U.S. patent application number 16/108213 was filed with the patent office on 2018-12-13 for capture probe.
The applicant listed for this patent is UT-BATTELLE, LLC. Invention is credited to Vilmos Kertesz, Gary J. Van Berkel.
Application Number | 20180356317 16/108213 |
Document ID | / |
Family ID | 57072153 |
Filed Date | 2018-12-13 |
United States Patent
Application |
20180356317 |
Kind Code |
A1 |
Kertesz; Vilmos ; et
al. |
December 13, 2018 |
Capture Probe
Abstract
A system for sampling a sample material includes a device for
directing sample into a capture probe. The device for supplying
sample material to the probe can be a device for radiating energy
to the surface to eject sample from the sample material. A probe
includes an outer probe housing having an open end. A liquid supply
conduit has an outlet positioned to deliver liquid to the open end.
An exhaust conduit removes liquid from the open end of the housing.
The liquid supply conduit can be connectable to a liquid supply for
delivering liquid at a first volumetric flow rate to the open end
of the housing. A liquid exhaust system can be in fluid connection
with the liquid exhaust conduit for removing liquid from the liquid
exhaust conduit at a second volumetric flow rate, which exceeds the
first volumetric flow rate such that gas with sample is withdrawn
with the liquid. The probe can produce a vortex of liquid in the
liquid exhaust conduit. A method for sampling a surface and a
sampling probe system are also disclosed.
Inventors: |
Kertesz; Vilmos; (Oak Ridge,
TN) ; Van Berkel; Gary J.; (Oak Ridge, TN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UT-BATTELLE, LLC |
OAK RIDGE |
TN |
US |
|
|
Family ID: |
57072153 |
Appl. No.: |
16/108213 |
Filed: |
August 22, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14682847 |
Apr 9, 2015 |
10060838 |
|
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16108213 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N 1/10 20130101; G01N
1/24 20130101; H01J 49/0463 20130101; G01N 2001/028 20130101; H01J
49/164 20130101; H01J 49/0418 20130101 |
International
Class: |
G01N 1/24 20060101
G01N001/24; G01N 1/10 20060101 G01N001/10 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002] This invention was made with government support under
contract No. DE-AC05-00OR22725 awarded by the U.S. Department of
Energy. The government has certain rights in this invention.
Claims
1. A system for sampling a sample material, comprising: a probe
comprising an outer probe housing having an inner wall and an open
end for communicating with a sample space; a liquid supply conduit
within the housing and having an outlet positioned to deliver
liquid to the open end of the housing; an exhaust conduit within
the housing for removing liquid from the open end of the housing;
the liquid supply conduit being connectable to a liquid supply for
delivering liquid at a first volumetric flow rate to the open end
of the housing; a liquid exhaust system in fluid connection with
the liquid exhaust conduit for removing liquid from the liquid
exhaust conduit at a second volumetric flow rate, the second
volumetric flow rate exceeding the first volumetric flow rate,
whereby gas containing sample from the sample space will be
withdrawn with liquid flowing into and through the liquid exhaust
conduit; and, a device for directing sample into the open end of
the probe communicating with the sample space.
2. The system of claim 1, wherein the device for directing sample
into the probe is a laser producing a laser beam.
3. The system of claim 2, wherein the sample is provided on a
support that is transparent to the wavelength and the laser is
positioned to direct the laser beam through the support to the
sample.
4. The system of claim 2, wherein the laser is positioned on the
same side of the support as the sample.
5. The system of claim 1, wherein the second volumetric flow rate
exceeds the first volumetric flow rate by at least 5%.
6. The system of claim 1, wherein the second volumetric flow rate
exceeds the first volumetric flow rate by between 5-50%.
7. The system of claim 1 wherein the probe produces a vortex of
liquid in the liquid exhaust conduit.
8. The system of claim 1, further comprising a gas guide between
the open end of the probe and the sample for focusing the flow of
gas into the liquid exhaust conduit.
9. The system of claim 1, further comprising a voltage source
electrically connected to create a voltage difference between the
sample surface and the probe.
10. The system of claim 1, wherein the device for directing sample
into the probe comprises an acoustic desorption device.
11. The system of claim 1, wherein the device for directing sample
into the probe comprises a droplet dispenser.
12. The system of claim 1, further comprising an analysis device in
liquid communication with the liquid exhaust system.
13. A method for sampling a sample material, comprising the steps
of: providing a probe having an open end communicating with a
sample space; providing a device for directing sample into the open
end of the probe; supplying liquid to the open end of the probe at
a first volumetric flow rate; removing the liquid from the open end
of the probe at a second volumetric flow rate, the second
volumetric flow rate exceeding the first volumetric flow rate;
operating the device to direct sample into the open end of the
probe communicating with the sample space; removing the sample
material and gas with the liquid removed from the open end of the
probe through an exhaust conduit of the probe.
