U.S. patent application number 10/126792 was filed with the patent office on 2002-10-17 for miniature solid phase microextraction holder.
This patent application is currently assigned to The Regents of the University of California. Invention is credited to Andresen, Brian D., Kelly, Fredrick R., Nunes, Peter J..
Application Number | 20020150513 10/126792 |
Document ID | / |
Family ID | 25266212 |
Filed Date | 2002-10-17 |
United States Patent
Application |
20020150513 |
Kind Code |
A1 |
Nunes, Peter J. ; et
al. |
October 17, 2002 |
Miniature solid phase microextraction holder
Abstract
A miniature solid phase microextraction (SPME) holder. The
miniature holder enables transportation and field use of SPME
fibers which are very fragile and will break with the slightest
impact. Also, the holder prevents cross contamination of samples
during transport. The SPME holder consists of a barrel with two end
caps, and includes a plunger that is connected to a commercial SPME
fiber assembly, one end cap filing over the SPME needle on one end
of the barrel and the other end cap fitting over the plunger. The
end caps are provided with seals that give the holder a hermetic
seal. The holder enables effective field use for the collection,
isolation, and concentration of trace amounts of residues air,
soil, etc.
Inventors: |
Nunes, Peter J.; (Danville,
CA) ; Kelly, Fredrick R.; (Modesto, CA) ;
Andresen, Brian D.; (Livermore, CA) |
Correspondence
Address: |
Alan H. Thompson
Assistant Laboratory Counsel
Lawrence Livermore National Laboratory
P.O. Box 808, L-703
Livermore
CA
94551
US
|
Assignee: |
The Regents of the University of
California
|
Family ID: |
25266212 |
Appl. No.: |
10/126792 |
Filed: |
April 18, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10126792 |
Apr 18, 2002 |
|
|
|
09834138 |
Apr 12, 2001 |
|
|
|
Current U.S.
Class: |
422/400 |
Current CPC
Class: |
G01N 2001/022 20130101;
G01N 2030/0095 20130101; G01N 2030/009 20130101; G01N 2001/005
20130101; G01N 2030/062 20130101; Y10T 436/255 20150115; G01N 1/405
20130101; Y10T 436/25 20150115; Y10S 436/808 20130101; B01L 1/52
20190801 |
Class at
Publication: |
422/104 ; 422/61;
422/99 |
International
Class: |
B01L 009/00 |
Claims
What is claimed is:
1. A holder for an SPME fiber, comprising: a plunger assembly in
which an SPME fiber is adapted to be mounted, and a pair of end
caps removably mounted to opposite ends of said plunger assembly in
a sealing relation to the plunger assembly.
2. The holder of claim 1, wherein said plunger assembly includes a
pair of removably interconnect barrel sections, each having an
opening extending longitudinally therethrough and in which an
associated SPME fiber is adapted to be mounted.
3. The holder of claim 2, wherein a first of said pair of barrel
sections is provided with a sheath mounted in said opening therein
and extending from said first barrel section for protecting an
associated SPME fiber, and wherein a second of said pair of barrel
section is provided with a pusher and constructed to be
rotationally and laterally moved to enable movement of an
associated SPME fiber within said sheath for exposing or retracting
such an associated SPME fiber.
4. The holder of claim 2, wherein each of said pair of barrel
sections is provided with seal which provides sealing with and
retaining of an associated end cap.
5. The holder of claim 4, wherein an outer end section of each of
said pair of barrel section has a reduced cross-section, a groove
located in each said reduced cross-sections, and wherein said seal
comprises an .sigma.-ring mounted in each groove.
6. The holder of claim 3, wherein one of said end caps includes a
member for retaining an outer end of said sheath.
7. The holder of claim 3, wherein said second of said pair of
barrel sections is constructed to include a U-shaped groove having
a pair of leg sections and an interconnecting section, and wherein
said pusher is provided with a member that is movable along said
U-shaped groove when said pusher is moved rotationally and
laterally.
