GB2208006A - Gas sensing device - Google Patents
Gas sensing device Download PDFInfo
- Publication number
- GB2208006A GB2208006A GB08719017A GB8719017A GB2208006A GB 2208006 A GB2208006 A GB 2208006A GB 08719017 A GB08719017 A GB 08719017A GB 8719017 A GB8719017 A GB 8719017A GB 2208006 A GB2208006 A GB 2208006A
- Authority
- GB
- United Kingdom
- Prior art keywords
- ion exchange
- exchange layer
- sensing device
- gas sensing
- gas
- Prior art date
- Legal status (The legal status 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 status listed.)
- Withdrawn
Links
- 238000005342 ion exchange Methods 0.000 claims abstract description 42
- 239000012530 fluid Substances 0.000 claims abstract description 16
- 125000000129 anionic group Chemical group 0.000 claims abstract description 15
- 125000002091 cationic group Chemical group 0.000 claims abstract description 15
- 229910001868 water Inorganic materials 0.000 claims abstract description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000012528 membrane Substances 0.000 claims abstract description 8
- 239000007788 liquid Substances 0.000 claims abstract description 5
- 229920000642 polymer Polymers 0.000 claims abstract description 5
- 239000006174 pH buffer Substances 0.000 claims abstract description 4
- 239000011148 porous material Substances 0.000 claims abstract description 4
- 239000000758 substrate Substances 0.000 claims description 11
- 230000002378 acidificating effect Effects 0.000 claims description 7
- 239000011248 coating agent Substances 0.000 claims 1
- 238000000576 coating method Methods 0.000 claims 1
- 239000007789 gas Substances 0.000 description 35
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 12
- 229910002092 carbon dioxide Inorganic materials 0.000 description 9
- 239000000523 sample Substances 0.000 description 9
- 150000002500 ions Chemical class 0.000 description 8
- 239000001569 carbon dioxide Substances 0.000 description 5
- 125000000524 functional group Chemical group 0.000 description 5
- 239000008346 aqueous phase Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000005192 partition Methods 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- DHMQDGOQFOQNFH-UHFFFAOYSA-N Glycine Chemical compound NCC(O)=O DHMQDGOQFOQNFH-UHFFFAOYSA-N 0.000 description 2
- 150000001450 anions Chemical class 0.000 description 2
- 239000000872 buffer Substances 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 2
- 150000001768 cations Chemical class 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 229920002818 (Hydroxyethyl)methacrylate Polymers 0.000 description 1
- 239000004471 Glycine Substances 0.000 description 1
- WOBHKFSMXKNTIM-UHFFFAOYSA-N Hydroxyethyl methacrylate Chemical compound CC(=C)C(=O)OCCO WOBHKFSMXKNTIM-UHFFFAOYSA-N 0.000 description 1
- 101150004094 PRO2 gene Proteins 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- 150000001408 amides Chemical class 0.000 description 1
- 235000001014 amino acid Nutrition 0.000 description 1
- 150000001413 amino acids Chemical class 0.000 description 1
- 125000003277 amino group Chemical group 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 238000004164 analytical calibration Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000008280 blood Substances 0.000 description 1
- 210000004369 blood Anatomy 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000010494 dissociation reaction Methods 0.000 description 1
- 230000005593 dissociations Effects 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 239000005373 porous glass Substances 0.000 description 1
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
A conductimetric gas sensing device comprises: an ion exchange layer 4 of porous material for saturation with water; means for measuring the conductance of the ion exchange layer; and a gas permeable membrane 5 impermeable to liquids arranged to separate the ion exchange layer from a test fluid 6 such that gas present in the test fluid diffuses through the membrane and dissolves into the ion exchange layer modifying its conductivity. The ion exchange layer 4 may be equimolar in anionic and cationic groups to act as a pH buffer, and may be formed from a polymer or a zwitterion species. <IMAGE>
Description
GAS SENSING DEVICE
This invention relates to a gas sensing device and, in particular, to a conductimetric gas sensing device, that is a gas sensing device which determines the partial pressure of a gas in a fluid sample by measuring the conductance of an aqueous solution in which the concentration of the gas is in equilibrium with the fluid sample.
One form of conductimetric gas sensor is described by J.S.
