Abstract: Provided is a method for multi-information fusion of gas sensitivity and chromatography and on-site detection and analysis of flavor substances using an electronic nose instrument. The electronic nose instrument includes a gas sensor array module (I), a capillary gas chromatographic column module (II), an automatic headspace sampling module (III), a computer control and data analysis module (IV), an automatic lifter (V) for headspace sampling, a large-volume headspace vapor generation device (VI) and two auxiliary gas sources (VII-1, VII-2). In the gas sampling period of T0-300-600 s, the gas sensor array module and the gas chromatography module have different flow rates, volumes and staring sampling time points of gas sampling, but have synchronous selection and analysis time points of multiple sensitive information.

Abstract: A method for monitoring air quality is described. The method includes measuring ethane and methane using a mobile sensor platform to provide sensor data. The sensor data includes methane data and ethane data captured at a nonzero mobile sensor platform speed. Methane and ethane peak(s) are identified in the sensor data. Correlation(s) between the methane and ethane peak(s) and/or between the methane peak(s) and at least one amount of 13C are determined. A source for the methane is determined based on the correlation.

Abstract: The exemplary embodiments may provide a collective insulating sleeve for a plurality of chromatography columns or may provide separate insulating sleeve for each of the chromatography columns in a plurality. As a result, column ovens are not needed, and pre-heaters may not be required for each chromatography column in some exemplary embodiments. Thus, parallel column arrangements in the exemplary embodiments may be more compact than conventional arrangements.

Abstract: A gas chromatograph is provided with: a sample gas generator (2) configured to generate a sample gas from an injected sample; a separation column (6) fluidly connected to an outlet of the sample gas generator, the separation column (6) being configured to separate components in the sample gas generated by the sample gas generator (2); a detector (8) fluidly connected to an outlet of the separation column (6), the detector (8) being configured to detect the components separated in the separation column (6); a plurality of gas supply sources (12A, 12B) each configured to supply a carrier gas for carrying the sample gas generated by the sample gas generator to the separation column (6); a switching unit (12A, 12B) fluidly connected to the plurality of gas supply sources, the switching unit being configured to switch such that one of the plurality of gas supply sources is fluidly connected to the sample gas generator (2); a regulator (16) interposed between the switching unit (14) and the sample gas generator (2)

Abstract: The gas chromatograph system 10 has the gas chromatograph 1, and a detector 2. The detector 2 has the redox unit 14. The redox unit 14 has the reaction tube 142, the oxidation zone 146 and the reduction zone 147. The reduction zone 147 is disposed on the downstream side of the oxidation zone 146. The reduction zone 147 is disposed out of a position perpendicular direction above the oxidation zone 146. Hence, even if the air heated around the oxidation zone 146 moved upward by convection, the reduction zone 147 is prevented from being exposed to such hot air.

Abstract: In one aspect, disclosed herein are devices comprising a disclosed hybrid microwave-thermal chemical reactor device. Also disclosed herein are methods of preparing hydrogen and a crystalline carbon material, such as a carbon nanotube, from methane using a hybrid heating comprising heating with both a thermal fluid and microwave irradiation of a catalyst. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.

Abstract: To suppress the influence of heat from an interface part on temperature control of a separation column and also to suppress the influence of room temperature fluctuation outside a main body.

Abstract: A compact rock pyrolytic analysis and evaluation instrument comprises a sample introduction system, a pyrolytic furnace, a bypass system, a total hydrocarbon amount and methane content analysis system, a signal acquisition control system and a computer. The pyrolytic furnace is respectively connected with the sample introduction system and the bypass system, the total hydrocarbon amount and methane content analysis system is connected with the bypass system, the signal acquisition control system is used for controlling and connecting the total hydrocarbon amount and methane content analysis system, and meanwhile, the signal acquisition control system is communicated with the computer. The disclosure simultaneously detects the total amount of hydrocarbons produced by rock pyrolysis and the content of methane gas produced by rock pyrolysis, and the obtained data are reliable.

Abstract: The present invention relates to a microplastic detection device and method based on a pyrolysis-mass spectrometry technology. The microplastic detection device based on a pyrolysis-mass spectrometry technology provided by the present invention is substantially a sealed gas path device system formed connected via pipelines. The device includes a working gas source, a pyrolysis device, a filter and a mass spectrometer which are connected in sequence. After a microplastic sample is placed into the pyrolysis device, the microplastic sample is decomposed in the pyrolysis device, and pyrolysis products from the microplastic sample driven by a carrier gas of the working gas source enter the mass spectrometer for detection and analysis after being filtered by the filter. Furthermore, the present invention provides a microplastic detection method based on a pyrolysis-mass spectrometry. The present invention is widely applied to the field of a microplastic detection technology.