8. The holder of claim 3, in combination with an SPME fiber
assembly located with said openings of said pair of barrel
sections, and comprising a spring, a pair of end members, and an
SPME fiber, and wherein lateral movement of said pusher in one
direction causes compression of said spring and outward movement of
said SPME fiber located within said sheath for exposure of an end
of said SPME fiber to a selected condition, and wherein lateral
movement of said pusher in an opposite direction withdraws said
SPME fiber to be within said sheath.
9. The combination of claim 8, wherein one of said pair of end
members of said SPME fiber assembly is positioned in an abutting
relation with an inner end of one of said pair of barrel
sections.
10. The combination of claim 8, wherein another of said pair of end
members of said SPME fiber assembly is removably secured to said
pusher.
11. The combination of claim 8, wherein said SPME fiber assembly
additionally includes a longitudinally extending member mounted to
at least contact an inner end of said SPME fiber, extend through
said spring and through one of said pair of end members, and at
least contact another of said pair of end members, whereby lateral
movement of said plunger causes lateral movement of said
longitudinally extending member and movement of said SPME
fiber.
12. An SPME holder, comprising: a pair of interconnected barrel
sections each having an opening extending therethrough, a pair of
end caps operatively mounted to said pair of barrel sections, each
of said pair of barrel sections having an opening extending
therethrough, one of said pair of barrel sections having a sheath
extending therefrom, another of said pair of barrel sections
including a pusher operatively connected thereto, an SPME fiber
assembly positioned in said openings in said pair of barrel
sections and having an SPME fiber extending into said sheath, a
pair of end members with one abutting an end of said one of said
pair of barrel sections and another removably mounted to said
pusher, a spring located intermediate said pair of end members, and
a longitudinally extending member within said spring and at least
adapted to contact said SPME fiber and said another end member,
whereby lateral movement of said pusher causes movement of said
SPME fiber within said sheath.
13. The SPME holder of claim 12, wherein said another of said pair
of barrel sections includes a groove, and wherein said pusher
includes a member adapted to move along said groove.
14. The SPME holder of claim 12, wherein one of said end caps is
provided with a member for retaining an end of said sheath.
15. The SPME holder of claim 12, wherein each of said barrel
sections is provided with a seal member which both seals with and
retains an associated end cap thereon.
16. The SPME holder of claim 15, wherein each seal member comprises
an .sigma.-ring.
17. The SPME holder of claim 12, wherein each of said pair of
interconnected barrel sections includes a threaded end section for
removably interconnecting said barrel sections.
18. The SPME holder of claim 12, wherein each of said pair of
barrel sections include an outer reduced diameter end section, said
pair of end caps being mounted to said reduced diameter end
sections.
19. The SPME holder of claim 18, wherein each of said reduced
diameter end sections is provided with a groove, and an
.sigma.-ring positioned in said groove.
Description
RELATED APPLICATION
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 09/834,138, filed Apr. 12, 2001, entitled
Solid Phase Microextraction Field Kit.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to the collection and
characterization of residues, particularly to a holder for solid
phase microextraction (SPME) fibers, and more particularly to a
miniature SPME holder for field applications.
[0003] Over the last decade, extensive efforts have been carried
out for development methods for characterization of various
chemicals, particularly for the characterization of high
explosives, chemical weapons, and biological weapons. These
activities have centered on the collection, isolation, and
concentration of trace amounts of these chemical residues in air,
soil, vegetation, swipe, and liquid samples. Considerable resources
have been applied to developing consistent and reliable methods for
field analysis of high explosives and chemical weapons related
materials.
[0004] Solid Phase Microextraction (SPME) is a widely recognized
approach for the collection of various chemical residues, and SPME
fibers and syringes are commercially available. SPME requires no
solvents, is sensitive to low nanogram signature species, and can
be repeatedly used in the field for the characterization of complex
samples. A significant attribute of SPME fibers is their
exceedingly high collection efficiencies. No chemical pretreatment
or solvent extractions are necessary when using SPME fibers with
GCS or GCS-MS instrumentation. However, there are some inherent
problems with field SPME. SPME fibers tend to be very fragile and
will break with the slightest impact. This makes transportation of
SPME difficult in the field. Also, since SPME fibers are used for
the sampling of potentially hazardous materials, the fibers need to
be transported in a container that would prevent collected
potentially lethal materials from contaminating the surroundings
during transportation, as well as prevent cross contamination of
different samples.
