WO1998022793A1 - Systeme de detection de substances chimiques - Google Patents

Systeme de detection de substances chimiques Download PDF

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Publication number
WO1998022793A1
WO1998022793A1 PCT/GB1997/003100 GB9703100W WO9822793A1 WO 1998022793 A1 WO1998022793 A1 WO 1998022793A1 GB 9703100 W GB9703100 W GB 9703100W WO 9822793 A1 WO9822793 A1 WO 9822793A1
Authority
WO
WIPO (PCT)
Prior art keywords
species
chemical
gas
sample
gas permeable
Prior art date
Application number
PCT/GB1997/003100
Other languages
English (en)
Inventor
Neville John Freeman
Original Assignee
Farfield Sensors Ltd.
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
Priority claimed from GBGB9623996.7A external-priority patent/GB9623996D0/en
Application filed by Farfield Sensors Ltd. filed Critical Farfield Sensors Ltd.
Publication of WO1998022793A1 publication Critical patent/WO1998022793A1/fr

Links

Classifications

    • 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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/483—Physical analysis of biological material
    • G01N33/497—Physical analysis of biological material of gaseous biological material, e.g. breath
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/02—Devices for withdrawing samples
    • G01N1/22—Devices for withdrawing samples in the gaseous state
    • G01N1/2202—Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling
    • G01N1/2214—Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling by sorption
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N35/00—Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor
    • G01N35/00584—Control arrangements for automatic analysers
    • G01N35/00722—Communications; Identification
    • G01N35/00732—Identification of carriers, materials or components in automatic analysers
    • G01N2035/00742—Type of codes
    • G01N2035/00752—Type of codes bar codes

