US20080274561A1 - Method and apparatus for determining a total concentration of a component in a mixture of components - Google Patents
Method and apparatus for determining a total concentration of a component in a mixture of components Download PDFInfo
- Publication number
- US20080274561A1 US20080274561A1 US12/173,552 US17355208A US2008274561A1 US 20080274561 A1 US20080274561 A1 US 20080274561A1 US 17355208 A US17355208 A US 17355208A US 2008274561 A1 US2008274561 A1 US 2008274561A1
- Authority
- US
- United States
- Prior art keywords
- components
- component
- sample
- reactor
- 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.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 29
- 239000000203 mixture Substances 0.000 title description 30
- 230000001590 oxidative effect Effects 0.000 claims abstract description 12
- 239000012528 membrane Substances 0.000 claims description 50
- 229920000554 ionomer Polymers 0.000 claims description 47
- 239000000758 substrate Substances 0.000 claims description 35
- 230000007246 mechanism Effects 0.000 claims description 11
- 238000001914 filtration Methods 0.000 claims description 10
- 239000000126 substance Substances 0.000 claims description 9
- 230000008878 coupling Effects 0.000 claims description 7
- 238000010168 coupling process Methods 0.000 claims description 7
- 238000005859 coupling reaction Methods 0.000 claims description 7
- 238000000151 deposition Methods 0.000 claims description 5
- 239000007789 gas Substances 0.000 description 82
- 238000001514 detection method Methods 0.000 description 26
- 239000007788 liquid Substances 0.000 description 18
- 230000035945 sensitivity Effects 0.000 description 18
- 239000000463 material Substances 0.000 description 17
- 230000004044 response Effects 0.000 description 15
- 238000009792 diffusion process Methods 0.000 description 13
- 239000000243 solution Substances 0.000 description 13
- 239000010408 film Substances 0.000 description 11
- 238000009736 wetting Methods 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 239000008151 electrolyte solution Substances 0.000 description 7
- 238000000926 separation method Methods 0.000 description 7
- 239000011888 foil Substances 0.000 description 6
- 239000006200 vaporizer Substances 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- 239000001257 hydrogen Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 4
- 239000006185 dispersion Substances 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 229910052717 sulfur Inorganic materials 0.000 description 4
- 239000011593 sulfur Substances 0.000 description 4
- 238000000357 thermal conductivity detection Methods 0.000 description 4
- 239000003792 electrolyte Substances 0.000 description 3
- 239000012530 fluid Substances 0.000 description 3
- 230000002411 adverse Effects 0.000 description 2
- 239000012811 non-conductive material Substances 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 239000000376 reactant Substances 0.000 description 2
- 230000008016 vaporization Effects 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- MPCRDALPQLDDFX-UHFFFAOYSA-L Magnesium perchlorate Chemical compound [Mg+2].[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O MPCRDALPQLDDFX-UHFFFAOYSA-L 0.000 description 1
- 229920000557 Nafion® Polymers 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- -1 carbon monoxide Chemical class 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 239000002274 desiccant Substances 0.000 description 1
- 238000002136 electrolytic conductivity detection Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 238000004255 ion exchange chromatography Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229920003223 poly(pyromellitimide-1,4-diphenyl ether) Polymers 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 239000002341 toxic gas Substances 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
Images
Classifications
-
- 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
- G01N30/62—Detectors specially adapted therefor
- G01N30/64—Electrical detectors
-
- 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
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0011—Sample conditioning
- G01N33/0013—Sample conditioning by a chemical reaction
-
- 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
- G01N30/12—Preparation by evaporation
- G01N2030/125—Preparation by evaporation pyrolising
-
- 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
- G01N30/62—Detectors specially adapted therefor
- G01N30/64—Electrical detectors
- G01N2030/645—Electrical detectors electrical conductivity detectors
-
- 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
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
- G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
- G01N33/0044—Sulphides, e.g. H2S
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T436/00—Chemistry: analytical and immunological testing
- Y10T436/25—Chemistry: analytical and immunological testing including sample preparation
- Y10T436/25375—Liberation or purification of sample or separation of material from a sample [e.g., filtering, centrifuging, etc.]
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T436/00—Chemistry: analytical and immunological testing
- Y10T436/25—Chemistry: analytical and immunological testing including sample preparation
- Y10T436/25875—Gaseous sample or with change of physical state
Definitions
- the invention relates to an apparatus for determining a total concentration of a gas or liquid component in a respective mixture of gas or liquid components.
- Detecting for the presence of particular components may be useful for a variety of reasons.
- an apparatus for detecting pollution or industrial emission may alert an individual responsible for limiting such contaminants as to when a given quantity of pollution has entered water systems or the atmosphere.
- a gas detection unit may be used for detecting the presence of dangerous chemical compounds, such as carbon monoxide, in a mixture of gases.
- a gas detection unit may be used for detecting a particular gas in equipment, such as an oxygen inhalation machine, for alerting staff as to the amount of oxygen remaining in the reservoir or given to the patient.
- multiple detectors may be needed to detect all of the compounds containing hydrogen, such as a detector for detecting H 2 O and another detector for CH 4 .
- the detectors' results may thereafter need to be summed, which may also introduce measurement error with respect to each detector, so that the total amount of hydrogen may be determined.
- FIG. 1 depicts a conventional TCD in accordance with the prior art.
- first, second, third, and fourth cells 1 , 2 , 3 , 4 respectively, appear to contain first, second, third and fourth heaters 1 a , 2 a , 3 a , and 4 a , respectively.
- Fluid being examined is typically led from an inlet 5 a (see arrow) of the first cell 1 , made to flow through first cell 1 and second cell 2 , and led out of an outlet 5 b (see arrow) of second cell 2 .
- a reference fluid is usually led from an inlet 6 a (see arrow) of third cell 3 , made to flow through third cell 3 and fourth cell 4 , and led out of an outlet 6 b (see arrow) of fourth cell 4 .
- first, second, third and fourth heaters 1 a , 2 a , 3 a and 4 a are most often connected to form an electrical bridge 7 and a predetermined current is normally supplied from a constant current supply 8 to bridge 7 .
- a detection circuit 9 may detect such unbalance voltage, and in that way, variation in thermal conductivity of the fluids being examined may be measured, wherein the variation may indicate the amount of a component present in a mixture.
- TCDs may have limited detection capabilities. As described in U.S. Pat. No. 5,295,389 to Nagata (“Nagata”), TCDs seem to be adversely affected due to the flow of gases that are to be detected, resulting in inaccurate gas measurements.
- the Sisti method and apparatus for detecting total sulfur concentration due to the possible limitations of the detector, may have limited sensitivity and/or accuracy.
- Sisti appears to relate to a method and apparatus that is limited to a determination of a single component and where a determination of multiple components may require multiple operations in succession.
- Another object of the invention is to provide a method and apparatus that determines the total concentration and having improved sensitivity and accuracy.
- a further object of the invention is to provide a method and apparatus that efficiently and contemporaneously detects total concentrations of multiple components.
- Yet another object is to provide a detection system that achieves the above objects while reducing interference from undesired components.
- a method and apparatus for determining a total concentration of a component in a sample including a reactor for oxidizing or reducing the sample, a chromatographic column coupled to the reactor for separating the component in the sample, and an electrochemical gas sensor coupled to the chromatographic column for detecting the component.
- an apparatus for determining a total concentration of a desired component in a sample including a reactor for oxidizing or reducing the sample, a filter coupled to the reactor for filtering out undesirable components and for permitting the desired component to pass through, and a detector coupled to the filter for detecting the component.
- the detector may be replaced with an electrochemical gas sensor or plurality of electrochemical gas sensors.
- an apparatus for determining a total concentration of various components in a sample including a reactor for oxidizing or reducing the sample, a first electrochemical gas sensor coupled to the reactor and having an adjustment mechanism and wherein the adjustment mechanism is selectively adjustable to detect for the presence of a selected one of a plurality of components.
- a second electrochemical gas sensor is also coupled to the reactor and has an adjustment mechanism, wherein the adjustment mechanism is selectively adjustable to detect for the presence of a selected one of a plurality of components.
- the sensors may simultaneously detect for the presence of two gas components in the sample. Additional sensors may permit simultaneous detection of multiple components
- the apparatus may also include a filter coupled to the reactor for filtering out undesirable components and for permitting desirable components to pass through to the first and second electrochemical gas sensors.
- a method for determining a total concentration of a component in a sample including the steps of oxidizing or reducing the sample in a reactor, separating the component from the sample using a separation device, and coupling an electrochemical gas sensor to the separation device for detecting the component.
- the method may also include the step of separating the component from the sample using a gas chromatograph column.
- the electrochemical gas sensor may be provided in accordance with the steps of providing a substrate having a surface for depositing electrodes thereon, depositing an electrode on the surface, contacting an ionomer membrane with the electrode, providing an opening in the ionomer membrane in an approximate area of the electrode, extending the opening from a first surface of the ionomer membrane to a second surface of the ionomer membrane for defining a passage, and placing a gas in the opening and simultaneously contacting the gas with both the electrode and ionomer membrane within the opening.
