WO1997031257A1 - Preparation of gaseous mixtures for isotopic analysis - Google Patents

Preparation of gaseous mixtures for isotopic analysis Download PDF

Info

Publication number
WO1997031257A1
WO1997031257A1 PCT/GB1997/000530 GB9700530W WO9731257A1 WO 1997031257 A1 WO1997031257 A1 WO 1997031257A1 GB 9700530 W GB9700530 W GB 9700530W WO 9731257 A1 WO9731257 A1 WO 9731257A1
Authority
WO
WIPO (PCT)
Prior art keywords
sample
mass spectrometer
gaseous
tube
analysis
Prior art date
Application number
PCT/GB1997/000530
Other languages
French (fr)
Inventor
Elizabeth Janine Jumeau
Original Assignee
Analytical Precision Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Analytical Precision Limited filed Critical Analytical Precision Limited
Priority to AU18886/97A priority Critical patent/AU1888697A/en
Publication of WO1997031257A1 publication Critical patent/WO1997031257A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/26—Drying gases or vapours
    • B01D53/268—Drying gases or vapours by diffusion
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N30/04—Preparation or injection of sample to be analysed
    • G01N30/06—Preparation
    • G01N30/14—Preparation by elimination of some components
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/40—Concentrating samples
    • G01N1/4005—Concentrating samples by transferring a selected component through a membrane
    • G01N2001/4011—Concentrating samples by transferring a selected component through a membrane being a ion-exchange membrane
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N2030/022—Column chromatography characterised by the kind of separation mechanism
    • G01N2030/025—Gas chromatography
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N30/04—Preparation or injection of sample to be analysed
    • G01N30/06—Preparation
    • G01N30/14—Preparation by elimination of some components
    • G01N2030/146—Preparation by elimination of some components using membranes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N30/04—Preparation or injection of sample to be analysed
    • G01N30/06—Preparation
    • G01N30/10—Preparation using a splitter

Abstract

Apparatus for preparing gaseous mixtures for isotopic analysis by a mass spectrometer comprises a sample tube (11) in which a sample to be prepared for analysis is contained. The sample tube (11) is connected to a gas separator in the form of a gas chromatography column (14) in which the gaseous mixture is split into different gaseous species. The gaseous species passes from the gas chromatography column (14) to the inlet of a mass spectrometer by way of an open split arrangement. A Nafion tube (22) is provided between the sample tube (11) and the gas chromatography column (14) which acts to remove water from the sample prior to separation. A novel construction of Nafion tube (22) is also disclosed.