[0005] The SPME field kit described and claimed in above-referenced
application Ser. No. 09/834,138 provides a solution to the
above-referenced problems and enables effective use of SPME for
field analysis. The SPME field kit includes an air tight container
in which is located a number of hermetically sealed individual
transport containers or tubes within which are located SPME
syringes, with the fiber of each syringe provided with a protective
cap. The transport container or tubes each include a sampling port
wherein material collected by one SPME fiber located within the
transport container or tube can be transferred to another SPME
fiber via the sampling port. The kit also contains a device for
extracting and/or inserting the protective cap on the SPME fiber,
as well as various spare parts, protective gloves and an
instruction manual.
[0006] SPME holders are also commercially available by the
manufacture of the SPME fibers, Sigma Aldrich and Supelco, but have
not been effective for field applications.
[0007] One disadvantage of the above-referenced field kit is the
size of the transport containers or tubes within which are located
the SPME syringes. The present invention provides SPME holder which
is small and robust. This miniature SPME holder is ideal for
transport, collection of highly toxic and pathogenic samples, safe
opening in the laboratory, and storage of important, highly toxic
samples for exact characterization in the laboratory and in the
field. Thus, the present invention provides a means for the safe
collection and handling of highly toxic, unknown samples by first
responders to the scene of an unknown release. Basically, the SPME
holder of this invention is composed of a barrel section, about the
size of a writing pen, and a pair of end caps which removably
attached to the barrel within which the SPME fiber is retained, and
the barrel and/or end caps are provided with seals for the
prevention of leakage from a contaminated SPME needle.
SUMMARY OF THE INVENTION
[0008] It is an object of the present invention to provide a solid
phase microextraction (SPME) holder which is field-deployable.
[0009] A further object of the invention is to provide an SPME
holder, small in size, that contains all necessary hardware for the
proper collection of trace compounds in complicated samples.
[0010] Another object of the invention is to provide a
field-deployable SPME holder which includes an SPME fiber
hermetically sealed in its own transport tube to avoid any
possibility of cross contamination.
[0011] Another object of the invention is to provide hermetically
sealed transport containers or holders for SPME fibers.
[0012] Another object of the invention is to provide an SPME holder
with a protective tube for the SPME, and to provide a device for
insertion and extraction of the fiber.
[0013] Another object of the invention is to provide an SPME holder
which is small, lightweight, robust, and field deployable.
[0014] Another object of the invention is to provide a miniature
SPME holder which is ideal for transport, collection of important,
highly toxic samples for exact characterization in the laboratory
and in the field.
[0015] Another object of the invention is to provide a miniature
holder for SPME fibers when enables safe collection and handling of
highly toxic, unknown samples by first responders to a release of
various materials.
[0016] Other objects and advantages of the present invention will
become apparent from the following description and accompanying
drawings. The present invention involves an SPME field deployable
holder for use in the collection, isolation, and concentration of
trace amounts of high explosives (HE), chemical weapons (CW),
biological warefare (BW) related materials, and other residues in
air, soil, vegetation, swipe, and liquid samples, and particularly
for field analysis of HE and CW-related materials. The holder of
this invention satisfies the needs for a field-deployable SPME
system for the proper collection of trace compounds in complicated
samples.
[0017] The invention broadly is a small, very robust SPME sampling
apparatus, and more specifically is a miniature SPME fiber holder.
The miniature SPME holder resolves the problems of the fragile
nature of the SPME fiber, the problem of cross contamination of the
samples, and the bulky size constraints.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings, which are incorporated into and
form a part of the disclosure, illustrate an embodiment of the
invention and, together with the description, serve to explain the
principles of the invention.
[0019] FIG. 1 illustrates an SPME transport tube or holder of
above-referenced application Ser. No. 09/834,138.
[0020] FIG. 2 illustrates an actual size embodiment of the
miniature SPME holder made in accordance with the present invention
to illustrate the size comparison of the two holders.
[0021] FIG. 3 is an enlarged view of the FIG. 2 holder, which is
basically composed of a two-section sample body or barrel and two
end caps.
[0022] FIG. 4 is a cross-sectional view of the FIG. 3 SPME
holder.