Definitions

  • This invention relates to a system for measuring chemicals in a test material and particularly relates to a system for measuring chemicals through use of array based chemical sensors.
  • a system for sensing chemicals comprising: a sensor; collecting means for collecting chemical species; removal means for removing the species and presenting them to the sensor; and interpretation means to interpret the information obtained .
  • a system for obtaining chemicals from gaseous liquid or solid samples comprising: a gas permeable means; a chemically absorbent material; sealing means for sealing the absorbent.
  • the system further comprises means for identifying the sample.
  • the means for identifying the sample comprises a bar code.
  • system further comprises means for presenting a sample to analytical means for subsequent analysis .
  • the collecting means comprises means for entrapping a chemical species.
  • the interpretation means comprises a pattern recognition algorithm.
  • test chemicals are presented to the entrapment means which means is capable of absorbing the materials of interest, enabling preconcentration of the species if required, and retaining the material for subsequent analysis.
  • the system further comprises means for progressively removing either serially or in parallel the entrapped materials.
  • the information obtained is logged, together with the response of the adjacent chemical sensing system for subsequent analysis.
  • the response of the chemical sensing system is a function of the removal procedure described hereinabove is analysed and information obtained on the test chemicals.
  • the system according to the present invention comprises a gas permeable membrane situated in a wall of a vessel, container or conduit.
  • the membrane is thus situated in the wall of a conveniently mechanically rigid structure within which the material to be analysed is restrained .
  • the gas permeable membrane has a pore size sufficiently small to retain bacteria in the case of materials which are suspect to microbial degradation.
  • the membrane further comprises a detector strip comprising a chemically absorbent material deposited on a gas impermeable backing matrix. Further, the membrane comprises a means to provide a gas tight seal to the gas permeable membrane of a sample restrainer and means to provide adhesion to the sample restrainer.
  • the system further comprises means to remove species in the absorbent material for subsequent presentation to analytical means .
  • a detector strip is adhered to a suitable point in a sample handling system such as the lid of a petri dish or sample vial or a conduit or mouthpiece for a breath sample.
  • a detector strip is positioned over a permeable membrane window.
  • the detector strip is removed and placed in a strip developer which removes the materials absorbed on the detector strip. This may be achieved by heating the strip and passing a suitable carrier gas over the strip to sweep the materials off.
  • system further comprises preconcentration means to concentrate the removed materials before presenting them to the appropriate analytical instrumentation .
  • Figure 1 is a schematic representation of a serial instrument suitable for forming part of a system according to the present invention
  • Figure 2 is a semi-parallel instrument suitable for forming part of a system according to the present invention
  • Figure 3 is a parallel instrument
  • Figure 4 is a detailed example of use of the system according to the present invention
  • Figure 5 is a schematic representation of a detector strip forming part of a device according to the present invention.
  • Figure 6 is a schematic representation of a method according to the present invention.
  • a system according to the present invention designated generally by the reference numeral 1.
  • the system comprises an entrapment means 2 used to capture materials in the test material.
  • the entrapment system could be replaced by a temperature ramp. This would have the effect of modulating the gas phase concentration of chemical species.
  • the entrapment means 2 may comprise a custom made absorbent material or a commercially available solid phase extraction material or a standard trap material packed into a column or applied as a thick layer to a flat plate or adhered to any other suitable support.
  • the absorbent material is held at a constant temperature and the test material is passed over or through the absorbent material for a fixed period of time.
  • the absorbed material is desorbed by desorption means 3 before being swept onto a chemical sensor 4.
  • a chemical sensor comprises an array of gas sensors. The desorption is effected in stages, the flow rate sweeping the entrapment device being held constant. It is important to ensure that the concentration of the desorbed materials is modified by this procedure and that the conditions of the desorption process are retained for subsequent processing.
  • the desorption process does not rely on a chromatographic effect as in gas chromatography for example, but simply the modification of the concentration of the analytes as a function of their absorption onto the trap. In other words it is not necessary to separate out the individual components of the test material completely.
  • This process may take the form of stepping up the temperature of the entrapment device in stages as shown in Figure 1 , or may be through use of a continuous temperature ramp (not shown ) .
  • the response of the chemical sensor 4 is monitored as a function of the desorption procedure.
  • the two data sets relating to the desorption process and the response of the chemical sensor are passed to an information processing engine 5.
  • the data processing engine 5 employs statistical techniques such as rank annihilation factor analysis and trilinear decomposition (RAFA, GRAM and TLD) in order to obtain information from the combination of data from the desorption process and the chemical sensor.
  • RAFA rank annihilation factor analysis and trilinear decomposition
  • GRAM trilinear decomposition
  • a semi-parallel device according to the present invention is designated generally by the reference numeral 2.
  • the device 20 rather than having a single entrapment/absorption device as shown in Figure 1 , there is a plurality of entrapment devices 22 and absorption devices 24 which are set to different conditions.
  • the entrapment systems may be held at constant conditions or simultaneously desorbed and gated with a single sensor unit 22. This enables the measurements to be made more rapidly.
  • a processing engine 26 analyses the two sets of data from devices 22, 24.
  • a fully parallel device is designated generally by the reference numeral 30.
  • the entrapment devices may be held at constant conditions or simultaneously desorbed, for example if there are less chemical sensing units than entrapment devices then again the outputs will need to be gated with the common sensing units. This enables measurements to be made still more rapidly.
  • the entrapment system 32 may be used in conditions where direct measurement may be difficult, in particular whilst making biological measurements where condensates or diffusion characteristics may make direct measurements difficult to make.
  • a sample of a patient's breath or a biological culture may be made using an entrapment device (a chemical photograph) which may be protected by a gas permeable membrane, the gases being absorbed into the material and presented for subsequent analysis.
  • a detector strip system suitable for use in such a membrane system is shown and designated generally by the reference numeral 50.
  • the gas permeable membrane 51 is an integral part of a retainer wall enclosure which allows materials from the internal environment 52 to pass through. This may be constructed using for example 100 ⁇ m thick membrane, although any material capable of permitting gases to pass through whilst retaining the required mechanical properties may be employed. This may be heated either directly or indirectly to prevent unwanted condensation (normally in cases where the materials under test are above ambient temperatures). These test materials permeate through the membrane and are absorbed into the entrapment system.
  • the entrapment system may comprise for example a thick tenax which is a standard chemical absorbent which may be printed onto the backing material 55.
  • the entrapment system 53 is supported by the backing material 55 which offers a suitable mechanical support and is resistant to gaseous diffusion (preventing the entrapment system from drawing materials through the backing materials).
  • the backing material may be a metallised material or metal foil although any material providing an appropriate barrier to gas transport whilst offering the desired mechanical properties may be employed.
  • the material is sealed by means of seal 54 to the body of the retainer 56. The seal is preferably capable of violation without comprising the integrity of the retainer and is resistant to gaseous diffusion.
  • the entrapment system is sealed to the gas permeable membrane providing a gas-tight seal and in the preferred embodiment can be broken by pulling the detector strip away from the restrainer body without violating the integrity of the membrane itself.
  • the seal 54 comprises an adhesive which is compatible with the backing material, the restrainer and the membrane such that the backing material is held in place and capable of removal when desired. Chemical materials within the restrainer are exchanged across the membrane into the entrapment system without violating the integrity of the contents of the restrainer .
  • the device further comprises an identifier in the form of a bar code on the reverse side of the detector strip.
  • a detector strip 61 is removed from the restrainer 56. It is usually removed by being torn off in the fashion of a medical sticking plaster without violating the membrane or contents.
  • a bar code on the reverse side of the strip may be read before further processing.
  • the detector strip 55 is then degassed by thermal means using for example thermal desorption forming part of a degassing system 62 which raised the temperature of the entrapment system resulting in the desorption of all absorbed species.
  • the system comprises a hood 63 which moves down impressing upon the top surface of the detector strip forming a seal and impinging it upon the base plate 64.
  • the back side of the strip is then heated by the base plate 64 to remove the absorbed materials.
  • the released materials are swept from the hood using an appropriate carrier gas. This is effected by heating the mechanical parts of the system to reduce absorption to internal surfaces. The surfaces are preconcentrated using ciro- focusing .
  • the resultant material is then presented to appropriate analytical instrumentation.
  • the detector strip is then output from the system.
  • the system may be adjusted to suit any particular analytical problem. This may be achieved by varying the temperature during the heating process using temperature wrapping techniques for example which may enable the disposal of certain proportions of the degassed materials.
  • a test gas is drawn through a glass sorption tube 40 which is approximately 5 mm in diameter and 50 mm long which is packed with activated charcoal which serves as an absorbent material .
  • the flow rate of the test gas is approximately 200 seem and the duration of the procedure is approximately 15 minutes.
  • the temperature of the sorption tube is approximately 20 °C. The flow rate, duration and temperature are controlled during the procedure. This phase constitutes the preconcentration stage in which the test gas is trapped on the sorbent material.
  • the tube is then heated by an external heater to a pre-defined temperature in this case a step of say 20 °C to 40 °C with no gas flow until the temperature remains stable at which point thermal equilibrium has been achieved.
  • a clean gas stream for example nitrogen is then used to flush the desorbed gases from the sorption tube to the sensor system which comprises an array of piso-electric quartz crystal oscillated sensors for example and the response of the sensor system is recorded and stored.
  • PCA principal component analyses

