Abstract: A method and apparatus for measuring the concentration of at least one gaseous component and/or vaporous component of a gaseous mixture in which a controlled sensor flame is introduced into the gaseous mixture and at least one narrow spectral band in the controlled sensor flame is optically measured. The concentration of the gaseous component using a result obtained from the optical measuring of the at least one narrow spectral band is then calculated. The method of this invention is particularly suitable for substantially real-time control of combustion processes.

Abstract: A method and apparatus according to the present invention monitors an emission gas, such as a carbon monoxide gas, from an emission source, such as a carbon monoxide source, by periodically sensing a concentration level of emission gas, such as carbon monoxide, in ambient air and generating a signal corresponding to the sensed concentration level of the emission gas. In response to the signal, a percent blood concentration value of the emission gas is determined. The calculated blood concentration value is compared to a threshold value, and if greater than the threshold value, the source of emission gas, such as carbon monoxide gas, is disabled. The blood concentration value can be determined on a predetermined time interval, and at least in part, can be based on a prior blood concentration value in combination with a current blood concentration value.

Abstract: The present invention provides an apparatus and method for determining the concentration of CO gas in a fuel reformate stream such as in a PEM fuel cell vehicle. This invention protects the fuel cell catalyst by controlling the reformate stream system to minimize the CO and reduce it by a novel catalyst system that selectively converts CO to methane but does not react with carbon dioxide and hydrogen. The catalyst may reduce the CO to methane by reaction with hydrogen. The preferred embodiment both monitors the CO by a thermal differential sensing means and an optical biomimetic sensor and or a conductivity sensor. These sensors respond to the CO gas and are monitored by one or more monitoring sensors such as the temperature and or conductivity difference between the control and the catalytic material such as nickel and in the biomimetic sensor an optical change is monitored.

Abstract: A testing elements for the calorimetric determination of oxidizable gas and/or vapor components in gas mixtures is provided. The testing element contains, besides usual oxidizing agents, at least one redox indicator, which is in the oxidized form. The redox indicator is preferably a benzidine derivative according to the general formula in which the radicals R are identical or different and denote a hydrogen, alkyl, aryl, halogen, trifluoromethyl, cyano, nitro, dialkylamino, ester, sulfoxyl ester, alkyloxy or aryloxy, X denotes a halogen, Y denotes a trifluoromethyl, cyano, nitro, dialkylamino, ester, sulfoxyl ester, alkyloxy or aryloxy, n is an integer from zero to three, and m equals 5−n. The testing elements are preferably designed as detector tubes that contain carrier materials, to which the oxidizing reagents and redox indicators are applied.

Abstract: An optical sensor is described for determining the concentration of a gas in gas mixtures, which can especially be used for determining the carbon monoxide content of the air. It includes a radiation source, a sensitive layer positioned on a translucent substrate, and a detector. The sensitive layer of the sensor contains a transition metal compound which forms a transition metal complex with the gas to be determined.

Abstract: An ultratrace detector system for hand-held gas chromatography having high sensitivity, for example, to emissions generated during production of weapons, biological compounds, drugs, etc. The detector system is insensitive to water, air, helium, argon, oxygen, and CO2. The detector system is basically composed of a hand-held capillary gas chromatography (GC), an insulated heated redox-chamber, a detection chamber, and a vapor trap. For example, the detector system may use gas phase redox reactions and spectral absorption of mercury vapor. The gas chromatograph initially separates compounds that percolate through a bed of heated mercuric oxide (HgO) in a silica—or other metal—aerogel material which acts as an insulator.

Abstract: An apparatus adapted for analyzing exhaust emissions by using a small fraction of a continuously-extracted exhaust sample combined with a pollutant-free diluent through a system of critical flow orifices at a predetermined and precisely controlled flow ratio. A small quantity of gas is extracted from the diluted exhaust gas available which is diluted with the contaminant-free air or nitrogen to produce a mixture having a dew point below ambient air temperature and satisfying the flow requirements of the analysis system. The diluted sample may then be analyzed to obtain the total mass of pollutants through identification of the instantaneous exhaust concentration rate and the exhaust mass flow rate or through identification of the concentration of pollutants collected in a sample bag and the total exhaust volume.