- the method may include coupling a plurality of electrochemical gas sensors to the separation device for detecting multiple components.
- the method may include filtering out undesirable components and permitting desirable components to pass through.
- a method for determining a total concentration of a component in a sample including the steps of oxidizing or reducing the sample in a reactor, filtering out undesirable components and permitting a desirable component to pass through using a filter, and coupling a detector to the filter for detecting the desirable component.
- the detector may further be replaced with an electrochemical gas sensor to the filter for detecting the desirable component.
- FIG. 1 depicts a thermal conductivity detector known in the prior art.
- FIG. 2 depicts an apparatus for determining a total concentration of a gas component in a gas mixture in accordance with the invention.
- FIG. 3 depicts one embodiment of the apparatus shown in FIG. 2 .
- FIG. 4 depicts another embodiment of the apparatus shown in FIG. 2 .
- FIG. 5 depicts another embodiment of the apparatus shown in FIG. 2 .
- FIG. 6 depicts another embodiment of the apparatus shown in FIG. 2 .
- FIG. 7 depicts a sensor for use with the apparatus shown in FIG. 2 .
- FIG. 8 depicts another sensor for use with the apparatus shown in FIG. 2 .
- FIG. 9 more particularly depicts an electrode to be used with the sensors of FIGS. 7 and 8 .
- FIG. 11 depicts a method for providing the apparatus shown in FIG. 2 .
- FIG. 2 depicts the apparatus 50 for determining a total concentration of a component, whether in a gaseous or liquid state, in a mixture, or sample, of gases or liquids.
- Apparatus 50 further includes reactor 54 for oxidizing and/or reducing the mixture so that the desired component may be detected by sensor 66 .
- a component desired to be detected by sensor 66 but which is not easily detectable, would be oxidized and/or reduced by reactor 54 .
- reactor 54 oxidizes/reduces a desirable component by heating the component together with a reactant gas 56 at a specified temperature.
- apparatus 50 may be used with either a gas or liquid state mixture 58
- the volume of mixture 58 should be low enough such that, upon being heated inside reactor 54 , mixture 58 converts into a gaseous state so that component, now in the gaseous state, may be detected by sensor 66 . It is desired for the entire mixture 58 to convert to a gaseous state because any component remaining dissolved in a liquid state mixture may not be easily detected by sensor 66 .
- vaporizer 72 is placed between the injector and reactor 54 because reactant 56 , if utilized to optionally facilitate oxidation and/or reduction, is a gas and may be mixed with mixture 58 .
- vaporizer 72 may be placed in any location where mixture 58 , in the liquid state, is to be converted to a gaseous state, such as between reactor 54 and gas chromatograph column (“GC”) 52 or between GC 52 and sensor 66 .
- GC gas chromatograph column
- reactor 54 and/or vaporizer 72 may be omitted from apparatus 50 , which results in mixture 58 exiting the injector and directly entering GC 52 .
- reactor 54 and/or vaporizer 72 would be needed to heat mixture 58 until mixture 58 converts into a gaseous state prior to entering GC 52 .
- GC 52 acts as a separation device and is used to separate the mixture or sample 58 into its respective components.
- the desirable component is ultimately detected by an electrochemical gas sensor 66 , which is coupled to an end of GC 52 where the gas components are exiting GC 52 .
- the combination of sensor 66 being coupled to GC 52 provides a system 50 for detecting a component having enhanced sensitivity and response time because sensor 66 provides numerous advantages over conventional detector cells 10 , as shown and described under FIG. 1 .
- Sensor 66 reduces the need for a component of the sample to be absorbed and dispersed in an electrolyte solution in order for an electrical measurement to be taken across electrodes in contact with the solution.
- Sensor 66 detects gas as the gas comes in contact with an electrode, thereby reducing response time and increasing sensitivity.
- the resolution, or detection capability, of sensor 66 is typically in the range of parts per billion, which is generally more sensitive than the conventional detector cell shown in FIG. 1 .
- Sensor 66 and its limitations are more particularly described under FIGS. 7-10 .
- apparatus 50 is to have sensor 66 directly coupled to GC 52 .
- a plurality of sensors may be directly coupled to GC 52 .
- sensors 66 and 66 ′ are connected in parallel to GC 52 . It is understood that apparatus 50 ′ of FIG. 3 should not be limited to two sensors but may have any number of sensors and that two sensors are shown for exemplary purposes.
- Sensor 66 ′ has the same limitations as sensor 66 and, to reduce repetition, only sensor 66 will be described.
- apparatus 50 ′ is capable of simultaneously detecting two desired components due to having both sensors 66 and 66 ′. More components may be simultaneously detected by adding more sensors. Sensors 66 and 66 ′ are preset to detect for the presence of different components by varying the applied potential across the sensing electrode (enumerated as 103 and 138 of FIGS. 7 and 8 ) of each sensor so that gases having an electrical signal that match the preset potential of the respective sensor are detected.
- FIG. 4 depicts another embodiment of the invention where, instead of coupling sensor 66 to GC 52 , filter 62 is coupled to GC 52 for removing undesirable components from mixture 58 .
- GC 52 merely separates components from one another where all components going into GC 52 exit GC 52 but exit in a particular order. Desirable and undesirable components exit GC 52 and, in some cases, undesirable components may interfere with the detection of desirable components. Therefore, filter 62 is used to enhance, or facilitate, detection of the desirable components by removing undesirable components. Filter 62 prevents particular components from passing through based on the chemical properties of the components.
- filter 62 may filter out all water or other compounds from passing through to detector 68 .
- filter 62 that removes undesirable components include any membrane dryer or drying agents, such as Nafion or magnesium perchlorate.
- Filter 62 suppresses undesirable components by reducing its ability to interfere with the detection of desirable components.
- H 2 S is difficult to detect with water present because water typically absorbs H 2 S.
- H 2 S dissolves in water and, therefore, water is typically an undesirable component of the mixture having H 2 S. With H 2 S being dissolved in or absorbed by water, proper detection of H 2 S is adversely affected and, hence, water lessens the likelihood of H 2 S being accurately detected by either detector 68 or sensor 66 .
- FIG. 5 depicts another embodiment of the invention where, instead of detector 68 shown in FIG. 3 , sensor 66 is used to enhance detection capabilities to ppb over the limited detection capabilities of detector 68 .
- GC 52 may be omitted when separation of the components of the gas mixture are not needed to detect the desirable component, particularly where it is likely the desired components are not dispersed throughout the gas mixture. For example, if detection of H 2 S is desired and the remaining components of the gas mixture do not have any hydrogen or sulfur, GC 52 may not be needed because there would not be any hydrogen or sulfur to separate.
- FIG. 6 depicts a further embodiment of the invention shown in FIG. 5 , where multiple filters 62 , 62 ′ and sensors 66 , 66 ′ are employed to simultaneously detect several desirable components. Because filter 62 ′ includes all of the limitations of filter 62 , and to reduce repetition, filter 62 will be described hereinafter. As shown, sensors 66 and 66 ′ are employed to, as described above, simultaneously detect at least 2 desirable components by presetting sensors 66 and 66 ′ to different applied potentials across the sensing electrode of each sensor.
- Filters 62 and 62 ′ are used to enhance detection by removing or suppressing different types of undesirable components based on various chemical properties of the undesirable components. Filters 62 and 62 ′ may be preset to chemically filter out predetermined undesirable components that are most likely to interfere with the component to be detected by the respective sensor 66 and 66 ′.
- FIG. 7 shows an electrochemical gas sensor of copending U.S. patent application Ser. No. 09/443,875, which may, but not necessarily, be used as sensor 66 .
- electrochemical gas sensor 92 includes substrate 111 , electrode 103 , and ionomer membrane 105 . Gas enters and exits sensor 92 through the inlet and outlet as shown. A portion of the gas entering sensor 92 diffuses through diffusion hole 120 and contacts electrode 103 , which detects the type of gas present in sensor 66 .
- sensor 66 ′ will not be described but is understood to include the limitations of sensor 66 .
- a reservoir 109 is provided containing electrolyte solution to wet ionomer membrane 105 . As shown, reservoir 109 and, therefore, the electrolyte solution is in contact with ionomer membrane 105 . Because reservoir 109 is located on a same side of ionomer membrane 105 as diffusion hole 120 , a length of diffusion hole is typically at least as long as a height of reservoir 109 .
- FIG. 8 depicts another electrochemical gas sensor 94 , which may, but not necessarily, be used as sensor 66 .
- Sensor 94 includes substrate 132 , ionomer membrane 134 , and electrode 138 .
- Gas enters sensor 94 through inlet 142 and is detected after diffusing through diffusion hole 144 to contact electrode 138 , which is in contact with ionomer membrane 134 .
- Gas exits sensor 94 through outlet 146 . It is understood that the gas may flow in a reversed direction where outlet 146 is the inlet and inlet 142 is the outlet.