14. The method of claim 13, wherein the device for directing sample
into the probe is a radiation source for directing a radiation beam
at sample material on a sample support.
15. The method of claim 14, wherein the radiation source is a
laser.
16. The method of claim 15, wherein the sample is provided on a
support that is transparent to the wavelength and the laser is
positioned to direct the laser beam through the support to the
sample.
17. The method of claim 15, wherein the laser beam emanates from
the same side of the support as the sample.
18. The method of claim 13, further comprising the step of
subjecting the removed liquid containing sample and gas to chemical
analysis.
19. The method of claim 13, wherein the liquid removed from the
open end forms a vortex in a liquid exhaust conduit.
20. The method of claim 13, wherein the device for directing sample
into the probe is a droplet dispenser.
21. The method of claim 13, wherein the second volumetric flow rate
exceeds the first volumetric flow rate by at least 5%.
22. The method of claim 13, wherein the second volumetric flow rate
exceeds the first volumetric flow rate by between 5-50%.
23. The method of claim 13, further comprising the step of
providing a gas guide between the open end of the probe and the
sample for focusing the flow of gas into the liquid exhaust
conduit.
24. The method of claim 13, further comprising the step of creating
a voltage difference between the sample and the probe.
25. The method of claim 13, wherein the device for directing sample
into the probe is an acoustic desorption energy source.
26. The method of claim 13, further comprising directing sample
material and gas with the liquid removed from the probe to an
analysis device.
27. A sampling probe system, comprising: an outer probe housing
having an inner wall and an open end for communicating with a
sample space; a liquid supply conduit within the housing and having
an outlet positioned to deliver liquid to the open end of the
housing; an exhaust conduit within the housing for removing liquid
from the open end of the housing; the liquid supply conduit being
connectable to a liquid supply for delivering liquid at a first
volumetric flow rate to the open end of the housing; and, a liquid
removal system in fluid connection with the liquid exhaust conduit
for removing liquid from the liquid exhaust conduit at a second
volumetric flow rate, the second volumetric flow rate exceeding the
first volumetric flow rate, whereby gas containing sample from the
sample space will be withdrawn with liquid flowing into and through
the liquid exhaust conduit.
28. The sampling probe system of claim 27, wherein liquid enters
the liquid exhaust conduit as a vortex.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
application Ser. No. 14/682,847, filed Apr. 9, 2015 and is related
to International application no. PCT/US16/26706, filed on Apr. 8,
2018, both entitled "CAPTURE PROBE", the disclosures of which are
hereby incorporated herein fully by reference in their
entireties.
FIELD OF THE INVENTION
[0003] This invention relates generally to sample analysis systems
and methods, and more particularly to sample analysis systems
utilizing sampling probes.
BACKGROUND OF THE INVENTION
[0004] The capture of sample particulates and airborne sample
material provides challenges with a liquid sampling probe,
particularly in the case where sample material is first ejected
from the sample by the application of radiant energy such as a
laser beam or by acoustic desorption, or otherwise where there is a
sample material that is airborne or otherwise ejected from a sample
surface. The sample material if airborne can disperse before it is
collected by the probe. An efficient liquid probe system for
capturing such sample material would be desirable.
SUMMARY OF THE INVENTION
[0005] A system for sampling a sample material includes a device
for supplying sample to a capture probe. The device for supplying
sample material to the probe can be a device for radiating energy
to the sample material to eject sample from the sample material.
The system also includes a probe comprising an outer probe housing
having an inner wall and an open end for communicating with a
sample space. A liquid supply conduit is provided within the
housing and has an outlet positioned to deliver liquid to the open
end of the housing. An exhaust conduit is provided within the
housing for removing liquid from the open end of the housing. The
liquid supply conduit can be connectable to a liquid supply for
delivering liquid at a first volumetric flow rate to the open end
of the housing. A liquid exhaust system can be in fluid connection
with the liquid exhaust conduit for removing liquid from the liquid
exhaust conduit at a second volumetric flow rate. The second
volumetric flow rate exceeds the first volumetric flow rate,
whereby gas containing sample from the sample space will be
withdrawn with liquid flowing through the liquid exhaust conduit.
The probe can produce a vortex of liquid in the liquid exhaust
conduit.
[0006] The device for radiating energy can be a laser producing a
laser beam. The sample can be provided on a support that is
transparent to the wavelength and the laser can be positioned to
direct the laser beam through the support to the sample. The laser
can be positioned on the same side of the support as the
sample.
