Abstract: 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.

Abstract: Method of sensing A method of sensing a target material in an environment is disclosed. The method comprises exposing a sensor to an environment for a first exposure period. The method further comprises, following the first exposure period, isolating the sensor from any target material in the environment for a first isolation period wherein the first isolation period is less than a characteristic recovery period for the sensor to return to a baseline after the first exposure period. The method further comprises, following the first isolation period, exposing the sensor to the environment for a second exposure period, and determining a concentration of the target material from a response of the sensor during the second exposure or a response of the sensor during the first and second exposure.

Abstract: 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.

Abstract: An apparatus for determining a presence, a concentration or a change in concentration of a target material in an environment is disclosed. The apparatus comprises first and second sensors configured to respond to the target material. The apparatus further comprises a fluid inlet in fluid communication with the environment, and a valve assembly having a first and second configuration. In the first configuration, the fluid inlet is in fluid communication with only the first sensor. In the second configuration, the fluid inlet is in fluid communication with the first sensor and the second sensor.

Abstract: A method of determining a presence, concentration or change in concentration of a first or second material in an environment is disclosed. The method comprises measuring a response of a first sensor to the first and second material, wherein the first sensor is one of a metal oxide sensor, an electrochemical sensor, a photoionisation sensor, an infrared sensor, a pellistor sensor, an optical particle monitor, a quartz crystal microbalance sensor, a surface acoustic wave sensor, a cavity ring-down spectroscopy sensor, or a biosensor. The method further comprises measuring a response of a second sensor to the first and second material, wherein the second sensor is another one of a metal oxide sensor, an electrochemical sensor, a photoionisation sensor, an infrared sensor, a pellistor sensor, an optical particle monitor, a quartz crystal microbalance sensor, a surface acoustic wave sensor, a cavity ring-down spectroscopy sensor, a biosensor or a field effect transistor sensor.

Abstract: A sensor system that removes responses from an interferent and/or corrects for baseline drift of a sensor to determine a presence, a concentration or a change in concentration of a target material in a gaseous environment. Fluid flowing into the system may be directed by a valve arrangement to either a first fluid flow path or a second fluid flow path. The target material may be absorbed by a filter material in the first fluid flow path. Fluid flowing along the second gas flow path passes directly to the sensor. Responses of the sensor to fluids from the first and second fluid flow paths may be used to determine a presence, concentration or change in concentration of the target material.

Abstract: A gas sensor system (100) for detecting conjugated hydrocarbons and/or esters in an environment. The gas sensor system includes two organic thin film transistor (OTFT) gas sensors (200, 300). The first OTFT gas sensor (200) allows for interaction of the conjugated hydrocarbon with the gas sensor's source and drain electrodes, and the second OTFT gas sensor (300) blocks the conjugated hydrocarbon from interacting with the gas sensor's source and drain electrodes. In the second gas sensor, a monolayer comprising 4-aminobenzenethiol and 4-fluorobenzenethiol may cover the source and drain electrodes preventing the conjugated hydrocarbon from interacting with the source and drain electrodes. The gas sensor system may be used to monitor a volatile conjugated hydrocarbon and/or an ester produced by fruit.

Abstract: An apparatus for determining a presence, a concentration or a change in concentration of a target material in an environment is disclosed. The apparatus comprises first and second sensors configured to respond to the target material. The apparatus further comprises a fluid inlet in fluid communication with the environment, and a valve assembly having a first and second configuration. In the first configuration, the fluid inlet is in fluid communication with only the first sensor. In the second configuration, the fluid inlet is in fluid communication with the first sensor and the second sensor.