Abstract: A method and apparatus is provided for modulating the flux of oxygen impinging on a calorimetric gas sensor. The method and apparatus are based on modulating the oxygen concentration of a gas mixture presented to the microcalorimeter between a predetermined high level and at a substantially zero value to create a modulated output to reduce the noise of the sensor and to eliminate its zero-offset.

Abstract: The concentration of a target gas is determined in an optical gas sensor system having an array of optical gas sensors wherein each sensor has a different sensitivity range for a target gas. An active sensor is selected from the array of optical gas sensors by determining which sensor has an optical transmittance value between 0% and 100%. Optical transmittance values of the active sensor are differentiated with respect to time. Concentration of the target gas is calculated as a function of both the rate of change of optical transmittance and the value of the optical transmittance at the beginning of the period over which the transmittance is differentiated. When a hazardous gas such as carbon monoxide is the target gas an alarm can be given when a threshold concentration is exceeded. Preferably, the transmittance values are converted to digital signals and processed in an eight-bit microprocessor to determine target gas concentration.

Abstract: The present invention discloses a method for improving the speed and sensitivity of optical spectroscopic techniques for remote detection of trace chemical species in a carrier gas. The disclosed method can be applied to any optical spectroscopic detection technique whose sensitivity decreases as the total pressure of the sample decreases. The method employs an inert and non-absorbing buffer gas to supplement the pressure exerted by the carrier gas. This ensures that the total pressure of the sample, and hence sensitivity of the detection technique, remains high. The method is especially useful when measuring concentration of chemical species produced at small rates, and therefore should prove useful for rapid serial screening of combinatorial libraries of compounds.

Abstract: The selectivity of response of resistive gas sensors to specific gases or vapors is improved by the selection of specified gas-sensitive materials which are not previously known for the applications described, which include detection of hydrocarbons in the presence of CO, H.sub.2 S, SO.sub.2, chlorine, NO.sub.2, CO.sub.2 (especially in low concentrations), CFC's, ammonia, free oxygen by determination of partial pressures, and numerous organic gases and vapors.

Abstract: A carbon monoxide sensor including a gas detecting portion and at least a pair of electrodes, wherein the gas detecting portion includes a metal oxide represented by a following formula;Cu.sub.1-x Bi.sub.x O.sub.y(0<x<1 and 1<y<1.5).

Abstract: A solid object carrying a catalyzer thereon is placed in a closed reaction chamber into which test gases are supplied and is heated up to a temperature of 1000.degree. C. Adsorbates are formed on the surface of the solid object under the test gas flow in the closed reaction chamber. Infrared radiations radiated from the adsorbates are emitted through an infrared-transmissive window hermetically formed on a wall of the closed reaction chamber, and are analyzed by an infrared radiation spectrometer and observed by a microscope. The infrared-transmissive window is cooled down by a cooling device attached thereto so that the temperature of the window does not exceed a certain level, e.g., 200.degree. C. Thus, the adsorbates formed on the solid object can be detected and analyzed under conditions where the test gas is actually flowing and the temperature of the solid object is elevated up to a high level.

Abstract: The invention relates to a method and apparatus for determining the concentration of at least carbon dioxide in a gas mixture on the basis of the absorption of infrared radiation (2), said apparatus comprising: a radiation source (1), the radiation emitted thereby being aligned to travel through a measuring cell (4) containing a gas mixture (6) to be analyzed; an optical band-pass filter (10), which is transmissive to a first wavelength band and positioned on the path of radiation emerging from the measuring cell or entering into the measuring cell through which the radiation passes; and a first detector (14), positioned in the radiating direction downstream of said first band-pass filter and used for detecting the radiation intensity falling thereon. Said optical band-pass filter (10) has a band-pass which lies within the wavelength range of 4.38 .mu.m-4.47 .mu.m for measuring the total concentration of carbon dioxide by means of the absorption spectrum of a molecule .sup.13 CO.sub.

