The disclosed system and method improve analysis of chemical samples for measurement of trace volatile chemicals, such as by Gas Chromatography (GC) and Gas Chromatography/Mass Spectrometry (GCMS). The system can include two traps in series, the first of which removes most of the unwanted water vapor, while the second trap preconcentrates the sample using a series of capillary columns of increasing adsorption strength. The sample can be backflushed from the second trap directly to a chemical analyzer without splitting which can maximize sensitivity. The system improves elimination of water vapor and fixed gases from the sample prior to analysis, resulting in detection limits as low as 0.001 PPBb. The second trap allows faster release of the sample upon injection to the chemical analyzer without additional focusing, and can be cleaned up faster when exposed to high concentration samples relative to packed traps.

A gas measuring device includes: a filter to which a power supply that applies a voltage or current is connected, which generates resistance heat, and which combusts a predetermined combustible gas in contact therewith; and a gas sensor configured to detect the combustible gas that has passed through the filter.

A small-sized, portable enclosure protects a gas sensor against degradation due to environmental exposure and changes in atmospheric conditions. The protective enclosure includes an inlet for introduction of a gas into the enclosure, an outlet for release of the gas upon completion of a sensing run, and a number of in-line filters that remove from the inflowing gas sample analytes, contaminants, and other materials that can compromise the integrity of the sensor or cause the sensor to degrade over time. The enclosure does not include any filters during the measurement phase of the sensing run in order to allow the gas sensor to accurately measure an unmodified gas mixture and/or analyte.

Breath sensor apparatus and methods of use are described herein where a flow control apparatus may generally comprise a sampling chamber defining a volume and one or more openings into the sampling chamber, at least one sensor in fluid communication with the sampling chamber, wherein the at least one sensor is configured to detect the analyte. The sampling chamber may also be configured to receive the breath sample into the sampling chamber and into contact with the at least one sensor via diffusion into the sampling chamber.

A gas sensor includes a support structure with a cavity, a sensing element sensitive to a gas and arranged in the cavity, and a filter spanning the cavity. The filter is a size selective filter.

A gas sensor apparatus (100) comprising a gas inlet (10); a first gas sensor (40); a first gas flow path between the inlet and the gas sensor; a humidifier (20) disposed between the gas inlet and the gas sensor in the first gas flow path of the gas sensor apparatus; and a dehumidifier (30) disposed between the humidifier and the first gas sensor in the first gas flow path. The gas sensor apparatus may have more than one gas flow path. The gas sensor apparatus may contain more than one sensor. The gas sensor apparatus may contain one or more filters for filtering a target gas or a non-target gas. The gas sensor apparatus may be used in detection of ethylene and/or 1-methylcyclopropene.

A gas sensing device includes chemoresistive gas sensing elements, wherein a material composition of a first chemoresistive gas sensing element is similar to a material composition of a second chemoresistive gas sensing element, wherein the first chemoresistive gas sensing element is exposed to an ambient mixture of gases so that first sensing signals depend on a concentration of a first gas and on a concentration of a second gas, wherein the gas sensing device includes a gas filter so that the second sensing signals depend on the concentration of the first gas to a lesser degree than the first sensor signals and so that the second sensing signals depend on the concentration of the second gas, and wherein the gas sensing device estimates the concentration of the first gas and/or the concentration of the second gas based on the first sensing signals and the second sensing signals.

The present invention concerns the use of a device comprising a porous electrode and an electrically insulating porous layer to remove oxygen in contact with a working electrode. The present invention also concerns the use of said device in contact to said working electrode to detect and/or quantify an analyte in presence of oxygen.

An evaporation closed chamber for detecting hazardous substance, having a closed chamber, an orifice plate, a pressure plate, a drive device and an elastic film, the orifice plate is mounted on any surface(s) of the closed chamber, the elastic film is arranged on the outer side of the orifice plate, the pressure plate is arranged on the outer side of the elastic film, and the drive device is in transmission connection with the pressure plate to drive the pressure plate to move forwards and backwards to press the elastic film against the orifice plate. The elastic film expands with the increase of internal temperature of the closed chamber and shrinks with the temperature decrease of the closed chamber such that the gas in the closed chamber can be timely compensated; the orifice plate prevents hazardous substance from leaving on the gas compensation device to influence test accuracy.

The invention provides a gas detection system and a method with eliminating influence of ambient temperature and humidity change, the gas detection system comprises a bare sensor, a reference sensor and a calculation module; the bare sensor is used to detect a target gas in an ambient gas to obtain a first feedback signal; the reference sensor is used to selectively isolate the target gas in the ambient gas to produce a zero gas and to detect the zero gas to obtain a second feedback signal, the calculation module is used to calculate a difference between the first feedback signal and the second feedback signal to obtain a third feedback signal, and to obtain a target gas concentration by calculating the third feedback signal according to a calibration formula. The invention improves the measurement accuracy to the target gas concentration, which are efficient and reliable and have good technical effects.