[0051] FIG. 20 illustrates one potential embodiment of a computer
system or controller that is used in conjunction with a CE-ESI mass
spectrometry system in accordance with various embodiments of the
innovations presented herein.
[0052] FIG. 21 illustrates a diagram of one potential
implementation of a channel surface coating of a separation
capillary tube useful as a sheathless interface for coupling a CE
process and an ESI-MS process.
DETAILED DESCRIPTION OF THE INVENTION
[0053] The innovations presented herein relate to improved systems
and methods integrating capillary electrophoresis (CE) with mass
spectrometry (MS). In some embodiments such a system provides an
integrated structure that as a whole is used to separate samples
containing molecules such as protein complexes, proteins, peptides,
glycans or drugs and/or metabolites using CE and to characterize
and/or identify the separated molecules using MS. The innovations
herein, in certain embodiments, apply to any capillary
electrophoresis (CE) system coupled with a mass spectrometer (MS)
system via electrospray ionization (ESI), and also apply to any MS
system.
[0054] FIG. 1 describes an overall system for CE-ESI-MS according
to one potential embodiment of the innovations described herein.
CE-ESI-MS system 100 includes a capillary electrophoresis (CE)
controller 110, a power supply 120, a capillary electrophoresis
analysis system 130, a cartridge 170, coolant tubes 140a and 140b,
capillaries 142 and 144, mass spectrometer inlet 152, mass
spectrometer 150, and mass spectrometer controller 160.
[0055] The basic functionality of the system is for a sample to be
selected and introduced to the inlet of separation capillary 142 of
FIG. 1 by CE analysis system 130. Power supply 120 provides a high
voltage, which in some embodiments is on the order of 30 kV, across
separation capillary 142. Conductive fluid capillary 144 introduces
a conductive fluid at a sprayer housing attached to MS inlet 152 to
enable ESI of the separated material where, in some embodiments, a
mass spectrometer 150 then analyzes the separated sample. Coolant
tube 140a cools separation capillary 142 and carries a coolant to
the sprayer housing. Coolant tube 140b returns the coolant to the
CE analysis system 130. Both capillaries are threaded through the
coolant tubes such that the tubes, and the coolant carried by the
tubes, surround a portion of the capillaries.
[0056] Power supply 120 comprises, in some embodiments, an isolated
power supply as described below. In some embodiments, CE analysis
system 130 comprises any device that functions to manage and
implement CE separation of sample materials, along with any other
tests on the materials that in some embodiments are done
concurrently or as part of the same system. As one non-limiting
example, CE analysis system 130 comprises a Beckman Coulter PA800
Pharmaceutical Analysis System.TM..
[0057] In some embodiments cartridge 170 comprises a removable,
replaceable cartridge that is integrated with coolant tubes 140a
and 140b, as well as capillaries 142 and 144, and a sprayer housing
(that is not shown but is discussed below) to form integrated
components of a cartridge assembly which connects to the mass
spectrometer 150 at mass spectrometer inlet 152.
[0058] In some embodiments, CE controller 110 and MS controller 160
are stand-alone computing devices, or any other acceptable device,
as further described by FIG. 20. Controllers in some embodiments
function to manage the operation of any component in the system, to
receive and analyze data from any part of the system, and to
monitor components of the system for errors. In various
embodiments, CE controller 110 and/or MS controller 160 are
integrated with their respective analysis systems, so that CE
controller 110 is integrated with CE Analysis System 130, and/or MS
controller 160 is integrated with mass spectrometer 150.
Additionally, in certain embodiments, any of the above described
components is/are integrated with any other component.
Isolated Power Supply
[0059] As described above, FIG. 2A describes a CE-ESI-MS system
using a known prior art electrical system configuration where CE
power supply 220a is not isolated. FIG. 2B describes a CE-ESI-MS
system where the CE power supply is isolated and floating.
[0060] FIG. 2B includes CE power supply 220b, inlet vial 232b,
conductive fluid vial 234b, electrospray assembly 252b, mass
spectrometer 250, and ESI-MS power supply 254. In the system of
FIG. 2B, the ESI-MS power supply 254 is grounded, and CE power
supply 220b is floating on top of the ES high voltage output 226 of
ESI-MS power supply 254. Therefore, if the voltage generated by
ESI-MS power supply 254 is 5 kV and the voltage generated by CE
power supply 220b is 30 kV, the voltage at CE high voltage output
222b, relative to ground, is 35 kV. This provides a higher CE power
supply voltage across sample capillary 242b for the purposes of
capillary electrophoresis compared to that which is provided across
sample capillary 242a. The term "ground" as used herein is defined
as earth ground, chassis ground, or electrical ground. The term
"floating ground" as used herein is defined as a circuit ground
that is isolated from ground.
[0061] Although various embodiments disclosed herein recite
specific voltages, the innovations presented herein are not limited
to specific voltages or voltage ranges, but apply to any acceptable
voltage ranges adequate for function of the described
implementation. As a non-limiting example, the voltage rating of an
isolated CE power supply is in some embodiments selected from the
group consisting of a voltage rating value between 0 kV and 50 kV
(inclusive), between 0 kV and 45 kV (inclusive), between 0 kV and
40 kV (inclusive), between 0 kV and 35 kV (inclusive), between 0 kV
and 30 kV (inclusive), between 0 kV and 25 kV (inclusive), between
0 kV and 20 kV (inclusive), between 0 kV and -50 kV (inclusive),
between 0 kV and -45 kV (inclusive), between 0 kV and -40 kV
(inclusive), between 0 kV and -35 kV (inclusive), between 0 kV and
-30 kV (inclusive), between 0 kV and -25 kV (inclusive), and
between 0 kV and -20 kV (inclusive).
[0062] In some embodiments the voltage rating of a non-electrically
isolated DC power supply for an ESI-MS power supply is, but is not
limited to being, selected from the group consisting of a voltage
rating value between 0 kV and 25 kV (inclusive), between 0 kV and
20 kV (inclusive), between 0 kV and 15 kV (inclusive), between 0 kV
and 10 kV (inclusive), between 0 kV and 5 kV (inclusive), between 0
kV and 4 kV (inclusive), between 0 kV and 3 kV (inclusive), between
0 kV and 2 kV (inclusive) and between 0 kV and 1 kV
(inclusive).
[0063] The input to output voltage isolation rating of a DC/DC
converter in some embodiments is, but is not limited to being,
selected from the group consisting of a voltage isolation rating
value between 1 kV and 200 kV (inclusive), between 5 kV and 150 kV
(inclusive), between 10 kV and 135 kV (inclusive), between 15 kV
and 125 kV (inclusive), between 20 kV and 110 kV (inclusive),
between 25 kV and 95 kV (inclusive), between 30 kV and 80 kV
(inclusive), between 35 kV and 65 kV (inclusive), between 40 kV and
50 kV (inclusive), between -1 kV and -200 kV (inclusive), between
-5 kV and -150 kV (inclusive), between -10 kV and -135 kV
(inclusive), between -15 kV and -125 kV (inclusive), between -20 kV
and -110 kV (inclusive), between -25 kV and -95 kV (inclusive),
between -30 kV and -80 kV (inclusive), between -35 kV and -65 kV
(inclusive), and between -40 kV and -50 kV (inclusive).
[0064] Additionally, in FIG. 2A, the electrospray voltage interacts
with the capillary electrophoresis separation voltage because the
ESI-MS Power Supply 254 that is used to ionize the separated
samples is in the return path of the CE power supply 220a. This
creates an additional variable in the capillary electrophoresis
component in the system. In the system of FIG. 2B, the electrospray
voltage does not interact with the capillary electrophoresis
separation voltage. This is a convenience which eliminates a
variable of capillary electrophoresis and mass spectrometry data.
Use of an isolated power supply thus allows the current returning
to the isolated CE power supply to return directly to the CE power
supply, bypassing any other components including the ESI-MS power
supply. The separation of the CE return current from the MS
delivered current enables measurement of the ESI current through a
resistor that is only placed in the current path of the MS power
supply, and not placed in the return path of the CE power
supply.
[0065] FIG. 3 provides additional details of one potential
embodiment of a CE-ESI-MS system 300 that includes an isolated
power supply. While CE-ESI-MS system 300 includes a CE analysis
system 330, a mass spectrometer 350, and other components similar
to the components of FIG. 2A, the system of FIG. 3 describes a
system that includes features as part of isolated CE power supply
320 that, in at least one potential embodiment, enable the
functionality of a CE-ESI-MS system with a floating power supply
that is not possible in the system of FIG. 2A.
[0066] Isolated CE power supply 320 includes a floating control 325
and a DC/DC converter 323, and a CE power supply 321. CE power
supply 321 is in some embodiments comparable to CE power supply
220a of FIG. 2A. CE power supply 321 provides CE separation
voltage, but has no integrated special function for dealing with
the necessities of isolation. Floating control 325 and DC/DC
converter 323 are in some embodiments integrated with CE power
supply 321 to enable operation as isolated CE power supply 320.
[0067] Floating control 325 is isolated from chassis ground but
maintains a link to CE analysis system 330 across communication
link 329. In some embodiments, communication link 329 comprises a
wireless communication link. Alternatively, communication link 329
comprises an optical communication link such as a link via an
optical fiber. An optical fiber communication link provides the
benefit of being highly resistive, and therefore able to function
across the isolation when the isolated CE power supply 320 is
floating on a large voltage. In some embodiments, optical coupler
devices with a sufficient isolation rating are used directly to
pass digital inputs and outputs. Because power supply units such as
CE power supply 321 frequently require analog input controls, but
optical couples are not directly functional for most such controls,
analog signals in some embodiments are first converted to a logic
pulse stream, routed through the same optical coupler devices used
for any digital signals, and then reconstructed back into analog
signals. In some embodiments, such translation is performed using
interface board 336 and control circuitry 325.
[0068] Voltage for the analog circuitry on the remote end is
provided by the host instrument DC supply and on the isolated end
by the DC/DC converter 323 which, in some embodiments, comprises a
DC switcher. Interface board 336 that is on the other side of the
communication from the floating control 325 is therefore able to
operate at the chassis ground with no risk of an electrical short
across communication link 329.
[0069] A DC/DC converter 323 similarly functions for providing
voltage outputs for control circuit 325 and CE power supply 321
while isolating these components of the isolated CE power supply
320. Converter 323 is therefore a high isolation voltage (40 kV, as
a non-limiting example) DC/DC power converter or DC switcher power
supply or power isolator (DC/DC converter) that is used to isolate
input power to the other components of the Isolated CE Power Supply
320. For example, in some embodiments DC/DC converter 323 accepts a
24V voltage input from the interface board 336, and using that
input voltage, provides an isolated output for use by the rest of
the components of isolated CE power supply 320 that are floating on
the voltage output of MS power supply 354. In such embodiments,
DC/DC converter provides reference and operation voltages across
large isolation voltages that in some embodiments are in the order
of 15 kV or more.
[0070] Isolated CE power supply 320 therefore functions using an
isolated communication channel in the form of communication link
329 and using an isolated voltage input from DC/DC converter
323.
[0071] In addition to the above described benefits of an isolated
power supply in a CE-ESI-MS system, certain embodiments include
improvements related to leakage current. FIGS. 4, 5, and 6 describe
different embodiments that include such improvements.