Abstract: Novel sensor devices composed of a crystalline colloidal array (CCA) polymerized in a hydrogel are disclosed. The hydrogels are characterized as being capable of shrinking and swelling in response to specific stimuli applied thereto. As the hydrogels shrink or swell, the lattice structure of the CCA embedded therein changes, thereby changing the wavelength of light diffracted by the CCA. Thus by monitoring the change in diffracted wavelength, the concentration of a stimulus is determined. The gels can be modified to sense numerous different stimuli. The sensor devices are specific in that they are modified to react with only one species or family of species. These sensors have various applications in areas including, for example, environmental and chemical systems, chemomechanical systems, sensor devices and medical diagnostic tools. Various methods for making and using these devices are also disclosed.

Abstract: The invention is directed to a method for determining the portion of a gaseous or vaporous component in a gas mixture utilizing a detecting substance which can enter into a chemical reaction with the component to produce a coloration of the detecting substance and utilizing a device for evaluating the coloration. The method includes the steps of: passing the gas mixture at a constant volume flow through a channel containing the detecting substance; detecting a reflectance signal I(t) within a defined spatially fixed length segment of the channel; determining a slope .DELTA.I/.DELTA.t at the start of the chemical reaction during a time interval .DELTA.t in which the detecting substance is present in excess; determining a saturation reflectance signal I.sup.100% toward the end of the chemical reaction which corresponds to an almost complete chemical conversion of the detecting substance within the length segment; and, determining a normalized slope in correspondence to the formal relationship: .DELTA.I/(I.sup.

Abstract: In a first embodiment of the present invention, a control method and system are provided in an exhaust emission sampling system for controlling a flow controller in order to compensate for the effects of changing water vapor content in a diluted sample having a predetermined dilution ratio. A water measuring device such as a relative humidity sensor generates a water vapor signal based on the amount of water vapor in the diluted sample. The water vapor signal is then processed within a control unit to obtain a value for the amount of water in the diluted sample. A control signal is generated by the control unit based on the amount of water vapor, flow rate of the exhaust emissions, and also, on the type of fuel used in the combustion process to control the flow controller which is, preferably, a mass flow controller.

Abstract: A substrate carrying a first electrode and a second electrode, the first and second electrodes being disposed adjacent to one another, the first electrode being disposed between the substrate and a gas-sensitive component, the gas sensitive component comprising an n-type semiconductor, the gas-sensitive component having a resistance that is gas-dependent and temperature-dependent, and the second electrode being disposed between the substrate and a non-gas-sensitive component, the non-gas-sensitive component comprising a n-type semiconductor and a p-type semiconductor, the non-gas-sensitive component having a resistance that is temperature-dependent and that is not gas-dependent and wherein the n-type semiconductor of the non-gas-sensitive component is Ga.sub.2 O.sub.3 and the p-type semiconductor of the non-gas-sensitive component is ZrO.sub.2.

Abstract: An apparatus and method are adapted for analyzing exhaust emissions by using a small fraction of a continuously-extracted exhaust sample combined with a pollutant-free diluent through a system of critical flow orifices at a predetermined and precisely controlled flow ratio. A small quantity of gas is extracted from the diluted exhaust gas available which is diluted with the contaminant-free air or nitrogen to produce a mixture having a dew point below ambient air temperature and satisfying the flow requirements of the analysis system.