Abstract: An apparatus for quantitatively analyzing gas, particularly oxygen, generated in a battery material, particularly a cathode material is provided. The apparatus contains a switching valve and a sampling loop in a pyrolyzer, thereby allowing an EGA method, which was used only for the qualitative analysis of gas generated from a solid sample, to be used for the quantitative analysis of gas generated at a specific temperature when heat is applied by the pyrolyzer in a battery material.

Abstract: A thermal desorption tube collection system uses a thermoelectric cooler to collect and concentrate gas samples. In some modes, the operation of the cooler is reversed to flow the concentrated sample directly into a separator such as a gas chromatography system. Components resolved in time by a thermal desorption separator accumulate in a sample cell and are analyzed by electromagnetic radiation-based spectroscopic techniques. Also presented are methods for analyzing biogas samples.

Abstract: In the present system and method, a conduit from a LC device continuously transports solvent, buffers, and analytes to the inlet of a solvent removal and analyte conversion device which evaporates the solvents, leaving non-volatile analytes for detection. The device comprises a rotating disk. The liquid chromatograph device can be any device using liquid chromatography to separate molecules. The solvents in the LC effluent can include, but are not limited to, water, methanol, acetonitrile, tetrahydrofuran, and acetone. After removal of the volatile components, the non-volatile analytes are converted with a concentrated energy source so that they may be detectable.

Abstract: A fluid pressure control apparatus includes a proportional solenoid valve having a solenoid portion and a valve portion operatively connected between a fluid inlet port and a fluid outlet port fluidly coupled to a pressure sensor. An electronic controller receives a first signal from the pressure sensor, receives a second signal corresponding to a pressure set point, and outputs a control signal to the solenoid valve. A flameproof/explosion proof or pressurized/purged enclosure houses the electronic controller and the solenoid portion of the solenoid valve, and a manifold block mounted to the enclosure covers and closes an opening of the enclosure. The manifold block includes internal passageways connecting the valve portion of the solenoid valve between the fluid inlet port and the fluid outlet port. The pressure sensor is arranged outside the enclosure, with the first signal from the pressure sensor being conducted into the enclosure via a fluid-tight electrical feedthrough.

Abstract: A thermal desorption tube for use with an electrical power source that includes a tube body having a tube middle portion, a gas inlet, and a gas outlet, a heating element having a first element end and a second element end, wherein the heating element is disposed within the tube body between the gas inlet and the gas outlet, wherein the heating element has a Temperature Coefficient of Resistance (TCR) value greater than 0.003 per degree Celsius, and wherein the first element end and the second element end are configured to electrically couple to a power source, and a sorbent material disposed within the tube middle portion, wherein the sorbent material is disposed in and occupies all available space within the tube middle portion surrounding, within, and adjacent the heating element, and wherein the sorbent material is in direct contact with the heating element.

Abstract: A method for monitoring air quality is described. The method includes measuring ethane and methane using a mobile sensor platform to provide sensor data. The sensor data includes methane data and ethane data captured at a nonzero mobile sensor platform speed. Methane and ethane peak(s) are identified in the sensor data. Correlation(s) between the methane and ethane peak(s) and/or between the methane peak(s) and at least one amount of 13C are determined. A source for the methane is determined based on the correlation.

Abstract: A system is disclosed that monitors participants in health-related programs, such as weight loss or exercise programs, and that provides automated, personalized health coaching to the program participants. The system includes breath analysis devices that are used by the program participants to generate ketone measurements, and includes a mobile application that runs on mobile devices of the participants and communicates with corresponding breath analysis devices. The system operates generally by monitoring ketone levels (such as acetone levels) and other attributes of the participants and by making personalized, machine-generated changes or updates to such programs to maintain program effectiveness and engagement. In some embodiments the system uses primary and secondary process flows to collect from the participants information that is used to select or recommend health program modifications.

Abstract: A real-time online analysis device for substance pyrolysis, including: a pyrolyzing system (1), a capturing system (2), a testing system (3) and a controlling system (4) is disclosed. The pyrolyzing system (1), the capturing system (2) and the testing system (3) are connected with the controlling system (4). The capturing system (2) has a cooling cavity (22) and a heating cavity (23) inside. The temperature of the cooling cavity (22) ranges from room temperature to ?200° C., and the temperature of the heating cavity (23) ranges from room temperature to 1000° C. A method for real-time online analysis of substance pyrolysis using the device is also disclosed. The present device can provide real-time online pyrolysis, capturing, separation and analysis of substances at a plurality of temperature points or ranges.