Symanski et al in the paper wconductimetric Sensor for Atmospheric
Carbon Dioxide' in Analytical Chemistry Vol. 55, No. 7, June 1983, pp 1152-1156. This sensor comprises a hydrophobic gas porous membrane which separates the gas sample from a thin layer of an aqueous phase. The gas diffuses through the membrane, to form an equilibrium concentration in the aqueous layer, thereby increasing the conductance of the aqueous layer. It is known both from theory and measurement that the specific conductivity k of the aqueous layer in such a device is proportional to the square root of the partial pressure of the gas in the fluid sample, for example pCO2 for carbon dioxide.The relationship is in the form: k t \ tXO HCO3 (K1.pCO212) where #io is the equivalent ionic conductance of the species i at infinite dilution and K1 is the equilibrium partition constant in the reaction:
C02(gas) + H20 H+ (aqueous) + HCO3 (aqueous)
The non-linearity of the relationship between the specific conductivity k and the partial pressure of gas in the test fluid sample can be a disadvantage of such a conductimetric gas sensing device. This is particularly so when small concentration changes about mean levels are of interest as, for example in clinical CO2 measurement, the square root dependence represents a severe limitation on the usuable dynamic concentration range of the sensor.
It is therefore an object of the present invention to provide a conductimetric gas sensor in which the measured conductivity is linearly related to the partial pressure of the gas in the fluid sample and which consequently has a high and uniform sensitivity to small differences in the partial pressure, and hence concentration, of the gas in the fluid sample over a wide range of partial pressures.
According to the present invention there is provided a conductimetric gas sensing device comprising:
an ion exchange layer of porous material for saturation with water;
means for measuring the conductance of the ion exchange layer; and
a gas permeable membrane impermeable to liquids arranged to separate the ion exchange layer from a test fluid such that gas present in the test fluid diffuses through the membrane and dissolves into the ion exchange layer modifying its conductivity.
Preferably, the ion exchange layer is equimolar in anionic (A ) and cationic (BE ) groups, to act as a pH buffer with respect to changes induced by dissolving an acidic or basic gas therein.
In one embodiment of the invention the ion exchange layer is formed from a polymer.
In an alternative embodiment of the invention the ion exchange layer is formed from a zwitterion species comprising at least one of each of an anionic and a cationic group.
Preferably, one surface of the ion exchange layer is arranged to be in contact with a pair of electrodes attached to an inert, electrically insulating substrate, to provide the means to measure the conductance of the said ion exchange layer.
In a preferred embodiment of the invention the ion exchange layer is disposed upon a layer of the substrate the said substrate being provided with the electrodes.
In an alternative embodiment of the invention the ion exchange layer is formed in a doating around a rod of the substrate provided with the electrodes.
The invention will now be described by way of example only and with reference to the accompanying drawings, of which:
Figure 1 shows an arrangement in accordance with one embodiment of the invention,
Figure 2 shows an arrangement in accordance with an alternative embodiment of the invention,
Figure 3 shows an equivalent circuit for the arrangement of
Figures 1 or 2.
In the arrangement shown in Figure 1, electrodes 1 and 2 are formed on or attached to an electrically insulating substrate 3.
The electrodes 1 and 2 are in contact with one side of an ion exchange layer 4, which is saturated with water before use. A retaining layer 5 is permeable to gases or vapours, but not to liquids. It is formed on, or attached to, the layer 4 and prevents the layer 4 from having any direct contact with a test fluid 6. The electrodes 1 and 2 are connected to an a.c. supply providing a low voltage, typically of the order of l00mV, at a frequency of the order of 10 kHz where the electrical resistance of the absorbed water dominates over the effects of series and parallel capacitances.
The purpose of the ion exchange layer 4 is to buffer the ionic concentration changes induced by the dissolving gas and hence linearise the relationship between gas partial pressure and conductivity in the aqueous phase. This layer, which preferably is equimolar in cationic, BH+, (e.g. amino) and anionic, A, (e.g. carboxyl) ion exchange groups and by itself makes minimal contribution to the conductivity of the aqueous phase, may be formed in the following ways.