[0023] FIG. 5 illustrates an embodiment of the barrel section of
the SPME holder with the end caps removed, and with the SPME fiber
retracted within a sheath.
[0024] FIG. 6 is similar to FIG. 5 but with the SPME fiber tip
extending from the sheath for exposure to a sample.
DETAILED DESCRIPTION OF THE INVENTION
[0025] The present invention involves a miniature SPME holder which
is field-deployable. Since there are some inherent problems with
field use of SPME because the SPME fibers, such as those made
commercially by Sigma Aldrich and Supelco, tend to be very fragile
and will break with the slightest impact. This make transportation
of the SPME difficult in the field. Also, because of the very
absorbent nature of SPME, cross contamination of samples during
transport must be prevented. Also, there has been a new for a field
SPME device that is small, lightweight, and robust. The invention
is a small, very robust SPME sampling apparatus which provides
solutions to the problems of the fragile nature of the SPME fiber,
the problem of cross-contamination of the samples, and bulky size
constraints. The SPME device of this invention enables the
collection, isolation, and concentration of trace amounts of, for
example, chemical weapons (CW) residues in air, soil, vegetation,
swipe, and liquid samples. The miniature SPME holder is ideal for
transport, collection of highly toxic samples for exact
characterization in the laboratory and in the field. The SPME
holder of the invention is about the size of a typical pen or
pencil and can readily be transported in a user's shirt pocket, for
example, and thus can be readily carried for the safe collection
and handling of highly toxic, unknown samples, by first responders
to the scene of a WMD release, for example.
[0026] The SPME holder consists of a stainless steel barrel with an
.sigma.-ring seal, a stainless steel plunger that is connected to a
commercial SPME fiber assembly, a stainless steel head cap with an
.sigma.-ring seal, and two titanium end caps that fit over an SPME
shielth which retains the SPME fiber on one end the plunger at the
other. The end caps with .sigma.-ring seals give the unit a
hermetic seal.
[0027] One of the titanium end caps has Teflon insert that prevents
out-gassing of the SPME fiber and also prevents vibration and
movement of the SPME shield or needle. Preventing movement is
critical as this prevents breakage of the fiber or removal of the
SPME polymer coating on the fiber.
[0028] The barrel houses the SPME fiber assembly, the plunger, the
head, and is secured to the end caps. It has milled grooves that
guide the plunger and allows the SPME fiber to be locked in the
exposed (expanded) position or the travel (retracted) position. The
barrel also has a Viton .sigma.-ring that seals against on end
cap.
[0029] The plunger is threaded on one end so that the commercial
SPME fiber assembly can be threaded into it. The plunger also has a
threaded hole that accommodates a set screw. The set screw moves
along the grooves and guides the plunger and SPME fiber assembly up
and down the barrel.
[0030] The head assembly threads into the barrel and holds the SPME
fiber assembly firmly in place. The head has a Viton .sigma.-ring
that creates a seal when the end cap is attached.
[0031] Referring now to the drawings, FIG. 1 illustrates the
transport tube or SPME holder of above-referenced application Ser.
No. 09/834,138, and is illustrated to show size comparison with the
embodiment of the miniature SPME holder of FIGS. 2, shown in
greater details in FIGS. 3-7. The transport tube or holder of FIG.
1, generally indicated at 10, comprises two housing sections 11 and
12, interconnected by a pair of twist and lock mechanisms, not
shown, located within portion 13 of housing section 11, with
housing sections 11 and 12 having external grooves 14 and 15,
respectively. The FIG. 1 transport tube has a length of 22.5 cm and
diameter of 2.7 cm.
[0032] The embodiment of the miniature SPME holder of FIGS. 2 and
3, generally indicated at 20, comprises two body or barrel sections
21 and 22 and two end sections or end caps 23 and 24, with barrel
sections 21 and 22 having a threaded interconnection, as seen in
FIG. 4, and wherein end caps 23 and 24 extend over and are
snap-action secured to barrel sections 21 and 22 by .sigma.-ring
seals, as shown in FIG. 4. The miniature holder of FIG. 2 has a
length of 14.5 cm and diameter of 9 mm.