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Immunology (AREA)
  • Biomedical Technology (AREA)
  • General Physics & Mathematics (AREA)
  • Biochemistry (AREA)
  • Pathology (AREA)
  • Molecular Biology (AREA)
  • Analytical Chemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Biophysics (AREA)
  • Hematology (AREA)
  • Urology & Nephrology (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Sampling And Sample Adjustment (AREA)

Abstract

Un système de détection de substances chimiques comprend un moyen collecteur muni d'un détecteur pour collecter des espèces chimiques, un moyen de déplacement pour déplacer les espèces chimiques et les présenter au détecteur, et un moyen d'interprétation pour interpréter les informations recueillies. Le système comprend avantageusement une membrane perméable au gaz située dans la paroi d'un récipient ayant une dimension des pores appropriée par rapport aux espèces chimiques devant être détectées.
PCT/GB1997/003100 1996-11-19 1997-11-19 Systeme de detection de substances chimiques WO1998022793A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB9623996.7 1996-11-19
GBGB9623996.7A GB9623996D0 (en) 1996-11-19 1996-11-19 Improved chemical sensing system
GBGB9626968.3A GB9626968D0 (en) 1996-11-19 1996-12-27 Chemical diagnostics system
GB9626968.3 1996-12-27

Publications (1)

Publication Number Publication Date
WO1998022793A1 true WO1998022793A1 (fr) 1998-05-28

Family

ID=26310424

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1997/003100 WO1998022793A1 (fr) 1996-11-19 1997-11-19 Systeme de detection de substances chimiques

Country Status (1)

