Abstract: A portable analytical test meter is designed for use with an associated analytical test strip. A test-strip-receiving module receives the analytical test strip and is electrically connected to a dummy load calibration circuit block. That block is configured to provide a dummy magnitude correction and a dummy phase correction; and a memory block is configured to store the dummy magnitude correction and the dummy phase correction. A method for calibrating a portable analytical test meter for use with an analytical test strip includes determining a dummy magnitude correction and a dummy phase correction of the portable analytical test meter using a dummy load calibration circuit block of the portable analytical test meter. The dummy magnitude correction and the dummy phase correction are stored in a memory block of the portable analytical test meter. Using the stored dummy magnitude correction and stored dummy phase correction, an analyte is determined.

Abstract: The presence of a select analyte in the sample is evaluated in an electrochemical system using a conduction cell-type apparatus. A potential or current is generated between the two electrodes of the cell sufficient to bring about oxidation or reduction of the analyte or of a mediator in an analyte-detection redox system, thereby forming a chemical potential gradient of the analyte or mediator between the two electrodes After the gradient is established, the applied potential or current is discontinued and an analyte-independent signal is obtained from the relaxation of the chemical potential gradient. The analyte-independent signal is used to correct the analyte-dependent signal obtained during application of the potential or current.

Abstract: Provided is a solid electrolyte including an epitaxial thin film crystal made of an electrolyte containing at least lithium.

Abstract: The present invention provides compositions and methods directed to an electrode initialization step for the electrochemical treatment of monolayers used in electrochemical detection of target analytes on the surface of a monolayer. Electrode initialization creates a more stable monolayer, and resolves variability within the electrochemical signal detected on the monolayer.

Abstract: A method of determining an analyte concentration employs a biosensor that includes a molecularly imprinted polymer film formed on a metal layer. The biosensor is connected to a charge/discharge circuit and charged and discharged during exposure to a solution containing an analyte. Voltage values during discharge are measured, and a characteristic parameter of the voltage values, which is associated with a concentration of the analyte detected by the biosensor, is determined. An unknown concentration of the analyte is determined by comparing the characteristic parameter to reference data representing a relation between known concentration of the analyte and the characteristic parameter of the biosensor. A biosensor, such as an anesthetic biosensor, is also disclosed.

Abstract: Described herein is a device comprising a plurality of first reaction electrodes arranged in an array, the plurality of first reaction electrodes configured to be exposed to a solution and having a capacitance; first circuitry configured to controllably connect the plurality of first reaction electrodes to a bias source and controllably disconnect the plurality of first reaction electrodes from the bias source; and second circuitry configured to measure a rate of charging or discharging of the capacitance. Also described herein is a method of using this device to sequence DNA.

Abstract: The present invention refers to a sensor (10) having a layer arrangement (12), wherein the layer arrangement (12) comprises at least a base layer (14), a middle layer (16) and an outer layer (18), wherein the middle layer (16) is arranged at least partly upon and in contact with the base layer (14) and wherein the outer layer (18) is arranged at least partly upon and in contact with the middle layer (16), wherein the base layer (14) comprises a metal, wherein the middle layer (16) comprises a metal oxide, and wherein the outer layer (18) is porous and comprises a material selected from the group comprising electrically conductive carbon compounds such as, more particularly, graphite or carbon nanotubes (CNTs), organic electrical conductors and base metals, and wherein electrical contacts can be formed with the base layer (14) and outer layer (18) for a conductivity measurement and/or a resistance measurement.

Abstract: A method for electrochemically detecting an analyte contained in a sample using a working electrode and a counter electrode, comprising: allowing an electrolyte solution which contains a solution prepared by dissolving an imidazolium iodide compound in a protic solvent to be into contact with the working electrode and the counter electrode; and electrochemically detecting the analyte contained in the sample in the presence of the electrolyte solution is disclosed. A kit to be used for the method for electrochemically detecting an analyte is also disclosed.

Abstract: A method for monitoring the metabolic state of an organelle in the presence of a potential organelle modulating agent is disclosed. A first organelle-modified bioelectrode is provided that is electrically coupled to a second electrode of opposite polarity in a circuit. The first bioelectrode is contacted with an aqueous carrier containing a biologically acceptable electrolyte and an effective amount of a potential organelle modulating agent and an effective amount of an organelle substrate. The substrate is reacted at the bioelectrode to form an ionic product that is released into the aqueous carrier-containing electrolyte to thereby provide a current at the second electrode when the circuit is closed. A metabolic flux data set is obtained during the reaction and is compared to a control metabolic flux data set obtained under the same conditions in the absence of the organelle modulating agent, thereby determining the metabolic state of the organelle.