[0007] The second volumetric flow rate can exceed the first
volumetric flow rate by at least 5%. The second volumetric flow
rate can exceed the first volumetric flow rate by between
5-50%.
[0008] The system can further include a gas guide between the open
end of the probe and the sample material for focusing the flow of
gas into the liquid exhaust conduit.
[0009] A voltage source can be electrically connected to create a
voltage difference between the sample material and the probe.
[0010] A method for sampling a sample material can include the step
of providing a device for directing sample into a capture probe.
The sample material can be positioned on a sample support. A
radiation energy source can be provided for directing a beam of
radiation at the sample material. A probe is provided having an
open end. The open end can be positioned a distance from the sample
and the sample support to define a sample space. Liquid can be
supplied to the open end of the probe at a first volumetric flow
rate. The liquid can be removed from the open end of the probe at a
second volumetric flow rate, the second volumetric flow rate
exceeding the first volumetric flow rate. The radiation energy
source can be operated to eject sample material from the sample.
The ejected sample material and gas from the sample space can be
removed with the liquid removed from the open end of the probe. The
removed liquid containing sample and gas can be subjected to
chemical analysis. The liquid removed from the open end can form a
vortex as it enters a liquid exhaust conduit.
[0011] The radiation energy can be a laser beam. The sample can be
provided on a support that is transparent to the wavelength and the
laser can be positioned to direct the laser beam through the
support to the sample. The laser beam can emanate from the same
side of the support as the sample.
[0012] The second volumetric flow rate can exceed the first
volumetric flow rate by at least 5%. The second volumetric flow
rate can exceed the first volumetric flow rate by between
5-50%.
[0013] The method can further include the step of providing a gas
guide between the open end of the probe and the sample for focusing
the flow of gas in the sample space and into the liquid exhaust
conduit.
[0014] The method can further include the step of creating a
voltage difference between the sample and the probe.
[0015] A sampling probe system can include an outer probe housing
having an inner wall and an open end for communicating with a
sample space, a liquid supply conduit within the housing and having
an outlet positioned to deliver liquid to the open end of the
housing, and an exhaust conduit within the housing for removing
liquid from the open end of the housing. The liquid supply conduit
can be connectable to a liquid supply for delivering liquid at a
first volumetric flow rate to the open end of the housing. A liquid
removal system can be in fluid connection with the liquid exhaust
conduit for removing liquid from the liquid exhaust conduit at a
second volumetric flow rate. The second volumetric flow rate
exceeds the first volumetric flow rate, whereby gas containing
sample from the sample space will be withdrawn with liquid flowing
through the liquid exhaust conduit. The liquid can enter the liquid
exhaust conduit as a vortex.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] There are shown in the drawings embodiments that are
presently preferred it being understood that the invention is not
limited to the arrangements and instrumentalities shown,
wherein:
[0017] FIG. 1 is a schematic diagram of a system for sampling a
surface.
[0018] FIG. 2B is an enlarged schematic diagram of area A in FIG.
1. FIG. 2A is an enlarged schematic diagram of area B in FIG.
2.
[0019] FIG. 3A is a plot of Rel. Area (%) vs. Probe-to-surface
Distance (mm); and FIG. 3B a schematic diagram illustrating the
distance h of the probe to the sample.
[0020] FIG. 4A is a plot of Rel. Area (%) vs. Probe Offset from
Vertical Center Line (mm); and FIG. 4B a schematic diagram
illustrating the position x of the probe from the center line.
[0021] FIGS. 5A-5C are plots of mass to charge (m/z) ratio vs. Rel.
Int. (%) for FIG. 5A polypropylene glycol; FIG. 5B bovine insulin
side chain B; and FIG. 5C horse heart cytochrome c.
[0022] FIG. 6A is a chemical structure diagram of the dye basic
blue 7, present in blue permanent marker ink; FIG. 6B is a
schematic diagram illustrating the oversampling methodology; FIG.
6C is an optical image of stamped blue ink grid pattern; and FIG.
6D is a chemical image of basic blue 7 from the same stamped ink
pattern.
[0023] FIG. 7A is a chemical structure diagram of
phosphatidylcholine lipid; FIG. 7B is an optical image of a portion
of a small animal brain thin section; and FIG. 7C is a chemical
image of the phosphatidylcholine lipid from the same portion of the
thin section.
[0024] FIG. 8A is a chemical structure diagram of raclopride; FIG.
8B is an optical image of a small animal brain thin section; FIG.
8C is an enlarged optical image of the thin section; and FIG. 8D is
a chemical image of raclopride from the same portion of the thin
section.