Abstract: A transition metal oxide based calorimetric non-methane hydrocarbon sensor (100) is constructed by disposing a transition metal based catalyst (105), preferably chromium oxide (Cr.sub.2 O.sub.3), onto a carrier (101). A temperature measurement device (103) is positioned thermally coupled to the transition metal based catalyst (105). A preferred application includes sensing non-methane heavy hydrocarbons in an automotive exhaust gas stream (803) by exposing a transition metal oxide catalyst based sensor (805) to the exhaust gas stream (803) and providing a signal (811) indicative of a concentration of non-methane heavy hydrocarbons and carbon monoxide (CO). Then, exposing a compensating sensor (807) to the same exhaust gas stream (803) and providing a compensating signal (813) indicative of a concentration of carbon monoxide (CO). By combining the signal (811) and the compensating signal (813), a measure of non-methane heavy hydrocarbons can be provided.

Abstract: A carbon monoxide (CO) detection system is connected into an anesthesia gas delivery system. The system comprises, among other things, a CO sensor unit containing an inexpensive, replaceable sensor that detects the presence of CO in anesthesia, an in-line adapter that exposes the detection unit to the main stream of the gas and can be placed in a variety of different locations along the gas stream and a side-stream adapter for the removal and analysis of gas stream samples using a CO sensor unit outside of the main gas stream. There is also apparatus capable of measuring the response of the sensors to CO exposure, and data acquisition and a data processing unit for storing, processing and displaying the CO sensor response data. In a preferred embodiment there is a carbon monoxide detection system comprising a detection unit including a sensor unit and a measurement unit. The sensor unit detects carbon monoxide based on the change or rate of change of the optical characteristics of the sensor unit.

Abstract: An NOx sensor has the sensor element made of an oxide, the resistance of which is varied in response to an NOx component in a gas to be measured, and a measuring portion for measuring a resistance variation of the sensor element and for detecting an NOx concentration in the gas to be measured. A catalyst is arranged at an upstream side of a flow of the gas to be measured with respect reach to the sensor element, which makes a partial pressure ratio of NO/NO.sub.2 reach to an equilibrium state and removes a CO component from the gas to be measured. A heater for adjusting a temperature is arranged at a position close to the sensor element, which maintains temperatures of the sensor element and the catalyst constant. An O.sub.2 sensor is arranged at a position close to the sensor element so that the measuring portion can detect accurately the concentration of Nox in the measurement gas by reference to the resistance of the sensor element.

Abstract: Trace levels of molecular oxygen are measured by introducing a gas containing the molecular oxygen into a target zone, and impacting the molecular oxygen in the target zone with electrons at the O.sup.- resonant energy level for dissociative electron attachment to produce O.sup.- ions. Preferably, the electrons have an energy of about 4 to about 10 eV. The amount of O.sup.- ions produced is measured, and is correlated with the molecular oxygen content in the target zone. The technique is effective for measuring levels of oxygen below 50 ppb, and even less than 1 ppb. The amount of O.sup.- can be measure in a quadrupole mass analyzer. Best results are obtained when the electrons have an energy of about 6 to about 8 eV, and preferably about 6.8 eV. The method can be used for other species by selecting the appropriate electron energy level.

Abstract: The present invention provides an apparatus and method for enhancing the response of a biometric sensor for sensing toxins by measuring the rate of change of sensor readings. An LED, optically coupled to the sensor and a photodiode, transmits light through the sensor to the photodiode. The photocurrent from the photodiode is converted to a digital sensor reading value proportional to the darkness of the sensor and is loaded into a microprocessor. In the microprocessor, the sensor readings are essentially differentiated to determine the rate of change of the sensor readings. The rate of change information is used to trigger an alarm condition indicative of a predetermined level of sensed toxins.

Abstract: An improved carbon monoxide sensor system has a dual sensor system having two sensors disposed in a series arrangement within a sensor housing. Each sensor is formed from a porous semi-transparent substrate that is impregnated with a different chemical sensor reagent. At lease one sensor substrate surface is treated with a chemical compound before being impregnated to increase average pore size and, thereby, increase the sensitivity of the sensor. One sensor is formed from a chemical sensor reagent designed to perform at a lower to middle humidity and temperature range. The other sensor is formed from a chemical sensor reagent designed to perform at a middle to high humidity and temperature range. The dual sensor system constructed in this manner provides good carbon monoxide sensitivity at temperature and humidity conditions required by the standards of UL-2034.