First, the ion exchange material may be polymeric (e.g.
polyacrylic or polystyrene based) and formed in a manner analagous to conventional ion exchange resins but either from an equimolar mixture of functional monomers carrying on the one hand anionic and on the other cationic functional groups or from a functional monomer carrying anionic and cationic functional groups in equimolar proportions. Second, the ion exchange material may be formed by anchorage, either of an equimolar mixture of functional groups carrying on the one hand anionic and on the other cationic functional groups plus a chemical linkage group or of a functional unit carrying both anionic and cationic exchange groups in equimolar proportions plus a chemical linkage group, to a previously formed porous support material.Examples of established anchorage methods are silane linkage to a porous glass support and amide linkage between an amino group and an activated carboxyl group, the one or the other being part of an immobile support matrix. The resins formed by the above methods will be equimolar or thereabouts in immobile anionic and cationic exchange groups.
Alternatively, monomeric or oligomeric rather than polymeric chemical units carrying anionic and/or cationic functional groups may be entrapped within a polymer gel matrix (e.g.
poly-hydroxy-ethyl-methacrylate), by performing the conventional polymerisation and/or crosslinking process for formation of the gel in the presence of amounts of the anion and cation carrying units. The polymer matrix may be formed with an appropriate pore size so as to restrict the mobility and hence associated conductivity of the anion and cation carrying units whilst allowing relatively free migration of the smaller ion derived from the dissolving gas, which is to be determined. In this case the ion exchange groups may not be completely immobile but their mobility may be sufficiently restricted compared with that of the mobile gas derived ion that the observed conductivity will be primarily due to the latter.
In each of the above cases the anionic and cationic groups within the ion-exchange layer 4 can act as a pH buffer with respect to the changes induced by dissolving an acidic or basic gas therein.
If the test fluid 6 contains an acidic gas, for example carbon dioxide, the water absorbed in the layer 4 becomes acidic. Some of the anionic groups (A ) then acquire an
H ion, forming immobile AH groups and an equal number of mobile negatives ions (eg HC03 ) in the water layer resulting in a
equilibrium with
[HCO3-] = (K2/[H+])pCO2 where K2 is the equilibrium partition constant in the reaction C02(gas) + H2O + nRov A ~ > HCO + R# AH + (n-l) R# A
3 The specific conductivity k of the water in the ion exchange lay is then given by the equation
A similar situation applies for a basic gas, for example ammonia, but involving the cationic exchange group BH+ the equilibrium being given by [NH4+ ] = (K3[H+])pNB3 where K3 is the equilibrium partition constant in the reaction
and the specific electrical conductivity being given by
Equations (1) and (2) show the linear relationship between the specific electrical conductivity and the partial pressure of the gas being measured, subject to the constraint that the immobile buffer ion is in sufficient excess to maintain [H+] effectively constant.
As an alternative to polymeric, monomeric and oligmeric materials, the ion exchange layer may instead be formed from a zwitterion species. A zwitterion species is a chemical which possesses at least one of each of a negative and a positive ion, so that over all it is electrically neutral. In this particular instance the zwitterion species carry both cationic (BH ) and an ionic (A-) groups in equimolar proportions (A -BH ) so as to carry, in the main, a net charge of zero over their effective operating range (e.g. glycine or other aminoacids around pub7), and may be employed either in immobile form as described previously or as freely diffusing species.In this freely diffusing case, if the test fluid 6 contains an acidic gas, for example carbon dioxide, such that the water absorbed in the layer 4 becomes acidic, then some of the anionic groups of the zwitterion acquire an H ion, forming mobile positive AH-BB+ groups and an equal number of mobile negative ions (e.g. HCO3-) in the water layer.
The change in specific conductivity, k, of the aqueous phase in the ion exchange layer on exposure to a change in carbon dioxide partial pressure, pro2, is then due to changes in the concentration of both bicarbonate and AB-BB+ and is given by
subject to the constraint that the zwitterion is in sufficient excess to maintain H+ effectively constant. A similar situation applies for a basic gas.
An alternative embodiment of the invention is shown in the arrangement in Figure 2, in which the reference numerals correspond with those in Figure 1. In this arrangement the substrate 3 comprises a rod, carrying the electrodes 1 and 2, coated with the ion exchange layer 4 and the retaining gas permeable layer 5. This arrangement provides a probe suitable for immersion in a stationary or flowing liquid. Alternatively, the probe arrangement might comprise a flat substrate with successive layers on one or on both sides of it.