Country Link
WO (1) WO1998022793A1 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1099102A1 (fr) * 1998-06-19 2001-05-16 California Institute Of Technology Utilisation d'une olfactometrie artificielle pour detecter le niveau de presence de substances a analyser
WO2001007903A3 (fr) * 1999-07-27 2001-08-16 Honeywell Inc Capteur de gaz avec dispositifs de chauffage en phase pour une sensibilite accrue
US7000452B2 (en) 2002-09-27 2006-02-21 Honeywell International Inc. Phased micro fluid analyzer
US7104112B2 (en) 2002-09-27 2006-09-12 Honeywell International Inc. Phased micro analyzer IV
US7367216B2 (en) 2002-09-27 2008-05-06 Honeywell International Inc. Phased micro analyzer V, VI
US7530257B2 (en) 2002-09-27 2009-05-12 Honeywell International Inc. Phased micro analyzer VIII
US9029028B2 (en) 2003-12-29 2015-05-12 Honeywell International Inc. Hydrogen and electrical power generator

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4040805A (en) * 1976-10-22 1977-08-09 Board Of Supervisors Louisiana State University Agricultural And Mechanical College Personal monitoring device, or dosimeter, for measuring exposure of personnel to organic vapors
GB2046903A (en) * 1979-03-27 1980-11-19 Du Pont Dosimeter for measuring gaseous contaminants
US4327575A (en) * 1980-03-24 1982-05-04 Locker Laurence D Monitoring apparatus and method for toxic vapors
US4980294A (en) * 1989-09-01 1990-12-25 National Research Council Of Canada/Conseil National De Recherches Du Canada Method for testing the freshness of fish
GB2250633A (en) * 1990-10-31 1992-06-10 Extrel Corp Preconcentrating gas samples for analysis
US5469369A (en) * 1992-11-02 1995-11-21 The United States Of America As Represented By The Secretary Of The Navy Smart sensor system and method using a surface acoustic wave vapor sensor array and pattern recognition for selective trace organic vapor detection
US5549819A (en) * 1995-01-17 1996-08-27 Hewlett-Packard Company Portable extraction instrument

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4040805A (en) * 1976-10-22 1977-08-09 Board Of Supervisors Louisiana State University Agricultural And Mechanical College Personal monitoring device, or dosimeter, for measuring exposure of personnel to organic vapors
GB2046903A (en) * 1979-03-27 1980-11-19 Du Pont Dosimeter for measuring gaseous contaminants
US4327575A (en) * 1980-03-24 1982-05-04 Locker Laurence D Monitoring apparatus and method for toxic vapors
US4980294A (en) * 1989-09-01 1990-12-25 National Research Council Of Canada/Conseil National De Recherches Du Canada Method for testing the freshness of fish
GB2250633A (en) * 1990-10-31 1992-06-10 Extrel Corp Preconcentrating gas samples for analysis
US5469369A (en) * 1992-11-02 1995-11-21 The United States Of America As Represented By The Secretary Of The Navy Smart sensor system and method using a surface acoustic wave vapor sensor array and pattern recognition for selective trace organic vapor detection
US5549819A (en) * 1995-01-17 1996-08-27 Hewlett-Packard Company Portable extraction instrument

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1099102A1 (fr) * 1998-06-19 2001-05-16 California Institute Of Technology Utilisation d'une olfactometrie artificielle pour detecter le niveau de presence de substances a analyser
EP1099102A4 (fr) * 1998-06-19 2005-07-13 California Inst Of Techn Utilisation d'une olfactometrie artificielle pour detecter le niveau de presence de substances a analyser
WO2001007903A3 (fr) * 1999-07-27 2001-08-16 Honeywell Inc Capteur de gaz avec dispositifs de chauffage en phase pour une sensibilite accrue
US6393894B1 (en) 1999-07-27 2002-05-28 Honeywell International Inc. Gas sensor with phased heaters for increased sensitivity
US7000452B2 (en) 2002-09-27 2006-02-21 Honeywell International Inc. Phased micro fluid analyzer
US7104112B2 (en) 2002-09-27 2006-09-12 Honeywell International Inc. Phased micro analyzer IV
US7367216B2 (en) 2002-09-27 2008-05-06 Honeywell International Inc. Phased micro analyzer V, VI
US7530257B2 (en) 2002-09-27 2009-05-12 Honeywell International Inc. Phased micro analyzer VIII
US9029028B2 (en) 2003-12-29 2015-05-12 Honeywell International Inc. Hydrogen and electrical power generator

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