Abstract: A gas chromatography guard column assembly is disclosed including a guard column having an inlet and an outlet. The guard column is disposed in a coil having a column coil aspect ratio of less than 15. A gas chromatography system is disclosed including an oven cavity, a heater assembly, an inlet, a guard column, an analytical column, and a detector. The guard column is in fluid communication with the inlet and is disposed in a guard column coil. The analytical column is in fluid communication with the guard column and is disposed in an analytical column coil. The detector is in fluid communication with the analytical column. The analytical column coil has an analytical column coil central axis aligned with a central axis of the heater assembly, and the guard column coil has a guard column coil central axis remote from the central axis of the heater assembly.

Abstract: An apparatus for separating a fluidic sample includes a fluid drive arrangement including fluid drive units for driving a mobile phase along a flow path to a sample separation unit, a sample accommodation volume for accommodating the fluidic sample and selectively fluidically coupleable with or decoupleable from the flow path, and a control unit. The control unit is configured to control pressure decoupling of at least part of at least one of the fluid drive units from the flow path, and enable the partially pressure-decoupled fluid drive unit(s) to pressurize the sample accommodation volume before fluidically coupling the sample accommodation volume with the flow path and/or to de-pressurize the sample accommodation volume after fluidically coupling the sample accommodation volume with the flow path for preparing a subsequent intake of fluidic sample in the sample accommodation volume.

Abstract: Various methods and apparatuses are provided for monitoring and detecting gas leaks. A method of determining a gas leak with a sensor assembly is provided. The sensor assembly includes a primary sensing device and a reference sensing device. The method includes receiving, via the primary sensing device, a first oxygen concentration level reading of a given area. The method also includes receiving, via the reference sensing device, a second oxygen concentration level reading of the given area. The method further includes comparing the first oxygen concentration level reading and the second oxygen concentration level reading. Based on the comparison, the method still further includes causing a transmission of a signal that a gas leak is occurring in an instance in which the first oxygen concentration level reading and the second oxygen concentration level reading have a difference greater than a threshold difference. A corresponding gas detection apparatus is also provided.

Abstract: A method for applying a heating sequence for a modulator includes, during a first period of time, heating a first heating zone disposed along a length of the modulator without heating a second heating zone to cause a sample trapped from a first transfer line at an entrance of the modulator to move from the first heating zone to the second heating zone. The method also includes, during a second time period, withdrawing the heating of the first heating zone to prevent the sample from entering the modulator from the first transfer line. During a third time period, the method includes heating the second heating zone without heating the first heating zone to reinject the sample into a second transfer line.

Abstract: A gas sampler includes a connection portion connectable to an introduction piping connected to a sample tank, a switching valve for switching a connection state between the connection portion and a sample loop, a pump, and a control device. A buffer flow path between the sample loop and the pump is configured to be selectively connectable to any one of a plurality of buffer tanks different in volume. A volume of the buffer flow path is greater than a volume of the introduction piping by a predetermined amount. The control device operates the pump in a state in which the switching valve is in a closed state to set an inside of the buffer flow path to a negative pressure, and thereafter stops the pump and make the switching valve in an open state to fill the sample loop with a sample gas by using the negative pressure of the buffer flow path.

Abstract: A method for monitoring air quality is described. The method includes measuring ethane and methane using a mobile sensor platform to provide sensor data. The sensor data includes methane data and ethane data captured at a nonzero mobile sensor platform speed. Methane and ethane peak(s) are identified in the sensor data. Correlation(s) between the methane and ethane peak(s) and/or between the methane peak(s) and at least one amount of 13C are determined. A source for the methane is determined based on the correlation.

Abstract: A portable gas analysis device having a separating column and a detector. The separating column is composed as a multi-capillary unit from parallel individual capillaries and, depending on the length, is bent into a compact shape, preferably even wound into multiple turns. A thermally conductive casing and a thermal stabilizing device are provided for the multi-capillary unit. The thermal stabilizing device comprises a temperature sensor, a heating element and control electronics. The casing protects the sensitive multi-capillary unit from mechanical actions; it acts as a protective space. The temperature-controlled casing also forms a space in which uniform and controlled conditions prevail and which in particular is isolated from the temperature and humidity of the environment, allowing reliable measurements outside a laboratory environment, in the field. This double effect of the casing for the capillaries in conjunction with the compact dimensions forms the true essence of the invention.