Abstract: A pressurized air tank air quality tester comprising a housing having a longitudinal bore disposed therein. The housing has at least one closure disposed on at least one of the ends of the housing for sealing the housing and forming an airtight test chamber therein. A valve connector is connected to one of the ends of the housing for fluidly communicating the pressurized air source with the test chamber. An indicating cartridge is removably disposed within the test chamber for indicating by color an excessive amount of a contaminant contained within the test chamber.

Abstract: An apparatus for indicating the presence of CO and oil in a compressed breathing air supply provided in a tank. An indicator contains a substance which undergoes an observable physical change when exposed to a contaminant. The indicator is activated and placed in a housing and connected to the air supply and the indicator observed. In a preferred embodiment, the indicator is a single use indicator and contains an indicating gel in a glass tube which is opened by breaking at the time of use. Appropriate reference indicia are provided so the user may visually determine the contaminant level.

Abstract: A catalyst composed of metal oxide particles among which are uniformly incorporated, in order to reduce the operating temperature of the catalyst, palladium particles.

Abstract: A solid state optical sensor for CO has a sensing material which includes a molybdenum, tungsten or vanadium color forming agent; a palladium, ruthenium or osmium catalyst; and an iron, chromium or cesium reversing agent. A redox property modifier and/or an interference suppressing agent may also be included. The chemistry is contained in a polymer embedding matrix, with permeation enhancer, if required. Solubility of the chemistry in the polymer matrix is enhanced by lipophilic counterions. The matrix with embedded sensing chemistry is coated on an optical substrate to form an optical transducer.

Abstract: A sensor which is selective to carbon monoxide relative to other reducing gases includes a Bi--Sr--Ca--Cu--O system metal oxide element.

Abstract: A molybdenum, tungsten or vanadium salt-palladium, ruthenium or osmium salt solution for CO detection is made reversible by addition of ferric, chromium (VI) or cerium (IV) ion. The system is made more CO specific by adding an interference control salt which forms white or colorless precipitates with interfering species. The operational and shelf life are extended by a mixture of counterions; the acetate counterion is particularly useful.

Abstract: A device for detecting the presence or concentration of an analyte, a method of making the device, and a method of detecting the presence or concentration of an analyte. The invention features one or more supports, such as beads, which carry a thin film of polymer substrate. The polymer substrate has a sensing reagent and a porous matrix. The sensing reagent alters the optical properties of the polymer substrate in the presence of analyte.

Abstract: A molybdenum salt-palladium salt solution for CO detection is made reversible by addition of ferric ion. The system is made more CO specific by adding an interference control salt which forms white or colorless precipitates with interfering species. The operational and shelf life are extended by a mixture of counterions; the acetate counterion is particularly useful.

Abstract: Method and apparatus for detecting and/or monitoring the presence of hydrocarbons in a fluid medium at a remote location, by sensing the presence of hydrocarbon-based fluid in the fluid medium in the remote location, generating a signal indicative of the sensed fluid, and transmitting the signal to monitoring means for indication of hydrocarbon contamination. The apparatus has multiple sensors at different vertical levels for sensing the fluid medium at a plurality of levels within the fluid.

Abstract: An apparatus and a method for sensing hydrocarbons and carbon monoxide in a measurement gas, e.g., the exhaust gas from an automobile engine. A solid state electrochemical oxygen pumping cell adds oxygen into the apparatus which contains a solid state combustibles sensor for sensing the hydrocarbons and carbon monoxide. The oxygen may be obtained from ambient air or by dissociation of gasses like water present in the measurement gas.