Abstract: Described herein is a gas meter system (5) for detecting toxic gas combinations including a housing (10) having an opening (20), a measuring cell (15) enclosed by the housing and comprising a plurality of gas sensors (17) in fluid communication with the environment via the opening in the housing, and an evaluating circuit (32). The gas sensors detects a concentration of a first gas and a concentration of a second gas so the evaluating circuit can identify a hazard due to an additive or synergistic toxic effect upon combined exposure to the first gas and the second gas. Related apparatus, systems, methods and/or articles are described.

Abstract: The present invention relates to a gas-monitoring assembly (100) and method for selectively determining the presence of a target gas in a gaseous environment that potentially comprises one or more interfering gases. Such gas-monitoring assembly and method specifically employ one or more gas sensors (S1) one or more getters (G1) arranged and constructed to reduce cross-interference caused by potential presence of the interfering gases in such gaseous environment to be monitored. The gas-monitoring assembly and method of the present invention are capable of monitoring a gaseous environment with respect to potential presence of multiple target gases that may interfere with one another.

Abstract: The present invention concerns an electrochemical sensor for determining oxygen dissolved in an aqueous measuring medium, a process for its production as well as a method for determining oxygen dissolved in an aqueous measuring medium using the electrochemical sensor.

Abstract: Described herein is an apparatus comprising an electrochemical cell that employs a capacitive counter electrode and a faradaic working electrode. The capacitive counter electrode reduces the amount of redox products generated at the counter electrode while enabling the working electrode to generate redox products. The electrochemical cell is useful for controlling the redox products generated and/or the timing of the redox product generation. The electrochemical cell is useful in assay methods, including those using electrochemiluminescence. The electrochemical cell can be combined with additional hardware to form instrumentation for assay methods.

Abstract: A microelectrochemical sensor includes an energy supply unit and a sensor unit. The energy supply unit is configured to generate electrical energy using a reference fluid. The sensor unit is configured to determine a concentration difference of a chemical species between a measuring fluid and the reference fluid. The measuring fluid has an unknown concentration of the species, and the reference fluid has a known concentration of the species. The sensor unit is electrically connected to the energy supply unit and is designed to determine the concentration difference using the electrical energy from the energy supply unit.

Abstract: Various embodiments of a gas sensor device and method of fabricating a gas sensor device are provided. In one embodiment a gas sensor device includes a base substrate, an electrolyte layer disposed on the base substrate and a plurality of potentiometric sensor units electrically coupled to the base substrate. Each potentiometric sensor unit includes an electrolyte layer disposed on the base substrate, a sensing electrode comprising tungsten oxide (WO3) and platinum (Pt), a reference electrode comprising Pt, and a plurality of connectors coupled to the plurality of potentiometric sensors to connect the plurality of potentiometric sensors in series.

Abstract: A sensor having a bifurcated flow path and method for using the same is disclosed. In some embodiments, the sensor has two flow channels into which sample flow is induced by capillary action, wherein the flow channels are in contact with electrodes configured to generate an electrochemical reaction in the flow channels which can be measured and correlated to the level of an analyte in the sample. In some embodiments, the levels of more than one analyte can be measured using a single sensor.

Abstract: The present invention provides for a device for detecting one or more target gas compounds, such as a volatile organic compound, such as formaldehyde, comprising a chamber comprising a gas inlet and a gas outlet, wherein the chamber is capable of absorbing one or more non-target gas compounds. When the device is in use, the gas outlet is in fluid communication with a detector capable of detecting the amount or concentration of the one or more target gas compounds.

Abstract: Scale formation on the electrode(s) of a liquor sensor can be prevented by continuously delivering a water-soluble scale inhibitor or dispersant into the vicinity of the electrodes of a liquor sensor device. Scale inhibitors include, for instance, polymers that are derived from acrylic acid, maleic acid, acrylamide acid, phosphonate, and combinations thereof. An aqueous mixture of scaling inhibitor continuously delivered to the probe tip of the liquor sensor that was placed in a kraft pulping liquor allowed the sensor to operate accurately for over a month without having to be cleaned of scale.