Abstract: The present invention relates to a preconcentrator for vapors and particles collected from air. The vapor preconcentrator is made from plural layer of coils. The coil is made of resistance alloy. The pitch size of the coil is made to precisely trap/filter out certain size of the particles during preconcentration. Multiple coils could be made with different pitch sizes to achieve multiple step filtrations. When the sample flow enters the preconcentrator chamber, it passes through the coils. The particles of different sizes are trapped on different layer of coils. The vapor sample can be trapped on any coils when interacted with the coil surface. They could be trapped without any affinitive coating as the preconcentrator is at relatively low temperature. Different coils or different sections of the coil can be coated with different material to trap chemicals of different classes.

Abstract: A connection mechanism for a suction device for vacuum membrane filtration applications, includes a support for receiving a membrane filter or a filtration base, a cavity formed below the membrane filter or the filtration base, a suction duct which opens centrally into the cavity, and a ventilation duct which opens laterally into the cavity. The connection mechanism further includes a closing element which can be moved into several switching positions and which can block or unblock both the suction duct and the ventilation duct depending on the switching positions.

Abstract: An upstream portion of a flow path is stored in a cell block. A filament for detecting thermal conductivity of a sample gas is stored in the upstream portion. The sample gas is led to a downstream portion of an exhaust pipe path through the flow path. The flow path is kept warm by a temperature retainer such that the temperature of the sample gas that passes through the exhaust pipe path does not decrease to a temperature equal to or lower than a liquefaction temperature of the sample gas. Alternatively, at least one portion including a downstream end of the exhaust pipe path is provided to be attachable to and detachable from another portion of the flow path.

Abstract: A gas chromatographic (GC) column using a zwitterionic compound and methods of use thereof are disclosed herein. The volatile free acids were observed to strongly retain on these zwitterionic compounds-based columns with excellent peak symmetry. By carefully tuning the structures of these zwitterionic compounds, different selectivity toward volatile free acids was demonstrated. These stationary phases possess a wide working range with thermal stabilities at higher temperatures.

Abstract: The invention relates to a system and to a method for separating into at least one of liquid and gas phase compounds contained in a sample. The system comprises: an oven (D1) for heating in an inert atmosphere according to a sequence of temperatures, a first experimental setup (M1) connected to oven (D1) when it is in operation, comprising circulating the effluent resulting from heating in an inert atmosphere towards collection of (U) this effluent, a second experimental setup (M2) connected to first experimental setup (M1) when the oven is no longer in operation, comprising vacuum circulation (PI, P.G., TP) of the effluent collected by the first setup towards (T1, T2) which separate the collected effluent into at least one of liquid and gas phases.

Abstract: A thermal desorption tube collection system uses a thermoelectric cooler to collect and concentrate gas samples. In some modes, the operation of the cooler is reversed to flow the concentrated sample directly into a separator such as a gas chromatography system. Components resolved in time by a thermal desorption separator accumulate in a sample cell and are analyzed by electromagnetic radiation-based spectroscopic techniques. Also presented are methods for analyzing biogas samples.

Abstract: Methods include treating a portion of a sample composition to be tested for presence of an analyte by depleting or blocking the target analyte. The treated composition may be used to equilibrate an acoustic wave sensor prior to exposing the sensor to the untreated sample composition for analysis. By using the treated sample composition, in which the analyte is depleted or blocked, to equilibrate the sensor, the sensor may be equilibrated with a composition having a similar viscosity and non-specific binding characteristics to the untreated sample composition, which should result in improved accuracy when analyzing the analyte in the untreated sample composition.

Abstract: A supercritical fluid device includes an analytical channel, a liquid delivery part for delivering a mobile phase constituting a supercritical fluid in the analytical channel, a back pressure regulator for controlling a pressure of the analytical channel so as to cause the mobile phase in the analytical channel to reach a supercritical state, a sample injecting device that includes a sample holder for holding a sample and a switching valve for switching between a state where the sample holder is arranged on the analytical channel and a state where the sample holder is not arranged on the analytical channel, a bypass channel whose one end is connected to a position upstream of the sample injecting device and whose other end is connected to a position downstream of the sample injecting device on the analytical channel, and an analytical column for separating a sample introduced by the sample injecting device into individual components, the analytical column is provided downstream of the position to which the ot

Abstract: The disclosure describes embodiments of an apparatus including a first gas chromatograph including a fluid inlet, a fluid outlet, and a first temperature control. A controller is coupled to the first temperature control and includes logic to apply a first temperature profile to the first temperature control to heat, cool, or both heat and cool the first gas chromatograph. Other embodiments are disclosed and claimed.