Abstract: An apparatus and method for the measurement of low levels of carbon dioxide in a sample employing membrane separation and ion-exchange technology. The difference in acid strength of carbonic acid and other acids is exploited by first treating the sample with a weak base in a membrane separator and then with a strong base in the membrane separator. In this manner, the carbonic acid is distinguished from the stronger acids. By converting carbonic acid to sodium carbonate, the conductivity level is enhanced facilitating more precise measurements.

Abstract: A passive gas sampling apparatus for detecting an analyte gas, which apparatus includes (1) a shell enclosing an adsorbent and (2) a diffusion tube extending through the shell and having (a) an inlet opening means outside the shell, through which the analyte gas may enter the diffusion tube, and (b) an outlet opening imbedded in the adsorbent inside the shell; and a method for using such apparatus.

Abstract: A carbon monoxide detecting sensor of a derivative of Ni(TBC) which reacts with carbon monoxide to form a carbon monoxide adduct with a concomitant change in color.

Abstract: An apparatus for detecting or measuring the concentration of an analyte gas in a gas sample, which apparatus comprises a donor polymer and a halogen-containing compound positioned to contact the analyte gas and capable of reacting with the analyte gas to yield halogen; and a method for using the apparatus.

Abstract: Improved process control is achieved in processes for which it is useful to control variable process conditions based upon on-line determinations of the concentration of weak acids and weak bases, or their soluble salts, in liquid streams of the processes. For example, amine system energy savings and waste treatment system control improvements are taught.

Abstract: The present invention relates to a biomimetic sensor for detecting the presence of airborne toxins, such as carbon monoxide, mercury, ethylene oxide, volatile organic materials, and hydrogen sulfide. The biomimetic sensor, which has a functional life of at least one year, comprises a porous, semi-transparent substrate into which is impregnated a self-regenerating chemical sensor reagent. The response of the biomimetic sensor mimics the human response to such toxins, with respect to sensitivity and affinity. The extended functional lifetime of the biomimetic sensor and the mimicking of the human response to the toxins are achieved by the use of a molecular encapsulant that encapsulates at least one component of the chemical sensor reagent.

Abstract: A catalytic combustion type CO gas sensor which is composed of an electrical circuit by serially arranging two coils composing an active section and a compensating section, and by providing serial bridge resistances, r.sub.1 and r.sub.2, opposing to the said coils, respectively, and via a gas sensitometer, and which determines the CO concentration based on the difference in value of resistance of both coils of the active section and the compensating section on catalytic combustion of CO, characterized by:(A) that the values of the resistance of coils of the active section and the compensating section and bridge resistances, r.sub.1 and r.sub.2, at a definite temperature are made substantially the same, and thus the temperature coefficients of the coil of the active section and the bridge resistance r.sub.1, and of the coil of the compensating section and the bridge resistance r.sub.2 are made approximately the same.(B) that the value of resistance of the coil of the active section at 150.degree.-200.degree.

Abstract: A carbon monoxide detector comprises a single monochromatic infrared source which is arranged to alternately direct light through two separate gas-containing test chambers. The first chamber is supplied with gas to be tested which has an unknown carbon monoxide content. A catalytic burning chamber is connected between the first and second chambers to receive gas from the first chamber, burn the carbon monoxide in the gas to carbon dioxide and supply the carbon monoxide free gas to the second chamber. A single infrared light detector is provided for receiving light as it comes alternately from the two chambers. The light from the two chambers is compared to determine the amount of carbon monoxide present in the gas of the first test chamber. Since the same background gas is provided in both chambers and only a single infrared source and detector are utilized, inaccuracies due to differences in background detection, infrared source intensity and infrared detector sensitivity are overcome.

Abstract: A briefcase contains components capable of sampling air for analysis. For example, air can be introduced into the briefcase through inlet ports and that air can be monitored for components of environmental tobacco smoke. A chemical collection device such as a sorbent tube can collect nicotine, a filter can collect respirable suspended particulate matter, and a chemical detector can monitor carbon monoxide levels. The environmental temperature and barometric pressure of the environment can be monitored also. Data is stored on a microcomputer within the briefcase, and can be transferred to a computer at a later time for data analysis.

