Abstract: An electrochemical gas sensor, for acid analyte gases, has an absorbent, which is suitable for absorbing a reaction product formed at the electrode. The electrochemical gas sensor further has a boron 5 compound, which is suitable for reacting chemically with the acid analyte gas. A process determines the concentrations of acid gases. A process uses an electrochemical gas sensor for determining the concentrations of acid gases.

Abstract: Ion sensing device includes a field-effect transistor including a bottom gate and a top gate, a reference electrode, and a driver circuit configured to measure concentration of ions in a sample solution into which the reference electrode and the top gate are immersed. The driver circuit includes a constant current source configured to supply a drain of the field-effect transistor with a constant current, and a voltage follower configured to receive a potential of the drain. The driver circuit is configured to supply the reference electrode with a constant reference potential, apply a constant voltage across an output of the voltage follower and the bottom gate, and output an output potential of the voltage follower.

Abstract: The present disclosure provides a biochemical test chip, including an insulating substrate, an electrode unit, a first insulating septum, a reactive layer and a second insulating septum. The electrode unit is located on the insulating substrate. The electrode unit includes a working electrode and a counter electrode. A current density of the counter electrode is greater than a current density of the working electrode. The first insulating septum is located on the electrode unit. The first insulating septum has an opening, which at least partially exposes the electrode unit. The reactive layer is located in the opening and is electrically connected to the electrode unit. The second insulating septum is located on the first insulating septum.

Abstract: A control system for a vehicle having an internal combustion engine with an exhaust system includes one or more oxygen (O2) sensors disposed proximate to a catalytic converter, a first bias circuit configured to provide a first bias voltage to the one or more O2 sensors, and a second bias circuit configured to provide a second bias voltage to the one or more O2 sensors. A controller is programmed to: upon detecting a cold start condition, connect the one or more O2 sensors to the first bias circuit to receive the first bias voltage to rapidly detect a usable signal indicating light off of the one or more O2 sensors, to thereby facilitate initiation of a closed loop feedback control to reduce exhaust emissions; and subsequently connect the one or more O2 sensors to the second bias circuit to receive the second bias voltage to operate in the closed loop feedback control.

Abstract: The present disclosure provides a biochemical test chip, including an insulating substrate, an electrode unit, a first insulating septum, a reactive layer and a second insulating septum. The electrode unit is located on the insulating substrate. The electrode unit includes a working electrode and a counter electrode. A current density of the counter electrode is greater than a current density of the working electrode. The first insulating septum is located on the electrode unit. The first insulating septum has an opening, which at least partially exposes the electrode unit. The reactive layer is located in the opening and is electrically connected to the electrode unit. The second insulating septum is located on the first insulating septum.

Abstract: Disclosed herein is a chemical sensing system, comprising: a sensor configured to adsorb an analyte; an electronic circuit to operate the sensor; and a microcontroller in communication with the sensor and the electronic circuit. The microcontroller can also be configured to provide a real-time signal indicative of a concentration of the analyte. The sensor can comprise a microelectromechanical system (MEMS) resonator and a sensing film configured to adsorb the analyte, the sensing film coating at least a portion of the sensor. The MEMS resonator can comprise a second sensor, such as an impedimetric sensor to measure at least a second property of the sensing film. The electronic circuit can process signals stemming from at least two properties of the same sensing film, such as the changes in mass and dielectric constant of the same sensing film due to adsorption of analyte.

Abstract: Devices for sequencing linear biomolecules (e.g., DNA, RNA, polypeptides, proteins, and the like) using quantum tunneling effects, and methods of making and using such devices, are provided. A nanofabricated device can include a small gap formed by depositing a thin film between two electrodes, and subsequently removing the film using an etching process. The width of the resulting gap can correspond with the size of a linear biomolecule such that when a part of the biomolecule (e.g., a nucleobase or amino acid) is present in the gap, a change in tunneling current, voltage, or impedance can be measured and the part of the biomolecule identified. The gap dimensions can be precisely controlled at the atomic-scale by, for example, atomic layer deposition (ALD) of the sacrificial film. The device can be made using existing integrated circuit fabrication equipment and facilities, and multiple devices can be formed on a single chip.

Abstract: The technology relates to a transportable gas detector unit configured to operate in a detection mode and a test mode for gas sensor testing and calibration. The transportable gas detector is configured with one or more gas sources mounted on the gas detector unit by mounting points to rigidly hold the gas sources in place when the gas detector unit is moved, enabling remote testing/calibration of gas sensors.

Abstract: A trace metal analysis detector and method of operating the same to detect metals in various fluid samples using boron doped diamond working electrodes.

Abstract: Various embodiments include a method for regenerating a coated particulate filter arranged in an exhaust-gas duct of a motor vehicle. The method may include: detecting a need for particulate filter regeneration; determining a first diagnosis value before initiating particulate filter regeneration; after determining the first diagnosis value, carrying out particulate filter regeneration; determining a second diagnosis value after particulate filter regeneration; determining a difference between the first determined diagnosis value and the second determined diagnosis value; comparing the determined difference with a threshold value; and identifying a particulate filter defect if the determined difference exceeds the threshold value.

Abstract: A gel for use in a pH or an ORP sensor, components of the gel comprising water, a reference electrolyte salt, a buffering system for adjusting pH of the gel, and a polymeric gelling agent, and the gel does not degrade under gamma irradiation.

Abstract: An implantable biosensor may be placed subcutaneously to monitor the concentration of an analyte in a body fluid. The biosensor may include an electrochemical cell and an antenna. The components of the biosensor, including the electrochemical cell and the antenna, may be disposed on a same substrate. The electrochemical cell may include multiple electrodes for performing electrochemical measurements that include a first measurement of the analyte concentration in the body fluid, a second measurement of a background interference present in the body fluid, and a third measurement of a pH level within the body fluid. The antenna may receive, from a transceiver, radio frequency (RF) waves for wirelessly powering the implantable biosensor. The antenna may further transmit, back to the transceiver, a backscatter signal encoding a result of the electrochemical measurements.

Abstract: Various example embodiments described herein relate to an electrochemical gas sensor. The electrochemical gas sensor can include a sensor cap having one or more solid features disposed on a surface of the sensor cap. The electrochemical gas sensor can include a counter electrode configured to generate a gas during use of the electrochemical gas sensor. The electrochemical gas sensor can include a vent assembly adapted to release at least a portion of the gas generated at the counter electrode out from the electrochemical gas sensor. The vent assembly can include a vent conduit and a vent membrane that defines a passage for the gas to flow from an extended portion of the counter electrode, to the vent conduit, via the vent membrane, so as to be vented from the electrochemical gas sensor.

Abstract: The invention is related to an electrode assembly for an electrochemical process comprising a current supply device, an elongated current distribution bar comprising first and second ends, and a sheet-shaped electrode substrate attached to the current distribution bar and having a longitudinal extension and a lateral extension. The current distribution bar comprises a first portion attached to the current supply device, a second portion extending along the electrode substrate, and a third portion extending between the first and second portions. The current distribution bar is bent between its first and second ends, and the current supply device is laterally and longitudinally positioned beyond the electrode substrate. The second portion at least partly extends longitudinally along the electrode substrate.

Abstract: A connected device with at least one sensor adapted to measure at least a physical quantity and to report a measure of this physical quantity to a remote device, the at least one sensor system providing an output Z which is then digitized in order to provide an output signal Y having a first and a second component, the first component being representative of the measured physical quantity X and the second component being representative of the structural noise R introduced by the at least one sensor. The connected device also has a noise generator configured to generate using as an input at least one parameter representative of the structural noise R a blurring noise V which is uncorrelated with said structural noise R; combine the digital output signal Y with the blurring noise V in order to generate a signal Y?; transmit signal Y? to the remote device.

Abstract: A method for testing electronic products implemented in an electronic device includes selecting a serial port connected with a slave device in serial communication with a product under test. An activation instruction is transmitted to the slave device, and the electronic product is started through the slave device. Data stored in at least one register of the electronic product and a state of the electronic product is obtained and a capacitance of at least one capacitor in the electronic product is measured. When the electronic product is found to be in an abnormal state, determining a cause of abnormality according to data of the electronic product and the capacitance of the at least one capacitor.

Abstract: Device and methods for controlling pH or ionic gradient comprising a multisite array of feedback electrode sets comprising electrodes and pH sensing elements. The electrodes can include a reference electrode, counter electrode, and a working electrode. The device and methods iteratively select an amount of current and/or voltage to be applied to each working electrode, apply the selected amount of current and/or voltage to each working electrode to change pH of a solution close to the working electrode, and measure the signal output of the sensing element. The multisite array can include feedback and non-feedback electrode sets.

Abstract: A sensor package, a sensor system, and a method for fabricating the sensor package are described that include a sensing chip having dispense chemistry disposed over an array of conductive elements. In an implementation, the sensor package may include a sensing chip that may include at least one conductive element, wherein the at least one conductive element may be part of an array of conductive elements defining a M by N matrix, where M is a number of rows of the at least one conductive element and N is a number of columns of the at least one conductive element. The sensing chip may further include dispense chemistry that may be disposed on the at least one conductive element and at least one contact pad. The sensor package may further include a microfluidic cap that may be positioned over at least a portion of the sensing chip, wherein the microfluidic cap and the sensing chip may define a cavity that may be configured to receive a fluid sample.

Abstract: Disclosed herein are devices, apparatus, systems, methods and kits for performing immunoassay tests on a sample. The A sensing apparatus is provided for detecting a plurality of different target analytes in a sample. The apparatus may comprise an array of sensing devices provided on a substrate, each sensing device in the array comprising a working electrode having (1) semiconducting nanostructures disposed thereon and (2) a capture reagent coupled to the semiconducting nanostructures that selectively binds to a different target analyte in the sample. The apparatus may also comprise sensing circuitry that (1) simultaneously detects changes to electron and ion mobility and charge accumulation in the array of sensing devices when the capture reagents in the array of sensing devices selectively bind to the plurality of different target analytes, and (2) determines the presence and concentrations of the plurality of different target analytes in the sample based on the detected changes.

Abstract: A biosensing chip is provided, including a substrate having a photoelectric conversion material, and an electrode disposed on the substrate and including two contact portions and an electrode pattern, wherein the photoelectric conversion material is a monocrystalline silicon material, and the electrode pattern includes micro-electrodes in the form of interdigitated sawtooth. The biosensing chip and the method using the same may distinguish a lesion site of cancer cells and the degree of cancer lesions.

Abstract: Devices for sequencing linear biomolecules (e.g., DNA, RNA, polypeptides, proteins, and the like) using quantum tunneling effects, and methods of making and using such devices, are provided. A nanofabricated device can include a small gap formed by depositing a thin film between two electrodes, and subsequently removing the film using an etching process. The width of the resulting gap can correspond with the size of a linear biomolecule such that when a part of the biomolecule (e.g., a nucleobase or amino acid) is present in the gap, a change in tunneling current, voltage, or impedance can be measured and the part of the biomolecule identified. The gap dimensions can be precisely controlled at the atomic-scale by, for example, atomic layer deposition (ALD) of the sacrificial film. The device can be made using existing integrated circuit fabrication equipment and facilities, and multiple devices can be formed on a single chip.

Abstract: The present disclosure relates to a method of manufacturing an ion-selective sensor element for a potentiometric sensor, the sensor element having a sensor element body and at least one glass layer arranged on the sensor element body, the method comprising applying the at least one glass layer to the sensor element body by means of a thermal spraying method, in which a powder of glass particles is sprayed onto the sensor element body.

Abstract: A sensor device is disclosed. The sensor device includes a monitor thin film transistor, a reference thin film transistor, and a control unit. The control unit is configured to determine a value measured from a sample based on a differential degree between output current of the reference thin film transistor and output current of the monitor thin film transistor.

Abstract: Provided is a gas sensor system with a gas sensor, and a microprocessor programmed to control the gas sensor with at least two operational modes. The first operational mode controls the gas sensor from a baseline level through analyte detection. Upon initiation of the recovery phase after analyte withdrawal, the gas sensor system switches to the second operational mode, which changes conditions of the gas sensor to (i) accelerate removal of the analyte from the gas sensor and (ii) accelerate recovery of the gas sensor output towards the baseline level. When no further analyte is detected, the gas sensor switches back to the first operational mode or to an additional operational mode to complete recovery.

Abstract: Various example embodiments described herein relate to an electrochemical gas sensor. The electrochemical gas sensor can include a sensor cap having one or more solid features disposed on a surface of the sensor cap. The electrochemical gas sensor can include a counter electrode configured to generate a gas during use of the electrochemical gas sensor. The electrochemical gas sensor can include a vent assembly adapted to release at least a portion of the gas generated at the counter electrode out from the electrochemical gas sensor. The vent assembly can include a vent conduit and a vent membrane that defines a passage for the gas to flow from an extended portion of the counter electrode, to the vent conduit, via the vent membrane, so as to be vented from the electrochemical gas sensor.

Abstract: Nanozymes capped with a radical-scavenging capping agent are disclosed for use in biosensing assays with improved sensitivity. The radical-scavenging capping agent facilitates the capture and retention of one or more radicals for enhancing a catalytic reaction. In some example embodiments, the nanozyme capped by the radical-scavenging capping agent is capable of catalyzing the decomposition of hydrogen peroxide or molecular oxygen. The capped nanozymes may be incorporated with an electrode, such as the working electrode of an electrochemical sensor, for achieving enhanced catalytic activity and a lower limit of detection. In some example embodiments, the radical-scavenging capping agent is or includes thiocyanate.

Abstract: A photo-interruptor unit includes a photo-interruptor and a supporting portion to detachably support the photo-interruptor. The supporting portion includes a hole which is formed on an attaching surface and through which a hook portion is inserted, and a guide portion to protrude from the attaching surface and guide the hook portion so that it deforms in a deformation direction when the photo-interruptor is moved in a movement direction intersecting an insertion direction. A regulating portion protrudes from the attaching surface and forms continuously with the guide portion to regulate a position in the movement direction of the photo-interruptor. The guide portion includes a first rib portion and a second rib portion that oppose one another in the deformation direction, and a distance between the first rib portion and the second rib portion in the deformation direction narrows toward a downstream direction of the movement direction.

Abstract: The present invention relates generally to systems for measuring pH. In particular, the present invention relates to a continuous flow system having one or more solid state pH sensors positioned within a fluid pathway of the system to provide continuous pH measurement.

Abstract: In order to make it possible to conduct a zero calibration even though an interference gas exists in a measurement area of a detector, a light absorbance analysis apparatus includes a detector that detects an intensity of light that transmits a gas, a total pressure sensor that measures a total pressure of the gas, an absorbance calculating part that calculates an absorbance based on an output value of the detector and a previously set zero reference value, a partial pressure—absorbance relation storing part that stores a partial pressure—absorbance relational data that indicates a relationship between a partial pressure of an interference gas that exists in a measurement area of the detector and an absorbance calculated by the absorbance calculating part, and a partial pressure calculating part that calculates an interference gas partial pressure as a partial pressure of the interference gas.

Abstract: Flexible transistors and electronic circuits incorporating the transistors are provided. The flexible transistors promote heat dissipation from the active regions of the transistors while preserving their mechanical flexibility and high-frequency performance. The transistor designs utilize thru-substrate vias (TSVs) beneath the active regions of thin-film type transistors on thin flexible substrates. To promote rapid heat dissipation, the TSVs are coated with a material having a high thermal conductivity that transfers heat from the active region of the transistor to a large-area ground.

Abstract: A potentiostat circuit for controlling a work electrode voltage and for measuring a work electrode current is disclosed. The disclosed potentiostat circuit implementations have a topology and include elements to provide a plurality of benefits. The plurality of benefits includes an enlarged range of controllable work electrode voltages and bidirectional work electrode current measurements, high immunity from temperatures variations and process mismatch. The disclosed potentiostat circuit implementations can be used in applications requiring accuracy, low power consumption, and small size. The applications can include portable and/or multichannel electrochemical applications.

Abstract: A tactile sensor including a first insulating layer, an intermediate layer of conductive soft polymer material, and a second insulating layer. The intermediate layer includes first and second electrically conductive strips located therein and the intermediate layer is positioned above the first insulating layer. The first and second electrically conductive strips are located within the same horizontal plane within the intermediate layer and the first and second electrically conductive strips are connected to an impedance measuring device.

Abstract: A three-electrode array local electrochemical information testing system and a testing method, the testing system comprising: a concentric ring three-electrode array, a high-speed switch and an electrochemical workstation, which are electrically connected in sequence; the concentric ring three-electrode array comprises a plurality of concentric ring three-electrode units, adjacent concentric ring three-electrode units being separated by an insulating material; a concentric ring three-electrode unit comprises a ring-shaped auxiliary electrode, a solid-state reference electrode and a wire-shaped working electrode; the ring-shaped auxiliary electrode and the solid-state reference electrode are both formed in an ring-shaped shape; the wire-shaped working electrode is located within the solid-state reference electrode, the wire-shaped working electrode being separated from the solid-state reference electrode by means of the insulating material; the solid-state reference electrode is located within the ring-shaped

Abstract: The invention provides the present invention provides a faecal detection sensor for an absorbent article. The sensor includes a faeces-sensitive material that reacts to the presence of a constituent of faecal matter, wherein the sensor exhibits an electrical property that changes following the reaction of the faeces-sensitive material. In embodiments of the invention the faeces sensitive material is a material that reacts due to the presence of a sulfur-containing compound in faecal matter, such as metallic faeces-sensitive materials, or is a material that reacts with a faecal enzyme and/or other constituents of faecal matter, such as organic faeces-sensitive materials.

Abstract: Compositions and methods for amplifying selected polynucleotides, including DNA and RNA, particularly in multiplex amplification reactions using common primers amplification. Generally, methods of the invention employ multiple steps such as template-specific hybridization, a linear amplification, partial degradation of nucleic acid, and ligation. At the end of the process the sequences of selected polynucleotides are flanked by the common sequences which can be used for exponential amplification using common primers. In some aspects the polynucleotides are associated with a barcode and the presence of the barcode is detected to measure the amount of the polynucleotide.

Abstract: An electrochemical gas sensor includes a housing comprising a gas inlet, an electrolyte within the housing, a working electrode in ionic contact with the electrolyte, a counter electrode in ionic contact with the electrolyte and a secondary electrode in ionic contact with the electrolyte. Reaction of target gas at the secondary electrode is less than reaction of target gas at the working electrode. Electronic circuitry of the gas sensor is configured to measure an output from the working electrode and an output from the at least one secondary electrode. A correction factor is determined for correcting the output from the working electrode on the basis of the working electrode output and the secondary electrode output during an assessment in which the electrochemical sensor is exposed to the target gas for a determined period of time.

Abstract: A voltage application detection unit detects an impedance of an oxygen sensor, which outputs a signal corresponding to a concentration of oxygen, based on a current change amount in the oxygen sensor caused by application of a voltage to the oxygen sensor. A current application detection unit detects the impedance based on a voltage change amount generated across the oxygen sensor caused by application of a current to the oxygen sensor. A detection switching unit switches between the voltage application detection unit and the current application detection unit to detect the impedance based on a state of the oxygen sensor.

Abstract: An electrochemical sensor is provided having a housing with an opening therein. The housing defines a chamber. The sensor includes a primary cell having a primary working electrode aligned with the opening in the housing so that the primary working electrode is exposed to an environment outside of the chamber. A primary counter electrode is sealed within the chamber. The sensor includes a secondary cell having a secondary working electrode sealed within the chamber, and a secondary counter electrode sealed within the chamber.

Abstract: A microfluidic device may include a microfluidic channel including an electrode placed at opposite ends of the microfluidic channel to create an electrical field within the channel and an ejection device to eject at least one cell porated within the electrical field. A cassette may include a substrate, a die coupled to the substrate, a microfluidic channel defined within the die, the microfluidic channel including a necked portion to receive a cell therein and at least two electrodes each placed at a first and a second end of the microfluidic channel to apply an electric field to the cell above a proration threshold and a cell ejection device to eject the cell from the die.

Abstract: An electrochemical device for diagnostic purposes, and particularly point-of-care diagnostic purposes, is capable of detecting quorum sensing molecules, such as AHL, within a biological sample with high precision. The device includes at least one reference electrode (RE), at least one counter electrode (CE), and two or more working electrodes (WEs). Each working electrode differs from the other working electrode(s) with respect to at least one of the following characteristics: surface area, size, material, and coating. The device also has a sample receiving area for receiving a biological sample, wherein the electrodes and the sample receiving area is fluidly connected, and a means for transferring the sample to the electrodes for measurement, and a means for displaying a result of the measurement.

Abstract: The present disclosure relates to a glass electrode including an analyte-sensitive glass membrane, an electrically conductive lead, and an intermediate layer which conductively connects the lead and the glass membrane to one another. According to the present disclosure, the intermediate layer is made of an electron- and/or ion-conducting polymer.

Abstract: The systems and methods of this disclosure enable evaluation, verification, and testing of toxic gas sensors without the need for a target gas cylinder. The systems and methods for testing toxic gas sensors over a broad range of frequencies facilitates evaluation and diagnosis of mechanisms underlying sensor performance. The systems and methods of this disclosure may be incorporated into portable gas sensing equipment for in field diagnostics.