[0033] As seen in FIG. 4, body or barrel section 21 has a
longitudinally extending opening 25 with internal threads 26 at one
end, and is provided with an external cut-away or reduced diameter
section 27 at an opposite in which is a groove 28 retaining an
.sigma.-ring seal 29. Body or barrel section 22 includes a reduced
outer diameter or cut-away section 30 having outer threads 31 which
cooperate with threads 26 of barrel section 21, and a reduced outer
diameter section or cut-away 32 having a groove 33 therein for
retaining an .sigma.-ring seal 34. Barrel section 22 is also
provided with a central longitudinally extending opening of two
difference diameter sections 35 and 36. As seen in FIG. 4, end cap
24 has an opening 37 in which a Teflon member or seal 38 having a
central opening 39 is mounted. Teflon seal 38 includes a tapered
surface 40 to provide easier entrance into opening 39 by a sheath
or tube 41 of a plunger assembly generally indicated at 42 and
which includes barrel sections 21 & 22, and with component
thereof positioned in opening 25 of barrel section 21, with the
sheath 41 extending through opening sections 35 and 36 of barrel
section 22. The exterior of the plunger assembly 42 is illustrated
in FIGS. 5 and 6, with certain of the interior components being
illustrated in FIG. 4. The plunger assembly 42, as shown in FIG. 4,
includes an annular member 43 located adjacent section 30 of barrel
section 22 and having an opening 44 through which a tube or rod 41'
passes and extends into sheath 41. Member 43 functions an end
support for a spring 45 with the opposite end of the spring 45
abutting a member 46 removably secured to a plunger on pusher 47
within end cap 23. As seen in FIG. 4, the plunger assembly 42 is
located intermediate end caps 23 and 24 when in its transport or
storage position. Spring 45 rod 41', member 43 and member 46
constitute components of a commercial SPME fiber assembly, with an
SPME fiber 48 being operatively mounted in member 43 and connected
to rod tube 41', and is movably mounted in sheath 41 as seen in
FIG. 6 when the plunger or pusher 47 is moved inwardly, as
described hereinafter with respect to FIGS. 5 and 6.
[0034] As seen in FIG. 4, but shown specifically in FIGS. 5 and 6,
reduced diameter end section 27 of end cap 21 also includes a
U-shaped groove having end leg sections 49 and 50 and an
interconnecting center section 51. A member, 52, such as a set
screw, is mounted in plunger or pusher 47 and is moved by
rotational (arrow a) and lateral movement (arrow b) of pusher 47
against spring 25 from groove leg section 49 through groove section
51 and into groove leg section 50 as seen in FIG. 6 whereby rod 41'
extends into sheath 41 and the SPME fiber 48 is extended from
sheath 41 for exposure to the environment. Upon exposure of fiber
to a sample, the pusher 47 is rotated as shown by arrow c and is
moved outwardly as indicated by arrow d by spring 25, as shown in
FIG. 5, whereby the exposed SPME fiber is withdrawn into sheath 41,
after which end caps 23 and 24 are positioned over reduced diameter
sections 27 and 32 of barrel sections 21 and 22 and retained and
sealed by the .sigma.-ring seals 29 and 34 via a frictional contact
between the seals and the end caps. Note that the end of sheath 41
is easily inserted into the Teflon member or seal 38 via the
tapered surface 40. After exposure, SPME fiber 48 can be safely
transported without the possibility of breakage or leakage to a
point of analysis, after which the end caps 23 and 24 are removed,
and the pusher is rotated and moved laterally to again expose the
end of SPME fiber 48. It has thus been shown that the present
invention provides a small, lightweight, robust holder for SPME
fibers and which provides safe transport of the unexposed or
exposed fiber, and includes seals which prevent any
cross-contamination by leakage from the exposed fiber. The SPME
holder can be readily transported and utilized by any first
responder to a scene of contamination, such as a WMD release.
[0035] While a specific embodiment of the invention and exemplary
materials have been illustrated and described to exemplify and
teach the principles of the invention, such are not intended to be
limiting. Modifications and changes may become apparent to those
skilled in the art, and it is intended that the invention be
limited only by the scope of the appended claims.
* * * * *