Abstract: Apparatus and methods are described for preparing, maintaining, and stabilizing sensors. The apparatus and methods for preparing sensors for use are utilized in advance of the sensor being removed from a sealed, sterilized package. The apparatus include packaging materials having electrical circuits capable of stabilizing a sensor to prepare the sensor for use. The methods for preparing a sensor for use includes methods of providing a solution to a sterilized packaging that contains a sensor connected to a sensor activating circuit, activating the circuit, and allowing the sensor to stabilize. These methods can be performed without compromising the packaging. The apparatus for stabilizing a sensor that is in use include a circuit connectable to the sensor that provides a signal to the sensor that prevents the sensor from becoming destabilized when disconnected from a monitoring device.

Abstract: A method of determining the charge of at least one test particle, comprising: applying one of an electric current or a voltage across an aperture connecting two chambers, whereby the chambers are at least partially filled with electrolyte and whereby the at least one test particle is suspended in the electrolyte of at least one of the chambers; measuring the other of the electric current or voltage across the aperture; varying a pressure differential between the two chambers; and determining the charge based on the measurements of the electric current or voltage.

Abstract: Detecting a leak from a site in a sealed system with a source of pressurized gas which is capable of passing through the site, a composition of matter which adheres to the surfaces of the system and which is capable of showing the presence of the gas escaping from the site. The method includes: injecting gas into the system to a pressure in excess of the surrounding pressure, and covering the external surface with the composition to identify the location of the site by the interaction of the escaping gas with the composition. The composition is foam that includes a surfactant which forms a least one bubble in the presence of escaping gas and an indicator which changes color in the presence of the escaping gas. The leak is an opening down to at least the size of a hole 0.001? in diameter. A gas detector may also be used.

Abstract: An apparatus for sensing of an interaction of a molecular entity with a membrane protein in a lipid bilayer comprises an array of sensor elements (21) arranged to output an electrical signal that is dependant on occurrences of the interaction. A detection circuit (3) comprised detection channels (30) capable of amplifying an electrical signal from a sensor element. More sensor elements (21) are provided than detection channels (30), and detection channels (30) are selectively connected to sensor elements (21) that have acceptable quality of performance in that a lipid bilayer is formed and that an acceptable number of membrane proteins are inserted, on the basis of the amplified electrical signals that are output from the detection channels. This improves the efficiency of utilization of the detection channels, due to inefficiency in the utilization of the sensor elements, resulting in a reduction in the cost of the apparatus and the ability to perform sensing using relatively small samples.

Abstract: Exemplary embodiments provide diagnostic devices, systems and methods for determining the presence or absence of one or more markers or characteristics in one or more samples. An exemplary diagnostic device may display a first two-dimensional machine-readable output to indicate the presence or absence of a first characteristic in a sample. Similarly, the exemplary diagnostic device may display a second two-dimensional machine-readable output to indicate the presence or absence of a second characteristic in a sample. An image capture device may be used to automatically detect the two-dimensional machine-readable output appearing in the diagnostic device. A computational device may be used to automatically determine whether the presence or absence of the first characteristic and/or the second characteristic based on the two-dimensional machine-readable output displayed in the diagnostic device.

Abstract: One or more charge pumps may be used to amplify the output voltage from a chemically-sensitive pixel that comprises one or more transistors. A charge pump may include a number of track stage switches, a number of boost phase switches and a number of capacitors. The capacitors are in parallel during the track phase and in series during the boost phase, and the total capacitance is divided during the boost phase while the total charge remains fixed. Consequently, the output voltage is pushed up.

Abstract: The present invention includes methods and compositions having at least one nanoparticle for analyzing a chemical analyte. The device includes an electrochemical cell connected to a measuring apparatus, wherein the electrochemical cell comprises a container and at least one electrode comprising a surface modification; a solution within the container comprising one or more chemical analytes and one or more metal nanoparticles in the solution, wherein one or more electrocatalytic properties are generated by the one or more metal nanoparticles at the at least one electrode and the contact of individual nanoparticles can be measured.