Description

PREPARATION QF GASEOUS MIXTURES FOR ISOTOPIC ANALYSIS
This invention relates to the preparation of gaseous mixtures for
isotopic analysis by a mass spectrometer and more particularly to apparatus
for carrying out the preparation of such mixtures.
When preparing gaseous mixtures as samples for isotopic analysis it
is usual to attempt to remove any moisture from the sample to prevent this
moisture reaching the mass spectrometer and to prevent isotopic interaction
with the sample prior to entry into the mass spectrometer. If this moisture reaches the mass spectrometer, it can interact with the sample in the
analysis chamber leading to errors in the results obtained for analysis of the
sample. For example, if a sample of whole breath is being prepared for
analysis, this typically contains nitrogen (N2), oxygen (O2), carbon dioxide
(CO2), water vapour and traces of volatile organic materials. If water
vapour is present in the sample, or in the analysis chamber of the
spectrometer, protonation of the carbon dioxide molecules can occur due
to a proton from the water molecule attaching itself to a carbon dioxide
molecule thereby forming an ion which is heavier by one mass unit which
can lead to spurious results on analysis. Prior to entry into the mass
spectrometer, if moisture is present in the sample preparation apparatus,
isotopic exchange of oxygen between the oxygen atoms in the moisture and
the carbon dioxide molecules in the sample can occur. It is an object of the present invention to provide an apparatus for
carrying out the preparation of mixtures for isotopic analysis in which
interaction between moisture and other gaseous species in the sample prior
to entry into the mass spectrometer, can be minimised thereby increasing
the accuracy of analysis made by a mass spectrometer.
It is also an object of the present invention to provide apparatus in
which the ingress of moisture from the sample into the mass spectrometer
can be prevented or at least minimised.
Thus and in accordance with a first aspect of the present invention
therefore there is provided apparatus for preparing gaseous mixtures for
isotopic analysis by a mass spectrometer, said apparatus comprising sample
storage means in which a sample to be prepared for analysis is contained,
said sample retention means being linked to a gas separation means in
which said sample is separated into constituent gaseous species and a feed
arrangement to feed said separated gaseous species to an inlet of a mass
spectrometer, wherein a water removal device is provided between said
sample storage means and said gas separation means whereby water
molecules can be removed from said sample prior to separation.
With this arrangement it is possible to prevent interaction between
moisture and gaseous species within the sample by the removal of water
molecules which can interact with other molecules. Furthermore, the
removal of moisture from the sample prior to separation means that no moisture reaches the mass spectrometer. Therefore any errors caused by
the presence of moisture are obviated or at least minimised. Furthermore,
removal of moisture from the sample prior to chromatographic separation
reduces the sample preparation time and therefore permits greater sample
throughput in the spectrometer.
Preferably said gas separation device is linked to said input of a mass
spectrometer using a feed arrangement and in a particularly preferred
embodiment said feed arrangement comprises a feed of the type referred to
as "open split" feed.
Preferably the water removal device comprises a device of a type
commonly referred to as a "Nafion (Registered Trade Mark)" device.
In accordance with a second aspect of the present invention therefore
there is provided a water removal device for use in an apparatus according
to the first aspect of the present invention, comprising a hollow tubular
member to receive a sample gaseous mixture and having an inlet and an
outlet thereto, said member being formed from a hydrophilic material
wherein said device further includes a wire which extends through said
tubular member from said inlet to said outlet whereby a sample gaseous
mixture can be introduced into the tubular member at said inlet and can be
constrained by said wire to pass between said wire and said membrane in
close proximity to said membrane to maximise water removal from said
sample. With this arrangement it is possible to increase the efficiency with
which water removal can be made from said sample.
The invention will now be described further by way of example only
and with reference to the accompanying drawings of which:-
Fig. 1 shows in diagrammatic form one
embodiment of apparatus according to the first
aspect of the present invention; and
Fig. 2 shows in diagrammatic form one embodiment of water removal device in
accordance with the second aspect of the present
invention.
Referring now to the figures, there is shown in Fig. 1 apparatus for
preparing a gaseous sample for isotopic analysis in a mass spectrometer
comprising a sample tube 1 1 in which a sample to be analysed is stored, a
water removal device 12 in the form of a "Nafion (Registered Trade MarkV
device linked to the sample tube 11 , a multi-port valve 13, a gas
chromatography column 14 to receive sample material from the water
removal device 12 and a feed arrangement 16 in the form of an "open split"
to feed sample material from the gas chromatography column 1 to an ion
source of a mass spectrometer (not shown).
The sample tube 1 1 contains a gaseous mixture sample for analysis
and is formed from a tube which is sealed at one end by a septum 17. A needle 18 passes through the septum 17 into the interior of the tube 1 1 and
is in fluid flow connection with the interior of the tube 1 1 via an internal
bore (not shown).
The needle 17 is connected to the "Nafion (Registered Trade Mark}"
device which forms the water removal device 12.
The device 12 is of conventional form and is shown more clearly in
Fig. 2 except that a metal wire 19 extends from the inlet 21 of a Nafion
tube 22 to an outlet 23 of the device whereby sample gas flowing through
the tube can be constrained to flow between the wire 19 and the internal
wall of the tube 22. The tube 22 is formed from a hydrophilic material in
conventional form which takes up any moisture from the gas. Preferably
the metal wire is formed from stainless steel, although, of course, any other suitable material can be used, as desired or as appropriate.
The device 12 is linked to a gas chromatography column 14 by a
multi-port valve 13. The multi-port valve 13 is also connected to a vent line
24 via which gas can be vented to atmosphere and an inert gas reservoir
26 via which inert gas can be supplied to the apparatus and a sample loop
37 to be described more fully hereinafter. The gas chromatography column
14 is packed with a suitable filling of any type as desired or as appropriate
typically chosen to provide a desired chromatographic resolution.
The gas chromatography column 14 is connected to a feed
arrangement 16 in the form of an open split of conventional form which feeds sample gas into an ion source of a mass spectrometer (not shown) for analysis.
In use, an inert gas, for example helium, is introduced into the sample
tube 1 1 by opening a valve 28 in a supply line from the inert gas reservoir
26 to the multi-port valve 13. The multi-port valve 13 is movable between
two positions and with the multi-port valve 13 in a first position this allows
the inert gas to be fed into the sample tube 1 1 via the device 12 and the
needle 18. During this operation the valve 29 in the vent line 24 is closed.
A pressure regulator 31 is provided in the supply line to regulate the
pressure of inert gas fed to the sample tube 1 1 and typically the pressure within the sample tube 1 1 is allowed to reach approximately 5Psi (30KPa)
above atmospheric pressure. Once the pressure in the sample tube 1 1 has
reached this level, the valve 28 is closed and the valve 29 in the vent line
24 is opened. The opening of the valve 29 causes the gaseous mixture in
the sample tube 1 1 to expand and this expands through the device 1 2 into
the region of the multi-port valve 13 and when the multi-port valve 13 is in
the first position, into the sample loop 33. The sample loop 33 consists of
a capillary tube which is connected across two ports of the multi-port valve
13. Upon passage through the device 12 the gaseous sample mixture
passes through the "Nafion (Registered Trade Mark)" tube 22 and is forced
by the metallic wire 19 to flow in close proximity to the hydrophilic material
of the tube 22. This forced flow of gas enables substantially all of the water to be removed from the sample gas by the hydrophilic material of the
tube 22. Thus the gas which emerges from the device 12 is dry.
The valve 13 is then moved into its second position and the sample
gas flows from the sample loop 33 into the gas chromatography column 14
by entrainment with a flow of inert gas from the reservoir 26, the flow of
inert gas being regulated by a flow controller 32. After passage through the
gas chromatography column 14, the gaseous components are separated in
time and pass through the feed arrangement 16 of a conventional open
split type into the ion source of the mass spectrometer for analysis. A connection 34 may exist between the feed arrangement 16 and the
Nafion device 12 whereby inert gas which is flowing through the open split
16 can be fed back to the Nafion device 12 to minimise wastage and use
of inert gas in the system.
A further advantage is obtained using the arrangement of the present
invention insofar as the water removal device 12 is not in the
chromatography carrier flow hence eliminating any possibility of
chromatographic resolution degradation which may otherwise result. Also
the time required for separation of the gaseous throughput is also
significantly reduced.
With this arrangement, a relatively low cost and yet efficient removal
of water can be achieved from a gaseous sample. Furthermore, as water
is removed prior to the gaseous chromatography column, elution time of the gaseous sample in this column is much reduced. Also as water is not
present in the sample preparation apparatus, there is no need to heat the
apparatus to avoid any condensation problems and the apparatus can
function efficiently at room temperature. Also the number of samples which
can pass through the apparatus is increased per unit of time compared to
existing arrangements.
It is of course to be understood that the invention is not intended to
be restricted to the details of the above embodiment which are described
by way of example only.
Thus for example, as the wire 19 is provided within the Nafion tube
22, it is possible to produce a coiled or otherwise convoluted tube 22 in
which the wire is similarly convoluted or coiled to maximise the length of
tube 22, to maximise waste removal, whilst allowing the tube 22 to remain
within manageable proportions.