[0025] FIG. 9A is a chemical structure diagram for Novolac resin;
FIG. 9B is an optical image of a photoresist pattern formed from
Novolac resin; and FIG. 9C is a chemical image of the chemical
components of the Novolac resin from the same portion of the
photoresist pattern.
[0026] FIG. 10A is a chemical structure for Novolac resin; FIG. 10B
is an optical image for a second photoresist pattern formed from
Novolac resin; and FIG. 10C is a chemical image of the chemical
components of the Novolac resin from the same portion of the this
second photoresist pattern.
[0027] FIG. 11 is a schematic diagram of a probe with vortex liquid
flow.
[0028] FIG. 12 is a schematic diagram of a probe with
plume-focusing gas flow.
[0029] FIG. 13 is a diagram illustrating computer model results for
gas flow into the exhaust conduit of a probe.
[0030] FIG. 14A is a schematic diagram of a system with a
plume-focusing gas guide spaced between the sample support and the
probe; FIG. 14B is a cross section of the gas guide in a first
focusing gas flow port configuration; and FIG. 14C is a cross
section of the gas guide in a second focusing gas flow port
configuration.
[0031] FIG. 15A is a schematic diagram of a system with a
plume-focusing gas guide in a baffle configuration; and FIG. 15B is
a cross section of the gas guide.
[0032] FIG. 16A is a cross section of a plume-focusing gas guide;
FIG. 16B is a vertical cross section; FIG. 16C is a no plume-gas
focusing guide; FIG. 16D is a gas guide having first height h; FIG.
16E is a gas guide having a second height h'; and FIG. 16F is a gas
guide having a third height h''.
[0033] FIG. 17A is a schematic diagram of a system with a
plume-focusing gas guide that is separated from the sample support;
and FIG. 17B is a cross section of the gas guide.
[0034] FIG. 18A is a cross section of a plume-focusing gas guide
that is detached from the sample support; FIG. 18B is a schematic
diagram illustrating guide wall height; schematic diagrams of FIG.
18C is a no plume-gas focusing guide; FIG. 18D is a gas guide
having first height h; FIG. 18E is a gas guide having a second
height h'; and FIG. 18F a gas guide having a third height h''.
[0035] FIG. 19 is a schematic diagram of a system enabling a
voltage difference to be applied between the sample and probe.
[0036] FIG. 20A is a schematic diagram of a system for sampling a
surface;
[0037] FIG. 20B is an enlarged area B; and FIG. 20C is a depiction
of liquid and gas flow into the probe.
[0038] FIG. 21 is a schematic diagram of a droplet dispenser for
supplying sample to the probe.
DETAILED DESCRIPTION OF THE INVENTION
[0039] FIG. 1-2 are schematic diagrams of a system for sampling a
surface. There is shown in the figures a system 20 for sampling a
sample area 32 including a sample surface 96 which includes a
device 28 for radiating energy to the surface 96 to eject sample
from the sample material. The invention can be utilized with many
different systems and methods for generating sample material and
directing the sample material into or toward the probe. The probe
is shown in a vertical orientation, but can also be used in other
orientations. The system also includes a probe 39 comprising an
outer probe housing 40 having an inner wall 41 and an open end 42
for communicating with a sample space 104. A liquid supply conduit
43 is provided within the housing and has an outlet positioned to
deliver liquid to the open end of the housing. An exhaust conduit
52 is provided within the housing 40 for removing liquid from the
open end 68 of the exhaust conduit 52. The position of the open end
68 relative to the open end 42 of the probe can vary to adjust flow
conditions into the exhaust conduit 52. The liquid supply conduit
can be an annular space between the exhaust conduit 52 and the
inner wall 41 of the housing 40. Other configurations are possible
for delivering solvent to the open end of the housing, for example,
one or more tubular liquid supply conduits.
[0040] The liquid supply conduit can be connectable to a liquid
supply such as intake line 72 for delivering liquid as shown by
arrow 56 at a first volumetric flow rate to the open end 42 of the
housing 40. A liquid exhaust system can be in fluid connection with
the liquid exhaust conduit 52 for removing liquid as shown by arrow
60 from the liquid exhaust conduit 52 at a second volumetric flow
rate. The second volumetric flow rate exceeds the first volumetric
flow rate, whereby gas containing sample from the sample space 104
will be withdrawn with liquid flowing through the liquid exhaust
conduit 52. The probe 39 can produce a vortex 45 of liquid in the
liquid exhaust conduit 52 as shown, although a vortex is not
necessary for functioning of the device. The relative diameters of
the liquid exhaust conduit 52 d.sub.1, the liquid supply conduit 43
d.sub.2 and the outer diameter of the probe 39 d.sub.3 can vary.