The equivalent circuit for the arrangement shown in Figure 1 or 2 is shown in Figure 3, where a.resistor 7 represents the electrical resistance of the water in the ion exchange layer 4, a capacitor 8 represents the parallel capacitance of the ion exchange layer 4 and capacitors 9 represent the series capacitance between each of the electrodes 1 and 2 and the ion exchange layer 4. The resistance of resistor 7 can be measured accurately if the frequency f is sufficiently high for the effective series capacitance to have a negligible effect, but not so high that the parallel capacitance affects the measurement. A typical frequency for usual electrode geometries is of the order of IOkHz and the voltage of the a.c. supply is typically below 1V to avoid causing dissociation within the water held in the ion exchange layer.
The invention thus provides a conductimetric gas sensing device with a linear response and the associated advantage of a wide dynamic range, making the sensor particularly suitable for measuring small changes in the concentration of a gas in a fluid as in, for example, measuring C02 concentrations in the blood.
The linear response of the device additionally makes for simple instrument calibration.
Claims (8)
1. A conductimetric gas sensing device comprising:
an ion exchange layer of porous material for saturation with water;
means for measuring the conductance of the ion exchange layer; and
a gas permeable membrane impermeable to liquids arranged to separate the ion exchange layer from a test fluid such that gas present in the test fluid diffuses through the membrane and dissolves into the ion exchange layer modifying its conductivity.
2. A conductimetric gas sensing device according to Claim 1, wherein the ion exchange layer is equimolar in anionic and cationic groups, to act as a pH buffer with respect to changes induced by dissolving an acidic or basic gas therein.
3. A conductimetric gas sensing device according to Claim 2, wherein the ion exchange layer is formed from a polymer.
4. A conductimetric gas sensing device according to Claim 2, wherein the ion exchange layer is formed from a zwitterion species comprising at least one of each of an anionic and a cationic group.
5. A conductimetric gas sensing device according to anyone of
Claims 1 to 4, wherein the ion exchange layer is arranged to be in contact with a pair of electrodes attached to an inert, electrically insulating substrate, to provide the means to measure the conductance of the said ion exchange layer.
6. A conductimetric gas sensing device according to Claim 5, wherein the ion exchange layer is disposed upon a layer of the substrate, the said substrate being provided with the electrodes.
7. A conductimetric gas sensing device according to Claim 5, wherein the ion exchange layer is formed in a coating around a rod of the substrate provided with the electrodes.
8. A conductimetric gas sensing device substantially as hereinbefore described with reference to Figures 1 and 3 or Figures 2 and 3 of the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08719017A GB2208006A (en) | 1987-08-11 | 1987-08-11 | Gas sensing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08719017A GB2208006A (en) | 1987-08-11 | 1987-08-11 | Gas sensing device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8719017D0 GB8719017D0 (en) | 1987-09-16 |
| GB2208006A true GB2208006A (en) | 1989-02-15 |
Family
ID=10622153
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08719017A Withdrawn GB2208006A (en) | 1987-08-11 | 1987-08-11 | Gas sensing device |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2208006A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2306658A (en) * | 1995-10-31 | 1997-05-07 | Christopher Arthur Sta Gillard | Device for measuring gas concentration electrically |
| US6004442A (en) * | 1994-10-18 | 1999-12-21 | Institut Fur Chemo- Und Biosensorik Munster E.V. | Analyte-selective sensor |