Abstract: An electrode array for the cyclic reduction and oxidation of a redox species in an electrolyte, wherein both electrodes are disposed on an insulating substrate and connected to a counter electrode for the application of a voltage, comprising: 1) a control electrode for reacting the redox species for cyclic electron transport between the electrodes: and b) a collector electrode disposed opposite the control electrode, wherein a layer structure composed of a second insulator and a charge transfer mediator disposed thereon is additionally disposed on the side of the collector electrode located opposite the insulating substrate for reacting the redox species Two methods for operating the electrode array are disclosed.

Abstract: A configuration is disclosed. In one aspect, the configuration includes a substantially planar electrode layer, in a first plane. The configuration further includes a substantially planar two-dimensional electron gas (2DEG) layer electrically connected in series with the electrode layer. The 2DEG layer is provided in a second plane substantially parallel with the first plane and located at a predetermined distance, in a direction orthogonal to the first plane, from the first plane. The 2DEG layer and the electrode layer are patterned such that the electrode layer overlays a part of the 2DEG layer, wherein the predetermined distance between the first plane and the second plane is selected to be sufficiently small for allowing electrostatic interaction between the electrode layer and the 2DEG layer.

Abstract: A dielectrophoretic particle concentrator includes first substrate, detection electrodes, second substrate, protrudent structure and edge wall structures. The first substrate extends along first direction. The detection electrodes are disposed on the first substrate and extend along second direction. The second direction crosses the first direction. The second substrate is disposed over the first substrate and extends along the first direction. The protrudent structure is disposed on the second substrate and protruded towards the first substrate. A top portion of the protrudent structure includes a line-like structure extending along the second direction and adjacent to the detection electrodes. The edge wall structures are integrated with the first substrate and the second substrate, to form pipe-like structure to enable a fluid flowing through the protrudent structure from an end to another end.

Abstract: Active carbon filters and systems that are operative to detect active carbon filter degradations are provided. The active carbon filter can include a carbon filter comprising activated carbon and defining a filter surface; a first piezoelectric wafer active sensor on the filter surface that is electrically isolated from the carbon filter; and a second piezoelectric wafer active sensor on the filter surface that is electrically connected to the filter surface; and an impedance monitoring device electrically connected to the first piezoelectric wafer active sensor and the second piezoelectric wafer active sensor. Methods are also disclosed for determining if any degradation has occurred in an active carbon filter.

Abstract: An amperometric electrochemical sensor with a fixed potential used in a probe for measuring the content of an oxidation reduction substance dissolved in a liquid, in particular the chlorine content. The sensor (1) includes an insulating substrate (2), a set of electrodes consisting of a working electrode (3), an auxiliary electrode (4) and a reference electrode, at least one of the working electrode (3) and auxiliary electrode (4) being configured on the insulating substrate (2). At least one of the working electrode (3) and auxiliary electrode (4) is covered with an insulating layer (8), the insulating layer (8) including at least one opening exposing at least one of the working electrode (3) and auxiliary electrode (4).

Abstract: Apparatus, systems and methods employing contact lenses with two-electrode electrochemical sensors are provided. In some aspects, the contact lens includes: a substrate that forms at least part of a body of the contact lens; and a circuit, disposed on or within the substrate, and including a two-electrode electrochemical sensor. The two-electrode electrochemical sensor can include: a working electrode; and a combination reference-counter electrode. The electrochemical sensor can be an amperometric sensor that senses a biological feature of a wearer of the contact lens. The working electrode can generate a signal indicative of the sensed analyte, and the combination reference-counter electrode can pass the signal generated from the working electrode. The signal can be employed to determine the analyte concentration of a solution in contact with the contact lens.

Abstract: Disclosed herein is a device that functions as a glucose sensor. The device has a reference electrode; a counter electrode, a working electrode; an electrically conducting membrane; an enzyme layer; a semi-permeable membrane; a first layer of a first hydrogel in operative communication with the working electrode; the first layer of the first hydrogel being operative to store oxygen; wherein the amount of stored oxygen is proportional to the number of freeze-thaw cycles that the hydrogel is subjected to; and a second layer of the second hydrogel. Disclosed too is a method that comprises using periodically biased amperometry towards interrogation of implantable glucose sensors to improve both sensor's sensitivity and linearity while at the same time enable internal calibration against sensor drifts that originate from changes in either electrode activity or membrane permeability as a result of fouling, calcification and/or fibrosis.