The distance between the sample and liquid surface 64 can vary, as
indicated by the arrows h in FIG. 2A. The distance from the inlet
of the liquid exhaust conduit 52 and the open end 42 of the housing
40 can also vary.
[0041] The excess of volume leaving the liquid exhaust conduit 52
at the second volumetric flow rate relative to the amount of liquid
entering the probe at the first volumetric flow rate results at the
entrance to the liquid exhaust conduit 52 in the draw of gas from
the sample space 104 into the liquid exhaust conduit 52.
Positioning of the open end 42 below the sample 96 at the point
where radiant energy strikes the sample 96 will cause sample
material to fall or otherwise be ejected toward the liquid surface
64. Liquid including the captured sample material will enter the
liquid exhaust conduit 52 and thereby collected for further
analysis. Airborne sample material ejected from the sample will be
assisted to the center of the liquid exhaust conduit 52 by gas flow
created by the greater volumetric flow of liquid out of the probe
39 through the exhaust conduit 52 than into the probe 39 through
the supply conduit 43.
[0042] The amount by which the second volumetric flow rate exceeds
the first volumetric flow rate can vary, and will in part depend
upon the characteristics of the sample, liquid, and probe size and
geometry. In one embodiment, the second volumetric flow rate can
exceed the first volumetric flow rate by at least 5%. In another
embodiment the second volumetric flow rate can exceed the first
volumetric flow rate by between 5-50%.
[0043] The device 28 for directing sample into the capture probe 39
can be a laser radiating energy such as a laser beam 92. The device
for radiating energy can radiate intense heat. The wavelength and
intensity of the energy can vary based upon the characteristics of
the sample being tested. The sample 96 can be provided on a support
100. The support 100 can be transparent to the wavelength of the
radiated energy such that the laser 28 can be positioned to direct
the laser beam 92 through the support to the sample 96. The laser
28 can be positioned on the same side of the support 100 as the
sample 96 such that a laser beam 93 emanates directly at the sample
96 without passing through the support 100. The device for
directing sample into the capture probe can be an acoustic
desorption device wherein a laser or other energy imparting device
is used to generate an acoustic wave which travels through the
sample support to impart energy to the sample and eject sample
material from the sample. The acoustic desorption can be laser
induced acoustic desorption. The invention can be used with other
means for ejecting sample material from the sample to the probe,
and many other devices and methods for directing sample into the
capture probe.
[0044] The system 20 can deliver to and remove solvent from the
probe 39 by any suitable means. The liquid intake line 72 receives
liquid from a suitable source such as a container or a liquid
supply line. A pump such as an HPLC pump (not shown) can be used to
meter solvent flow into the probe 39. The liquid can be any
suitable solvent for the sample material, such as water, methanol,
or acetonitrile. Other solvents are possible. A T-connection 76 can
include a fitting 78 to engage the probe 39 and make a fluid
connection with fitting 79 and between the liquid supply line 72
and the liquid supply conduit 43. A fitting 80 can make a
connection between the liquid exhaust conduit 52 and the liquid
exhaust line 86. The exhaust line 86 can be connected to inlet 120
of a chemical analysis device such as a mass spectrometer. Other
connection materials and methods are possible.
[0045] The system 20 can have other features. A 90 degree prism 88
can be provided to direct the laser beam through a microscope
objective 84. A light source 108 can be provided. A video monitor
116 can be provided. A mass spectrometer 124 or other chemical
analysis device can be provided and can have a monitor 128 and a
suitable control 132 joystick or other control device.
[0046] FIG. 3 is FIG. 3A a plot of Rel. Area (%) vs.
Probe-to-surface Distance (mm); and FIG. 3B a schematic diagram
illustrating the distance h of the probe to the sample. FIG. 3A
illustrates that capture of material ejected from the surface is
relatively constant to a 1.5 mm spacing.
[0047] FIG. 4 is FIG. 4A a plot of Rel. Area (%) vs. Probe Offset
from Vertical Center Line (mm); and FIG. 4B a schematic diagram
illustrating the position x of the probe from the center line. The
plot of FIG. 4A illustrates that capture of material ejected from
the surface is relatively stable with probe movement illustrated by
arrow x in FIG. 4B up to 1 mm from the vertical center line. In
this embodiment gravity helps to direct ablated material down
towards the capture liquid.
[0048] FIG. 5 is a plot of mass to charge (m/z) vs. Rel. Int. (%)
for FIG. 5A polypropylene glycol; FIG. 5B bovine insulin side chain
B; and FIG. 5C horse heart cytochrome c obtained using positive ion
mode electrospray ionization mass spectrometry for detection. FIG.