- ionomer membrane 134 is wetted by solution 152 , which is contained in reservoir 156 .
- electrolyte solution and reservoir 109 were placed on the same side of substrate 111 as electrode 103 .
- the electrolyte solution wetted ionomer membrane 105 to enhance the sensitivity of sensor 92 in the same manner as solution 152 enhances the sensitivity of sensor 94
- reservoir 109 being on the same side of substrate 111 inhibits a length L of diffusion hole 120 from being reduced, which would reduce gas diffusion time and thereby improve sensor sensitivity.
- length L could not be shortened more than height H of reservoir 109 . Therefore, time required for gas to diffuse from the inlet through diffusion hole 120 to contact electrode 103 was difficult to reduce due to the length L of diffusion hole being of a minimum dimension not less than the height H of reservoir 109 .
- Sensor 94 of FIG. 8 overcomes this disadvantage by wetting ionomer membrane 134 , via hole 136 in substrate 132 , with solution 152 located on a side of substrate 132 opposite from electrode 138 . Because of the position of reservoir 156 , length L′ can be shortened, thereby reducing gas diffusion time and improving the sensitivity of sensor 94 . The more length L′ is reduced, the faster the response time of sensor 94 . In some embodiments, length L′ is less than 1.4 mm. In other embodiments, length L′ is less than 1 mm. In further, embodiments, length L′ is less than 0.5 mm. In still further embodiments, length L′ is less than 0.1 mm.
- length L′ or a thickness of ionomer membrane 134 may be reduced until it is flush with or below a surface of electrode 138 .
- diffusion hole 144 is eliminated because length L′ is flush with or below a surface of electrode 138 . All that is required is for ionomer membrane 134 , of any length L′, to be in contact with electrode 138 so that gas entering through inlet 142 provide a desired gas/ionomer membrane/electrode interface.
- the response time of sensor 94 is less than approximately 2 seconds, more preferably less than approximately 1 second, and most preferably less than approximately 0.5 seconds. In some embodiments, the response time is less than approximately 0.1 seconds.
- Substrate 132 is of an electrically non-conductive material for providing a surface upon which electrode 138 is placed.
- substrate 132 is a thin foil having insulative, or electrically non-conductive, properties, such as Kapton or any other material.
- the foil is not metallic or conductive.
- the foil may also be flexible as compared to ceramic or glass.
- the thickness of the foil, or substrate 132 is generally less than approximately 4 mils and preferably less than approximately 1 mil. The thinner substrate 132 , the faster ionomer membrane 134 is wetted and this positively affects sensor response time. Therefore, as the thickness of substrate 132 approaches 0 mils, the response time is further reduced.
- sensor 94 may include wicking material 154 to facilitate or enhance wetting of ionomer membrane 134 by solution 152 .
- Wicking material 154 is typically of a material that absorbs liquid, such as a sponge. Hence, as shown in FIG. 8 , wicking material 154 will draw solution 152 upwardly from reservoir 156 toward ionomer membrane 134 .
- reservoir 156 and substrate 132 are separable from one another where wicking material 154 is placed between reservoir 156 and substrate 132 .
- wicking material is placed within reservoir 156 and reservoir comes in contact with substrate 132 .
- substrate 132 and reservoir 156 are made not separable from one another but are formed as one unit. Wicking material 154 may optionally be used with any of these embodiments of reservoir 156 and substrate 132 .
- substrate 132 further includes at least one hole 136 extending from a first surface 162 of substrate 132 to a second surface 164 of substrate 132 , thereby forming a thru-hole, for permitting solution 152 to pass, or diffuse, through at least one hole 136 to contact ionomer membrane 134 .
- wicking material 154 would be positioned in a closer relationship to ionomer membrane 134 than where substrate 132 is of a thick material. Where substrate 132 is a foil, solution 152 absorbed by wicking material 154 would more easily wet ionomer membrane 134 .
- wicking material 154 would be in contact, through at least one hole 136 , with ionomer membrane 134 .
- wicking material 54 in addition to or instead of being between substrate 132 and solution 152 , is placed within at least one hole 136 .
- a plurality of holes 136 are placed in substrate 132 . It is understood that hole 136 is of any diameter, length, shape, or dimension. Also, the more holes 136 in substrate 132 , in any location, the better ionomer membrane 134 is wetted. Hence, the hole 136 or plurality of holes 136 may act as a form of wetting control to ionomer membrane 134 , as too much wetting or too little wetting negatively affects sensitivity. Moreover, hole 136 may be, in addition or instead of being round, a square shaped or polygonal shaped hole.
- Hole 136 may further be a slit or aperture of any kind. All that is required of hole 136 is that it provides a passage from first surface 162 to second surface 164 so that solution 152 diffuses through hole 136 to contact ionomer membrane 134 .
- FIG. 9 depicts an exploded view of the electrode shown in FIGS. 7 and 8 .
- a thin film 234 of electrolytic material which may be the same material as the ionomer membranes of FIGS. 7 and 8 , may optionally be placed on electrode 103 or 138 to increase the area of contact between the ionomer membrane 105 or 134 , electrode 103 or 138 , and gas to include the surface of electrode 103 or 138 . Gas diffuses throughout film 234 , which is in contact with the surface of electrode 103 or 138 . As a result of the increased contact area, the sensing area is increased and response time is minimized. Gas diffuses faster through film 234 when film 234 has a minimal thickness. Hence, the thinner film 234 is, the faster the response time is for sensor 92 or 94 .
- the interface in the approximate area of electrode 103 or 138 would be substantially smaller, limited to an area where ionomer membrane 105 or 134 comes in contact with electrode 103 or 138 .
- This contact area would generally be a linear contact point defining an approximate circumference of electrode 103 or 138 .
- film 234 has a thickness less than 2 micrometers. Ideally, film 234 should be as thin as possible to maximize sensor response time and sensitivity. Hence, sensor 92 or 94 may further comprise film 234 having a thickness of less than 1 micrometer. A film having such reduced thickness permits faster gas diffusion and, thus, faster response times.
- Film 234 is an electrolytic medium, which includes all the limitations of ionomer membrane 105 or 134 and may be, but need not be, the same material as ionomer membrane 105 or 134 .
- Film 234 is in a solid state because it has more structural integrity than liquid state electrolyte, thereby permitting a consistently uniform thickness over electrode 103 or 138 . This enhances sensor repeatability and facilitates functionality for liquid state electrolyte would be difficult to maintain in a fixed position on the surface of electrode 103 or 138 .
- the response time of sensor 92 or 94 may further be improved by reducing the size of the inlet and outlet of each sensor 92 or 94 .
- the gas is more concentrated while inside the sensor due to there being less internal volume for the gas to disperse.
- Less dispersion and a more concentrated gas generally results in a more easily detected gas and, therefore, reduced response time of sensor 92 or 94 .
- the volume in which gas may disperse is reduced.
- Such dispersion is generally referred to as axial dispersion because the dispersion is approximately along the axis containing a center point of sensor 92 or 94 .
- the inlet and outlet have a diameter of approximately 1 mm.
- the inlet and outlet need not be round but may be of any shape so long as gas may be injected into and extracted from sensor 92 or 94 .
- Such shapes include 3 sided, 4 sided, or polygonal geometries.
- sensor 94 may also include cover 150 on ionomer membrane 134 for minimizing the vaporization or evaporation of electrolyte solution 152 as solution 152 is absorbed and passed upwardly through ionomer membrane 134 .
- Cover 150 is in contact with the surface of ionomer membrane 134 opposite from substrate 132 .
- Cover 150 does not block any portion of either diffusion hole 144 or electrode 138 because doing so would hinder gas detection and negatively affect sensor sensitivity.
- Cover 150 is not needed for sensor 66 to operate properly and may be eliminated in its entirety.
- the length L′ of the diffusion path is the height of both ionomer membrane 134 and cover 150 .
- length L′ is the height of membrane 134 .
- FIG. 10 depicts another electrochemical gas sensor 96 , which may, but not necessarily, be used as sensor 66 .
- sensor 96 includes sensing electrode 202 , counter electrode 204 , and reference electrode 206 .
- sensor 96 includes filter 209 between counter electrode 204 and reference electrode 206 for wetting these electrodes. Further, filter 208 may be placed between sensing electrode 202 and reference electrode 206 for wetting these electrodes. Filter 208 includes the same limitations as filter 209 .
- Sensor 96 further includes gas inlet 212 for permitting gas to enter sensor 96 for detection upon reaction with ionomer membrane 216 and sensing electrode 202 .
- wick 220 is in contact with the electrolyte solution in reservoir 222 and filter 208 , which in turn is in contact with reference electrode 206 , another filter 208 , and sensing electrode 202 .
- platinum contact strips may be placed in select areas of sensor 96 to enhance sensitivity and conductivity.
- a platinum strip may be placed between membrane 216 and sensing electrode 202 , between reference electrode 206 and filter 208 , between filter 209 and counter electrode 204 , or all of the above.