Abstract: The multiplexed electrochemical microfluidic paper-based analytical device comprises multiple detection zones for the detection of multiple biochemical analytes from one single sample. Cavity valves integrated on the device will deliver the sample to different detection zones. These analytes include, but are not limited to, urea, creatinine, creatine, glucose, lactate, ethanol, uric acid, cholesterol, pyruvate, creatinine, ?-hydroxybutyrate, alanine aminotrasferase, aspartate aminotransferase, alkaline phosphatase, and acetylcholinesterase (or its inhibitors). This system will provide a simple and low-cost POC approach to obtain quantitative and multiple biological information from one sample (e.g. one drop of blood).

Abstract: A sensor system, device, and methods for determining the concentration of an analyte in a sample is described. Gated voltammetric pulse sequences including multiple duty cycles of sequential excitations and relaxations may provide a shorter analysis time and/or improve the accuracy and/or precision of the analysis. The disclosed pulse sequences may reduce analysis errors arising from the hematocrit effect, variance in cap-gap volumes, non-steady-state conditions, mediator background, a single set of calibration constants, under-fill, and changes in the active ionizing agent content of the sensor strip.

Abstract: Detecting a leak from a site in a sealed system with a source of pressurized gas which is capable of passing through the site, a composition of matter which adheres to the surfaces of the system and which is capable of showing the presence of the gas escaping from the site. The method includes: injecting gas into the system to a pressure in excess of the surrounding pressure, and covering the external surface with the composition to identify the location of the site by the interaction of the escaping gas with the composition. The composition is foam that includes a surfactant which forms a least one bubble in the presence of escaping gas and an indicator which changes color in the presence of the escaping gas. The leak is an opening down to at least the size of a hole 0.001? in diameter. A gas detector may also be used.

Abstract: A biosensor is disclosed comprising a support; a conductive layer composed of an electrical conductive material such as a noble metal, for example gold or palladium, and carbon; slits parallel to and perpendicular to the side of the support; working, counter, and detecting electrodes; a spacer which covers the working, counter, and detecting electrodes on the support; a rectangular cutout in the spacer forming a specimen supply path; an inlet to the specimen supply path; a reagent layer formed by applying a reagent containing an enzyme to the working, counter, and detecting electrodes, which are exposed through the cutout in the spacer; and a cover over the spacer. The biosensor can be formed by a simple method, and provides a uniform reagent layer on the electrodes regardless of the reagent composition.

Abstract: Various embodiments provide a system for detecting one or more analytes in a fluid. The system comprises: a controller adapted to obtain one or more sample streams of the fluid. The controller is configured in use to form a plurality of output streams. Each output stream comprises at least part of one of the one or more sample streams. The system further comprises: a detector adapted to receive from the controller the plurality of output streams and comprising a plurality of sensors. Each sensor is operable to detect an interaction between a corresponding detecting agent and a corresponding analyte. The detector is configured in use to detect one or more said interactions using the plurality of output streams to determine if the fluid contains one or more said analytes. A corresponding method is also provided.

Abstract: The present invention relates to a cartridge for conducting diagnostic assays. The cartridge consists of an assembly of components that are easily assembled. The cartridge provides means for receiving a patient sample, precisely controlling fluid introduction, onboard storage of assay fluid and conducting different assay protocols and detection of a plurality of analytes. Methods of use for the cartridge are described. The disclosed invention is suitable for point of care environments or any place where rapid, ultrasensitive testing is required.

Abstract: Gas sensors are provided. The gas sensors include a gas sensing element having metal oxide nanoparticles and a thin-film heating element. Systems that include the gas sensors, as well as methods of using the gas sensors, are also provided. Embodiments of the present disclosure find use in a variety of different applications, including detecting whether an analyte is present in a gaseous sample.

Abstract: A test method for the ketone number of an animal specimen is characterized in that a test parameter datasheet is set up by data modeling. Then a specimen from tested animal body is obtained. Next, the specimen is dripped onto the sensing end of an electrochemical test specimen, and an electrochemical tester is prepared. A test value correction procedure is built into or input to the electrochemical tester. With a parameter adjustment mode, the operational parameters of test value correction procedure unique to the electrochemical tester could be adjusted for adapting to the test mode of the species of tested animals. The sensing end of the electrochemical test specimen is inserted into the measurement slot of the electrochemical tester, so the ketone number of the specimen is displayed by the electrochemical tester.