Claims

CIAI S
1 . Apparatus for preparing gaseous mixtures for isotopic analysis by a mass spectrometer, said apparatus comprising sample storage means in
which a sample to be prepared for analysis is contained, said sample
retention means being linked to a gas separation means in which said
sample is separated into constituent gaseous species and a feed
arrangement to feed said separated gaseous species to an inlet of a mass
spectrometer, wherein a water removal device is provided between said
sample storage means and said gas separation means whereby water molecules can be removed from said sample prior to separation.
2. Apparatus according to claim 1 wherein the gas separation device is
linked to said input of a mass spectrometer using a feed arrangement of the
"open split" type.
3. Apparatus according to claim 1 or claim 2 wherein the water removal
device comprises a device of the type commonly referred to as a "Nafior"
device.
4. A water removal device for use in an apparatus according to claim 1
comprising a hollow tubular member to receive a sample gaseous mixture
and having an inlet and an outlet thereto, said member being formed from
a hydrophilic material wherein said device further includes a wire which
extends through said tubular member from said inlet to said outlet whereby
a sample gaseous mixture can be introduced into the tubular member at said inlet and can be constrained by said wire to pass between said wire and
said membrane in close proximity to said membrane to maximise water
removal from said sample.
PCT/GB1997/000530 1996-02-26 1997-02-26 Preparation of gaseous mixtures for isotopic analysis WO1997031257A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU18886/97A AU1888697A (en) 1996-02-26 1997-02-26 Preparation of gaseous mixtures for isotopic analysis