- FIG. 11 depicts a method 300 for determining a total concentration of a component in a gas sample.
- Method 300 includes injecting 301 the sample into a reactor, oxidizing or reducing 303 the sample in a reactor and separating 304 the desirable gas component to be detected from the gas sample using a separation device, which may be a GC or other device for separating the desirable component(s) from the remainder of the gas sample.
- Method 300 also includes detecting 306 the desirable component(s) using a detection device, such as known or novel detectors and/or sensors.
- method 300 may optionally include the step of vaporizing 302 the sample (in a vaporizer) until it is converted to a gaseous state.
- the vaporizer may be omitted because the reactor, used for oxidizing or reducing 303 the sample, may also suffice in converting the sample in a liquid state to a gaseous state.
- method 300 may also include the step of coupling 308 at least one electrochemical gas sensor to the separation device for detecting 306 the component.
- method 300 may also include the step of providing a substrate having a surface, depositing an electrode on the surface, contacting an ionomer membrane with the electrode, providing an opening in the ionomer membrane in an approximate area of the electrode, introducing a gas into the opening toward the electrode, and simultaneously contacting the gas with both the electrode and ionomer membrane.
- method 300 may also include the step of filtering 310 out undesirable components and permitting desirable components to pass through to the detection step.
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Immunology (AREA)
- Engineering & Computer Science (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Physics & Mathematics (AREA)
- Pathology (AREA)
- Analytical Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Combustion & Propulsion (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
Abstract
The invention relates to a method and apparatus for determining a total concentration of a component in a sample, including a reactor for oxidizing or reducing the sample, a chromatographic column coupled to the reactor for separating the component in the sample, and an electrochemical gas sensor coupled to the chromatographic column for detecting the component. In further embodiments, a filter may be used instead of or in addition to the column. Moreover, multiple sensors may be used instead of or in addition to the column for simultaneously detecting multiple components.
Description
- This patent application is a divisional of currently pending U.S. patent application Ser. No. 10/675,629, filed Sep. 30, 2003, the content of which is incorporated herein by reference.
- The invention relates to an apparatus for determining a total concentration of a gas or liquid component in a respective mixture of gas or liquid components.
- Detecting for the presence of particular components may be useful for a variety of reasons. With respect to environmental concerns, an apparatus for detecting pollution or industrial emission, whether in the liquid or gaseous state, may alert an individual responsible for limiting such contaminants as to when a given quantity of pollution has entered water systems or the atmosphere. A gas detection unit may be used for detecting the presence of dangerous chemical compounds, such as carbon monoxide, in a mixture of gases. In the medical field, a gas detection unit may be used for detecting a particular gas in equipment, such as an oxygen inhalation machine, for alerting staff as to the amount of oxygen remaining in the reservoir or given to the patient.
- Known methods and apparatuses have been developed to detect the presence of gases or liquids. Typical systems include gas chromatography, ion chromatography, electrolytic conductivity detection, and conductometric measurement. However, these detection systems have generally been expensive, cumbersome, or shown to have low sensitivities and slower response times. In situations where a generally quick response time may be desired, such as detecting toxic gases or a lack of oxygen in an oxygen inhalation machine, detection systems having enhanced abilities to quickly detect particular gases or liquids are usually favorable.
- Systems for detecting gases appear to be disclosed in U.S. Pat. No. 4,843,016 to Fine, U.S. Pat. No. 5,268,302 to Rounbehler et al., U.S. Pat. No. 6,458,328 to Wreyford, and U.S. Pat. No. 5,152,963 to Wreyford. In these systems, a gas chromatograph column appears to be placed prior to the reactor so that components of the mixture may be separated from one another prior to being oxidized and/or reduced. This apparatus often permits particular compounds to be detected upon exiting the reactor. For example, a detector coupled to the reactor may be used to detect H2S while other compounds, such as H2O, CH4, SO2, or SO3, may not be detected by the detector.
- However, if a total concentration of hydrogen is desired using the apparatuses shown in Fine, Rounbehler, or two Wreyford patents, multiple detectors may be needed to detect all of the compounds containing hydrogen, such as a detector for detecting H2O and another detector for CH4. The detectors' results may thereafter need to be summed, which may also introduce measurement error with respect to each detector, so that the total amount of hydrogen may be determined.
- U.S. Pat. No. 4,293,308 to Sisti et al. (“Sisti”) appears to relate to a method and apparatus for determining a total concentration of sulfur in a gas sample. Sisti seems to teach a reactor for combusting a gas sample and oxygen, followed by a gas chromatograph column for separating components of the combustion mixture from one another. The separated components seem to then be conveyed to a known thermal conductivity detector (“TCD”) for detection.
-
FIG. 1 depicts a conventional TCD in accordance with the prior art. As shown, first, second, third, andfourth cells fourth heaters inlet 5 a (see arrow) of thefirst cell 1, made to flow throughfirst cell 1 andsecond cell 2, and led out of anoutlet 5 b (see arrow) ofsecond cell 2. A reference fluid is usually led from aninlet 6 a (see arrow) ofthird cell 3, made to flow throughthird cell 3 andfourth cell 4, and led out of anoutlet 6 b (see arrow) offourth cell 4. In addition, first, second, third andfourth heaters electrical bridge 7 and a predetermined current is normally supplied from a constantcurrent supply 8 to bridge 7. - When an unbalance voltage is generated in
bridge 7, adetection circuit 9 may detect such unbalance voltage, and in that way, variation in thermal conductivity of the fluids being examined may be measured, wherein the variation may indicate the amount of a component present in a mixture. - However, TCDs may have limited detection capabilities. As described in U.S. Pat. No. 5,295,389 to Nagata (“Nagata”), TCDs seem to be adversely affected due to the flow of gases that are to be detected, resulting in inaccurate gas measurements.
- Hence, the Sisti method and apparatus for detecting total sulfur concentration, due to the possible limitations of the detector, may have limited sensitivity and/or accuracy. Moreover, Sisti appears to relate to a method and apparatus that is limited to a determination of a single component and where a determination of multiple components may require multiple operations in succession.
- What is desired, therefore, is an improved detection system that determines a total concentration of a component from a mixture of components. What is also desired is a detection system having enhanced sensitivity and accuracy. A further desire is a detection system that efficiently and contemporaneously detects total concentrations of multiple components. A still further desire is a detection system that efficiently detects total concentrations of multiple components while reducing interference from undesired components.
- Accordingly, it is an object of the invention to provide a method and apparatus that determines a total concentration of a specified component in a mixture of components.
- Another object of the invention is to provide a method and apparatus that determines the total concentration and having improved sensitivity and accuracy.
- A further object of the invention is to provide a method and apparatus that efficiently and contemporaneously detects total concentrations of multiple components.
- Yet another object is to provide a detection system that achieves the above objects while reducing interference from undesired components.
- These and other objects of the invention are achieved by provision of a method and apparatus for determining a total concentration of a component in a sample, including a reactor for oxidizing or reducing the sample, a chromatographic column coupled to the reactor for separating the component in the sample, and an electrochemical gas sensor coupled to the chromatographic column for detecting the component.
- In further embodiments, the electrochemical gas sensor may also include a substrate having a surface for depositing electrodes thereon, an ionomer membrane in contact with the surface of the substrate and having a first surface and a second surface, an electrode in contact with the surface of the substrate, an opening extending from the first surface to the second surface in a location proximate to the electrode for defining a passage, and a gas in the opening and simultaneously contacting the electrode and the ionomer membrane for providing a three way contact between the gas, electrode, and ionomer membrane within the opening.
- In another embodiment of the invention, an apparatus for determining a total concentration of a desired component in a sample is provided, including a reactor for oxidizing or reducing the sample, a filter coupled to the reactor for filtering out undesirable components and for permitting the desired component to pass through, and a detector coupled to the filter for detecting the component.
- In a variation of this embodiment, the detector may be replaced with an electrochemical gas sensor or plurality of electrochemical gas sensors.
- In another embodiment of the invention, an apparatus for determining a total concentration of various components in a sample is provided, including a reactor for oxidizing or reducing the sample, a first electrochemical gas sensor coupled to the reactor and having an adjustment mechanism and wherein the adjustment mechanism is selectively adjustable to detect for the presence of a selected one of a plurality of components. A second electrochemical gas sensor is also coupled to the reactor and has an adjustment mechanism, wherein the adjustment mechanism is selectively adjustable to detect for the presence of a selected one of a plurality of components. In this embodiment, the sensors may simultaneously detect for the presence of two gas components in the sample. Additional sensors may permit simultaneous detection of multiple components
- In further embodiments, the apparatus may also include a filter coupled to the reactor for filtering out undesirable components and for permitting desirable components to pass through to the first and second electrochemical gas sensors.
- In another aspect, a method for determining a total concentration of a component in a sample is provided, including the steps of oxidizing or reducing the sample in a reactor, separating the component from the sample using a separation device, and coupling an electrochemical gas sensor to the separation device for detecting the component.