Abstract: Reactive gases like, for example reducing gases, specifically carbon monoxide, are detected in a gas mixture, particularly in air, with extremely high sensitivity and with high precision using a gas detector in which the attenuation of the intensity of an infrared radiation beam by a catalyst layer is utilized. Such catalyst layer contains at least one transition metal selected from at least one of the groups I, VII, and VIII of the Periodic Table of the Chemical Elements. Preferably, chemical elements are used having an atomic weight in the range of about 100 to about 205. The detection of carbon monoxide is particularly sensitive using a catalyst layer which substantially contains a metal capable of forming a carboncarbonyl compound with carbon monoxide.

Abstract: A system for monitoring ambient carbon monoxide. Light from a source (14) is directed against a measuring element (10) which darkens in color as it absorbs carbon monoxide. The light reflected from the element is received by a photocell (16) which generates an electrical signal proportional to the intensity of the reflected light received thereby. The signal is sampled periodically, and stored in a microprocessor (24) which computes the rate of change of the signals. The periodic measurement of the intensity of the light can be varied in response to the rate of change of the light intensity measurement. When the rate of change reaches a level indicative of an unsafe level of ambient carbon monoxide, an alarm (34) is energized. Light from the source is simultaneously directed against a reference element (12) with the light reflected therefrom being received by a photocell (18) which generates an electrical signal proportional to the intensity of the light received thereby.

Abstract: The invention is concerned with apparatus for equilibrating an aqueous solution with gas. The apparatus includes a gas vessel having therewithin a gas of a selectable composition at a pressure above ambient atmospheric pressure. Flow control means receive flow from the vessel and control a flow rate therefrom. A solution tube is provided having an aqueous solution therewithin. Conduit means lead from the flow control means to the tube below a liquid level of the aqueous solution. Means are also provided for causing the gas to be delivered within the aqueous solution below the liquid level as a plurality of bubbles. The process of the present invention is directed at simultaneously equilibrating a plurality of aqueous solutions each with one of a plurality of gas compositions.

Abstract: An n-type semiconductor gas detecting element. The semiconductor oxide is bismuth molybdate having the composition Bi.sub.2 O.sub.3.3MoO.sub.3 and the gas detecting element formed therewith has high sensitivity to combustible gas. The detection of the combustible gases is based upon the change of electrical conductivity of a thick film of the semiconductor oxide detecting element resulting from the combustible gas component in an oxygen-containing atmosphere.

Abstract: There are disclosed an improved CO indicating composition consisting essentially of fumed silica having dispersed thereon dry residues of impregnation with a solution of palladium sulfate, sulfuric acid and ammonium molybdate, a CO indicator comprising a strip of a composite of expanded, amorphous-locked tetrafluoroethylene polymer and fumed silica having dried residues of impregnation with the aforesaid solution, an improved detector containing said indicating composition or said indicator, and improved process for detecting CO comprising exposing pre-dried air to the indicating composition or said indicator to effect a color change, extracting colored material with distilled water or an aqueous buffer solution, and measuring the depth of color in the resulting extract.

Abstract: Method and apparatus for determining the gaseous content of a diluent, such as determining the oxygen or carbon dioxide content of blood. A sample of the diluent whose gaseous content is to be measured is anaerobically pumped past a junction tee after being placed in a reservoir. A second diluent, not part of the sample, is equilibrated with a gas (not the gas to be measured) in a first tonometer. This second equilibrated diluent is pumped past the junction tee where it is mixed with the diluent sample. The gas in the second diluent is selectively chosen to drive the gas to be measured into the dissolved phase. The diluent mixture is then allowed to flow through an appropriate sensor that senses the presence of the gas to be measured. This first measurement is stored in a suitable controller, such as a microprocessor.