5A is the result of the analysis of a propylene glycol mixture
containing PPG 425--0.1 nmole spotted on a Director.RTM. slide. The
capture solvent was 80/20/0.1 (v/v/v) methanol/water/formic acid at
200 .mu.L/min. FIG. 5B is the result for the analysis of bovine
insulin side chain B (3494 Da)-0.3 nmol spotted on a Director.RTM.
slide. The capture solvent was 50/50/0.1 (v/v/v)
acetonitrile/water/formic acid flowing at 200 .mu.L/min. FIG. 5C is
the result for horse heart cytochrome c (12360.2 Da)-81 pmol
spotted on a Director.RTM. slide. These mass spectra illustrate
that with this system a wide variety of organic and biological
molecules can be ejected from the surface using a laser, captured
in a liquid, ionized and mass analyzed, with the molecules
remaining intact.
[0049] Testing of the chemical imaging capability of this system
was performed using a stamped ink grid containing the dye basic
blue 7 (m/z 478 having the chemical structure shown in FIG. 6A).
There is shown in FIG. 6B a schematic diagram illustrating a
sampling methodology termed oversampling, where the laser spot 180
is scanned over an incremental step 188 on ink line 184 in the
direction of arrow 192 leaving a sampled area 196. The laser spot
size d was 50 .mu.m, the surface scan speed 10 .mu.m/s, with 2.5
.mu.m steps between lanes and 51 lane scans. Capture liquid flow
was methanol+0.1% formic acid at 200 .mu.L/min. Analysis was
performed with AB Sciex Triple TOF 5600+, full scan m/z 100-1000
using positive ion mode electrospray ionization, 250 ms acquisition
time. A 355 nm Nd:YAG laser was used at 10 Hz, 60 .mu.J/pulse. The
chemical image shown in FIG. 6D correlates well with the optical
image shown in FIG. 6C. The pixel size was 2.5 .mu.m.times.2.5
.mu.m.
[0050] There is shown in FIG. 7A a chemical structure diagram of
the phosphatidylcholine lipid from mouse brain detected using a
selected reaction monitoring tandem mass spectrometry mode to
improve detection selectivity. The mouse brain tissue was placed on
a PEN 1.0 slide. The laser spot was 50 .mu.m. The acquisition
parameters were 50 .mu.m/s and 20 .mu.m steps with 151 lanes.
Solvent flow was 200 .mu.L/min, methanol+0.1% formic acid. Analysis
was performed with AB Sciex Triple TOF 5600+, using positive ion
mode electrospray ionization product ion m/z 760.6.fwdarw.184.06
(CE=45 eV), 250 ms acquisition time. A 355 nm Nd:YAG laser was used
at 10 Hz, 60 .mu.J/pulse. The chemical image shown in FIG. 7C
correlates well with the optical image shown in FIG. 7B. The image
pixel size was 12 .mu.m.times.20 .mu.m.
[0051] There is shown in FIG. 8A a chemical structure diagram of
raclopride. Raclopride has a high affinity for dopamine D-2
receptors in rat brain. Rats were IV-dosed with 2 mg/kg raclopride
and sacrificed 5 minutes post dose. The excised brain was flash
frozen, sectioned at 6 .mu.m thick, and thaw mounted on PEN 1.0
slides. The imaging was performed on 9 .mu.m.times.10 .mu.m pixels,
with a 12.times.10 .mu.m laser spot. The acquisition parameters
were 40 .mu.m/s and 10 .mu.m steps with 151 lanes. Solvent flow was
200 .mu.L/min, methanol+0.1% formic acid. Analysis was performed
with AB Sciex Triple TOF 5600+, using positive ion mode
electrospray ionization and selected reaction monitoring m/z
347.1.fwdarw.112 (CE=45 eV), 250 ms acquisition time. A 355 nm
Nd:YAG laser was used at 10 Hz, 60 .mu.J/pulse. The chemical image
shown in FIG. 8D correlates well with the optical image shown in
FIG. 8C.
[0052] There is shown in FIG. 9A a chemical structure diagram for
Novolac resin, having a 120 Da monomer unit. The experiment was
performed on Novolac resin developed positive photoresist (1.5
.mu.m thick) on glass. A 355 nm Nd:YAG laser was used at 10 Hz, 25
.mu.J/pulse. Analysis was performed by AB Sciex 5500 using negative
ion mode electrospray ionization and selected reaction monitoring
(m/z227.2.fwdarw.107.2 (CE=30 eV), 50 ms dwell time). The surface
scan speed was 6.7 .mu.m/s, with 2.5 .mu.m/lane step and 17 .mu.m
ablation spot. Solvent flow was 200 .mu.L/min methanol. The total
acquisition time was 4.5 h. The chemical image shown if FIG. 9C
correlates well with the optical image shown in FIG. 9B. The pixel
size was 2.5 .mu.m.times.2.5 .mu.m.