- The method may also include the step of separating the component from the sample using a gas chromatograph column.
- The electrochemical gas sensor may be provided in accordance with the steps of providing a substrate having a surface for depositing electrodes thereon, depositing an electrode on the surface, contacting an ionomer membrane with the electrode, providing an opening in the ionomer membrane in an approximate area of the electrode, extending the opening from a first surface of the ionomer membrane to a second surface of the ionomer membrane for defining a passage, and placing a gas in the opening and simultaneously contacting the gas with both the electrode and ionomer membrane within the opening.
- In a further aspect, the method may include coupling a plurality of electrochemical gas sensors to the separation device for detecting multiple components. In yet a further aspect, the method may include filtering out undesirable components and permitting desirable components to pass through.
- In another aspect of the invention, a method for determining a total concentration of a component in a sample is provided, including the steps of oxidizing or reducing the sample in a reactor, filtering out undesirable components and permitting a desirable component to pass through using a filter, and coupling a detector to the filter for detecting the desirable component. The detector may further be replaced with an electrochemical gas sensor to the filter for detecting the desirable component.
- The invention and its particular features and advantages will become more apparent from the following detailed description considered with reference to the accompanying drawings.
-
FIG. 1 depicts a thermal conductivity detector known in the prior art. -
FIG. 2 depicts an apparatus for determining a total concentration of a gas component in a gas mixture in accordance with the invention. -
FIG. 3 depicts one embodiment of the apparatus shown inFIG. 2 . -
FIG. 4 depicts another embodiment of the apparatus shown inFIG. 2 . -
FIG. 5 depicts another embodiment of the apparatus shown inFIG. 2 . -
FIG. 6 depicts another embodiment of the apparatus shown inFIG. 2 . -
FIG. 7 depicts a sensor for use with the apparatus shown inFIG. 2 . -
FIG. 8 depicts another sensor for use with the apparatus shown inFIG. 2 . -
FIG. 9 more particularly depicts an electrode to be used with the sensors ofFIGS. 7 and 8 . -
FIG. 10 depicts another sensor for use with the apparatus shown inFIG. 2 . -
FIG. 11 depicts a method for providing the apparatus shown inFIG. 2 . - In accordance with the invention,
FIG. 2 depicts theapparatus 50 for determining a total concentration of a component, whether in a gaseous or liquid state, in a mixture, or sample, of gases or liquids.Apparatus 50 further includesreactor 54 for oxidizing and/or reducing the mixture so that the desired component may be detected bysensor 66. Typically, a component desired to be detected bysensor 66, but which is not easily detectable, would be oxidized and/or reduced byreactor 54. As shown inFIG. 2 ,reactor 54 oxidizes/reduces a desirable component by heating the component together with areactant gas 56 at a specified temperature. - Although
apparatus 50 may be used with either a gas orliquid state mixture 58, ifmixture 58 is in the liquid state, the volume ofmixture 58 should be low enough such that, upon being heated insidereactor 54,mixture 58 converts into a gaseous state so that component, now in the gaseous state, may be detected bysensor 66. It is desired for theentire mixture 58 to convert to a gaseous state because any component remaining dissolved in a liquid state mixture may not be easily detected bysensor 66. Hence, in the event a volume ofliquid state mixture 58 may not convert entirely to a gaseous state insidereactor 54,vaporizer 72 is placed between the injector andreactor 54 becausereactant 56, if utilized to optionally facilitate oxidation and/or reduction, is a gas and may be mixed withmixture 58. In further embodiments,vaporizer 72 may be placed in any location wheremixture 58, in the liquid state, is to be converted to a gaseous state, such as betweenreactor 54 and gas chromatograph column (“GC”) 52 or betweenGC 52 andsensor 66. - In some embodiments where the desired components are easily detected, such as H2S in a gaseous state,
reactor 54 and/orvaporizer 72 may be omitted fromapparatus 50, which results inmixture 58 exiting the injector and directly enteringGC 52. In other embodiments, ifmixture 58 is a liquid,reactor 54 and/orvaporizer 72 would be needed to heatmixture 58 untilmixture 58 converts into a gaseous state prior to enteringGC 52. -
GC 52 acts as a separation device and is used to separate the mixture orsample 58 into its respective components. Upon exitingGC 52, the desirable component is ultimately detected by anelectrochemical gas sensor 66, which is coupled to an end ofGC 52 where the gas components are exitingGC 52. The combination ofsensor 66 being coupled toGC 52 provides asystem 50 for detecting a component having enhanced sensitivity and response time becausesensor 66 provides numerous advantages over conventional detector cells 10, as shown and described underFIG. 1 . -
Sensor 66 reduces the need for a component of the sample to be absorbed and dispersed in an electrolyte solution in order for an electrical measurement to be taken across electrodes in contact with the solution.Sensor 66 detects gas as the gas comes in contact with an electrode, thereby reducing response time and increasing sensitivity. Moreover, the resolution, or detection capability, ofsensor 66 is typically in the range of parts per billion, which is generally more sensitive than the conventional detector cell shown inFIG. 1 .Sensor 66 and its limitations are more particularly described underFIGS. 7-10 . - One embodiment of
apparatus 50 is to havesensor 66 directly coupled toGC 52. In further embodiments, a plurality of sensors may be directly coupled toGC 52. As shown inFIG. 3 ,sensors GC 52. It is understood thatapparatus 50′ ofFIG. 3 should not be limited to two sensors but may have any number of sensors and that two sensors are shown for exemplary purposes. -
Sensor 66′ has the same limitations assensor 66 and, to reduce repetition, onlysensor 66 will be described. - In the embodiment shown in
FIG. 3 ,apparatus 50′ is capable of simultaneously detecting two desired components due to having bothsensors Sensors FIGS. 7 and 8 ) of each sensor so that gases having an electrical signal that match the preset potential of the respective sensor are detected. -
FIG. 4 depicts another embodiment of the invention where, instead of couplingsensor 66 toGC 52,filter 62 is coupled toGC 52 for removing undesirable components frommixture 58. As described above,GC 52 merely separates components from one another where all components going intoGC 52exit GC 52 but exit in a particular order. Desirable and undesirable components exitGC 52 and, in some cases, undesirable components may interfere with the detection of desirable components. Therefore, filter 62 is used to enhance, or facilitate, detection of the desirable components by removing undesirable components.Filter 62 prevents particular components from passing through based on the chemical properties of the components. - Hence, filter 62 may filter out all water or other compounds from passing through to
detector 68. Examples offilter 62 that removes undesirable components include any membrane dryer or drying agents, such as Nafion or magnesium perchlorate.Filter 62 suppresses undesirable components by reducing its ability to interfere with the detection of desirable components. In a further example, H2S is difficult to detect with water present because water typically absorbs H2S. In other words, H2S dissolves in water and, therefore, water is typically an undesirable component of the mixture having H2S. With H2S being dissolved in or absorbed by water, proper detection of H2S is adversely affected and, hence, water lessens the likelihood of H2S being accurately detected by eitherdetector 68 orsensor 66. -
FIG. 5 depicts another embodiment of the invention where, instead ofdetector 68 shown inFIG. 3 ,sensor 66 is used to enhance detection capabilities to ppb over the limited detection capabilities ofdetector 68. - It should be known that in further embodiments,
GC 52 may be omitted when separation of the components of the gas mixture are not needed to detect the desirable component, particularly where it is likely the desired components are not dispersed throughout the gas mixture. For example, if detection of H2S is desired and the remaining components of the gas mixture do not have any hydrogen or sulfur,GC 52 may not be needed because there would not be any hydrogen or sulfur to separate. -
FIG. 6 depicts a further embodiment of the invention shown inFIG. 5 , wheremultiple filters sensors filter 62′ includes all of the limitations offilter 62, and to reduce repetition, filter 62 will be described hereinafter. As shown,sensors sensors -
Filters Filters respective sensor -
FIG. 7 shows an electrochemical gas sensor of copending U.S. patent application Ser. No. 09/443,875, which may, but not necessarily, be used assensor 66. As shown,electrochemical gas sensor 92 includes substrate 111,electrode 103, andionomer membrane 105. Gas enters and exitssensor 92 through the inlet and outlet as shown. A portion of thegas entering sensor 92 diffuses throughdiffusion hole 120 and contacts electrode 103, which detects the type of gas present insensor 66. As stated above, for the purposes of simplicity,sensor 66′ will not be described but is understood to include the limitations ofsensor 66. - To enhance sensitivity to
sensor 92, areservoir 109 is provided containing electrolyte solution towet ionomer membrane 105. As shown,reservoir 109 and, therefore, the electrolyte solution is in contact withionomer membrane 105. Becausereservoir 109 is located on a same side ofionomer membrane 105 asdiffusion hole 120, a length of diffusion hole is typically at least as long as a height ofreservoir 109. -
FIG. 8 depicts anotherelectrochemical gas sensor 94, which may, but not necessarily, be used assensor 66.Sensor 94 includessubstrate 132,ionomer membrane 134, andelectrode 138. Gas enterssensor 94 throughinlet 142 and is detected after diffusing throughdiffusion hole 144 to contactelectrode 138, which is in contact withionomer membrane 134. Gas exitssensor 94 throughoutlet 146. It is understood that the gas may flow in a reversed direction whereoutlet 146 is the inlet andinlet 142 is the outlet. - To enhance the sensitivity of