| WO2000034764A1 (en) * | 1998-12-10 | 2000-06-15 | Gerlinde Bischoff | Measuring probe and method for measuring the concentration of agents in gases and/or liquids |
| EP1124130A2 (en) * | 2000-02-11 | 2001-08-16 | Siemens Aktiengesellschaft | Semiconductor gas sensor with a buffer system |
| WO2003067241A2 (en) * | 2002-02-05 | 2003-08-14 | Stefan Felix Raible | Gas sensor and method for producing the same |
| WO2013061245A1 (en) * | 2011-10-28 | 2013-05-02 | Koninklijke Philips Electronics N.V. | Sensor for fluid-soluble gas |
| WO2013061293A1 (en) * | 2011-10-28 | 2013-05-02 | Koninklijke Philips Electronics N.V. | Sensor for fluid-soluble gas |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1031739A (en) * | 1963-11-07 | 1966-06-02 | Wayne Kerr Lab Ltd | Improvements in or relating to humidity sensing elements and their manufacture |
| GB1360847A (en) * | 1970-10-16 | 1974-07-24 | Gen Electric | Carbon dioxide sensor |
| GB2052755A (en) * | 1979-05-18 | 1981-01-28 | Neotronics Ltd | Gas detecting and measuring apparatus |
| GB2096324A (en) * | 1981-04-08 | 1982-10-13 | Nat Res Dev | Conductimetric gas sensor |
| GB2113400A (en) * | 1981-12-08 | 1983-08-03 | Sharp Kk | Moisture responsive electrical element |
-
1987
- 1987-08-11 GB GB08719017A patent/GB2208006A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1031739A (en) * | 1963-11-07 | 1966-06-02 | Wayne Kerr Lab Ltd | Improvements in or relating to humidity sensing elements and their manufacture |
| GB1360847A (en) * | 1970-10-16 | 1974-07-24 | Gen Electric | Carbon dioxide sensor |
| GB2052755A (en) * | 1979-05-18 | 1981-01-28 | Neotronics Ltd | Gas detecting and measuring apparatus |
| GB2096324A (en) * | 1981-04-08 | 1982-10-13 | Nat Res Dev | Conductimetric gas sensor |
| GB2113400A (en) * | 1981-12-08 | 1983-08-03 | Sharp Kk | Moisture responsive electrical element |
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6004442A (en) * | 1994-10-18 | 1999-12-21 | Institut Fur Chemo- Und Biosensorik Munster E.V. | Analyte-selective sensor |
| GB2306658A (en) * | 1995-10-31 | 1997-05-07 | Christopher Arthur Sta Gillard | Device for measuring gas concentration electrically |
| WO2000034764A1 (en) * | 1998-12-10 | 2000-06-15 | Gerlinde Bischoff | Measuring probe and method for measuring the concentration of agents in gases and/or liquids |
| US6767747B1 (en) | 1998-12-10 | 2004-07-27 | Gerlinde Bischoff | Measuring probe and method for measuring the concentration of agents in gases and/or liquids |
| EP1124130A3 (en) * | 2000-02-11 | 2003-12-17 | Siemens Aktiengesellschaft | Semiconductor gas sensor with a buffer system |
| EP1124130A2 (en) * | 2000-02-11 | 2001-08-16 | Siemens Aktiengesellschaft | Semiconductor gas sensor with a buffer system |
| DE10204458A1 (en) * | 2002-02-05 | 2003-08-14 | Stefan Raible | gas sensor |
| WO2003067241A2 (en) * | 2002-02-05 | 2003-08-14 | Stefan Felix Raible | Gas sensor and method for producing the same |
| WO2003067241A3 (en) * | 2002-02-05 | 2004-03-11 | Stefan Felix Raible | Gas sensor and method for producing the same |
| WO2013061245A1 (en) * | 2011-10-28 | 2013-05-02 | Koninklijke Philips Electronics N.V. | Sensor for fluid-soluble gas |
| WO2013061293A1 (en) * | 2011-10-28 | 2013-05-02 | Koninklijke Philips Electronics N.V. | Sensor for fluid-soluble gas |
| CN103907018A (en) * | 2011-10-28 | 2014-07-02 | 皇家飞利浦有限公司 | Sensor for fluid-soluble gas |
| JP2015501185A (en) * | 2011-10-28 | 2015-01-15 | コーニンクレッカ フィリップス エヌ ヴェ | Fluid soluble gas sensor |
| RU2613199C2 (en) * | 2011-10-28 | 2017-03-15 | Конинклейке Филипс Н.В. | Sensor for fluid-soluble gas |
| US9726630B2 (en) | 2011-10-28 | 2017-08-08 | Koninklijke Philips N.V. | Sensor for fluid-soluble gas |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8719017D0 (en) | 1987-09-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |