A gas sensor includes a suction inlet, a housing communicating with the suction inlet, a gas sensor array disposed in an inside of the housing, and a suction unit disposed at an end of the housing. The suction unit is configured to perform a first suction conveying a gas component in air to the gas sensor array through the suction inlet, and perform a second suction conveying the gas component to the gas sensor array at a flow rate smaller than a flow rate of the first suction. The suction unit is configured to perform the second suction together with the first suction. The gas sensor array is configured to operate while the suction unit performs the second suction.

A method for determining a carbon content of a sample in a TOC analyzer, includes the steps of: directing a carrier gas from an inlet through a high temperature furnace to an analysis unit; stopping the flow of the carrier gas through the high temperature furnace; injecting the sample into the high temperature furnace, which is used to vaporize and/or oxidize the sample at a high temperature to form water vapor and carbon dioxide gas; waiting until the sample injected into the high temperature furnace is vaporized; starting the flow of the carrier gas through the high temperature furnace and thereby transporting the carbon dioxide gas produced during vaporization and/or oxidation of the sample to an analysis unit; and determining the carbon content of the sample by means of the analysis unit on the basis of the carbon dioxide gas produced during the oxidation of the sample.

A method of operating a gas sensor for a gas analyte including a sensing component includes, in a first mode, interrogating the sensor by periodically applying an electrical signal to the sensing component of the sensor, measuring sensor response to the electrical signal which is indicative of a sensitivity of the sensor each time the electrical signal is applied to the sensing component, determining whether one or more thresholds have been exceeded based upon the sensor response determined each time the electrical signal is applied to the sensing component, and entering a second mode, different from the first mode in analysis of the sensor response to the periodically applied electrical signals, if one or more thresholds are exceeded.

In some embodiments, a method of operating a gas sensor includes setting power to a heater in contact with a MOx sensor to provide a temperature that is below a threshold temperature; holding the temperature below the threshold temperature for a period of time to reduce ozone concentration in a gas sample in contact with the MOx sensor; increasing power to the heater to increase the temperature of the MOx sensor to an operating temperature; acquiring resistance data from the MOx sensor at the operating temperature; and processing the resistance data to provide a result related the gas sample.

The present application is directed to a multi-sensor gas sampling detection system and method for detecting and measuring the radicals in a radical gas stream and includes at least one radical gas generator in communication with at least one gas source. The radical gas generator may be configured to generate at least one radical gas stream which may be used within a processing chamber. As such, the processing chamber is in fluid communication with the radical gas generator. At least one analysis circuit in fluid communication with the radical gas generator may be used in the detection and measurement system. The analysis may be configured to receive a defined volume and/or flow rate of the radical gas stream. In one embodiment, the analysis circuit may be configured to react at least one reagent with radicals within the defined volume of the radical gas stream thereby forming at least one chemical species within at least one compound stream. At least one sensor module within the analysis circuit may be configured to measure a concentration of the chemical species within the compound stream. One or more flow measurement modules may be in fluid communication with the sensor module. During use, the flow measurement module may be configured to measure the volume of at least one of the compound stream and radical gas stream.

A sensitive, compact detector measures total reactive nitrogen (NO.sub.y), as well as NO.sub.2, NO, and O.sub.3. In all channels, NO.sub.2 is directly detected by laser diode based cavity ring-down spectroscopy (CRDS) at 405 nm. Ambient O.sub.3 is converted to NO.sub.2 in excess NO for the O.sub.3 measurement channel. Likewise, ambient NO is converted to NO.sub.2 in excess O.sub.3. Ambient NO.sub.y is thermally dissociated at 700 C to form NO.sub.2 or NO in a heated quartz inlet. Any NO present in ambient air or formed from thermal dissociation of other reactive nitrogen compounds is converted to NO.sub.2 in excess O.sub.3 after the thermal converter. The precision and accuracy of this instrument make it a versatile alternative to standard chemiluminescence-based NO.sub.y instruments.

A filed portable analyzer capable of performing both the sampling and analytical procedures required by U.S. EPA Method 25 utilizing a small volume injection of sample onto a cryotrap cooled by a Stirling linear drive charged with helium to replace the field sampling condensate trap. The cryotrap is followed by the specified sorbent column/traps to ensure precise compatibility with prior reported compliance test results. The analytical system utilizes an oxidation catalyst and reduction catalyst to remove the potential for differing response factors on the FID from different compounds.

An analyzer determining/classifying aircraft air contaminants using a contaminant collector comprises a microporous medium, a bypass; a sensor generating frequency response when contaminant mass is added to/removed from the sensor, receiving contaminants desorbed from the medium; a first sample flow path, passing through the collector; a second sample flow path, bypassing the collector; a frequency measurement device, measuring response generated by the sensor as contaminant is added to and removed; a computer readable medium bearing a contaminant recognition program and calibration data; and, a processor executing the program, the program including a module classifying the contaminant and measuring response signal magnitudes, and a module using the data for comparison with magnitude of the response generated by the sensor to calculate contaminant concentration and determine a target value for contaminant type, and using measured response magnitudes to adjust first sample flow rates and/or flow durations based upon measured response magnitudes.

Provided herein is a solar powered system for a gas sampling and analysis for placement and operation remote from conventional infra-structure that utilizes a minimum of power to obtain a sample extracted from a source such as a pipeline or well-head, conditions the extracted sample, transmits the conditioned sample through vacuum jacketed tubing to an analyzer while maintaining the sample at a temperature and pressure preventing phase transition, condensation or component partitioning.

A replaceable spectroscopic detector used in volatile organic compounds testing devices, such as a portable breath testing device for roadside drug testing or a testing device for any air handling systems, such as those used for indoor agriculture, which reversibly sorb compounds and prepare a concentrated sample in a single gas cell configured for performing spectroscopy of the contents within the cell. The disclosed invention comprising; one or more check valves, a source of electromagnetic radiation and an electromagnetic receiver that releasably connects to a volatile organic compounds testing device such that it is replaceable and is configured for performing spectroscopy and passing exhaled breath and/or airflow through a disposable and replaceable reversibly engaging cartridge comprising a reversible sorbent and a gas cell configured for spectroscopy. The invention further comprises a heater that preferably is included in the cartridge for heating the cell and desorbing the sorbed compounds preparing a concentrated sample inside the gas cell.