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB9604037.3A GB9604037D0 (en) 1996-02-26 1996-02-26 Preparation of gaseous mixtures for isotopic analysis
GB9604037.3 1996-02-26

Publications (1)

Publication Number Publication Date
WO1997031257A1 true WO1997031257A1 (en) 1997-08-28

Family

ID=10789418

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1997/000530 WO1997031257A1 (en) 1996-02-26 1997-02-26 Preparation of gaseous mixtures for isotopic analysis

Country Status (3)

Country Link
AU (1) AU1888697A (en)
GB (1) GB9604037D0 (en)
WO (1) WO1997031257A1 (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1243917A1 (en) * 2001-03-23 2002-09-25 Instrumentarium Corporation Nitric oxide analyzer
US6716637B2 (en) 2001-03-23 2004-04-06 Instrumentarium Corp. Chemiluminescent gas analyzer
US7213443B2 (en) 2002-04-16 2007-05-08 University Of Bern Process and apparatus for providing gas for isotopic ratio analysis
US7985597B2 (en) 2002-04-16 2011-07-26 Universitat Bern Process and apparatus for providing a gaseous substance for the analysis of chemical elements or compounds
CN104007006A (en) * 2014-05-27 2014-08-27 张家港朗亿机电设备有限公司 Dehumidification pipe of atmospheric sampling measuring instrument
CN104007005A (en) * 2014-05-27 2014-08-27 张家港朗亿机电设备有限公司 Atmospheric dust concentration measurement equipment and method
KR101489730B1 (en) 2013-02-13 2015-02-04 고려대학교 산학협력단 Water extraction unit
CN104677700A (en) * 2015-03-17 2015-06-03 天津市环境监测中心 Sampling system suitable for sampling fine particles in fixed-source droplet-containing flue gas
CN108426754A (en) * 2018-01-25 2018-08-21 河南平高电气股份有限公司 Generate the method and device of the gaseous sample of specified moisture

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2211270A1 (en) * 1972-12-22 1974-07-19 Kalle Ag
US4725551A (en) * 1983-11-29 1988-02-16 Tracer Research Corporation Rapid leak detection system
US5012052A (en) * 1988-03-22 1991-04-30 Indiana University Foundation Isotope-ratio-monitoring gas chromatography-mass spectrometry apparatus and method
US5424539A (en) * 1992-12-18 1995-06-13 Finnegan Mat Gmbh Process for the analysis of gaseous components by mass spectrometry

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2211270A1 (en) * 1972-12-22 1974-07-19 Kalle Ag
US4725551A (en) * 1983-11-29 1988-02-16 Tracer Research Corporation Rapid leak detection system
US5012052A (en) * 1988-03-22 1991-04-30 Indiana University Foundation Isotope-ratio-monitoring gas chromatography-mass spectrometry apparatus and method
US5424539A (en) * 1992-12-18 1995-06-13 Finnegan Mat Gmbh Process for the analysis of gaseous components by mass spectrometry

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1243917A1 (en) * 2001-03-23 2002-09-25 Instrumentarium Corporation Nitric oxide analyzer
US6716637B2 (en) 2001-03-23 2004-04-06 Instrumentarium Corp. Chemiluminescent gas analyzer
US7213443B2 (en) 2002-04-16 2007-05-08 University Of Bern Process and apparatus for providing gas for isotopic ratio analysis
US7985597B2 (en) 2002-04-16 2011-07-26 Universitat Bern Process and apparatus for providing a gaseous substance for the analysis of chemical elements or compounds
KR101489730B1 (en) 2013-02-13 2015-02-04 고려대학교 산학협력단 Water extraction unit
CN104007006A (en) * 2014-05-27 2014-08-27 张家港朗亿机电设备有限公司 Dehumidification pipe of atmospheric sampling measuring instrument
CN104007005A (en) * 2014-05-27 2014-08-27 张家港朗亿机电设备有限公司 Atmospheric dust concentration measurement equipment and method
CN104677700A (en) * 2015-03-17 2015-06-03 天津市环境监测中心 Sampling system suitable for sampling fine particles in fixed-source droplet-containing flue gas
CN108426754A (en) * 2018-01-25 2018-08-21 河南平高电气股份有限公司 Generate the method and device of the gaseous sample of specified moisture

Also Published As

Publication number Publication date
AU1888697A (en) 1997-09-10
GB9604037D0 (en) 1996-04-24

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