[0072] FIGS. 4, 5, and 6 illustrate CE-ESI-MS systems having an
isolated CE power supply 420, 520, and 620, respectively. Each
isolated CE power supply includes a DC/DC converter (423, 523, and
623, respectively) an isolated control circuit (425, 525, and 625,
respectively) and an internal CE power supply (421, 521, and 621,
respectively). In FIGS. 4, 5, and 6, the electrical path along
separation capillary is shown as CE load 440, 540, and 640,
respectively, and the ESI-MS electrical return path for MS power
supply 454, 554, and 654 is shown as MS load 450, 550, and 650,
respectively. FIGS. 4, 5, and 6 include a voltage limit resistor
484, 584, and 684, respectively. FIGS. 4 and 5 also include a sense
resistor 482 and 582, respectively. FIGS. 4 and 5 additionally
include an amplifier 490 and 590, respectively.
[0073] Voltage limit resistor 484 acts as a current limit resistor,
which protects both the current sense circuit that includes
amplifier 490 and also protects the non-floating electrospray
ionization-mass spectrometer power supply in the event of a
failure. One non-limiting example of such a failure that is
detected in some embodiments by sense resistor 482 and amplifier
490 is the formation of a salt bridge during capillary
electrophoresis operation.
[0074] Along with voltage limit resistor 484, sense resistor 482
and amplifier 490 are in some embodiments part of a current sense
circuit that detects leakage current. Whereas in standard CE-ESI-MS
systems a visual or data based failure of sample separation or some
other obvious system failure in the data is generally the first
sign of system failure, the use of a current sense circuit in some
embodiments provides feedback to automatically shut down operation
if a fault mode is detected. The salt bridge failure mentioned
above is a non-limiting example of a failure which is detected
using some embodiments of the current sense circuit.
[0075] If leakage occurs, voltage limit resistor 484, which has a
high value, prevents damage both to the current sense circuit
comprising amplifier 490 and to the (non-isolated, non-floating)
mass spectrometer power supply 454 because most of the voltage will
appear across this voltage limit resistor 484. One non-limiting
example of a high value voltage limit resistor 484 is a resistor
having a value of 200 megaOhms. The DC/DC converter 423 is
functionally in parallel with the current sense resistor 482, the
voltage limit resistor 484, and the (non-isolated, non-floating)
ESI-MS power supply 454. In case of leakage, the DC/DC power
converter 423 in some embodiments is designed to withstand the sum
of the CE `separation capillary` and electrospray voltages in order
to avoid damage to the system.
[0076] As described above for power supply ratings, the resistor
values of voltage limit resistor 484 and sense resistor 482 are not
limited to the specific values used for example purposes. For
example, a current sense resistor according to the present
innovations includes any value that enables the current sensing
function and allows the described system to function. A current
sense resistor, in one embodiment, comprises a resistor having a
rating value between 1 kOhm and 503 kOhms, inclusive.
[0077] In one embodiment, voltage limit resistor 484 comprises a
resistor having a value that is selected from the group consisting
of between 10 megaOhms and 500 megaOhms (inclusive), between 50
megaOhms and 400 megaOhms (inclusive), between 100 megaOhms and 300
megaOhms (inclusive), between 150 megaOhms and 250 megaOhms
(inclusive), between 175 megaOhms and 225 megaOhms (inclusive),
between 185 megaOhms and 215 megaOhms (inclusive), between 190
megaOhms and 210 megaOhms (inclusive), and between 195 megaOhms and
205 megaOhms (inclusive).
[0078] In a conventional (grounded) CE-ESI-MS system such as the
one shown in FIG. 2A, as well as in embodiments without a current
detecting circuit, the leakage current generally is extremely
difficult to detect, or only detectible with high margins of error,
because the leakage current returns to the CE high voltage power
supply along with the current delivered to the CE `separation
capillary` by bypassing the return current terminal in the CE high
voltage supply. The current delivered to the CE `separation
capillary` will not return to the CE high voltage power supply
through its return terminal (shown as CE HV return); instead it
returns through the ground connection of the ESI-MS Power Supply.
The leakage current will bypass all of the other circuitry,
capillaries, and power supplies and return to the CE high voltage
power supply through the connection to ground. To sense the current
flowing through the ESI-MS power supply, the current sense resistor
482, which in some embodiments has a value in the order of 500
kOhms, is inserted between the high voltage output of the
(non-isolated, non-floating) ESI-MS power supply 454 and the
floating ground of the CE power supply 421. This is done out of the
path of any current returning to CE power supply 421.
[0079] The voltage across the current sense resistor 482 then
represents the sum of the electrospray ionization current delivered
by the (non-isolated, non-floating) ESI-MS power supply 454 and any
leakage current due to a fault condition caused by, as a
non-limiting example, a salt bridge. An amplifier measures this
voltage, and an absolute value amplifier ensures the signal can be
read if the power supply polarity is reversed.
[0080] FIG. 5 shows an alternative embodiment of CE-ESI-MS system
including a current sense circuit. In the embodiment shown in FIG.
5, the sense resistor 582 is grounded and placed outside the
isolated CE power supply 520. The voltage limit resistor 584
remains on the high power side of the MS power supply 554 in order
to serve in the protective function described above. Sense resistor
582 and amplifier 590 provide the sensing function in this
alternative embodiment, and enable a controller or fault detection
system to identify excess current and shut the system down, since
sense resistor remains out of the return path of CE power supply
521 but in the path of any leakage current before it returns to the
isolated CE supply 521. By operating outside of the isolated CE
power supply, the current sense circuitry including amplifier 590
and sense resistor 582 in some embodiments lowers the usage and
reliance on communication link 529, and in some embodiments reduces
design complexity by reducing the number of components and
complexity of components operating at the high floating
voltage.
[0081] Finally, FIG. 6 shows an additional alternative embodiment
without the leakage current sensing function shown in FIGS. 4 and
5. FIG. 6 includes voltage limit resistor 684 and does not have any
equivalent to sense resistor 582 or amplifier 590. A high rated
voltage limit resistor 684 in such embodiments continues to perform
the protective function without the additional circuitry and fault
detection controls necessary for the current sensing circuitry to
function. Instead, at least some embodiments of FIG. 6 provide a
lower cost and/or easier to implement solution, while protecting
the system components from damage. As described above, a fault
condition associated with a salt bridge, as a non-limiting example,
in some embodiments is detected from identifiable performance
degradation in sample separation, or identifiable characteristics
of output data that do not conform with expected or acceptable data
characteristics. Voltage limit resistor 684 in some embodiments
protects MS power supply 654 from damage until such characteristics
are identified and the system halted for repair.
CE Consumable Cartridge
[0082] FIG. 7 shows an aspect of a CE-ESI-MS system such as
CE-ESI-MS system 100 of FIG. 1. FIG. 7 includes sample vials 732,
conductive fluid vials 734, adapter 760, MS power supply 754, CE
Power supply 720, and cartridge assembly 710. Cartridge assembly
710 includes separation capillary 742, conductive fluid capillary
744, cartridge 712, coolant tubes 740a and 740b, and sprayer
housing 750. Sprayer housing 750 includes electrical contact 752,
as well as other significant elements described in more detail
below, especially in regard to FIGS. 15-17.
[0083] In some embodiments cartridge assembly 710 functions as a
consumable assembly that enables capillaries to be inserted and
removed much more easily than in traditional CE-ESI-MS systems.
Interfacing a CE system with a mass spectrometer is a delicate and
time consuming process. Traditional CE-ESI-MS alignment requires
interfacing the inlet of an ESI sprayer tipped separation capillary
to the CE system, and positioning the ESI sprayer tip accurately at
the inlet of a MS for a proper ion spray. A prebuilt CE capillary
holder cartridge assembly with at least one portion of the ESI
sprayer tipped separation capillary enclosed in at least one
protective holder simplifies the CE-MS interface. Some embodiments
of such a cartridge assembly comprise an ESI sprayer tip enclosed
in a protective sprayer housing that mounts readily on a mechanical
stage at the inlet of the MS. More particularly, some embodiments
of such a cartridge assembly comprise a sheathless ESI sprayer tip
enclosed in a protective sprayer housing that mounts readily on a
mechanical stage at the inlet of the MS. Some embodiments of such a
cartridge assembly comprise a portion of a separation capillary
enclosed in a CE cartridge that mounts readily on the CE system
without requiring delicate operation. For a sheathless ESI sprayer
tipped separation capillary, the conductive fluid necessary to make
electrical contact with the inner bore of the capillary is in some
embodiments supplied by the CE system through a conductive fluid
capillary, wherein a portion of the conductive fluid capillary is
enclosed in the CE cartridge that mounts readily on the CE system.
Thus, in some embodiments, a cartridge assembly of the innovations
presented herein is selected from the group consisting of a
cartridge assembly comprising an ESI sprayer tip enclosed in a
protective sprayer housing, a cartridge assembly comprising a
portion of a separation capillary enclosed in a CE cartridge, a
cartridge assembly comprising a portion of a conductive fluid
capillary enclosed in a CE cartridge, or a combination thereof.
Moreover, in some embodiments, a cartridge assembly of the
innovations presented herein is selected from the group consisting
of a cartridge assembly comprising a sheathless ESI sprayer tip
enclosed in a protective sprayer housing, a cartridge assembly
comprising a portion of a separation capillary enclosed in a CE
cartridge, a cartridge assembly comprising a portion of a
conductive fluid capillary enclosed in a CE cartridge, or a
combination thereof.
[0084] The benefit of a cartridge assembly 710 is therefore both in
the connection to a CE analysis system such as CE analysis system
130 of FIG. 1 and in the connection to a mass spectrometer such as
mass spectrometer 150 of FIG. 1. On the CE analysis side of
cartridge assembly 710, improved functionality is in some
embodiments provided by disposing capillaries within a protective
cartridge that in some embodiments interfaces with a CE analysis
system as a cartridge, and not as individual capillaries. The fixed
position and protective cartridge housing capillaries 744 and 742
in some embodiments additionally prevents damage to the fragile
capillaries.
[0085] The same advantageous, prebuilt cartridge assembly 710 also
provides a benefit with respect to cooling, where inflow and
outflow of cooling fluid in some embodiments occur via a cartridge
712 interfacing with a CE analysis system. In one potential
embodiment, cooling fluid enters cartridge 712 on the side of
separation capillary 742, and enters cooling tube 740a at an
interface within cartridge 712 that is sealed. Cooling fluid flows
toward sprayer housing 750, and enters a fluid return block, where
the separation capillary 742 that is threaded inside cooling tube
740a separates from cooling tube 740a. Cooling fluid is blocked by
a seal from flowing toward the MS inlet where separation capillary
742 provides separated sample material to the ESI-MS input. The
cooling fluid instead returns to cartridge 712 via cooling tube
740b that contains conductive fluid capillary 744 threaded within
cooling tube 740b. The cooling fluid then exits cooling tube 740b
and cartridge 712 to return to CE analysis system to be
re-circulated through the cooling system. The cooling fluid thus
travels a cooling fluid circuit through a cooling system.
[0086] On the MS side of the connection with the cartridge assembly
710, improved functionality is in some embodiments provided by an
integrated ESI sprayer tip as part of sprayer housing 750. Sprayer
housing 750 in some embodiments provides increased electrical
safety by placing the electrical path to MS power supply 754 and CE
power supply 720 on an adapter 760 which is attached to the mass
spectrometer and rarely moved. In some embodiments electrical
contact is made as the sprayer housing 750 is inserted into the
adapter 760 and electrical contact 752 on the exterior of sprayer
housing 750 makes connection with an electrical contact on the
inside of adapter 760. Making this electrical connection without
the need for the electrical connection to move with the sprayer
housing 750 provides a benefit of reduced risk of damage to the
electrical connection and reduced risk to an installer.
[0087] Further, mechanical damage is in some embodiments prevented
through the use of a sprayer housing 750. A High Sensitivity Porous
Sprayer (HSPS) capillary tip is very fragile and requires
protection when it is not installed. In some embodiments this
device has an automatically retracting and extending cover that
protects the sprayer tip when it is not installed. Additionally,
the fragile capillary sprayer tip within sprayer housing 750 does
not need to be attached and adjusted directly. Instead, in some
embodiments x, y, z position adjustments are made to the sprayer
housing 750 and/or to the adapter 760 with the sprayer housing 750
inserted and attached.
[0088] The improvements described above of additional protection
for the capillary tip, integrated liquid cooling, and fixed
protective connection points for the capillary at both the CE and
MS interfaces are benefits and improvements not previously
known.
[0089] FIG. 8 shows an alternative embodiment of portions of a
cartridge assembly. FIG. 8 shows ESI sprayer tip 858 of separation
capillary 842 disposed inside retracting protective housing 854,
protective sheaths 845a and 845b, capillary cassette 846,
conductive fluid capillary 844 shown both exposed for interface
with a vial and disposed inside coolant tubing, cartridge 812,
coolant manifold 848, and electrical contact 852.
[0090] In certain embodiments, conductive fluid capillary 844 is
assembled into a capillary cassette that plugs into a CE analysis
instrument directly. In some embodiments, separation capillary 842
is assembled into a capillary cassette that plugs into a CE
analysis instrument directly. In some embodiments, separation
capillary 842 and conductive fluid capillary 844 are each assembled
into discrete capillary cassettes that each plug into a CE analysis
instrument directly. In alternate embodiments, such as the
embodiment shown in FIG. 8, the conductive fluid capillary 844 is
first assembled into the capillary cassette 846 and then attaches
to the CE analysis instrument through an interface cartridge 812 to
form a coolant interface. A protective sheath 845b houses the
capillary and prevents breakage when the capillary is not
installed. When the capillary is installed, the protective sheath
retracts to expose the capillary as shown in FIG. 8 with sheath
845b. A similar mechanism exists for the separation capillary 842
which is shown within protective sheath 845a in a protective (not
retracted) position.
[0091] In some embodiments, prior to assembly of a cartridge
assembly with capillaries, each capillary is first integrated with
a discrete capillary cassette and housed within a discrete
protective sheath. In some embodiments each such protective sheath
is inserted into an open slot within cartridge 812 as part of the
creation of a cartridge assembly. In some embodiments protective
sheaths 845a and 845b continue to protect the associated
capillaries after completion of a cartridge assembly. In
alternative embodiments, discrete protective sheaths 845a and 845b
are integrated with cartridge 812 prior to insertion of each
capillary cassette 846. Additional details related to capillary
cassettes will be discussed below.
[0092] Each capillary is threaded through a discrete tubing which
encases the coolant flow and which leads up to a coolant manifold
848. The conductive fluid capillary 844 delivers electrolyte to a
conductive (e.g., steel, as a non-limiting example) tube that
surrounds the separation capillary in the sprayer housing. At this
point the conductive fluid capillary truncates. The separation
capillary 842 is surrounded by the conductive electrolyte fluid as
it passes through the conductive (e.g., steel, as a non-limiting
example) tube; then the ESI sprayer tip 858 of separation capillary
842 extends beyond the conductive tube. As the ESI sprayer tip 858
is very fragile, it is covered by a protective housing 854 that in
some embodiments retracts when the assembly is installed into the
MS. A feature is built into the cartridge assembly that will allow
electrical contact at 852 to be established when installed as
described above with respect to electrical contact 752 in FIG. 7.
The coolant manifold 848, the electrical contact 852 and the
protective housing 854 for the ESI sprayer tip 858 form a
consolidated end of the cartridge assembly at the MS end of one
potential embodiment of a CE-ESI cartridge assembly.
[0093] FIGS. 9A and 9B show an additional view of one potential
embodiment of a cartridge 912 that in some embodiments is part of a
cartridge assembly. Cartridge 912 includes installed capillary
cassettes that are protected by the shown protective sheaths 945.
In FIG. 9A, protective sheaths 945 are shown in a retracted
position to allow separation capillary 942 and conductive fluid
capillary 944 to interface with their respective vials as part of a
CE analysis system. In FIG. 9B, protective sheaths 945 are shown in
a protective non-retracted (extended) position such that the
capillaries 942 and 944 are protected but also not able to operate
or interface with the appropriate vials. Additionally, in the
embodiment shown in FIGS. 9A and 9B, cartridge 912 includes
insertion guides 998 that in some embodiments assist in the ease of
connecting (or disconnecting) cartridge 912 with a CE analysis
system. In some embodiments, such a CE analysis system has
receiving slots that match insertion guides 998 to provide a secure
position and placement of the cartridge 912 within the CE system,
and to appropriately position the capillaries 942 and 944 and
protective sheaths 945 so that the capillaries will be readily able
to interface with the appropriate vial when a CE analysis system is
operating.
[0094] Further still, in some embodiments insertion guides 998
assist in moving cartridge 912 within a CE analysis system. In
certain embodiments, such as the embodiment shown in FIG. 7, a CE
analysis system has a set of vials, and includes automation for
moving a capillary to the appropriate vial or for moving an
appropriate vial to a capillary. In certain embodiments, a
cartridge such as cartridge 912 is moved by and within a CE
analysis system to multiple vials with protective sheath 945
protecting the capillaries during movement. In certain embodiments,
multiple vials are moved by and within a CE analysis system to an
at least one capillary housed in a cartridge such as cartridge 912
with protective sheath 945 in some embodiments protecting the
capillaries during vial movement.
[0095] FIGS. 10A, 10B, 10C, and 10D show further additional detail
of some alternative embodiments of capillary cassettes and of
protective sheaths. FIG. 10A shows protective sheath 1045 in a
protective extended position. FIG. 10B shows protective sheath 1045
in a retracted position. FIGS. 10A and 10B additionally show seal
1043, capillary interface 1041, and separation capillary 1042.
Capillary interface 1041 provides a path for the separation
capillary 1042 to extend from the protective sheath 1045 when the
sheath 1045 is in the retracted position as in FIG. 10B. Seal 1043
surrounds the separation capillary 1042 at a point that provides a
stop for coolant fluid that surrounds separation capillary 1042 and
cools it, such that the conductive fluid is contained by a cooling
tube and various seals including seal 1043 that allows separation
capillary 1042 access to a sample vial while the conductive fluid
that cools the separation capillary 1042 is contained and prevented
from leaking. As shown in FIG. 10A, in some embodiments capillary
interface 1041 is structured to fit with a portion of seal 1043
that surrounds a portion of separation capillary 1042 when the
protective sheath 1045 is retracted as in FIG. 10B. In certain
embodiments, similar structures exist for an associated conductive
fluid capillary.
[0096] FIG. 10C shows one potential alternative embodiment
including a capillary cassette and protective sheath as described
above. In certain embodiments, the capillary interface 1041
functions as a guide to direct the capillary out of a protective
sheath without damaging the capillary. In some embodiments, this
further functions with an interface block target 1090 which accepts
capillary 1042 as it is guided out of capillary interface 1041 into
an interface block having interface block target 1090, such that
the capillary is guided while in use to limit damage to capillary
1042 and to guide the capillary. Thus, in some embodiments, in
order to ensure the end of capillary 1042 is aligned correctly with
an interface block, a capillary interface 1041 is integrated into
the bottom of the sheath with a tapered guiding feature. In some
embodiments, the guide feature has a narrow pass through that is
designed to always fall within the interface block target 1090. The
top of the capillary interface 1041 guide feature is wider to allow
for a higher degree of initial misalignment of the capillary. In
some embodiments, this allows the capillary to physically rest on
the wall of the guide feature in order to correct any lateral
offset created by a poor exit angle of the capillary from the
cartridge.
[0097] FIG. 10D shows a potential alternative embodiment including
a sheath 1072d and cartridge 1045d having a mechanical stop 1084 to
manage movement of sheath 1072d as it retracts and extends. As
discussed above, to protect the exposed capillaries affixed to a
cartridge, two sliding and lockable sheaths are attached to the
separation (separation capillary) and conductive fluid (conductive
fluid capillary) sides of a cartridge. The sheaths are capable of
moving vertically to alternatively cover and expose the capillary
ends for protection of the capillary ends. In one potential
embodiment shown in FIG. 10D, the sheaths lock in place to prevent
them from prematurely sliding upwards and exposing the capillary to
potential damage. In certain embodiments, a separate feature
prevents the sheaths from sliding completely off the cartridge.
[0098] FIG. 10D thus shows mechanical stop 1084 and flexible finger
detent 1082 which connect to prevent the sheath from sliding upward
and exposing the capillary to damage. Pivot point 1080 enables
flexible finger detent 1082 to move in the direction of flex 1098
shown, so that in some embodiments flexible finger detent 1082
moves away from mechanical stop 1084, and the sheath slides upward
to expose the capillary at the appropriate time. In certain
embodiments, the cartridge assembly matches a CE instrument such
that the locking feature itself is a combination of the mechanical
stop 1084 on the sheath and the flexible finger detent 1082 on the
cartridge that match an interface with a CE instrument. When the
cartridge assembly is installed onto a correctly configured CE
instrument, the flexible finger detent 1082 is disengaged allowing
the sheath 1072d to slide upwards when pressed against an interface
block. The actual method of disengagement can be variable. In
certain embodiments the disengagement relies upon a cam lobe and
dowel pin arrangement. In such an embodiment, upon removal of the
cartridge assembly from the CE system, the sheaths are pulled
downwards relative to the cartridge until the locking finger is
aligned with the detent on the sheath.
[0099] In still further alternative embodiments, alternate means
for controlling and managing the protective sheath and locking the
sheath into position may be provided. For example, in one
alternative embodiment, a spring loaded cartridge is structured
with a spring instead of a flexible finger detent with a mechanical
stop. Alternatively, magnetic latches, locking mechanisms with a
plurality of screws to hold the sheath in place, or an external
lock fitted to the outer surface of the sheath may be used. Such
embodiments, however, must be designed to prevent arcing with a
metal spring during operation, when the voltage operations
described herein may result in arcs across gaps within the design
parameters shown in the cartridge and sheath embodiments discussed
herein.
[0100] Additional details of alternative embodiments of a cartridge
and sheath are disclosed in FIGS. 11A-G. As detailed above, FIG.
10C describes a system including an interface block target 1090 and
a capillary interface 1041 with guide features to assist in
preventing capillary damage as the sheath is retracted and the
capillary extended outside the sheath for use. FIG. 10C shows
capillary 1042 in a protected position. FIG. 11A, shows an
embodiment in a position with the capillary extended outside of the
sheath.
[0101] As shown in FIGS. 10A-B, in some embodiments each capillary
has a seal surrounding a portion of the capillary within a sheath,
such that when the sheath is retracted, the capillary is guided
through an interface, and the seal then comes in contact with the
interface at the extreme position with the capillary extended
outside the sheath. In some embodiments, in order to rinse, fill,
or purge a capillary or to inject a sample into a capillary, an air
tight seal is required between the capillary and the interface
block. The liquid cooling system requires a liquid tight seal
between the capillary and cartridge as well. The capillary must be
retained within the consumable cartridge to prevent the capillary
from pulling out of the assembly. In certain embodiments, the seal
must be long enough to pass through a guiding feature in order to
be able to fully contact the cartridge, capillary, and interface
block at the same time.
[0102] The details of one potential embodiment in such a position
are shown in FIG. 11A, with seal 2310 in contact with an interface
block air/interface block seal surface 2520, the seal passing
through guide pass through 2518, and the capillary extending from
the capillary seal surface 2514 out through the seal at
air/interface block seal surface 2520. Coolant inside the cartridge
is blocked from exiting the cartridge at coolant/cartridge seal
surface 2512 where the capillary enters the seal 2310 just above
capillary/seal surface 2514. Seal center support 2516, that in some
embodiments is a part of a seal clip discussed below, supports seal
2310 to prevent excessive lateral deformation which may damage the
capillary. The upper portion of the seal thus serves to contain
coolant within the cartridge and prevent leaks through the seal
where the capillary has been inserted while the lower portion
maintains a pressure seal against the interface block.
[0103] Alternative examples of seals are shown in FIGS. 11B, 11C,
11D, and 11E. In FIGS. 11B and 11D, seal 2310 which is the same
seal shown in FIG. 11A is detailed. Seal 2310 includes, in some
embodiments, a longer seal surface than seal 2302 of FIGS. 11C and
11E, and thus is improved in certain embodiments by a seal center
support 2316 which is part of clip 2312. In some embodiments clip
2312 functions to hold the seal 2310 in place in the cartridge when
a capillary is inserted in seal 2310. This is especially true since
minor forces on a capillary which is inserted in seal 2310 may push
seal 2310 within a position inside the cartridge over many uses,
and to provide adequate seal surfaces clip 2312 must hold the seal
2310 in the appropriate position. In some embodiments, the clip
snaps onto the cartridge to retain the seal against the cartridge.
The seal itself is pulled through the clip prior to being installed
onto the cartridge. A cylindrical center section supports the long
neck of the seal. Two shoulders on the seal are supported by the
center section. In combination with each other, a long seal can be
implemented that does not buckle under the compression load
experienced during cartridge installation.
[0104] In certain embodiments, a septum at the top portion of the
seal that is pierced by the capillary during the assembly process
provides sufficient friction to retain the capillary within the
assembly. In alternative embodiments, the septum is placed at other
portions of the seal where the seal is in contact with the
capillary, or in some embodiments any other suitable method such as
an adhesive or additional clip is used to prevent movement of the
capillary within seal 2310.
[0105] FIG. 11F shows an additional illustration of an embodiment
with seal 2210 in a positon to interface with interface block 2260
on a side of a cartridge with the separation capillary (sample
capillary) 2252 and electrode 2256.
[0106] FIGS. 11C, 11E, and 11G show an alternative embodiment of a
seal 2302 with clip 2304. Additional detail of a seal 2302 at an
interface position in a cartridge is shown in FIG. 11G, with
capillary interface 1141 and separation capillary 1142 shown when
the associated sheath is retracted, and separation capillary 1142
extends out from the protective sheath. In certain embodiments, the
cartridge of FIG. 11G with seal 2302 does not include a capillary
guide surface, and seal 2302 simply supports the capillary 1142 as
it extends, with the capillary extending through a tube into the
target area containing the separation material. In various
alternative embodiments, the same type of seal is used on both the
conductive fluid side and the separation side of a cartridge, or
different types of seals are used on different sides of the
cartridge. Similarly, the guide interface in conjunction with an
interface block as described above is used on either, both, or
neither side of the cartridge in some embodiments.
[0107] FIGS. 12-14 show various alternative embodiments of a
cartridge assembly for use with an improved CE-ESI-MS system. In
FIG. 12, the ESI sprayer tipped separation capillary 1242 is at the
outlet end of the cartridge 1212 and the conductive fluid capillary
1244 is at the inlet end of the cartridge 1212.
[0108] A portion of each capillary (1242 and 1244) is surrounded by
a capillary temperature control fluid tube 1240. The temperature
control fluid is pumped into the tubes 1240 by the CE system. Fluid
enters into the cartridge 1212 from the inlet end (left side of
FIG. 12) and exits back into the CE system from the outlet end
(right side of FIG. 12). The fluid return block 1248 diverts the
temperature control fluid from the inlet tube into the outlet tube.
As compared to previously described embodiments, this means that
the cooling fluid surrounds a portion of conducting fluid capillary
1244 as the fluid moves toward fluid return block 1248 and the
cooling fluid surrounds a portion of separation capillary 1242 as
the cooling fluid returns to cartridge 1212 from fluid return block
1248. The CE separation capillary 1242 and the conductive fluid
capillary 1244 exit the fluid return block 1248 through sealed
fittings 1294. A portion of each of the two capillaries is enclosed
in a protective housing 1270 after exiting from the coolant return
block 1248. Although not shown here, in some embodiments the whole
assembly including coolant tubes 1240 is protected by an enclosure.
By design, a user can easily mount the cartridge 1212 on a CE
analysis system. In alternative embodiments, the temperature
control fluid tubes 1240, the fluid return block 1248, and the
capillary protective housing 1270 exit an associated CE analysis
system from a side panel that covers a receiving slot for cartridge
1212. The protective housing 1270 in some embodiments then is
mounted on a mechanical stage at the inlet of the MS to generate
electrospray.
[0109] Additionally, cartridge 1212 has a window or optical
aperture 1296. This enables the user to utilize an optical detector
of a CE analysis system to detect sample during separation as the
sample passes through the optical window. The sample then continues
on to protective housing 1270 to be input to a mass spectrometer.
In alternative embodiments, where use of the optical window is not
required, the capillaries 1244 and 1242 in some embodiments switch
positions, such that the conductive fluid capillary 1244 passes
through window 1296. This does not provide any analysis benefit,
but merely allows cartridge 1212 to be used versatilely, that is,
in some embodiments with the right hand side (as seen in FIG. 12)
of the cartridge housing a portion of conductive fluid capillary
1244 without any negative effects.
[0110] The arrangement shown in FIG. 13 is identical to the
configuration of FIG. 12 except for a redesigned cartridge 1312, an
alternate fluid return block 1348, and the location of the
separation and conductive fluid capillaries in each cartridge.
Cartridge 1312 is a simpler version of cartridge 1212. It is
designed to simplify assembly of the product and save production
cost. It does not have a window, which further simplifies the
cartridge and reduces costs. FIG. 13 also discloses a different
design for the fluid return block 1348 than the fluid return block
of FIG. 12. In FIG. 12, the ESI sprayer tipped separation capillary
1242 and the conductive fluid capillary 1244 exit the fluid return
block 1248 through two separate sealed fittings 1294. In FIG. 13,
the ESI sprayer tipped separation capillary 1342 and the conductive
fluid capillary 1344 exit the fluid return block 1348 through one
sealed fitting 1394. The capillaries then continue into the sprayer
housing 1370.
[0111] FIG. 14 shows an additional alternative embodiment for a
cartridge assembly. FIG. 14 includes separation capillary 1442,
conductive fluid capillary 1444, window 1496, protective tubes
1441, mounting block 1448, and sprayer housing 1470. Cartridge 1412
shows a capillary cartridge similar to cartridge 1212 of FIG. 12
modified such that the ESI sprayer tipped separation capillary 1442
and conductive fluid capillary 1444 exit from the side of the
cartridge 1412. This design does not have capillary temperature
control fluid tubes. Instead, protective tubes 1441 protect the
capillaries 1442 and 1444 from mechanical damage after exiting from
the cartridge. The capillaries are loaded into the cartridge 1412
through tubes 1441. The tubes guide the capillaries to appropriate
ports of the cartridge 1412. The ESI sprayer tipped separation
capillary 1442 passes through the optical aperture 1496. In some
embodiments ESI sprayer tipped separation capillary 1442 has an
optical capillary window at the cartridge aperture 1496 as
described above to enable the user to utilize an optical detector
of a CE analysis system to detect sample during separation as it
passes through the optical window. The two capillaries pass through
a mounting block 1448 which takes the place of the unnecessary
fluid return block.
[0112] The mounting block 1448 helps to mechanically mount
capillaries 1442 and 1444 to the side panel of a CE analysis system
as they exit the instrument. In some embodiments the two
capillaries are enclosed in a protective housing 1470 after exiting
from mounting block 1448.
[0113] Although several cartridge assemblies are described above,
the innovations presented herein are not limited to the
configurations shown previously. Also included is any configuration
which comprises a capillary holder which is readily mountable on a
CE analysis system wherein the capillary holder includes an at
least one retractable portion, an ESI sprayer tipped separation
capillary, and a mechanical enclosure for the ESI sprayer tip of
the separation capillary wherein the mechanical enclosure includes
an at least one retractable portion and wherein the mechanical
enclosure is readily mountable on a mass spectrometer to form an
electrospray. The capillary temperature control fluid tubes, the
fluid return block, the conductive fluid capillary, or a
combination thereof are optional depending on the application and
the design of the ESI sprayer tip. In some embodiments, the ESI
sprayer tipped separation capillary has an optical window with, or
optionally without, an integrated optical aperture allowing the
separation capillary to interface with an optical detector. In
certain embodiments it is preferable to have the optical detection,
and thus the optical window, near the inlet of a mass spectrometer,
just before the protective ESI sprayer tip housing. However in some
embodiments the optical window on the separation capillary is
located anywhere along its length. In some embodiments the
separation capillary comprises a terminal portion that includes an
ESI sprayer tip. In some embodiments the separation capillary
comprises a terminal portion that includes a sheathless ESI sprayer
tip, a non-limiting example of which is a High Sensitivity Porous
Sprayer (HSPS) capillary tip. In some embodiments, the ESI sprayer
tip with an associated capillary and the separation capillary are
separate capillaries, being connected with each other by a suitable
union device.
[0114] FIG. 15 shows additional details of a sprayer housing 1570.
As shown by FIG. 15, separation capillary 1542 with surrounding
cooling tube 1540a, and conductive fluid capillary 1544 with
surrounding cooling tube 1540b enter the sprayer housing 1570 at
the bottom left hand side as shown in the figure. Conductive fluid
contact portion 1510a, which is also shown as 1610a in FIG. 16A and
described in greater detail in FIG. 17, depicts where the
conductive fluid contacts a cylindrical inner surface of an
electrically conductive slug (stainless steel slug 1722 of FIG.
17), occupies a cylindrical volume within a needle (needle 1728 of
FIG. 17), and contacts an outer cylindrical surface of a portion of
the separation capillary that is enclosed within the slug and
needle. Conductive fluid contact portion 1510b, which is also shown
as conductive fluid contact portion 1610b in FIG. 16A, depicts
where the conductive fluid occupying a cylindrical volume within
the needle contacts the etched portion of the separation capillary
which is contained within the needle.
[0115] In certain embodiments with a fragile ESI capillary output
such as ESI capillary output 1571 in FIG. 15 which in certain
embodiments is an etched capillary tip used with a sheathless (no
sheath flow) ESI sprayer, the capillary tip at the output is
extremely fragile and susceptible to breaking with minimal contact.
This is true in comparison to some non-etched tips and especially
in comparison to steel needle assemblies, which provide greater
strength but have reduced sensitivity and system resolving power.
During use on a mass spectrometer in fragile etched capillary tip
embodiments, it is necessary to have the etched capillary tip
exposed in order to generate stable ESI flow. Certain embodiments
thus use a spring loaded retractable sheath installed onto the
housing that secures the etched capillary. In certain of such
embodiments, the housing supports the capillary at a location where
etching has not been performed, and the etched portion of the
capillary is cantilevered from this point out of the housing. The
retractable sheath surrounds the etched portion of the capillary,
but does not contact the capillary in certain of such embodiments,
and a spring holds the sheath in a fully extended position at any
point that the assembly is not installed onto an adapter. In some
of such embodiments, a feature on the sheath interfaces with the
housing and prevents it from being ejected under the spring load.
Examples of various embodiments of a retracting protective sheath
are described in FIG. 15 and FIGS. 16A, 16B, and 16C.
[0116] FIG. 15 also describes retracting protective sheath 1572,
sheath assembly 1574, and ESI capillary output 1571. Similar
elements are shown in FIG. 16A as retracting protective sheath
1672, sheath assembly 1674, and ESI capillary output 1671. FIG. 15
shows retracting protective sheath 1572 in the retracted position.
When sprayer housing 1570 is inserted into an adapter at the input
of a mass spectrometer, retracting protective sheath 1572 is pushed
back toward the open cavity/slot toward the back of sheath assembly
1574. Thus, the act of inserting the sprayer housing 1570 into the
adapter removes the protective sheath 1572 and puts ESI capillary
output 1571 in position to deliver separated molecules as
electrospray to the mass spectrometer. Thus, ESI capillary output
1571 is a capillary output-proximal end portion of the capillary,
with the other end of the ESI capillary being a capillary
input-proximal end portion of the capillary.
[0117] FIGS. 16A, 16B, and 16C show additional details relating to
aspects of embodiments including a retracting protective sheath.
FIG. 16A shows retracting protective sheath 1672 in the protective
position to cover ESI capillary output 1671. In some embodiments
sheath assembly 1674 includes a spring or some other mechanism to
hold the retracting protective sheath in the protecting position
when the sprayer housing is not engaged with an adapter as shown in
FIG. 16B.
[0118] FIGS. 16B and 16C show an embodiment including a spring 1697
which pushes retracting protective sheath 1672b out into a position
where an ESI capillary output is protected by the sheath. In FIG.
16B, retracting protective sheath 1672b is extended, and in FIG.
16C, retracting protective sheath 1672b is retracted. Retention
fingers 1699 function in opposition to spring 1697 such that when
the retracting protective sheath 1672b is fully extended out into
the protective position, retention fingers 1699 prevent the sheath
from overextending due to the force of spring 1697. In various
other alternative embodiments, the specific arrangements and shapes
of the retractable sheath, spring, and housing assembly are
arranged in different positions to fulfill the same function. While
certain embodiments with an internal spring conserve space, in
alternative embodiments, the spring is mounted externally and the
sheath is retained internally. In other alternative embodiments,
retention fingers are exchanged for other means such as a press fit
bushing to hold the sheath on, quarter turn locks, other mechanical
stops, or any other such retention means.
[0119] FIG. 17 shows conductive fluid contact portion 1710 of a
sprayer tip housing for use with an improved CE-ESI-MS system.
Conductive fluid contact portion 1710 includes coolant return 1704,
separation capillary 1742, conductive liquid capillary 1744, liquid
stop deformation portion 1712, coolant manifold 1714, double lumen
tube 1715, ferrule 1716, stainless steel ring 1718, coolant
manifold threads 1720, stainless steel slug 1722, slug thread 1724,
sprayer housing body 1726, and needle 1728.
[0120] Coolant manifold 1714 acts with ferrule 1716 to deform
double lumen tube 1715 such that the coolant in coolant return 1704
is sealed from leaking further to the right of deformed portion
1712. The capillaries both enter double lumen tube 1715. In some
embodiments, the conductive fluid capillary 1744 extends into
double lumen tube 1715. In other embodiments, the conductive fluid
capillary 1744 extends through double lumen tube 1715. In some
embodiments, including the embodiment shown in FIG. 17, the
conductive fluid capillary 1744 extends through, but no further
than, double lumen tube 1715. However, the separation capillary
then enters needle 1728 which directs the capillary to the output
of the sprayer housing where it acts as an input to the mass
spectrometer. As part of the sprayer housing, sprayer tip housing
body 1726 provides further structural support and protection for
the separation capillary. In some embodiments slug thread 1724
includes a protruding screw, stud, or other contact that allows a
connection to be made with an electrical contact of the adapter to
provide the high voltage return connection to an isolated CE power
supply. This electrical connection goes from the isolated CE power
supply to the adapter, to the screw or electrical contact on the
sprayer housing, to the stainless steel slug 1722, to the
conductive liquid (from conductive liquid capillary 1744) within
slug 1722, to the conductive liquid within needle 1728, and through
the etched portion of the separation capillary wherein said etched
portion is disposed within the terminal portion of needle 1728 that
is nearest the output of the sprayer housing.
[0121] In one potential embodiment, sprayer housing body 1726,
ferrule 1716, and coolant manifold 1714 are all created from
polyether ether ketone (PEEK). In alternative embodiments, other
materials that have the characteristic of being insusceptible to
temperature, chemicals, or a combination thereof, and that do not
present out gassing issues, are used in place of PEEK for any of
the described elements of the sprayer housing.
[0122] FIGS. 18 and 19 show two embodiments of a sprayer housing,
an adapter, and a mass spectrometer in accordance with certain
embodiments of an improved CE-ESI-MS system according to the
innovations presented herein. FIG. 18 shows sprayer housing 1870,
adapter 1860, and mass spectrometer 1850. As previously described,
adapter 1860 in some embodiments is mounted and aligned with mass
spectrometer 1850. In some embodiments this attachment is transient
and in other embodiments this attachment is longstanding or even
permanent. A benefit of various embodiments of the innovations
presented herein is the ability to make a complex and/or difficult
attachment of the sprayer outlet to mass spectrometer 1850 by
housing the sprayer outlet in sprayer housing 1870 which is
operably connectable with adapter 1860 which is operably
connectable with mass spectrometer 1850 to provide for leaving the
adapter 1860 attached so that a much simpler and/or easier
connection of the sprayer outlet to the mass spectrometer is
sustained (or readily repeated).
[0123] As shown in FIG. 18 and described above, electrical
connection 1853 is attached to adapter 1860, and enables an
electrical connection from a power supply to the separation
capillary through a number of elements including the conductive
fluid from a conductive fluid capillary when sprayer housing 1870
is inserted into adapter 1860.
[0124] In one potential embodiment, adapter 1860 has a first
interface for receiving a sprayer housing and a second interface
for coupling with a mass spectrometer, with an axial capillary
passageway extending from an opening of the first interface to an
opening of the second interface. The axial capillary passageway is
also referred to as a capillary lumen. The axial capillary
passageway is positioned to allow a capillary from the sprayer
housing to pass through the axial capillary passageway, out the
second interface, and into an input of the mass spectrometer. In
certain embodiments, the adapter also has an outer surface and an
inner surface, where the inner surface defines at least a portion
of the axial capillary passageway. As part of electrical connection
1853, adapter 1860 includes a resistive electrical adapter path
from a first section of the outer surface to a first section of the
inner surface, where the inner surface is in a position to
interface with a resistive electrical path of the sprayer housing,
such as slug 1722. When the resistive electrical path of the
sprayer housing contacts the first section of the inner surface, a
resistive electrical path is created as part of the circuit shown
in FIGS. 1, 2B, and 3-6.
[0125] Sets of adapters thus are created in some embodiments such
that a first adapter and a second adapter have identical or
equivalent sprayer housing interface surfaces as part of the inner
surface at an input portion of the first interface for each
adapter. The second interface for each adapter in such embodiments,
however, has differing outer surface areas which match different
input topologies for different mass spectrometer devices. In this
way, a set of adapters may be placed on different mass spectrometer
devices to enable a single sprayer housing to interface with the
different mass spectrometer devices.
[0126] Among some embodiments sprayer housing 1870 attaches to
adapter 1860 in a variety of ways. In one potential embodiment,
sprayer housing 1870 includes a protrusion that fits into a hooked
groove in adapter 1860. As sprayer housing 1870 is inserted and
twisted in adapter 1860, the hook and protrusion lock the pair
together along with a spring force from a retracting sprayer sleeve
(such as, as a non-limiting example, retracting protective sheath
1672 of FIG. 16A) at the tip of sprayer housing 1870. Other
potential embodiments use latches, a plurality of screws used as
screw fasteners, or any other acceptable attachment to secure the
adapter 1860 with sprayer housing 1870.
[0127] Further, FIG. 18 shows x, y, z adjustment control 1851.
Adjustment control 1851 allows fine adjustments to the electrospray
input position to be made when calibrating the system for use. With
sufficiently high tolerances on the interfaces between sprayer
housing 1870 and adapter 1860, alignment and measurements are
equivalent in some embodiments to calibrations made without sprayer
housing 1870 and adapter 1860, with much lower connection time, and
much greater ease of connection, once adapter 1860 is initially
installed. In some embodiments, x, y, z adjustment control 1851 is
controlled electronically using an electronic control system, or is
manually adjustable by a user, or both. In various embodiments, x,
y, z adjustment control 1851 mechanically adjusts the electrospray
input position using adjustable screws which move the input
position when the screw is rotated. Alternately, electronic,
micro-electronic systems (MEMS), hydraulic, magnetic, or any other
means are used in some embodiments to position the input as part of
adjustment control 1851.
[0128] FIG. 19 shows another alternative embodiment including
sprayer housing 1970, adapter 1960, and mass spectrometer 1950,
with electrical connection 1953 and x, y, z adjustment control
1951. Although there are various different mass spectrometry
systems with differing input connection requirements such as MS
1950 and MS 1850 of FIG. 18, the use of an adapter such as adapter
1960 and adapter 1860 of FIG. 18, respectively, enables uniform
sprayer housing 1970 (1870 of FIG. 18) to interface with such
different mass spectrometers, or any other mass spectrometer having
an appropriately created adapter. This provides a benefit where the
high use and fragile capillary components that are most likely to
break are disposed so as to be compatible across systems in an easy
to use interface, such that cartridge assemblies may be used across
systems when, as a non-limiting example, a capillary is broken or
some other part of a cartridge assembly is worn or
non-functional.
[0129] In certain embodiments, a sprayer housing includes a
protective sheath similar to retracting protective sheath 1672
shown in FIG. 16A and to 1672b shown in FIGS. 16B-C. In such
embodiments, an etched tip that is extremely fragile and subject to
damage during connection to, or during removal from, a MS device is
protected. In some of such embodiments, the protective sheath 1672
(or 1672b) and a retention means such as retention fingers 1699 are
specifically designed to match one side of an adapter such as
adapter 1860 in FIG. 18 or adapter 1960 in FIG. 19. In such
embodiments, the adapter is inserted into the MS device,
accommodating significant adjustments and alignments without risk
of damage to the the fragile etched tip of a capillary. Once the
adapter is aligned, risk of damage to the etched capillary tip is
significantly reduced, since the motion of insertion into the
adapter is specifically designed to minimize the chance of a
fragile etched capillary tip impacting a surface of the adapter. In
some embodiments this is done by specifically designing the spring
force from spring 1697, the surface and motion of the retracting
protective sheath 1672 (or 1672b), and the restriction of retention
fingers 1699 to match an associated adapter. Similarly, in some
embodiments the maximum extension of an etched capillary tip is
designed with the adapter, to fix the extension of an etched
capillary tip outside of a sheath 1672 (or 1672b) in retracted
position. Then, when a sprayer housing with a protective sheath is
inserted into an adapter, the spring 1697 compresses and the
retracting protective sheath 1672 (or 1672b) retracts so the etched
tip of the capillary extends through the adapter and into the input
of the MS device.
[0130] A use of an adapter specifically matched to a sprayer
housing and retracting protective sheath 1672 (or 1672b) enables a
finely managed movement of the fragile etched portion of a
capillary into (and/or out of) the MS device. A single type of
adapter such as, as a nonlimiting example, adapter 1860 in FIG. 18
or adapter 1960 in FIG. 19 on multiple MS devices thus allows
multiple different MS devices to be used with one or more sprayer
housings specifically designed for an adapter on the MS devices to
minimize risk of damage to the tip of an etched capillary while
enabling the flexibility of moving the sprayer to different MS
devices.
[0131] FIG. 20 provides a schematic illustration of one embodiment
of a computer system 2000 that in some embodiments is used with
aspects of an improved CE-ESI-MS system, as described herein,
and/or functions, for example, as various parts of capillary
electrophoresis controller 110, mass spectrometer controller 160,
CE analysis system 130, power supply 120, or mass spectrometer 150
of FIG. 1. In some embodiments computer system 2000 is usable for
any component that requires control or electronic communication. It
should be noted that FIG. 20 is meant only to provide a generalized
illustration of various components, any one or more of which in
some embodiments is (are) utilized, as appropriate. FIG. 20,
therefore, broadly illustrates how individual system elements are
implemented in a relatively separated fashion in some embodiments
or in a relatively more integrated manner in other embodiments.
[0132] The computer system 2000 is shown comprising hardware
elements that in some embodiments are electrically coupled via a
bus 2005 (or are otherwise in communication, as appropriate). In
some embodiments the hardware elements include one or more
processors 2010, including, without limitation, one or more
general-purpose processors and/or one or more special-purpose
processors (such as digital signal processing chips, graphics
acceleration chips, and/or the like); one or more input devices
2015, which in some embodiments include, without limitation, a
mouse, a keyboard, and/or the like; and one or more output devices
2020, which in some embodiments include, without limitation, a
display device, a printer, and/or the like.
[0133] In some embodiments the computer system 2000 further
includes (and/or is in communication with) one or more storage
devices 2025, which in some embodiments comprise, without
limitation, local and/or network accessible storage and/or in some
embodiments include, without limitation, a disk drive, a drive
array, an optical storage device, a solid-state storage device such
as a random access memory ("RAM") and/or a read-only memory
("ROM"), which in some embodiments is programmable,
flash-updateable, and/or the like. In some embodiments the computer
system 2000 also includes a communications subsystem 2030, which in
some embodiments includes, without limitation, a modem, a network
card (wireless or wired), an infra-red communication device, a
wireless communication device, and/or chipset (such as a
Bluetooth.RTM. device, an 802.11 device, a WiFi device, a WiMax
device, cellular communication facilities, etc.), and/or the like.
The communications subsystem 2030 in some embodiments permits data
to be exchanged with a network (such as the network described
below, to name one non-limiting example), and/or any other devices
described herein. In many embodiments, the computer system 2000
further comprises a working memory 2035 or additional memory
systems, which in some embodiments include a RAM or ROM device, as
described above.
[0134] In some embodiments the computer system 2000 also comprises
software elements which in some embodiments comprise computer
programs of the innovations presented herein, and/or are designed
to implement methods of said innovations and/or configure systems
of said innovations. Merely by way of non-limiting example, one or
more procedures described with respect to the method(s) discussed
above in some embodiments is (are) implemented as code and/or
instructions executable by a computer (and/or a processor within a
computer). In some embodiments a set of these instructions and/or
code is (are) stored on a computer readable storage medium, such as
the storage device(s) 2025 described above. In some embodiments,
the storage medium is incorporated within a computer system, such
as the system 2000. In other embodiments, the storage medium is
separate from a computer system (i.e., a removable medium, such as
a compact disc, etc.), and/or provided in an installation package,
such that the storage medium in some embodiments is used to program
a general purpose computer with the instructions/code stored
thereon. In some embodiments these instructions take the form of
executable code, which is executable by the computer system 2000
and/or in some embodiments takes the form of source and/or
installable code, which, upon compilation and/or installation on
the computer system 2000 (e.g., using any of a variety of generally
available compilers, installation programs,
compression/decompression utilities, etc.), then takes (take) the
form of executable code.
[0135] It will be apparent to those skilled in the art that
substantial variations are in some embodiments made in accordance
with specific requirements. For example, in some embodiments
customized hardware also is used, and/or particular elements are
implemented in hardware, software (including portable software,
such as applets, etc.), or both. Further, connection to other
computing devices such as network input/output devices is employed
in some embodiments.
[0136] The terms "machine-readable medium" and "computer readable
medium", as used herein, refer to any medium that participates in
providing data that causes a machine to operate in a specific
fashion. In an embodiment implemented using the computer system
2000, various machine-readable media are involved in providing
instructions/code to processor(s) 2010 for execution and/or are
used to store and/or carry such instructions/code (e.g., as
signals). In many implementations, a computer readable medium is a
physical and/or tangible storage medium. Such a medium takes many
forms among various embodiments, including but not limited to,
non-volatile media, volatile media, and transmission media.
Non-volatile media includes, for example, optical or magnetic
disks, such as the storage device(s) 2025. Volatile media includes,
without limitation, dynamic memory, such as working memory shown as
working memory 2035 in FIG. 20. Transmission media includes coaxial
cables, copper wire, and fiber optics, antenna, including wires
that comprise the bus 2005, as well as various components of the
communications subsystem 2030 (and/or media by which the
communications subsystem 2030 provides communication with other
devices). Hence, transmission media also in some embodiments take
the form of waves (including, without limitation, radio, acoustic,
and/or light waves, such as those generated during radio-wave and
infra-red data communications).
[0137] Various forms of machine-readable media are involved in some
embodiments in carrying one or more sequences of one or more
instructions to the processor(s) 2010 for execution. Merely by way
of non-limiting example, the instructions in some embodiments are
initially carried on a magnetic disk and/or optical disc of a
remote computer. In some embodiments a remote computer loads the
instructions into its dynamic memory and sends the instructions as
signals over a transmission medium to be received and/or executed
by the computer system 2000. These signals, which are in some
embodiments in the form of electromagnetic signals, acoustic
signals, optical signals, and/or the like, are all non-limiting
examples of carrier waves on which instructions are encoded, in
accordance with various embodiments of the invention.
[0138] The communications subsystem 2030 (and/or components
thereof) in some embodiments will receive the signals, and the bus
2005 then in some embodiments carries the signals (and/or the data,
instructions, etc., carried by the signals) to the working memory
2035, from which the processor(s) 2010 retrieve(s) and execute(s)
the instructions.
Sheathless Interface Capillary
[0139] Capillary electrophoresis (CE) is an intrinsically low flow
separation technique and includes, but is not limited to, Capillary
Zone Electrophoresis (CZE; also known as free-solution CE [FSCE]),
Capillary Gel Electrophoresis (CGE), Capillary Isoelectric Focusing
(CIEF), Isotachophoresis (ITP), Electrokinetic Chromatography
(EKC), Micellar Electrokinetic Capillary Chromatography (MECC OR
MEKC), Micro Emulsion Electrokinetic Chromatography (MEEKC),
Non-Aqueous Capillary Electrophoresis (NACE), and Capillary
Electrochromatography (CEC).
[0140] Electroosmotic flow (EOF), also known as electroosmosis, is
bulk fluid motion when an electric field is applied across a
capillary or microchannel. The velocity of this motion is
proportional to the applied electric field and is dependent on both
the material used to construct the microchannel and the solution in
contact with the microchannel wall. This motion results from
electrical forces acting on ions in an electrical double layer
(Debye Layer), a thin layer of ions that is located near a wall
exposed to an aqueous solution. EOF can occur in, for example,
natural unfiltered water, solutions of electrolye, and buffered
solutions. EOF may be operative in chemical separation techniques,
notably CE. For example, in CE a capillary column may comprise
silica with silanol groups exposed on a channel surface of a tube
wall. The exposed silanol groups are ionized above pH 3, thereby
creating a negatively charged inner capillary surface. Cations
present in ionic solutions will migrate toward the negatively
charged wall forming a Debye Layer. Generation of an electrical
potential across the column causes cations to migrate towards the
cathode. EOF results as the solvated cations clustered at the
capillary walls drag the bulk solution in tow towards the cathode
during a CE separation. Generally, EOF of a buffer or electrolyte
solution is greater than that of the electrophoretic flow of the
analytes during a CE separation process.
[0141] A CE process can be coupled with an electrospray
ionization-mass spectrometry (ESI-MS) process using a sheath flow
interface, a split-flow interface, or a sheathless interface.
Sheathless interface technology has been limited by a problem.
Historically, it has been thought that significant EOF is needed to
successfully couple CE and ESI-MS using a sheathless interface. For
example, it has been thought to be impossible to use neutrally
coated separation capillaries in a sheathless interface of a
CE-ESI-MS system. As a result, most studies have reported the use
of a positively charged capillary, which can generate a stable and
strong EOF at acidic pH. In this context, using acidic pH, the
potential interaction between analytes (positively charged at
acidic pH) and the surface of the capillaries (positively charged
as well) can be avoided. It is a finding of the innovations
presented herein that, contrary to such expectation, significant
EOF is not needed for sheathless interface coupling of a CE process
and an ESI-MS process when using a separation capillary tube
comprising a channel, a channel surface of a tube wall, and an
etched capillary outlet-proximal end portion of a tube wall wherein
the etched capillary outlet-proximal end portion of a tube wall of
the separation capillary tube is porous to a flow of an electrical
charge, and wherein the channel surface of a tube wall of the
separation capillary tube underlies a coating layer proximal to the
channel surface of a tube wall and a coating layer distal to the
channel surface of a tube wall.
[0142] Reduction of flow with ESI into the nanoflow region has been
reported to improve assay sensitivity and reduce ion suppression
with ESI-MS. CE-ESI-MS performance parameters that are
significantly improved as a result of the innovations presented
herein include, but are not limited to: (a) an ability to generate
a stable ESI at an ultra-low flow rate, upstream from an ESI
process, of less than or equal to 20 nL/min, (b) an orders of
magnitude enhancement of detection sensitivity into the femto-,
atto-, or zepto-mole range (depending on selected analyte and mass
spectrometer), (c) a decrease of ion suppression phenomenon, (d) an
EOF that can be reduced to less than 1.times.10-7 cm2V-1S-1, and
(e) a peak capacity having a value of 200 or more.
[0143] FIG. 21 provides a non-limiting example of a separation
capillary tube that is useful with a sheathless interface for
coupling a CE process and an ESI-MS process. A channel surface
(glass surface) of a tube wall of a bare fused silica separation
capillary tube is represented. The separation capillary tube may
have dimensions comprising, as a non-limiting example, 30 .mu.m
inner diameter (i.d.).times.150 .mu.m outer diameter (o.d.). In
another non-limiting example, the separation capillary tube may
have dimensions comprising 30 .mu.m i.d..times.360 .mu.m o.d. Such
cross-sectional dimensions are in some embodiments combined with a
length dimension of 100 cm or of 110 cm, as non-limiting examples.
Silica groups (-Si(OH)3) of said channel surface (glass surface)
contact the hydrophilic bifunctional compound
.gamma.-methacryloxypropyltrimethoxysilane through a first covalent
bond, and .gamma.-methacryloxypropyltrimethoxysilane also contacts
a second coating compound, cross-linked linear polyacrylamide, by a
second covalent bond. Such capillary tubes comprising this
two-layer coat are stored either in a dry condition or in a
MES/citrate buffer without spermine.
[0144] An example of the innovations presented herein is the OptiMS
Neutral Surface Cartridge (30 .mu.m i.d..times.100 cm total length)
sold by Beckman Coulter, Inc. which includes an implementation of
the separation capillary tube that is useful as a sheathless
interface for coupling a CE process and an ESI-MS process. The
OptiMS Neutral Surface Cartridge is used in the CESI 8000 High
Performance Separation-ESI Module that also is sold by Beckman
Coulter, Inc. and that is designed for mass spectrometry
applications that include, but are not limited to, analysis of
charged and polar molecules. It consists of a CESI cartridge
coupled with an OptiMS sprayer housing. The assembly includes a
temperature controlled separation capillary tube (30 .mu.m
i.d..times.100 cm total length). Each capillary end is protected by
a self-retracting housing.
[0145] In some embodiments of the innovations herein, the etched
capillary outlet-proximal end portion of a tube wall of the
separation capillary tube that is useful as a sheathless interface
for coupling a CE process and an ESI-MS process comprises an inner
tube diameter that does not taper or that has a constant value. In
some embodiments the etched capillary outlet-proximal end portion
of the separation capillary tube wall has a wall thickness of less
than 10 .mu.m. In some embodiments the etched capillary
outlet-proximal end portion of the separation capillary tube wall
has a wall thickness of 5 .mu.m, or of about 5 .mu.m. In some
embodiments, the coating layer proximal to the channel surface of a
tube wall comprises a hydrophilic bifunctional compound covalently
bound to said channel surface of a tube wall. In some embodiments,
the hydrophilic bifunctional compound is selected from the group
consisting of .gamma.-methacryloxypropyltrimethoxysilane,
.beta.-methacryloxypropyltrimethoxysilane,
.alpha.-methacryloxypropyltrimethoxysilane, (3-glycidyloxypropyl)
trimethoxysilane, 3-(trimethoxysilyl)propyl acrylate,
3-(trimethoxysilyl)propyl methacrylate, vinyltrimethoxysilane ,
vinyltriacetoxysilane, vinyltri(.beta.-methoxyethoxy)silane, and
vinyltrichlorosilane. In some embodiments, the hydrophilic
bifunctional compound is
.gamma.-methacryloxypropyltrimethoxysilane.
[0146] In some embodiments, the coating layer distal to the channel
surface of a tube wall of the separation capillary tube that is
useful with a sheathless interface for coupling a CE process and an
ESI-MS process comprises a surface that contacts an electrolyte
solution during an electrophoresis process. It is this surface that
contacts contents of the channel (e.g. electrolyte solution,
buffered solution, water) during a CE process. In some embodiments,
the surface that contacts an electrolyte solution during an
electrophoresis process is a neutral surface. In some embodiments,
the neutral surface comprises cross-linked linear polyacrylamide.
In some embodiments, the neutral surface comprises cross-linked
linear polyacrylamide that is covalently bound. In some
embodiments, the neutral surface comprises cross-linked linear
polyacrylamide that is covalently bound with the hydrophilic
bifunctional compound that is covalently bound to the channel
surface of a tube wall.
[0147] In some embodiments, the separation capillary tube that is
useful as a sheathless interface for coupling a CE process and an
ESI-MS process comprises, during its operation as a component of a
sheathless interface of a CE process, an electroosmotic flow (EOF)
having a value less than or equal to 1.times.10-7 cm2V-1S-1. In
some embodiments, the separation capillary tube comprises, during
its operation as a component of a sheathless interface of a CE
process, an EOF having a value less than or equal to 1.times.10-6
cm2V-1S-1. In some embodiments, the separation capillary tube
comprises, during its operation as a component of a sheathless
interface of a CE process, an EOF having a value less than or equal
to 1.times.10-5 cm2V-1S-1.
[0148] In some embodiments, the separation capillary tube that is
useful as a sheathless interface for coupling a CE process and an
ESI-MS process comprises, during its operation as a component of a
sheathless interface of a CE process, a sensitivity having a value
that is less than or equal to 1 femtomole. In some embodiments, the
separation capillary tube comprises, during its operation as a
component of a sheathless interface of a CE process, a sensitivity
having a value that is less than or equal to 10 attomoles. In some
embodiments, the separation capillary tube comprises, during its
operation as a component of a sheathless interface of a CE process,
a sensitivity having a value that is less than or equal to 100
zeptomoles.
[0149] In some embodiments, the separation capillary tube that is
useful as a sheathless interface for coupling a CE process and an
ESI-MS process comprises, during its operation as a component of a
sheathless interface of a CE process, a flow rate upstream from an
ESI process having a value that is less than or equal to 10 nL/min.
In some embodiments, the separation capillary tube comprises,
during its operation as a component of a sheathless interface of a
CE process, a flow rate upstream from an ESI process having a value
that is less than or equal to 100 nL/min.
[0150] In some embodiments, the separation capillary tube that is
useful as a sheathless interface for coupling a CE process and an
ESI-MS process comprises, during its operation as a component of a
sheathless interface of a CE process, a peak capacity having a
value greater than or equal to 50. In some embodiments, the
separation capillary tube comprises, during its operation as a
component of a sheathless interface of a CE process, a peak
capacity having a value greater than or equal to 200. In some
embodiments, the separation capillary tube comprises, during its
operation as a component of a sheathless interface of a CE process,
a peak capacity having a value greater than or equal to 400. Peak
capacity is a measure of the number of peaks that are separable
from one another during a CE-ESI-MS process.
[0151] In some embodiments, the separation capillary tube that is
useful as a sheathless interface for coupling a CE process and an
ESI-MS process comprises, during its operation as a component of a
sheathless interface of a CE process, a capillary run life having a
value that is greater than or equal to 75 runs. In some
embodiments, the separation capillary tube comprises, during its
operation as a component of a sheathless interface of a CE process,
a capillary run life having a value that is greater than or equal
to 100 runs. In some embodiments, the separation capillary tube
comprises, during its operation as a component of a sheathless
interface of a CE process, a capillary run life having a value that
is greater than or equal to 300 runs. Capillary run life is the
total number of runs during which a separation capillary provides
acceptable performance.
[0152] In some embodiments, the separation capillary tube that is
useful as a sheathless interface for coupling a CE process and an
ESI-MS process comprises an inner tube diameter, wherein the inner
tube diameter has a value selected from the group consisting of
between 5 .mu.m and 10 .mu.m (inclusive), between 5 .mu.m and 15
.mu.m (inclusive), between 5 .mu.m and 20 .mu.m (inclusive),
between 5 .mu.m and 25 .mu.m (inclusive), between 5 .mu.m and 30
.mu.m (inclusive), between 5 .mu.m and 35 .mu.m (inclusive),
between 5 .mu.m and 40 .mu.m (inclusive), between 5 .mu.m and 45
.mu.m (inclusive), between 5 .mu.m and 50 .mu.m (inclusive),
between 30 .mu.m and 50 .mu.m (inclusive), between 25 .mu.m and 35
.mu.m (inclusive), and between 15 .mu.m and 45 .mu.m
(inclusive).
[0153] In some embodiments, the separation capillary tube that is
useful as a sheathless interface for coupling a CE process and an
ESI-MS process comprises a length, wherein the length has a value
selected from the group consisting of between 5 cm and 300 cm
(inclusive), between 25 cm and 250 cm (inclusive), between 50 cm
and 200 cm (inclusive), between 75 cm and 150 cm (inclusive), and
between 100 cm and 125 cm (inclusive). In some embodiments, the
separation capillary tube has dimensions including 30 .mu.m inner
diameter.times.150 .mu.m outer diameter. In some embodiments, the
separation capillary tube has dimensions including 30 .mu.m inner
diameter.times.360 .mu.m outer diameter.
[0154] In some embodiments, the separation capillary tube that is
useful as a sheathless interface for coupling a CE process and an
ESI-MS process comprises an etched capillary outlet-proximal end
portion of a separation capillary tube, wherein the etched
capillary outlet-proximal end portion has a length, wherein said
length has a value selected from the group consisting of between 5
mm and 100 mm (inclusive), between 10 mm and 90 mm (inclusive),
between 15 mm and 85 mm (inclusive), between 20 mm and 80 mm
(inclusive), between 25 mm and 75 mm (inclusive), between 30 mm and
70 mm (inclusive), between 35 mm and 65 mm (inclusive), and between
40 mm and 60 mm (inclusive).
[0155] Thus, the separation capillary tube that is useful as a
sheathless interface for coupling a CE process and an ESI-MS
process yields significant performance enhancements such as
improved peak capacity and improved sensitivity, which are
particularly important for analyzing, inter alia, peptides,
proteins, drugs, metabolites, very complex samples that may only be
available in minute amounts, or a combination thereof. The
innovations herein provide for negligible non-specific interactions
during a CE process between an inner wall of a capillary tube (or a
coating surface thereof) and analytes (peptides, proteins, drugs,
metabolites, and/or very complex samples), thereby allowing
separations having improved efficiencies. Moreover, the innovations
herein enable integration of very powerful pre-concentration
methodologies including, but not limited to, transient
isotachphoresis and electrokinetic supercharging.
[0156] Uses of the innovations herein include, but are not limited
to, characterizing therapeutic proteins; identifying proteins that
make up a specific proteome; characterizing post-translational
modifications; studying a metabolomic fingerprint related to a
particular condition; and quantifying drugs and their metabolites
in a minute or complex sample matrix.
[0157] While the invention has been described with respect to
exemplary embodiments, one skilled in the art will recognize that
numerous modifications are possible. For example, the methods and
processes described herein in some embodiments are implemented
using hardware components, software components, and/or any
combination thereof. As a further non-limiting example to the
embodiments described above, in certain embodiments, adjustments of
an x, y, z control as described herein are automated using
hardware, software, or a combination thereof. Further, while
various methods and processes described herein are described in
some embodiments with respect to particular structural and/or
functional components for ease of description, methods of the
invention are not limited to any particular structural and/or
functional architecture, but instead can be implemented on any
suitable configuration. Similarly, while various functionalities
are ascribed to certain system components, unless the context
dictates otherwise, this functionality in some embodiments is
distributed among various other system components in accordance
with different embodiments of the invention.
[0158] As described above, potential uses of the innovations
presented herein include, but are not limited to, analysis of
protein complexes, proteins, peptides, glycans or drugs/metabolites
using CE and characterization/identification of the resulting
separated molecules using MS. Additionally, in some embodiments the
innovations herein are used with molecular analysis, protein
analysis, carbohydrate analysis, glycoprotein analysis, small
molecule analysis, chiral analysis, ion analysis, drug analysis,
and genetic analysis. Genetic analysis includes DNA sequencing,
genotyping, single nucleotide polymorphism (SNP) analysis, short
tandem repeat (STR) analysis, DNA fingerprinting analysis, nucleic
acid analysis, genotyping analysis, oligonucleotide purity
analysis, plasm id analysis, single-stranded conformational
polymorphism (SSCP) analysis, and quantification by direct
hybridization analysis. Further, this list is not exhaustive and is
not limiting, as a person of ordinary skill in the art may
recognize additional potential uses for various embodiments
according to the innovations described herein.
[0159] Moreover, while the procedures comprised in the methods and
processes described herein are described in a particular order for
ease of description, unless the context dictates otherwise, various
procedures may be reordered, added, and/or omitted in accordance
with various embodiments of the invention. Moreover, the procedures
described with respect to one method or process may be incorporated
within other described methods or processes; likewise, system
components described according to a particular structural
architecture and/or with respect to one system may be organized in
alternative structural architectures and/or incorporated within
other described systems. Hence, while various embodiments are
described with--or without--certain features for ease of
description and to illustrate exemplary features, the various
components and/or features described herein with respect to a
particular embodiment can be substituted, added, and/or subtracted
from among other described embodiments, unless the context dictates
otherwise. Consequently, although the invention has been described
with respect to exemplary embodiments, it will be appreciated that
the invention is intended to cover all modifications and
equivalents within the scope of the following claims.
[0160] Thus, according to various embodiments there are described
various embodiments including but not limited to the embodiments
below. There is described, for example, an electrical circuit
comprising a first dc power supply having a first output and a
first input; a first resistive electrical path connected to a
ground that provides a first dc power supply return from the first
output to the first input; a second dc power supply having a second
output and a second input; a second resistive electrical path that
provides a second dc power supply return from the second output to
the second input, wherein the second resistive electrical path is
isolated from the ground, and wherein the first output is
electrically coupled with the second input; an isolated control
circuit that is electrically coupled with the second dc power
supply and is isolated from the ground, wherein the isolated
control circuit is communicatively coupled with an interface board
via a communication link, and wherein the communication link
maintains isolation from the ground; and a DC/DC converter that
provides isolated input power to the second dc power supply and the
isolated control circuit.
[0161] There is also described an electrical circuit of wherein the
second resistive electrical path is electrically coupled to an
electro-spray (ES) assembly. There is also described an electrical
circuit wherein the ES assembly is electrically coupled to an
adapter, and wherein the ES assembly comprises a sprayer housing,
and wherein the sprayer housing comprises a needle, a spring wound
around the needle, a retracting protective sheath coupled to the
spring. There is also described an electrical circuit wherein the
ES assembly is coupled to a mass spectrometer via the adapter.
There is also described an electrical circuit wherein the ES
assembly comprises a conductive slug portion that provides a
resistive electrical ES assembly path from an external surface of
the ES assembly to a conductive fluid contact area inside the ES
assembly; and wherein the second resistive electrical path
comprises the resistive electrical ES assembly path.
[0162] There is also described an electrical circuit wherein the
second resistive electrical path further comprises a resistive
electrical adapter path as part of an adapter that couples the ES
assembly to a mass spectrometer. There is also described an
electrical circuit wherein the first output is electrically coupled
with the second input via the resistive electrical ES assembly
path. There is also described an electrical circuit wherein the
first resistive electrical path comprises a conductive fluid
capillary path that is part of a capillary electrophoresis (CE)
analysis system. There is also described an electrical circuit
wherein the interface board is part of the CE analysis system, and
wherein the CE analysis system communicates with the isolated
control circuit via the interface board to control the second DC
power supply. There is also described an electrical circuit wherein
the interface board is part of the CE analysis system; wherein the
communications link is an optical communications link; wherein the
interface board receives an analog control signal, converts the
analog control signal to a digital logic pulse stream which is
routed to the isolated control circuit; and wherein the isolated
control circuit converts the digital logic pulse stream back into
the analog control signal and controls the second DC power supply
using the analog control signal.
[0163] There is also described an electrical circuit further
comprising a voltage limit resistor coupled directly with the first
dc power supply, wherein said voltage limit resistor is in the
first resistive electrical path and is not in the second resistive
electrical path. There is also described an electrical circuit
wherein the communication link and the DC/DC converter each is able
to withstand a voltage greater than or equal to a maximum output
voltage of the first dc power supply, a maximum output voltage of
the second dc power supply, or a voltage that is a sum of said
maximum output voltages. There is also described an electrical
circuit wherein the maximum output voltage of the first dc power
supply is a value between -10 kV and +10 kV, inclusive. There is
also described an electrical circuit wherein the maximum output
voltage of the second dc power supply is a value between -30 kV and
+30 kV, inclusive. There is also described an electrical circuit
wherein the voltage limit resistor has a resistive value between 10
megaOhms and 500 megaOhms, inclusive. There is also described an
electrical circuit further comprising a leakage detection circuit
operably coupled with the voltage limit resistor that measures
leakage current. There is also described an electrical circuit
wherein the leakage detection circuit comprises: a sense resistor
coupled directly to the voltage limit resistor; and an amplifier
coupled with the sense resistor and the voltage limit resistor;
wherein the sense resistor and the amplifier are disposed in the
first resistive electrical path and are not disposed in the second
resistive electrical path.
[0164] There is also described an electrical circuit wherein the
leakage detection circuit comprises: a sense resistor coupled
indirectly with the voltage limit resistor; and an amplifier
coupled directly with the sense resistor, wherein the amplifier is
indirectly coupled with a first side of the voltage limit resistor
via the first DC power supply and is indirectly coupled with a
second side of the voltage limit resistor via a mass spectrometer
load and the sense resistor; and wherein the sense resistor and the
amplifier are disposed in the first resistive electrical path and
are not disposed in the second resistive electrical path.
[0165] There is also described an electrical circuit wherein the
resistive value of the sense resistor is a value between 1 kOhm and
503 kOhms, inclusive. There is also described a cartridge assembly
comprising: a cartridge including a housing; a protective sheath
configured to be coupled with the cartridge; a capillary coupled
with the protective sheath, wherein the capillary and the
protective sheath are disposed to move with respect to one another
between a first position and a second position, wherein an end
portion of the capillary is protected in the first position and
wherein the end portion of the capillary is operably disposed in
the second position.
[0166] There is also described a cartridge assembly wherein the
protective sheath is a first protective sheath, the capillary is a
first capillary, and wherein the cartridge assembly comprises a
second protective sheath and a second capillary. There is also
described a cartridge assembly, wherein the second capillary and
the second protective sheath are disposed to move with respect to
one another between a third position and a fourth position, wherein
an end portion of the second capillary is protected in the third
position and wherein the end portion of the second capillary is
operably disposed in the fourth position.
[0167] There is also described a cartridge assembly further
comprising first and second cooling tubes respectively surrounding
the first and second capillaries, wherein the first and second
cooling tubes are configured to contain a cooling fluid. There is
also described a cartridge assembly wherein the cooling fluid
circulates in the first and second tubes in a cooling circuit.
There is also described a cartridge assembly further comprising a
seal between the capillary and the housing. There is also described
a cartridge assembly wherein the protective sheath comprises a
capillary interface, wherein the capillary interface is configured
to receive the seal. There is also described a cartridge assembly
wherein the housing of the cartridge comprises a window which
exposes at least a portion of the capillary. There is also
described a cartridge assembly further comprising a sprayer housing
coupled with the capillary. There is also described a cartridge
assembly wherein the protective sheath is a first protective
sheath, and wherein the cartridge assembly further comprises a
sprayer housing coupled with the capillary, wherein the sprayer
housing includes a third protective sheath and a capillary
output-proximal end portion of the capillary, the third protective
sheath surrounding at least a portion of the capillary
output-proximal end portion of the capillary.
[0168] There is also described a cartridge assembly wherein the
third protective sheath is retractable; wherein the capillary and
the third protective sheath are disposed to move with respect to
one another between a fifth position and a sixth position as the
third protective sheath retracts, wherein the capillary
output-proximal end portion of the capillary is protected in the
fifth position and wherein the capillary output-proximal end
portion of the capillary is operably disposed in the sixth
position, such that the third protective sheath guides the
output-proximal end portion of the capillary to the sixth
position.
[0169] There is also described a cartridge assembly wherein the
sprayer housing further comprises a spring coupled to the third
protective sheath and a body of the sprayer housing such that the
spring compresses when the third protective sheath is retracted,
and the spring exerts a force to extend the third protective
sheath.
[0170] There is also described a cartridge assembly further
comprising a needle disposed within the sprayer housing, the needle
surrounding a portion of the first capillary such that the first
capillary extends through the needle; wherein coils of the spring
surround at least a portion of the needle. There is also described
a cartridge assembly wherein the third protective sheath further
comprises at least one retention finger that locks into a first
area of the sprayer housing when the third protective sheath is in
an extended position to prevent the third protective sheath from
further extending away from the sprayer housing.
[0171] There is also described a cartridge assembly wherein the
protective sheath comprises a tapered guide pass through in an end
portion of the protective sheath, the tapered guide pass through
being tapered such that an anterior portion of the tapered guide
pass through that is proximal to the capillary is wider than an
exterior portion of the guide pass through that is distal to the
capillary, the tapered guide pass through positioned such that when
the protective sheath is in the first position, the capillary is
within the protective sheath and as the protective sheath moves to
the second position, the end portion of the capillary passes
through the tapered guide pass through to a position exterior to
the protective sheath in the second position. There is also
described a cartridge assembly further comprising a sprayer housing
coupled with the capillary, wherein the sprayer housing comprises a
double lumen tube, a coolant manifold, and a ferrule, wherein the
ferrule is disposed to deform a portion of the double lumen
tube.
[0172] There is also described a cartridge assembly further
comprising a sprayer housing coupled with the capillary, wherein
the sprayer housing comprises a first electrical contact configured
to contact a second electrical contact on an adapter. There is also
described a cartridge assembly, wherein the adapter is selected
from the group consisting of at least a first adapter cooperatively
configured with a first MS system, a second adapter cooperatively
configured with a second MS system, and a third adapter
cooperatively configured with a third MS system, wherein said at
least first, second, and third adapters are cooperatively
configured with said sprayer housing. There is also described a
cartridge assembly wherein the cartridge comprises a flexible
finger detent; and the protective sheath comprises a mechanical
stop; and wherein with the capillary and the protective sheath in
the first position, the flexible finger detent and the mechanical
stop interface to prevent movement of the protective sheath to the
second position, thereby disposing the protective sheath in a
locked position, unless the flexible finger detent is flexed about
a pivot point. There is also described a cartridge assembly further
comprising: means for locking the protective sheath in the first
position.
[0173] There is also described a cartridge assembly, wherein the
protective sheath protects and guides an end portion of the
capillary during its insertion into, or removal from, an interface
block of a capillary electrophoresis system. There is also
described a cartridge assembly, wherein the third protective sheath
protects and guides the at least a portion of the capillary
output-proximal end portion of the capillary, which is optionally
etched, during its insertion into, or removal from, a mass
spectrometry system.
[0174] There is also described an adapter, wherein said adapter is
a part of a capillary electrophoresis electrospray ionization mass
spectrometry (CE-ESI-MS) system that adapts an electrospray housing
containing an end portion of a separation capillary to an input of
a mass spectrometer of the CE-ESI-MS system, and wherein said
adapter comprises: an inner surface; and an outer surface; and a
first input comprising a first input opening and a first portion of
the inner surface; and a first output, wherein an axial capillary
passageway extends from the first input to the first output, the
axial capillary passageway surrounded by at least a second portion
of the inner surface; and a high voltage resistive path that
extends from a first electrical contact on the outer surface to a
second electrical contact on a section of the first portion of the
inner surface. There is also described an adapter, wherein the
first portion of the inner surface comprises a hooked groove. There
is also described an adapter further comprising a plurality of
screws extending from the outer surface to the first portion of the
inner surface. There is also described an adapter, wherein the
outer surface comprises a first portion of the outer surface that
is structured to interface with a mass spectrometer input.
[0175] There is also described an adapter wherein the outer surface
comprises a plurality of adjustment contact points coupled to an x,
y, z adjustment control, the x, y, z adjustment control comprising
a means for fine adjustments to the position and orientation of the
first output. There is also described an adapter wherein the inner
surface comprises: a means for interfacing with a retractable
capillary sheath that is part of a sprayer housing; and a means for
securing at least a first portion of the sprayer housing within a
first portion of the axial capillary passageway.
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