Abstract: A stacked testing assembly (100) includes a microfluidic cartridge (10) for analyzing a fluid sample and a testing setup, said microfluidic cartridge includes a number of layers (1, 2) stacked in a height direction with many different kinds of combinations, said testing setup (20) is capable of assembling and testing all kinds of said layers combinations with no change to the setup.

Abstract: Provided is a system comprising a conduit from a gas chromatograph column to a single reactor comprising a Fe, Co, Pt, Ni, Rh, Pd and/or Ru catalyst(s), with hydrogen and oxygen feed conduits for providing hydrogen and oxygen to the reactor, and a conduit from the reactor to an FID detector. This allows one to practice a method for the detection and quantification of organic molecules from a gas chromatograph which comprises passing the effluent from a gas chromatograph column to a reactor comprising a Fe, Co, Pt, Ni, Rh, Pd and/or Ru catalyst; adding hydrogen and air/oxygen to the reactor; reacting the effluent from the gas chromatograph column in the reactor to sequentially oxidize then reduce all organic containing molecules to CH4 by heating to an elevated temperature, and passing the reactor effluent to an FID.

Abstract: A carrier gas flow path of at least from a trap to an analyzing portion is shared between a state wherein a sample component is trapped within the trap and a state wherein the sample component is not trapped within the trap. In this case, even after the sample has been introduced into the analyzing portion through the carrier gas flow path, there is a time interval over which the carrier gas flows within the carrier gas flow path. This makes it possible, through the carrier gas that flows within the carrier gas flow path afterward, to remove the sample component from within the flow path, despite there being a sample component within the carrier gas flow path at the time of sample introduction, thus making it possible to prevent the sample component from remaining within the flow path after sample introduction.

Abstract: A gas chromatography instrument comprising a first autoinjector in communication with a first column, a second autoinjector in communication with a second column, a first flame ionization detector in communication with the first column, a second flame ionization detector in communication with the second column, wherein the first column is housed in a first compartment and the second column is housed in a second compartment.

Abstract: A mechanism is provided for detecting air-pollution anomalies. A historical air-pollution pattern is identified for each of a plurality of air-pollution monitoring stations. For each of the plurality of air-pollution monitoring stations, responsive to receiving real-time data from a particular air-pollution monitoring station, the real-time data is compared to the historical air-pollution pattern associated with the particular air-pollution monitoring station. A density difference value is generated based on the comparison of the real-time data to the historical air-pollution pattern associated with the particular air-pollution monitoring station and a determination is made as to whether the density difference value is greater than a predetermined confidence threshold.

Abstract: A sample preparation apparatus for an elemental analysis system comprising a sample combustion and/or reduction and/or pyrolysis arrangement for receiving a sample of material to be analyzed, and producing therefrom a sample gas flow containing atoms, molecules and/or compounds; a gas chromatography (GC) column into which the sample gas flow is directed; a heater for heating at least a part of the GC column; and a controller for controlling the heater. The controller is configured to control the heater so as to increase the temperature of at least the part of the GC column while the sample gas flow in the GC column elutes.

Abstract: A column assembly for gas chromatography, which is coolable by a fluid, includes a capillary column, a heating element for heating at least a portion of the capillary column, and a tube having a lumen and in contact with at least one of the capillary column and the heating element. When energized, the heating element raises the temperature of the capillary column. To lower the temperature of the capillary column, a fluid flows through the tube, and heat is transferred from the capillary column to the fluid in the tube.

Abstract: A method for preparing a sample for analysis includes separating a gas sample into at least one component sample in a separation unit. The output of the at least one component sample from the separation unit is detected, for example, using a thermal conductivity detector. A hydrocarbon in the component sample is combusted in a combustion unit to generate a combustion product. The at least one component sample is collected in a sample collector and supplied to an analysis unit. In some embodiments, the analysis unit may be used to determine an isotopic ratio of the at least one component sample.

Abstract: Assorted apparatus and methods optimize the detection of gas entrapped in drilling fluid. A mudlogging injection system can have a processor that autonomously injects sample gas into a gas chromatograph with near atmospheric pressures to optimize sample gas testing time and accuracy. The processor can autonomously detect errors, such as gas chromatograph detector drift, and conduct chromatograph adjustments to ensure accurate detection of different constituent gases entrapped in the drilling fluid.

Abstract: A sensing system for detecting a substance in a dialysate. The system includes a hydrophobic barrier capable of allowing the substance in the dialysate to equilibrate through the barrier to a gas. The system also includes a detector capable of detecting the gas and an interface disposed between the hydrophobic barrier and the detector and configured to allow transport of the gas between the hydrophobic barrier and the detector following a concentration gradient of the gas along the interface.

Abstract: The present invention relates to a method for simulating a chromatographic run on a chromatograph (5) with a computation device (3) comprising at least one processor (7) and an associated digital memory (9), wherein the chromatographic run uses a mobile phase (31) comprising a mixture of at least two eluent constituents having different chromatographic properties and forming an eluent profile (33). The invention also relates to a computer program for performing the method, and an apparatus comprising a computation device and a chromatograph for performing the method.

Abstract: An isotope ratio of a continuous sample is measured in an isotope ratio spectrometer. At least one sample isotope ratio is measured over a measurement time period tns, (n?1) and a sample concentration cns is measured over at least a part of the measurement time period tns. A reference gas concentration cnref for the spectrometer is selected for reference to the sample measured during the measurement time period tns, on the basis of the measured sample concentration cnref. An isotope ratio of the reference gas is measured at the selected reference gas concentration cnref in the spectrometer. The at least one isotope ratio of the sample measured during the measurement time period tns is calibrated using the measured isotope ratio of the reference gas at the corresponding reference gas concentration cnref and a plurality of calibrated isotope ratios and a plurality of sample gas concentration measurements are determined, each being for a different time.

Abstract: The invention relates to a controlled combustion system for the simultaneous analysis of the thermodynamic efficiency of combustion and total polluting emissions in solids with combustible potential, including: a pre-chamber, a combustion chamber, a heat transfer unit which includes a connection for a device that analyses combustion gases to determine the performance of combustion and burning, and a unit for storing the combustion emissions, which comprises a container for storing the sample and a means of collecting samples for the simultaneous collection of gases and particulate matter for analyzing the combustion emissions.

Abstract: An efficient absorption spectroscopy system is provided. The spectroscopy system may be configured to measure solid, liquid or gaseous samples. Vacuum ultra-violet wavelengths may be utilized. Some of the disclosed techniques can be used for detecting the presence of trace concentrations of gaseous species. A preferable gas flow cell is disclosed. Some of the disclosed techniques may be used with a gas chromatography system so as to detect and identify species eluted from the column. Some of the disclosed techniques may be used in conjunction with an electrospray interface and a liquid chromatography system so as to detect and identify gas phase ions of macromolecules produced from solution. Some of the disclosed techniques may be used to characterize chemical reactions. Some of the disclosed techniques may be used in conjunction with an ultra short-path length sample cell to measure liquids.

Abstract: An injection port for a gas chromatograph (GC) is operated such that, during an injection sequence, an inert gas is used for sample transfer to the analytical column while hydrogen is subsequently utilized for the majority of the analytical separation. This allows for a high degree of chromatographic efficiency, while also reducing unwanted chemical reactions involving hydrogen and/or reactive solvents in a hot injection port. Certain embodiments also provide an increased margin of safety when using hydrogen, since the total flow may be limited such that the concentration of hydrogen in the GC oven never exceeds a safety limit, such as the lower explosive limit.

Abstract: An apparatus for detecting a presence of at least one analyte in a gas sample. The apparatus comprises a pump for drawing a gas sample from an ambient air, a passage having first and second ends, a chamber connected to the first end and containing a concentrating element for collecting at least one analyte from the gas sample, a chromatographic separator connected to a second end of the passage, and a gas source for streaming a carrier gas via the chamber to transfer the at least one analyte toward at least one chemical detector, via the chromatographic separator, in a first direction. The pump draws the gas sample via the chamber in a second direction and the first and second directions are substantially opposing to one another.

Abstract: Processes and apparatuses are provided for the liberation of one or more volatile organic compounds from a test sample. The processes include exposing a sample to light of a wavelength less than 400 nm, subjecting the sample to heat, and collecting one or more volatile organic compounds produced from the sample. The volatile organic compounds are detected by any of various methods, and are optionally identified by methods such as FTIR. The processes and apparatus provide for improved detection of relevant volatile organic compounds that are otherwise undetectable by traditional processes.