sensor 94,ionomer membrane 134 is wetted by solution 152, which is contained inreservoir 156. InFIG. 7 , electrolyte solution andreservoir 109 were placed on the same side of substrate 111 aselectrode 103. Although the electrolyte solution wettedionomer membrane 105 to enhance the sensitivity ofsensor 92 in the same manner as solution 152 enhances the sensitivity ofsensor 94,reservoir 109 being on the same side of substrate 111 inhibits a length L ofdiffusion hole 120 from being reduced, which would reduce gas diffusion time and thereby improve sensor sensitivity. As shown inFIG. 7 , length L could not be shortened more than height H ofreservoir 109. Therefore, time required for gas to diffuse from the inlet throughdiffusion hole 120 to contactelectrode 103 was difficult to reduce due to the length L of diffusion hole being of a minimum dimension not less than the height H ofreservoir 109. -
Sensor 94 ofFIG. 8 overcomes this disadvantage by wettingionomer membrane 134, viahole 136 insubstrate 132, with solution 152 located on a side ofsubstrate 132 opposite fromelectrode 138. Because of the position ofreservoir 156, length L′ can be shortened, thereby reducing gas diffusion time and improving the sensitivity ofsensor 94. The more length L′ is reduced, the faster the response time ofsensor 94. In some embodiments, length L′ is less than 1.4 mm. In other embodiments, length L′ is less than 1 mm. In further, embodiments, length L′ is less than 0.5 mm. In still further embodiments, length L′ is less than 0.1 mm. In fact, length L′ or a thickness ofionomer membrane 134 may be reduced until it is flush with or below a surface ofelectrode 138. In some embodiments,diffusion hole 144 is eliminated because length L′ is flush with or below a surface ofelectrode 138. All that is required is forionomer membrane 134, of any length L′, to be in contact withelectrode 138 so that gas entering throughinlet 142 provide a desired gas/ionomer membrane/electrode interface. - As a result of the reduced length L′ of
sensor 94, the response time ofsensor 94 is less than approximately 2 seconds, more preferably less than approximately 1 second, and most preferably less than approximately 0.5 seconds. In some embodiments, the response time is less than approximately 0.1 seconds. - To further enhance sensitivity, a thickness of
substrate 132 is reduced to improve wetting by solution 152.Substrate 132 is of an electrically non-conductive material for providing a surface upon which electrode 138 is placed. Optionally,substrate 132 is a thin foil having insulative, or electrically non-conductive, properties, such as Kapton or any other material. The foil is not metallic or conductive. The foil may also be flexible as compared to ceramic or glass. The thickness of the foil, orsubstrate 132, is generally less than approximately 4 mils and preferably less than approximately 1 mil. Thethinner substrate 132, thefaster ionomer membrane 134 is wetted and this positively affects sensor response time. Therefore, as the thickness ofsubstrate 132 approaches 0 mils, the response time is further reduced. - Optionally, in some embodiments,
sensor 94 may include wickingmaterial 154 to facilitate or enhance wetting ofionomer membrane 134 by solution 152.Wicking material 154 is typically of a material that absorbs liquid, such as a sponge. Hence, as shown inFIG. 8 , wickingmaterial 154 will draw solution 152 upwardly fromreservoir 156 towardionomer membrane 134. - As shown,
reservoir 156 andsubstrate 132 are separable from one another wherewicking material 154 is placed betweenreservoir 156 andsubstrate 132. In other embodiments, wicking material is placed withinreservoir 156 and reservoir comes in contact withsubstrate 132. In further embodiments,substrate 132 andreservoir 156 are made not separable from one another but are formed as one unit.Wicking material 154 may optionally be used with any of these embodiments ofreservoir 156 andsubstrate 132. - As shown in
FIG. 8 ,substrate 132 further includes at least onehole 136 extending from afirst surface 162 ofsubstrate 132 to asecond surface 164 ofsubstrate 132, thereby forming a thru-hole, for permitting solution 152 to pass, or diffuse, through at least onehole 136 to contactionomer membrane 134. In the embodiments wheresubstrate 132 is a foil, or a thin non-conductive material, wickingmaterial 154 would be positioned in a closer relationship toionomer membrane 134 than wheresubstrate 132 is of a thick material. Wheresubstrate 132 is a foil, solution 152 absorbed by wickingmaterial 154 would more easilywet ionomer membrane 134. Optionally, wickingmaterial 154 would be in contact, through at least onehole 136, withionomer membrane 134. In some embodiments, wickingmaterial 54, in addition to or instead of being betweensubstrate 132 and solution 152, is placed within at least onehole 136. - To further facilitate wetting of
ionomer membrane 134 by solution 152, oroptional wicking material 154, a plurality ofholes 136 are placed insubstrate 132. It is understood thathole 136 is of any diameter, length, shape, or dimension. Also, themore holes 136 insubstrate 132, in any location, thebetter ionomer membrane 134 is wetted. Hence, thehole 136 or plurality ofholes 136 may act as a form of wetting control toionomer membrane 134, as too much wetting or too little wetting negatively affects sensitivity. Moreover,hole 136 may be, in addition or instead of being round, a square shaped or polygonal shaped hole.Hole 136 may further be a slit or aperture of any kind. All that is required ofhole 136 is that it provides a passage fromfirst surface 162 tosecond surface 164 so that solution 152 diffuses throughhole 136 to contactionomer membrane 134. -
FIG. 9 depicts an exploded view of the electrode shown inFIGS. 7 and 8 . As shown, to enhance sensitivity ofsensor thin film 234 of electrolytic material, which may be the same material as the ionomer membranes ofFIGS. 7 and 8 , may optionally be placed onelectrode ionomer membrane electrode electrode film 234, which is in contact with the surface ofelectrode film 234 whenfilm 234 has a minimal thickness. Hence, thethinner film 234 is, the faster the response time is forsensor - Without
film 234, the interface in the approximate area ofelectrode ionomer membrane electrode electrode - In some embodiments,
film 234 has a thickness less than 2 micrometers. Ideally,film 234 should be as thin as possible to maximize sensor response time and sensitivity. Hence,sensor film 234 having a thickness of less than 1 micrometer. A film having such reduced thickness permits faster gas diffusion and, thus, faster response times.Film 234 is an electrolytic medium, which includes all the limitations ofionomer membrane ionomer membrane -
Film 234 is in a solid state because it has more structural integrity than liquid state electrolyte, thereby permitting a consistently uniform thickness overelectrode electrode - Optionally, the response time of
sensor sensor sensor sensor sensor - Optionally, as shown in
FIGS. 8 and 9 ,sensor 94 may also includecover 150 onionomer membrane 134 for minimizing the vaporization or evaporation of electrolyte solution 152 as solution 152 is absorbed and passed upwardly throughionomer membrane 134. Cover 150 is in contact with the surface ofionomer membrane 134 opposite fromsubstrate 132. Cover 150 does not block any portion of eitherdiffusion hole 144 orelectrode 138 because doing so would hinder gas detection and negatively affect sensor sensitivity. Cover 150 is not needed forsensor 66 to operate properly and may be eliminated in its entirety. For embodiments wheresensor 94 includescover 150, it is understood that the length L′ of the diffusion path is the height of bothionomer membrane 134 andcover 150. For embodiments wheresensor 94 does not includecover 150, length L′ is the height ofmembrane 134. -
FIG. 10 depicts anotherelectrochemical gas sensor 96, which may, but not necessarily, be used assensor 66. As shown,sensor 96 includessensing electrode 202,counter electrode 204, andreference electrode 206. -
Optionally sensor 96 includesfilter 209 betweencounter electrode 204 andreference electrode 206 for wetting these electrodes. Further,filter 208 may be placed betweensensing electrode 202 andreference electrode 206 for wetting these electrodes.Filter 208 includes the same limitations asfilter 209. -
Sensor 96 further includesgas inlet 212 for permitting gas to entersensor 96 for detection upon reaction withionomer membrane 216 andsensing electrode 202. - To draw electrolyte up from
reservoir 222,wick 220 is in contact with the electrolyte solution inreservoir 222 andfilter 208, which in turn is in contact withreference electrode 206, anotherfilter 208, andsensing electrode 202. - Optionally, platinum contact strips may be placed in select areas of
sensor 96 to enhance sensitivity and conductivity. A platinum strip may be placed betweenmembrane 216 andsensing electrode 202, betweenreference electrode 206 andfilter 208, betweenfilter 209 andcounter electrode 204, or all of the above. -
FIG. 11 depicts amethod 300 for determining a total concentration of a component in a gas sample.Method 300 includes injecting 301 the sample into a reactor, oxidizing or reducing 303 the sample in a reactor and separating 304 the desirable gas component to be detected from the gas sample using a separation device, which may be a GC or other device for separating the desirable component(s) from the remainder of the gas sample.Method 300 also includes detecting 306 the desirable component(s) using a detection device, such as known or novel detectors and/or sensors. - If the sample is of a quantity that may be difficult to convert to a gaseous state, such as a sample greater than 1 ml,
method 300 may optionally include the step of vaporizing 302 the sample (in a vaporizer) until it is converted to a gaseous state. For smaller quantities of liquid, the vaporizer may be omitted because the reactor, used for oxidizing or reducing 303 the sample, may also suffice in converting the sample in a liquid state to a gaseous state. - In further embodiments,
method 300 may also include the step ofcoupling 308 at least one electrochemical gas sensor to the separation device for detecting 306 the component. In some of these further embodiments,method 300 may also include the step of providing a substrate having a surface, depositing an electrode on the surface, contacting an ionomer membrane with the electrode, providing an opening in the ionomer membrane in an approximate area of the electrode, introducing a gas into the opening toward the electrode, and simultaneously contacting the gas with both the electrode and ionomer membrane. - Moreover,
method 300 may also include the step of filtering 310 out undesirable components and permitting desirable components to pass through to the detection step. - Although the invention has been described with reference to a particular arrangement of parts, features and the like, these are not intended to exhaust all possible arrangements or features, and indeed many other modifications and variations will be ascertainable to those of skill in the art.
Claims (18)
1. An apparatus for determining a total concentration of a desired component in a sample, comprising:
a reactor for oxidizing or reducing the sample;
a gas chromatograph column coupled to said reactor for separating the component in the sample;
at least two chemical filters coupled to said reactor, each chemical filter for filtering out a different undesirable component and for permitting the desired component to pass through based upon chemical properties of the undesirable and desirable components; and
a detector directly coupled to each of said at least two filters for detecting the desired component.
2. The apparatus according to claim 1 , wherein said detector is a plurality of electrochemical sensors for detecting multiple components.
3. The apparatus according to claim 1 , further comprising a chromatographic column positioned between said reactor and said filter for separating the component in the sample.
4. The apparatus according to claim 1 , wherein said at least two filters are arranged in parallel to one another.
5. The apparatus according to claim 1 , wherein said at least two filters permit the desired component to pass through.
6. The apparatus according to claim 2 , wherein said plurality of electrochemical sensors have a mechanism to adjust the sensors.
7. The apparatus according to claim 6 , wherein said the adjustment mechanism on said electrochemical sensors is selectively adjustable to detect for the presence of a selected one of a plurality of components.
8. The apparatus according to claim 7 , wherein plurality of electrochemical sensors simultaneously detect for the presence of gas components in the sample.
9. A method for determining a total concentration of a component in a sample, comprising the steps of:
oxidizing or reducing the sample in a reactor;
using a first chemical filter for filtering out a first undesirable component and permitting a desirable component to pass through based upon chemical properties of the undesirable and desirable components;
using a second chemical filter for filtering out a second undesirable component and permitting a desirable component to pass through based upon chemical properties of the undesirable and desirable components; and
directly coupling a detector to each filter for detecting the desirable component.
10. The method according to claim 9 , further comprising the step of separating the sample into its respective components.
11. The method according to claim 9 , further comprising the step of arranging the at least two filters in parallel with one another.
12. The method according to claim 9 , further comprising the step of separating the component from the sample using at least one electrochemical gas sensor.
13. The method according to claim 9 , further comprising the step of coupling a plurality of electrochemical gas sensors to the separating device for detecting multiple components.
14. The method according to claim 9 , further comprising the step of using a gas chromatograph column for filtering out undesirable components
15. An apparatus for determining a total concentration of various components in a sample, comprising:
a reactor for oxidizing or reducing the sample;
a first electrochemical gas sensor coupled to said reactor and having an adjustment mechanism, wherein said adjustment mechanism is selectively adjustable to detect for the presence of a selected one of a plurality of components; and
a second electrochemical gas sensor coupled to said reactor and having an adjustment mechanism, wherein said adjustment mechanism is selectively adjustable to detect for the presence of a selected one of a plurality of components.
16. The apparatus according to claim 15 , wherein each of said first and second electrochemical gas sensors further comprises a substrate having a surface for depositing electrodes thereon; an ionomer membrane in contact with said surface of said substrate and having a first surface and a second surface; an electrode in contact with said surface of said substrate; an opening extending from said first surface to said second surface in a location proximate to said electrode for defining a passage; and a gas in said opening and simultaneously contacting said electrode and said ionomer membrane for providing a three way contact between said gas, electrode, and ionomer membrane within said opening.
17. The apparatus according to claim 15 , further comprising a plurality of electrochemical gas sensors coupled to said reactor and each of said plurality of electrochemical gas sensors having a respective adjustment mechanism for detecting each of the various components.
18. The apparatus according to claim 15 , further comprising a filter coupled to said reactor for filtering out undesirable components and for permitting desirable components to pass through to said first and second electrochemical gas sensors.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/173,552 US20080274561A1 (en) | 2003-09-30 | 2008-07-15 | Method and apparatus for determining a total concentration of a component in a mixture of components |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/675,629 US7410558B2 (en) | 2003-09-30 | 2003-09-30 | Method and apparatus for determining a total concentration of a component in a mixture of components |
US12/173,552 US20080274561A1 (en) | 2003-09-30 | 2008-07-15 | Method and apparatus for determining a total concentration of a component in a mixture of components |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/675,629 Division US7410558B2 (en) | 2003-09-30 | 2003-09-30 | Method and apparatus for determining a total concentration of a component in a mixture of components |
Publications (1)
Publication Number | Publication Date |
---|---|
US20080274561A1 true US20080274561A1 (en) | 2008-11-06 |
Family
ID=34377211
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/675,629 Expired - Fee Related US7410558B2 (en) | 2003-09-30 | 2003-09-30 | Method and apparatus for determining a total concentration of a component in a mixture of components |
US12/173,552 Abandoned US20080274561A1 (en) | 2003-09-30 | 2008-07-15 | Method and apparatus for determining a total concentration of a component in a mixture of components |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/675,629 Expired - Fee Related US7410558B2 (en) | 2003-09-30 | 2003-09-30 | Method and apparatus for determining a total concentration of a component in a mixture of components |
Country Status (3)
Country | Link |
---|---|
US (2) | US7410558B2 (en) |
EP (1) | EP1673621A2 (en) |
WO (1) | WO2005033693A2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN107727774A (en) * | 2017-11-28 | 2018-02-23 | 中国科学院电子学研究所 | More sensing chromatogram detectors and detection method |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AT502949A1 (en) * | 2005-08-22 | 2007-06-15 | Allg Unfallversicherungsanstal | METHOD AND DEVICE FOR DETERMINING THE INGREDIENTS OF LUBRICANTS EMITTED IN THE ATMOSPHERE OF COOLING LIQUIDS |
Citations (23)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3725009A (en) * | 1968-06-24 | 1973-04-03 | J Lovelock | Detection of trace gases utilizing an electron capture detector |
US3847546A (en) * | 1972-10-04 | 1974-11-12 | Chromalytics Corp | Method and system for thermal analysis |
US4293308A (en) * | 1978-10-13 | 1981-10-06 | Carlo Erba Strumentazione S.P.A. | Method and apparatus for the analysis of sulphur contents in samples |
US4464925A (en) * | 1982-05-17 | 1984-08-14 | Hewlett-Packard Company | Hydrogen, deuterium thermal conductivity detector |
US4594879A (en) * | 1982-10-28 | 1986-06-17 | Yokogawa Hokushin Electric Corporation | Thermal conductivity detector |
US4663113A (en) * | 1983-06-20 | 1987-05-05 | Research Corporation | Reactor radioactive emission monitor |
US4668635A (en) * | 1984-04-04 | 1987-05-26 | Cerberus Ag | Method of detecting reative gases in a gas mixture |
US4820386A (en) * | 1988-02-03 | 1989-04-11 | Giner, Inc. | Diffusion-type sensor cell containing sensing and counter electrodes in intimate contact with the same side of a proton-conducting membrane and method of use |
US4843016A (en) * | 1974-10-07 | 1989-06-27 | Thermedics Inc. | Detection system and method |
US4888295A (en) * | 1984-03-02 | 1989-12-19 | The United States Of America As Represented By The United States Department Of Energy | Portable system and method combining chromatography and array of electrochemical sensors |
US4914037A (en) * | 1987-02-27 | 1990-04-03 | Shell Oil Company | Method and apparatus for analysis of a sample for nitrogen |
US5073502A (en) * | 1990-06-27 | 1991-12-17 | United Technologies Corporation | Method and apparatus for analyzing total organic halogens |
US5152963A (en) * | 1986-08-04 | 1992-10-06 | Wreyford Donald M | Total sulfur analyzer system operative on sulfur/nitrogen mixtures |
US5268302A (en) * | 1990-05-29 | 1993-12-07 | Thermedics Inc. | Selective, high speed detection of vapors with analysis of multiple GC-separated portions |
US5295389A (en) * | 1991-08-21 | 1994-03-22 | Yamatake-Honeywell Co., Ltd. | Thermal conductivity detector |
US5379630A (en) * | 1993-06-28 | 1995-01-10 | Hewlett-Packard Company | Thermal conductivity detector |
US5612225A (en) * | 1992-08-31 | 1997-03-18 | Fisons Instruments S.P.A. | Process and apparatus for determining total nitrogen content by elemental analysis |
US5637506A (en) * | 1994-11-10 | 1997-06-10 | Minnesota Mining And Manufacturing Company | Solid phase extraction using composite sheet for direct measurement of radioactivity |
US6458328B1 (en) * | 1999-03-05 | 2002-10-01 | Antek Instruments, L.P. | Staged oxidation chamber for enhanced nitrogen and sulfur detection |
US20030106811A1 (en) * | 1999-11-19 | 2003-06-12 | Prohaska Otto J. | Electrochemical sensor having improved response time |
US6592817B1 (en) * | 2000-03-31 | 2003-07-15 | Applied Materials, Inc. | Monitoring an effluent from a chamber |
US20030164312A1 (en) * | 1999-11-19 | 2003-09-04 | Prohaska Otto J. | Method and apparatus for enhanced detection of a specie using a gas chromatograph |
US6830730B2 (en) * | 2001-09-11 | 2004-12-14 | Spectrolanalytical Instruments | Method and apparatus for the on-stream analysis of total sulfur and/or nitrogen in petroleum products |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4818348A (en) * | 1987-05-26 | 1989-04-04 | Transducer Research, Inc. | Method and apparatus for identifying and quantifying simple and complex chemicals |
US6682638B1 (en) * | 1999-11-19 | 2004-01-27 | Perkin Elmer Llc | Film type solid polymer ionomer sensor and sensor cell |
DE10034879C2 (en) * | 2000-07-18 | 2002-06-06 | Siemens Ag | Arrangement for total sulfur determination |
-
2003
- 2003-09-30 US US10/675,629 patent/US7410558B2/en not_active Expired - Fee Related
-
2004
- 2004-09-30 EP EP04789507A patent/EP1673621A2/en not_active Withdrawn
- 2004-09-30 WO PCT/US2004/032564 patent/WO2005033693A2/en active Application Filing
-
2008
- 2008-07-15 US US12/173,552 patent/US20080274561A1/en not_active Abandoned
Patent Citations (24)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3725009A (en) * | 1968-06-24 | 1973-04-03 | J Lovelock | Detection of trace gases utilizing an electron capture detector |
US3847546A (en) * | 1972-10-04 | 1974-11-12 | Chromalytics Corp | Method and system for thermal analysis |
US4843016A (en) * | 1974-10-07 | 1989-06-27 | Thermedics Inc. | Detection system and method |
US4293308A (en) * | 1978-10-13 | 1981-10-06 | Carlo Erba Strumentazione S.P.A. | Method and apparatus for the analysis of sulphur contents in samples |
US4464925A (en) * | 1982-05-17 | 1984-08-14 | Hewlett-Packard Company | Hydrogen, deuterium thermal conductivity detector |
US4594879A (en) * | 1982-10-28 | 1986-06-17 | Yokogawa Hokushin Electric Corporation | Thermal conductivity detector |
US4663113A (en) * | 1983-06-20 | 1987-05-05 | Research Corporation | Reactor radioactive emission monitor |
US4888295A (en) * | 1984-03-02 | 1989-12-19 | The United States Of America As Represented By The United States Department Of Energy | Portable system and method combining chromatography and array of electrochemical sensors |
US4668635A (en) * | 1984-04-04 | 1987-05-26 | Cerberus Ag | Method of detecting reative gases in a gas mixture |
US5152963A (en) * | 1986-08-04 | 1992-10-06 | Wreyford Donald M | Total sulfur analyzer system operative on sulfur/nitrogen mixtures |
US4914037A (en) * | 1987-02-27 | 1990-04-03 | Shell Oil Company | Method and apparatus for analysis of a sample for nitrogen |
US4820386A (en) * | 1988-02-03 | 1989-04-11 | Giner, Inc. | Diffusion-type sensor cell containing sensing and counter electrodes in intimate contact with the same side of a proton-conducting membrane and method of use |
US5268302A (en) * | 1990-05-29 | 1993-12-07 | Thermedics Inc. | Selective, high speed detection of vapors with analysis of multiple GC-separated portions |
US5073502A (en) * | 1990-06-27 | 1991-12-17 | United Technologies Corporation | Method and apparatus for analyzing total organic halogens |
US5295389A (en) * | 1991-08-21 | 1994-03-22 | Yamatake-Honeywell Co., Ltd. | Thermal conductivity detector |
US5612225A (en) * | 1992-08-31 | 1997-03-18 | Fisons Instruments S.P.A. | Process and apparatus for determining total nitrogen content by elemental analysis |
US5379630A (en) * | 1993-06-28 | 1995-01-10 | Hewlett-Packard Company | Thermal conductivity detector |
US5637506A (en) * | 1994-11-10 | 1997-06-10 | Minnesota Mining And Manufacturing Company | Solid phase extraction using composite sheet for direct measurement of radioactivity |
US6458328B1 (en) * | 1999-03-05 | 2002-10-01 | Antek Instruments, L.P. | Staged oxidation chamber for enhanced nitrogen and sulfur detection |
US20030106811A1 (en) * | 1999-11-19 | 2003-06-12 | Prohaska Otto J. | Electrochemical sensor having improved response time |
US20030164312A1 (en) * | 1999-11-19 | 2003-09-04 | Prohaska Otto J. | Method and apparatus for enhanced detection of a specie using a gas chromatograph |
US7013707B2 (en) * | 1999-11-19 | 2006-03-21 | Perkinelmer Las, Inc | Method and apparatus for enhanced detection of a specie using a gas chromatograph |
US6592817B1 (en) * | 2000-03-31 | 2003-07-15 | Applied Materials, Inc. | Monitoring an effluent from a chamber |
US6830730B2 (en) * | 2001-09-11 | 2004-12-14 | Spectrolanalytical Instruments | Method and apparatus for the on-stream analysis of total sulfur and/or nitrogen in petroleum products |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN107727774A (en) * | 2017-11-28 | 2018-02-23 | 中国科学院电子学研究所 | More sensing chromatogram detectors and detection method |
Also Published As
Publication number | Publication date |
---|---|
US20050069456A1 (en) | 2005-03-31 |
EP1673621A2 (en) | 2006-06-28 |
WO2005033693A2 (en) | 2005-04-14 |
WO2005033693A3 (en) | 2006-01-12 |
US7410558B2 (en) | 2008-08-12 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7237430B2 (en) | Method and apparatus for enhanced detection of a specie using a gas chromatograph | |
US4227984A (en) | Potentiostated, three-electrode, solid polymer electrolyte (SPE) gas sensor having highly invariant background current characteristics with temperature during zero-air operation | |
US4790925A (en) | Electrochemical gas sensor | |
US3223597A (en) | Method and means for oxygen analysis of gases | |
US4073698A (en) | Method and device for the detection and measurement of carbon monoxide in the presence of hydrogen | |
US5759368A (en) | Electrochemical gas sensor | |
USRE31915E (en) | Gas detecting and measuring device | |
US5683570A (en) | Gas detection method | |
US20060000723A1 (en) | Electrochemical sensor having improved response time | |
US5085760A (en) | Electrochemical gas sensors | |
US20080274561A1 (en) | Method and apparatus for determining a total concentration of a component in a mixture of components | |
CA2240147C (en) | A method and apparatus for measuring ethanol vapour concentration | |
US20060237333A1 (en) | Method for the detection of carbon monoxide in a hydrogen-rich gas stream | |
JP2009128177A (en) | Gas analyzer and fuel cell | |
CA2051255A1 (en) | Process and apparatus for the electrochemical determination of oxygen in a hemogasanalyzer | |
JP2954174B1 (en) | Constant potential electrolytic gas sensor | |
JP3912202B2 (en) | Gas chromatograph analysis system | |
EP0059636A1 (en) | Apparatus for determining the presence of combustible constituents in a mixture | |
KR960005363B1 (en) | Electrochemical gas sensor | |
CA1150770A (en) | Method and device for the detection of hydrazine | |
RU218460U1 (en) | Electrochemical gas and vapor detector | |
US20230358703A1 (en) | Electrochemical sensor including a measuring cell and an oxidation component and process using such a sensor | |
JPH02240538A (en) | Analysis apparatus for ozone in solution | |
RU69641U1 (en) | DEVICE FOR ANALYSIS OF THE CONTENT OF CARBON MONOXIDE IN THE AIR | |
JPH0697226B2 (en) | Gas chromatograph |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |