Abstract: A measurement device of the present invention is provided with a sensor holding part (10) which detachably holds a sensor having an electrode terminal at its one end, a connection terminal (14) which elastically contacts the electrode terminal of the sensor to take out a signal required for analysis, an ejection mechanism having a pushing member (11) which is extrudably attached to the device body, and pushes the sensor that is held by the sensor holding part (10) with the electrode terminal thereof elastically contacting the connection terminal (14) while releasing the contact between the sensor electrode terminal and the connection terminal (14), thereby to eject the sensor from the sensor holding part (10), and a first brake part (13) which elastically contacts the sensor to brake the movement of the sensor in the ejection direction while performing the extrusion operation of pushing out the sensor by the ejection mechanism.

Abstract: There is disclosed means for quickly solving instability of sensor sensitivity performances found in an initial stage and stabilizing the sensor sensitivity performances, when immersing a chemical sensor kept under a dry state in a buffer solution used as a storage liquid and applying a measurement bias between a working electrode and a reference electrode to make first use of the chemical sensor for measurement in which the chemical sensor is used. To make the first use of the chemical sensor, after immersing the chemical sensor kept under a dry state in the buffer solution used as the storage liquid, a first initial treatment bias having the same direction as that of the measurement bias and possessing an absolute value larger than that of the measurement bias is applied between the working electrode and the reference electrode for a first initial treatment time.

Abstract: A method for monitoring a select analyte in a sample in an electrochemical system. The method includes applying to the electrochemical system a time-varying potential superimposed on a DC potential to generate a signal; and discerning from the signal a contribution from the select analyte by resolving an estimation equation based on a Faradaic signal component and a nonfaradaic signal component.

Abstract: In one embodiment, the present invention is directed to a pulsed electrochemical detection method comprising (a) flowing a liquid sample stream including at least one analyte past a working electrode in a flow-through cell; (b) applying at least three pulsed electrical potentials to the working electrode, (1) a first conditioning potential, (2) a second detection and oxidative cleaning potential, and (3) a third reductive cleaning potential, said second potential being higher than said first and third potentials and said first potential being higher than said third potential; and (c) detecting the output from said working electrode during the time period of applying said second potential.

Abstract: The invention relates to a device and a method for performing maintenance on an apparatus. The device has a flow duct with a wall section in which at least one apparatus which projects into the flow duct and which is to be reworked after a certain operating time is arranged. A vessel which is open towards the wall section is arranged to as to be movable relative to the wall section in such a way that in an open position it is arranged at a distance from the apparatus, and in a second position forms, together with the wall section, a sealed volume which is separated from the rest of the flow duct and in which the maintenance of the apparatus is performed.

Abstract: The gas sensor control apparatus is for controlling a gas sensor including a sensor element having a solid electrolyte layer, and first and second electrodes located on opposite sides of the solid electrolyte layer, the first electrode serving as a gas detecting electrode, the second electrode serving as a reference electrode, the sensor element generating, as a sensor output, a current flowing between the first and second electrodes having a value depending on concentration of a specific gas component contained in a gas under measurement. The gas sensor control apparatus includes a determination function of determining whether or not it is time for the gas sensor to start operation, and a control function of forcibly supplying oxygen from a side of the second electrode to a side of the first electrode on a temporary basis when a determination result of the first function becomes affirmative.

Abstract: Systems and methods for detecting glucose in a sample using, for example, a regenerable sensor are described. The sensor may, for example, include boronic acid to detect with great sensitivity and at a low cost the glucose in the sample.

Abstract: An electrochemical sensor system and membrane and method thereof for increased accuracy and effective life of electrochemical and enzyme sensors.

Abstract: A thin deck water property sensor includes a base, an upper lid, a positive and negative probe, an electric connection element, a processing unit and a display unit. The base and the upper lid are coupled together to form a flat deck. The upper lid has a recess to hold sample water to be tested. The positive and negative probe is extended into the recess in contact with the sample water. The electric connection element has one end connecting to the processing unit and another end coupling with a conductive elastic member. The conductive elastic member is connected to the positive and negative probe. The processing unit receives charged signals of the sample water to generate a test result which is displayed on the display unit.

Abstract: The invention relates to a system for continuous monitoring of analytes in a biological fluid, the system having increased life by virtue of inherent regeneration of sensors employed. An embodiment of the invention includes a biosensor, a sampling device for providing a sample of the biological fluid, device(s) for passing a flow of a background fluid through the flow passage at selectable flow rates, device(s) for injecting the sample into the flow of background fluid, and device(s) for increasing the flow rate of the combined flow. An embodiment of the invention provides device(s) for achieving a washing action at the signal generating portion.

Abstract: A method and apparatus for conditioning a sensor to measure an oxidation reduction potential of an aqueous solution such that the time to obtain a reliable oxidation reduction potential measurement is substantially reduced. Such conditioning is often necessary when the sensor is moved from potentiometric equilibrium (e.g., the sensor is cleaned, the sensor is exposed to air, and the like). The method may comprise generating a current through a measurement electrode and a reference electrode of the sensor for a duration of time. A reliable oxidation reduction potential measurement can be made as the voltage across the measurement electrode and the reference electrode stabilizes after the duration of time. Depending on the aqueous solution, the stabilized value can be constant or variable.

Abstract: A two-step chemical treatment method for chemically conditioning a sensor element comprising an electrolyte in ionic communication with a first electrode and a second electrode is described. The method comprises treating at least a portion of a sensor element with a first solution comprising an inorganic base, a carbonate salt and an acid salt; heating the sensor element; treating at least a portion of the sensor element with a second solution comprising an inorganic base and a carbonate salt; and drying the sensor element. The gas sensors comprising the two-step treated sensor elements have reduced lean shift, green effect, sensor output amplitude drop, and the light-off time is improved.

Abstract: A system for highly sensitive electrochemical detection of trace nitro-aromatic compounds in air, uses a carbon or carbon/gold working electrode with a surface that is modified to increase the electron transfer kinetics of nitro-aromatic compounds. Chemical modifiers of the working electrode surface include amino-aromatic compounds such as aniline and its derivatives. The detection method involves dissolving trace nitro-aromatic compounds in an electrolyte including aprotonic solvents, or dipolar solvents, in the electrochemical cell including a working electrode, a reference electrode and an auxiliary electrode. Voltage is varied across the working electrode and the reference electrode, and an electrical current is measured between the working electrode and the auxiliary electrode. The measured electrical peak current is a sensitive indication of the concentration of the trace compounds. This invention is appropriate for portable, field-testing of trace explosive compounds in air.

Abstract: A gas sensor element which may be employed in measuring the concentration of gas such O2, NOx, or CO. The gas sensor element consists of an electrochemical cell made up of a solid electrolyte body formed by a partially stabilized zirconia and a pair of electrodes disposed on the solid electrolyte body. The electrochemical cell is subjected to an aging treatment in which the dc current is applied to the electrodes at a given voltage to enhance the activation of the electrochemical cell.

Abstract: An automatable measuring, cleaning and calibrating device for pH-electrodes or electrodes for measuring redox potentials, specifically in process engineering, having an electrode armature which keeps the measuring electrode in an operating position or in a maintenance position, whereby the electrode is retained in the maintenance position in a rinsing chamber in which a cleaning and calibration procedure can be performed. The device has a pump device to supply cleaning fluid and calibration solutions to the rinsing chamber over a delivery line connecting the pump device and the rinsing chamber. In order to configure the device more compactly, the pump device includes several feeds on its intake side, and a device is furnished to selectively activate a particular feed, and the media (cleaning fluid, calibration solution, etc.) brought selectively over the particular feeds to the pump device reach the rinsing chamber over the common delivery line.

Abstract: A method of treating a gas sensor comprising: disposing the gas sensor in a basic agent solution comprising a basic agent selected from the group consisting of Group IA of the Periodic Table of Elements, Group IIA of the Periodic Table of Elements, and combinations comprising at least one of the foregoing metals, wherein the gas sensor comprises an electrolyte disposed between and in ionic communication with a first electrode and a second electrode; disposing the gas sensor in an acidic agent solution; wetting at least a portion of a porous protective layer of the gas sensor with an alkaline-carbonate solution; and heating the gas sensor.

Abstract: Re-usable, energy-efficient apparatus for the restoration of corrosion-damaged reinforced concrete and a method for controlling the same. The apparatus includes a combination electrode device in a sandwich construction that includes a dimensionally stable electrode, a reusable electrolyte reservoir, an ion exchanger element, a reference electrode, a power-switching device for anodic regulation, and a measuring system for determining the capacity of the ion exchanger element to take up ions. Use of this combination electrode device prevents the formation of active chlorine during extraction of chlorine from reinforced concrete.

Abstract: A method of manufacturing a gas sensor element which includes a solid electrolyte body, a target gas electrode a reference gas electrode provided on a surface of the solid electrolyte body so as to be exposed to a reference gas and the manufacturing method includes exposing the gas sensor element to a gas atmosphere containing at least one of a hydrocarbon gas, a CO2 gas, and a H2 gas and applying an ac voltage to said target gas electrode and the reference gas electrode. Each of the target gas electrode and the reference gas electrode is made up of a plurality of crystal grains defined by grain boundaries having a total length of 1000 &mgr;m or more in a surface area of 100 &mgr;m2.

Abstract: An oxygen sensor includes an electrolytic cell having a solid electrolyte capable of conducting oxygen ions at high temperatures and two electrodes oppositely attached to the electrolyte. The electrodes are generally made of porous, electron-conducting material, typically platinum, stable in high temperature. The electrolytic cell is treated with alternating current (AC) at a relatively high temperature for a period of time. The electrode treatment reduces impedance of the oxygen sensor. The electrode treatment can be used as a step in sensor manufacturing, as part of the warm-up cycle of an operational sensor or as part of a maintenance or repair schedule.

Abstract: The present invention relates to an electrode assembly that is capable of both solution measurement and in-line self-cleaning. Specifically, such electrode assembly comprises a central electrode and a measurement circuit for solution measurement, and an auxiliary electrode and an auxiliary current sourse for generating gas during intervals between solution measurement cycles, so as to remove any solid or liquid residues that may passivate the central electrode, thereby cleaning and rejuvenating the central electrode and preparing it for the next solution measurement cycle.

Abstract: A reference electrode assembly having a constrained-diffusion liquid junction between a liquid junction solution and a sample solution having separate flow paths, said assembly comprising a flow cell having attached thereto a constraint comprising a region of porous material permeable to water and salts; a remote reservoir for holding said liquid junction solution; a means for moving said liquid junction solution from said reservoir to said constraint; and a reference contact region is provided. This unique configuration provides a reference electrode device of the constrained-diffusion liquid junction type useful in pH and/or ion-selective electrode (ISE) potentiometric sensors and is particularly suitable for use in a mini-integrated electrochemical analyzer.

Abstract: Aqueous membrane permeable by mass transport to a charged and uncharged species of interest, comprising a synthetic polymeric material and a surface active agent which is miscible with the synthetic polymer. The surface active agent is distributed throughout the membrane and is present in an amount such as to provide for the permeability of the membrane to the species of interest.

Abstract: A method for analyzing a liquid test sample by electrochemiluminescence. The method includes at least one specific biochemical binding reaction that leads to the formation of a complex which contains a chemiluminescence marker and the binding of the complex to a magnetic microparticle. Detection is carried out in a measuring cell having a working electrode in order to determine the concentration of the marked microparticle. The detection cycle includes a purification step, a conditioning step, a recovery step and a measuring step. A specified potential profile is applied to the working electrode during these steps. Between the conditioning step and the recovery step, an additional potential pulse with an oxidizing and/or a reducing potential is inserted into the voltage shape of the detection cycle in order to improve the deposit of the microparticle.

Abstract: An electrochemical sensor (A, A′) is specific for the detection of peroxyacetic acid in a solution which also contains hydrogen peroxide. A potential is applied between a reference electrode (120, 120′) and a working electrode (118, 118′). A read voltage (FIG. 7) is selectively pulsed across a counter electrode (122, 122′) and the working electrode. The current flowing between the working electrode and the counter electrode is dependent on the peroxyacetic acid concentration in the solution (FIG. 6). By careful selection of the read voltage, the contribution of hydrogen peroxide to the current flow is virtually negligible. The sensor effectively measures peroxyacetic acid concentrations in the range generally employed in sterilization and disinfection baths (100-3000 ppm.).

Abstract: This invention provides a method for monitoring the function and/or regeneration of a gas probe. The invention includes a measurement of first and second pump currents of the gas probe and a determination of a difference between the first and second pump currents (&Dgr;I). If &Dgr;I exceeds a pregiven value, then a saturation pump voltage is applied and the difference between a resulting pump current and a previously stored minimum pump current (&Dgr;I plus) is determined. If &Dgr;I plus exceeds a pregiven value, then a regeneration voltage is applied.

Abstract: In performing control to supply power to a heater by detecting the impedance of a sensor element and feeding it back for control, a heater control device for an air-fuel ratio according to the invention can prevent damage to the heater or the sensor element by suppressing an excessive rise in the temperature of the heater and hence the sensor element even when the impedance of the sensor element has increased due to degradation of the sensor element. The heater control device includes: a feedback control unit which, based on the impedance of the air-fuel ratio sensor element, controls supply power to the heater for heating the air-fuel ratio sensor; a half-activation time detection unit which detects the half-activation time of the air-fuel ratio sensor; and a power limiting unit which, based on the half-activation time detected by the half-activation time detection unit, limits the power that is feedback-controlled by the feedback control unit.

Abstract: A system and method for rapid hydration and reduced out-of-warm-up baseline drift for chemical, electrochemical and enzyme sensors.

Abstract: One embodiment of a method for producing a gas sensor, comprises: disposing said gas sensor in a basic agent solution comprising a basic agent comprises a hydroxide of a metal selected from the group consisting of Group IA of the Periodic Table of Elements; Group IIA of the Periodic Table of Elements, and combinations comprising at least one of the foregoing basic agents, wherein said gas sensor comprises an electrolyte disposed between and in ionic communication with a first electrode and a second electrode; and disposing said gas sensor in an acidic agent solution.

Abstract: Each gas sensing element, with a measured gas sensing electrode and a reference gas sensing electrode provided on opposite surfaces of a solid electrolytic body, is manufactured to have a limit current value whose initial value is offset from a target value. Electric power is supplied to each manufactured gas sensing element to adjust the limit current value from the initial value to the target value.

Abstract: 1. An apparatus for treating a measuring probe has a treatment chamber (104) with a chamber inlet (106) and a chamber outlet (108). A conveyor device (110) selectively conveys one of a plurality of treatment media (G, W, R, E, Z) from its respective supply port (118a, 118b, 118c, 118d, 118e) to the chamber inlet (106) and into the treatment chamber (104). The conveyor device (110) has a collector conduit (120) and a conveyor pump (122), the latter arranged between the collector conduit (120) and the chamber inlet (106). Each of the supply ports (118a, 118b, 118c, 118d, 118e) has its own shutter device (124a, 124b, 124c, 124d, 124e) arranged directly at the collector conduit (120).

Abstract: An electrochemical sensor system and membrane and method thereof for increased accuracy and effective life of electrochemical and enzyme sensors.

Abstract: A sensor module for monitoring chemical properties of oil well fluids comprises at least one electrochemical sensor for a chemcal species, for example to detect pH and chloride ion concentration. A micro-porous barrier separates the electrochemical sensors from the environment of the module, the micro-porous barrier being of a material which is readily wetted by water. Periodic application of a current pulse between the barrier and a counter electrode enables fouling material to be removed from the micron barrier.

Abstract: An amperometric electrochemical gas sensor includes a permanent electrical resistance means disposed between two electrodes, one of which is the working electrode, the electrical resistance means having an electrical resistance of between about 10&OHgr; and 200 k&OHgr;. This resistance means provides a permanent shorting link between the electrodes, and constantly maintains the sensor in a ready-to-work condition.

Abstract: In a method and an apparatus for measuring a concentration of at least one dissolved chemical entity in a liquid medium, employing a counter electrode, a working electrode and a reference electrode immersed in the liquid medium, at least one measurement potential is applied to the working electrode relative to the reference electrode, corresponding to a measurement voltage during at least a part of a measurement period, thereby causing the dissolved chemical entity to participate in an electrochemical reaction at the working electrode, the chemical reaction resulting in a measurement evoked current. Compensation for potential drift at the reference electrode is achieved by comparing the measurement evoked current with a predetermined value, and decreasing or increasing the measurement voltage by an incremental value, in a negative or a positive incremental step, so that the measurement current approaches a predetermined value.

Abstract: An amperometric electrochemical gas sensor includes a permanent electrical resistance means disposed between two electrodes, one of which is the working electrode, the electrical resistance means having an electrical resistance of between about 10 &OHgr; and 200 k&OHgr;. This resistance means provides a permanent shorting link between the electrodes, and constantly maintains the sensor in a ready-to-work condition.

Abstract: A miniature reference electrode with improved stability and durability formed of a miniature silver/silver chloride reference electrode with high stability and general applicability as a reference electrode. The miniature reference electrode includes, on electrode substrate, a thin-film backbone metal pattern and a thin-film silver pattern formed in electrical contact with a portion of the thin-film backbone metal pattern. A silver chloride layer is set on a portion of the thin-film silver pattern. The silver chloride layer is in contact with a portion of thin-film electrolyte layer via hydrophobic thin-film insulating layer. The thin-film electrolyte layer is impregnated with a saturated solution of potassium chloride for making contact to the outside via a thin-film liquid junction pattern. When in use, the thin-film liquid junction pattern (31) is impregnated with the electrolyte, while its end portion is recessed in an aqueous solution.

Abstract: A method for electrochemical detection (ECD) is disclosed. The illustrated embodiments are particularly adapted to use in detection of analytes separated by capillary electrophoresis. The method is a voltammetric ECD, including a preparatory positive potential pulse, an optional stabilizing pulse at a negative potential, an analytical pulse at extreme negative potentials (e.g., −300 mV to −1,500 mV), and a positive cleaning potential pulse. The methods have been shown to detect analytes previously considered to be electrochemically inactive using more traditional electrochemical methods. Examples of such analytes include various drugs, antibiotics, and peptides.

Abstract: A process for operating an electrochemical measuring cell (1) is described, with which it is possible to carry out gas concentration measurements already shortly after switching on the measuring cell (1). The process includes the steps that potential voltage pulses are applied to the measuring cell (1) in a state of readiness of the measuring cell (1), in which the potential voltage is switched off. A system and device are also described.

Abstract: The present invention concerns new electrochemical biosensors for the determination of analytes concentration in sample solutions or suspensions, based on composite transducers containing an electro-conducting material, in the form of powder or grains, a chemical mediator, optionally a substance capable of sorption of said chemical mediator, and a solid binding maker, which is a compound in solid state at room temperature; said biosensors are prepared by incorporating a biocatalyst into the bulk of said composite transducers or by applying a biocatalytic layer onto their surface.

Abstract: A method of stabilizing pump current in a gas sensor through suppression of oscillations of the pump current which result from pulsations of measured gas is provided. The gas sensor includes an oxygen pump element, an oxygen concentration cell element and a measurement gap between the oxygen pump element and the oxygen concentration cell element, and is operative to control the pump current through the oxygen pump element so that an output voltage of the oxygen concentration cell element is constant in order that an oxygen concentration in the measurement gap is maintained constant and detect an oxygen concentration in the measured gas on the basis of the pump current. The method comprising adjusting an activity of electrodes of an oxygen pump element so as to change a responsiveness in control of the pump current and thereby reduce an amplitude of the oscillations of the pump current.

Abstract: The apparatus of the invention includes a flow chamber having an inlet, an outlet, and a removable cover. The cover includes fittings for mounting a reference electrode assembly, a measuring electrode assembly, and a combined counter electrode/thermistor probe. According to the one illustrative embodiment invention, the flow chamber is substantially cylindrical with the inlet located near the bottom of the chamber and the outlet located near the top of the chamber. The axes of the inlet and outlet lie in the same plane as and are parallel to a diameter of the chamber. The inner diameter of the inlet is reduced to approximately ⅛″ so that the velocity of water entering the chamber is increased. The inner diameter of the outlet is approximately ¼″ so that the velocity of water exiting the chamber is less than the velocity of water entering the chamber.

Abstract: A potentiometric electrode and method for the determination of an analyte in a sample by linearly correlating potential at the electrode with the concentration of the analyte in the sample.

Abstract: A measuring device for determining the oxygen partial pressure in human brain tissue has a probe (5) with a tube (7) of tissue-compatible plastic material in a measuring region surrounding an electrolyte-filled volume (8). Immersed in the electrolyte, which contains acetate, is a polaragraphic cathode (11) with a limited exposed surface and an anode (13). The tube is oxygen permeable in the measuring region. The electrodes are electrically connected to a measuring apparatus which applies a DC voltage at a first polarity to the electrodes (11, 13) and determines a measuring current using a measuring amplifier. A regenerating device causes the electrodes to be supplied with a regenerating voltage reversed from the first polarity for times and at current magnitudes based on the measurement current and duration.

Abstract: An electrochemical oxygen sensor with a measuring electrode, an atmospheric oxygen electrode as a reference electrode, and an auxiliary electrode in an electrolyte is improved such that a stable measured signal is obtained even during changes in the position of the measuring cell. To accomplish this, the auxiliary electrode is arranged in the vicinity of the measuring electrode and a protective electrode is provided between the measuring electrode and the auxiliary electrode.

Abstract: A sensor cleaning method and a detection apparatus enabling easy and correct measurement for an uninterrupted prolonged time duration of the gas concentration.The method is based on the value of a limiting current generated on applying a dc voltage across a pair of positive and negative electrodes of a sensor in which the electrodes are formed of a porous material and arranged in intimate contact with the surface of a solid electrolyte substrate exhibiting oxygen ion conductivity and in which pores of the negative electrode are used simultaneously as gas diffusion limiting holes for limiting the amount of diffusion of the gas for measurement. If the limiting current characteristics of sensor versus applied voltage are deteriorated, a voltage opposite to that used during measurement is applied for restoring the characteristics to a normal value.

Abstract: There are proposed an air/fuel ratio sensor which can detect a wide range of an air/fuel ratio and provides a simple structure, a superior mechanical strength or durability and a reduced manufacture cost, and a method of detecting the air/fuel ratio using the air/fuel ratio sensor. An air/fuel ratio sensor 1 is formed of a detecting portion 2 and a heater portion 3 laminated via a porous body 16. In the detecting portion 2, on an inner face of a plate-like solid electrolytic body 5, a reference electrode 7 is provided for controlling an oxygen gas diffusion rate, and on an outer face of the solid electrolytic body 5, a measurement electrode 6 is provided. A surface of the measurement electrode 6, on which the diffusion rate is not controlled, is covered with a protective layer 14 having an ventilation property to a degree to which the diffusion rate is not substantially controlled. A lead portion 7b of the reference electrode 7 is a porous layer which substantially controls the diffusion rate.

Abstract: Methods are described for extending the service life of implantable sensors having a silver-containing anodic reference electrode maintained at a high impedance, at least one noble metal cathodic working electrode, and at least one noble metal anodic counter electrode maintained at a low impedance, particularly sensors for the in vivo detection of oxygen and/or glucose in bodily fluids. The methods described involve increasing the input impedance of the reference electrode up to a maximum for implanted circuitry and shielding said electrode, and/or alternating the operating roles of the reference and working electrodes, switching the working electrodes with counter electrodes in the circuit, reversing the polarities of the reference and working electrodes, and sequentially activating each electrode in a plurality of working and/or reference electrodes in the circuit.

Abstract: A method of detecting an activated condition of a wide range air-fuel ratio sensor is provided. With this method, application of a current to a heater is started idiately after an engine is started (S00). Then, a current Icp for pumping is passed through an electromotive force cell (S10). A lapse of a predetermined time Tin is waited for (S18). After a lapse of time Tin, a voltage Vs across both electrodes of the electromotive force cell is detected (S20) and labeled as Vs0 (S22). Then, application of Icp is suspended (S30) and a routine is held on standby until a time of 25 ms elapses (S35). At the point of time when the time of 25 ms has elapsed, the voltage across the electrodes on the opposite sides of the electromotive force cell is detected (S40) and labeled as Vs1 (S45). A resistance value Rs1 is calculated from Vs0, Vs1 and Icp (S50).

Abstract: A portable clinical system for providing a rapid electrochemical analysis of biological sera of interest at the point-of-care using a portable analyzer unit and a multi-sensor electrochemical plug-in cartridge analyzing system is disclosed which features a plug-in module including a reusable sensor cartridge having an inlet port for receiving a sample, an outlet drain port and array of self-calibrating electrochemical sensors, a plurality of electrical interfaced terminals for interfacing with the portable analyzer unit. An integral flushing system is provided for cleaning and allowing recalibration of the sensor between sample analyses. Connection devices on the analyzer unit and plug-in multi-use test module are provided for removably attaching the module to the analyzer unit. The connection devices are configured to receive a single-use sensor cartridge interchangeably and without modification with said plug-in multi-use test module.

Abstract: The invention relates to an electrochemical sensor to determine the concentration of a gas to be quantified, comprising a housing, a measuring electrode comprising a catalystically active material which causes a reaction of the gas to be quantified, a counterelectrode comprising a carbon material, and a solid electrolyte in contact with the measuring electrode and the counterelectrode, wherein the solid electrolyte is prepared by swelling a solid matrix comprising an acrylate polymer with an electrolytic solution comprising at least one acid, and wherein the carbon material in the counterelectrode has a specific surface of at least 40 m.sup.2 /g and comprises reversibly oxidizable or reducible electrochemically active surface compounds.