Disclosed herein is a method for selectively reducing, using electrical energy, CO.sub.2 to carbon monoxide or formic acid, a catalyst for use in the method, and an electrochemical reduction system. The method for producing carbon monoxide or formic acid by electrochemically reducing carbon dioxide of the present invention includes (a) reacting carbon dioxide with a metal complex represented by formula (1), and (b) applying a voltage to a reaction product of the carbon dioxide and the metal complex represented by formula (1):

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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.

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.

A gas analyzer and a method for performing mass spectrometry analysis includes a membrane configured to receive an input flow of carrier gas. The membrane defines a variable thickness region between first and second positions along an input face of the membrane and separates the analyte sample into an output flow of analyte molecules. A mass spectrometer is disposed downstream of the membrane and includes an input orifice for receiving the output flow. The mass spectrometer is configured to perform a response profile analysis of the analyte molecules in the sample analyte.

Method for adapting the concentration of a sample gas in a gas mixture to be analysed by a gas chromatograph assembly (10), the gas chromatograph assembly (10) comprising a sample gas inlet (20) for introducing a sample gas to be analysed, a secondary gas inlet (40), a gas chromatograph infrared sensor (12), a gas chromatograph column (26), and a gas chromatograph bypass (28) parallel to the column (26), characterized by a) introducing an amount of sample gas through the sample gas inlet (20), b) introducing an amount of secondary gas through the secondary gas inlet (40), c) mixing the sample gas and the secondary gas to a gas mixture and conducting the gas mixture via the gas chromatograph bypass (28), d) circulating the gas mixture in a gas conducting loop (52) comprising the gas chromatograph bypass (28), the gas chromatograph infrared sensor (12) and not comprising the gas chromatograph column (26), e) analysing the gas mixture thus obtained by means of gas chromatography employing the gas chromatograph column (26) and the gas chromatograph infrared sensor (12).

Method for adapting the concentration of a sample gas in a gas mixture to be analysed by a gas chromatograph assembly (10), the gas chromatograph assembly (10) comprising a sample gas inlet (20) for introducing a sample gas to be analysed, a secondary gas inlet (40), a gas chromatograph infrared sensor (12), a gas chromatograph column (26), and a gas chromatograph bypass (28) parallel to the column (26), characterized by a) introducing an amount of sample gas through the sample gas inlet (20), b) introducing an amount of secondary gas through the secondary gas inlet (40), c) mixing the sample gas and the secondary gas to a gas mixture and conducting the gas mixture via the gas chromatograph bypass (28), d) circulating the gas mixture in a gas conducting loop (52) comprising the gas chromatograph bypass (28), the gas chromatograph infrared sensor (12) and not comprising the gas chromatograph column (26), e) analysing the gas mixture thus obtained by means of gas chromatography employing the gas chromatograph column (26) and the gas chromatograph infrared sensor (12).

A thermoresistive gas sensor includes two identical, flat meshes that consist of a semiconductor material with a predetermined type of conductivity and that are interconnected in sections of an electric measuring bridge that are diametrically opposite one another, wherein each mesh of the two identical, flat meshes has mesh webs that extend parallel, adjacent to one another and that are connected electrically in parallel at the ends, where the mesh webs of the two meshes extend alternately adjacent to one another in a shared mesh plane horizontally across a window opening in a carrier plate.

A ventilation system includes an electrochemical filter for depleting alkyl phenols, especially 2,6-diisopropyl phenol, in breathing gas. A method uses the filter for removing alkyl phenols, especially 2,6-diisopropyl phenol, from breathing gas.

Example aspects of a volatile organic compound detection device, a wearable health monitoring device, and a method of monitoring a user's health are disclosed. The volatile organic compound detection device can comprise a collector comprising a collector material configured to collect volatile organic compounds given off from a user's skin; a separator comprising a gas chromatography column configured to separate mixtures of the volatile organic compounds into their constituent chemicals; and an identifier comprising a detector and a processor, the detector configured to transduce the constituent chemicals into a signal, the processor configured to process the signal to identify specific volatile organic compounds indicative of a health condition.

A sensor module includes a sensor configured to detect a specific substance in a sample, a first channel, and a second channel The first channel supplies a first fluid as the sample to the sensor. The second channel supplies a second fluid different from the first fluid to the sensor. The second channel includes a second fluid buffer tank for holding the second fluid for a fixed time interval.