Abstract: A gas sensor element including: a first ceramic layer (300) including a solid electrolyte (320); a pair of electrode portions (330) and (333) at least partially disposed on opposing surfaces of the solid electrolyte; a support member (341) surrounding a part of an outer peripheral edge of at least one electrode portion (330) of the pair of electrode portions and having a notch (341N), a part of the electrode portion extending in the notch; and a second ceramic layer (242) disposed on a side where the at least one electrode portion (330) is present, so as to be in contact with a surface of the support member, the gas sensor element being obtained by stacking the first ceramic layer (300), the support member (341) and the second ceramic layer (242), wherein the second ceramic layer covers at least a part of the notch.

Abstract: Devices that include a substrate; a source region and a drain region formed within the substrate and having a channel region provided therebetween; a first insulating layer formed over the channel region; a first floating gate formed over the first insulating layer, the first floating gate configured to respond to an analyte in a target material; and a second gate formed over the first floating gate, the second gate capacatively coupled but not electrically connected to the first floating gate.

Abstract: An actuating and sensing module includes a first substrate, a second substrate, an actuating device and a sensor. A gas flow channel is formed by stacking the first substrate and the second substrate. The gas inlet, the gas flow channel and the gas outlet are in communication with each other to define a gas flow loop. The actuating device is disposed in the gas inlet of the second substrate and electrically connected to a control circuit to obtain a driving power. The sensor is disposed in the gas flow loop and electrically connected to a control circuit of the first substrate to transmit sensed data. While the actuating device drives outside gas from the outside, the gas is transported into the gas flow loop and sensed by the sensor.

Abstract: A sensor system including devices and methods for determining the concentration of an analyte in a sample is described. Input signals including amperometric and voltammetric duty cycles of excitations and relaxations may provide a shorter analysis time and/or improve the accuracy and/or precision of the analysis. The disclosed system may reduce analysis errors, thus improving measurement performance, by adjusting the potential and/or scan rate in response to output currents obtained from voltammetric scans. The disclosed system also may determine the concentration of more than one ionizable species in the sample by adjusting the potential and/or scan rate in response to output currents obtained from voltammetric scans. The multiple, determined concentrations may be used to determine the concentration of multiple analytes or to correct the concentration determined for an analyte, thus improving the measurement performance of the system.

Abstract: A process variable transmitter for measuring a process variable includes a process variable sensor configured to sense a process variable and provide a sensor output. Measurement circuitry receives the sensor output and provides a measured output related to the process variable. Output circuitry provides a device output on a two-wire process control loop based upon the measured output. The output circuitry has a transfer function that is a function of an adjustable analog circuit component. A motorized actuator is configured to adjust the adjustable analog circuit component to thereby change the transfer function of the output circuitry. An optional calibration controller is also provided.

Abstract: A measurement circuit may include a transistor having a first terminal, a second terminal, and a third terminal, wherein the first terminal is coupled to a first reference voltage. The measurement circuit may further include a first operational amplifier including a first input coupled to the second terminal of the transistor and an output coupled to the third terminal of the transistor. The first operational amplifier may further include a second input configured to receive a second reference voltage. The measurement circuit may also include a first unity-gain voltage follower including a second operational amplifier having a first input coupled to the first input of the first operational amplifier. Methods of measuring a threshold voltage, semiconductor devices, and electronic systems are also described.

Abstract: The present invention relates generally to components prepared by additive manufacturing (AM) methods, along with methods of preparing such components by AM. More especially, there is provided a process for the production of a component of an ignition device using an AM method by forming a layer of metal or alloy on a surface of a metal or alloy substrate; fusing the layer to the substrate; and repeating the addition of such layers upon one another to form a deposited metal or alloy attachment on the substrate.

Abstract: A system includes a system housing including an inlet, at least one gas sensor responsive to a first analyte gas other than oxygen within the system housing and in fluid connection with the inlet, and a sensor responsive to oxygen within the system housing and in fluid connection with the inlet. The sensor responsive to oxygen is formed to be chemically separate from the at least one gas sensor responsive to the first analyte gas other than oxygen. The sensor responsive to oxygen is responsive to a change in the concentration of oxygen arising from creation of a driving force in the vicinity of the inlet to provide an indication of a state of a transport path between the inlet of the system and the at least one gas sensor responsive to the first analyte gas other than oxygen.