[0053] There is shown in FIG. 10A the chemical structure for
Novolac resin; Solvent flow was 200 .mu.L/min methanol. A 355 nm
Nd:YAG laser was used at 10 Hz, 25 .mu.J/pulse. Analysis was
performed by AB Sciex 5500 using negative ion mode electrospray
ionization and selected reaction monitoring (m/z 227.2.fwdarw.107.2
(CE=30 eV), 50 ms dwell time). The scan speed was 6.7 .mu.m/s, with
0.5 .mu.m/lane step and 17 .mu.m ablation spot. Solvent flow was
200 .mu.L/min methanol. The total acquisition time was 2 h. The
chemical image shown in FIG. 10C correlates well with the optical
image shown in FIG. 10B. The pixel size was 0.5 .mu.m.times.0.5
.mu.m.
[0054] FIG. 11 is a schematic diagram of a probe and liquid vortex
within. Liquid supplied through the liquid supply conduit 43 forms
a liquid surface 64 at the open end of the probe 40. The liquid
surface 64 captures sample material that has been ejected from the
sample by the radiant energy or other sample introduction method.
The over aspiration of liquid through the liquid exhaust conduit 52
relative to the volumetric flow rate of liquid through the liquid
supply conduit 43 draws gas containing airborne sample material
from space 68 into the liquid exhaust conduit. Depending on the
liquid flow and geometry a vortex 45 can be formed by liquid
flowing into the liquid exhaust conduit.
[0055] FIG. 12 is a schematic diagram of a probe with
plume-focusing gas flow. Radiant energy such as laser beam 92 in
transmission mode, or beam 160 in reflection mode from the same
side of the support 100 as is the sample 96, strikes the sample 96
and creates a plume 178 of ejected sample material, which can be
particulates, gaseous species or other airborne material. Gas flow
182 drawn from the ambient environment by the probe flows generally
radially inward toward the plume 178 to focus the plume and direct
particulates and gas into the surface 64 and into the liquid
exhaust conduit 52 in the direction of arrow 48. The precise
direction and extent of focusing gas flow can vary depending on
system geometry and operating characteristics. The ambient focusing
gas can be air or another gas. FIG. 13 is a diagram illustrating
computer model results for focusing gas flow 198 into the modeled
exhaust conduit 204 of a probe 202. The model illustrates how the
focusing gas guides the sample plume into a center space 203 and
then into the exhaust conduit 204.
[0056] FIG. 14A is a schematic diagram of a system with a
plume-focusing gas guide 232 spaced between the probe 40 and sample
support 100. The gas guide 232 has a series of apertures 233 to
direct focusing gas flow 234 radially inward. FIG. 14B is a cross
section of the gas guide 232 showing the radially inward focusing
gas flow 234. FIG. 14C is a cross section of an alternative gas
guide 238 in a second focusing gas flow port configuration in which
more tangentially oriented guide ports 239 are provided and direct
focusing gas flow 240 in a cyclonic pattern so as to create gas
vortex 242.
[0057] FIG. 15A-15B is a schematic diagram of a system with a
plume-focusing gas guide 280 in a baffle configuration and
connected to the support 100. Focusing gas 284 flows under the
baffle guide 280 where it contacts the support 100 and is directed
radially inward as illustrated by arrows 294.
[0058] FIG. 16A-16F illustrates a plume-focusing gas guide baffle
290 with a variety of heights. FIG. 16C illustrates the case of no
baffle guide, and FIG. 16D-16F illustrates baffles guides 290,
290', and 290'' which have a respectively greater height h.
[0059] FIG. 17A-17B a schematic diagram of a system with a
plume-focusing gas guide 320 that is separated from the sample
support 100. The detached position of the gas guide 320 creates a
circumferential channel 324 through which radially inwardly
directed focusing gas flow 328 can pass, where it moves in flow 332
toward the liquid exhaust conduit 52. FIG. 18A-18F illustrates the
plume-focusing gas guide 320 at a variety of different heights h,
including the case with no gas guide.
[0060] FIG. 19 is a schematic diagram of a system with a
voltage-applying source 340 and electrical connections 344 to the
support 100 and 348 to the probe 39. The application of a voltage
difference will assist in the transport of charged components in
the plume 178 to the probe 39. The voltage difference that can be
applied can vary.
[0061] FIG. 20A is a schematic diagram of a system 400 for sampling
a surface. The system 400 has a base unit 402 having a probe 39 and
liquid supply and exhaust assembly as previously describe and
illustrated by area C and FIG. 20B. A camera 112 and eyepiece 412
can be provided. A UV shield 416 can also be provided. A commercial
laser microdissection system such as the LMD 7000 from Leica can be
used and has an optical bright field and fluorescent microscope in
addition to laser ablation capability. Other systems and
configurations are possible to generate sample and direct it toward
and into the probe. FIG. 20C illustrates vortex flow at the open
end of the probe.
[0062] It is possible to direct sample into the capture probe by
means other than ejecting the sample from a sample material. There
is shown in FIG. 21A a schematic diagram of a droplet dispenser 430
for supplying sample to the probe 39. The droplet dispenser can
contain solvent and sample from any source, and can be oriented in
any direction to direct droplets into or toward the probe by any
suitable means. The droplets 434 can be sized by the flow rate and
orifice diameter of the droplet dispenser 430 such that the
diameter of the droplets 434 can be less than the diameter of the
liquid exhaust conduit 52 and can be dispensed directly into the
liquid exhaust conduit 52. Gas flow 444 into the exhaust conduit
guides the sample droplets 442 into the liquid exhaust conduit
52.
[0063] A method for sampling a surface can include the step of
directing sample into a capture probe. The directing step can
include the step of providing a sample support for retaining a
sample. A device such as a radiation energy source, an acoustic
ablation source, or a droplet dispenser can be provided for
directing sample into the probe, for example by a beam of radiation
striking the sample such that sample is ejected into the probe. A
probe is provided having an open end. The open end can be
positioned a distance from the sample and the sample support to
define a sample space. Liquid can be supplied to the open end of
the probe at a first volumetric flow rate. The liquid can be
removed from the open end of the probe at a second volumetric flow
rate, the second volumetric flow rate exceeding the first
volumetric flow rate. The radiation energy source can be operated
to eject sample material from the sample. The ejected sample
material and gas from the sample space can be removed with the
liquid removed from the open end of the probe. The removed liquid
containing sample and gas can be subjected to chemical analysis.
The liquid removed from the open end can form a vortex. The method
can further include the step of providing a gas guide between the
open end of the probe and the sample for focusing the flow of gas
into the liquid exhaust conduit. The method can further include the
step of creating a voltage difference between the sample and the
probe.
[0064] The method can further include the step of performing
chemical analysis on liquid drawn into and passing through the
exhaust conduit. The chemical analysis device can be at least one
selected from the group consisting of high performance liquid
chromatography and mass spectrometry. The analytical instrument for
example can be any instrument utilized for analyzing analyte
solutions. Exemplary analytical instruments include, but are not
limited to, mass spectrometers, ionization sources, spectroscopy
devices, separation methods, and combinations thereof. Exemplary
ionization sources include, but are not limited to electrospray
ionization (ESI), atmospheric pressure chemical ionization (APCI),
electrospray chemical ionization (ESCi), atmospheric pressure
photo-ionization (APPI) or inductively coupled plasma (ICP).
Exemplary separation methods include, but are not limited to liquid
chromatography, solid phase extraction, HPLC, capillary
electrophoresis, or any other liquid phase sample cleanup or
separation process. Exemplary mass spectrometers include, but are
not limited to, sector time-of-flight, quadrupole mass filter
three-dimensional quadrupole ion trap, linear quadrupole ion trap,
Fourier transform ion cyclotron resonance orbitrap and toroidal ion
trap.
[0065] A processor 404 shown in FIG. 20 can be provided to control
operation of the device, and particularly the flow rates of the
liquid supply, liquid exhaust and vortex as desired. The processor
can also control the operation of the sample-supplying device such
as the laser 200. The processor can receive sensor signals and
provide control signals to suitable valves and control circuitry to
control operation of these devices and the system in general.
[0066] The system of the invention can also be operated in an
overflow mode in which the first volumetric flow rate exceeds the
second volumetric flow rate. Such a system is described in a
copending United States patent application entitled "Open Port
Sampling Interface" filed on even date herewith, the disclosure of
which is hereby fully incorporated by reference.
[0067] Ranges: throughout this disclosure, various aspects of the
invention can be presented in a range format. It should be
understood that the description in the range format is merely for
convenience and brevity and should not be construed as an
inflexible limitation on the scope of the invention. Accordingly,
the description of a range should be considered to have
specifically disclosed all the possible subranges as well as
individual numerical values within that range. For example,
description of a range such as from 1 to 6 should be considered to
have specifically disclosed subranges such as from 1 to 3, from 1
to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as
well as individual numbers within that range for example, 1, 2,
2.7, 3, 4, 5, 5.3 and 6. This applies regardless of the breadth of
the range.
[0068] This invention can be embodied in other forms without
departing from the spirit or essential attributes thereof, and
accordingly, reference should be had to the following claims to
determine the scope of the invention.
* * * * *