Abstract: The disclosure provides monolithic electrodes including a substrate defining a walled cavity having a floor, an electrically conductive cathode layer overlaying the cavity floor, an electrically conductive contact pad overlaying the substrate, an electrically conductive via in electrical communication with the cathode layer and the contact pad, and a porous membrane layer overlaying the cavity and defining a chamber formed by the porous membrane layer, the walled cavity, and the cavity floor. The disclosure also provides pH transducers including monolithic indicator and reference electrodes, and methods of making and using monolithic pH electrodes and transducers.

Abstract: Scale formation on the electrode(s) of a liquor sensor can be prevented by continuously delivering a water-soluble scale inhibitor or dispersant into the vicinity of the electrodes of a liquor sensor device. Scale inhibitors include, for instance, polymers that are derived from acrylic acid, maleic acid, acrylamide acid, phosphonate, and combinations thereof. An aqueous mixture of scaling inhibitor continuously delivered to the probe tip of the liquor sensor that was placed in a kraft pulping liquor allowed the sensor to operate accurately for over a month without having to be cleaned of scale.

Abstract: A biosensor for detecting an analyte in a sample of body fluid and methods for manufacturing the biosensor are disclosed. In one embodiment, a biosensor includes at least two electrical conductors embedded within an electrically insulating test element body. The electrical conductors are exposed at two ends of the test element body and a reagent, for example a reagent adapted to test for blood glucose, is applied to one end. In one form, the test element body is cylindrical with a circular or non-circular cross-sectional shape. In other embodiments, the test elements are manufactured by a resin pultrusion process in which resin embedded with electrical conductors is dried or cured, shaped and cut into segments, and reagent applied to one end of each segment.

Abstract: There is provided an electrolyte solution including a solvent formed from a sulfone, and a magnesium salt dissolved in the solvent.

Abstract: A systems and apparatus for measuring non-electroactive materials in liquids using electrochemical detection. A first electrical activity of a electroactive material is detected in absence of a target non-electroactive material (Step 120). A second electrical activity of the electroactive material is detected in presence of the target non-electroactive material (Step 130). A difference between the first and second electrical activities is obtained, and based on the obtained difference, a concentration of the target non-electroactive material is identified (Step 140).

Abstract: According to one embodiment of the present invention, an electrochemical sensor (10) for detecting the concentration of analyte in a fluid test sample is disclosed. The sensor (10) includes a counter electrode having a high-resistance portion for use in detecting whether a predetermined amount of sample has been received by the test sensor.

Abstract: An electrochemical gas sensor includes a housing, a first working electrode within the housing and having a first section of gas transfer medium and a first layer of catalyst on the first section of gas transfer medium, and at least a second working electrode within the housing and having a second section of gas transfer medium and a second layer of catalyst on the second section of gas transfer medium. At least one of the first section of gas transfer medium and the second section of gas transfer medium includes at least one area in which the structure thereof has been irreversibly altered to limit diffusion of gas through the at least one of the first section of gas transfer medium or the second section of gas transfer medium toward the other of the at least one of the first section of gas transfer medium and the second section of gas transfer medium.

Abstract: A method is provided for determining the presence or amount of an analyte in a sample and includes the steps of contacting a faradaic working electrode to a solution comprising the optionally pre-processed sample and an electrolyte, contacting a capacitive counter electrode to the solution, supplying electrical energy between the faradaic working electrode and the capacitive counter electrode sufficient to provide for faradaic charge transfer at the faradaic working electrode, and measuring at least one of (i) light, (ii) current, (iii) voltage, and (iv) charge to determine the presence or amount of the analyte in the sample.

Abstract: A method for operating a measurement for a sample on an electrochemical test strip including at least two electrodes is provided. The method includes steps of applying a first voltage between the two electrodes during an interference-removal period after an incubation period succeeding a moment when the sample is detected, and applying a second voltage between the two electrodes during a test period, wherein the first voltage is larger than the second voltage, the first voltage includes one of a first fixed voltage and a first set of plural pulse voltages, and the second voltage includes a second fixed voltage.

Abstract: Disclosed is a method of measuring sample reaction results on a biosensor having a working electrode and other electrodes, including: applying voltage between the working electrode and each of the other electrodes and detecting the amount of current flowing through the working electrode to determine whether or not a sample is injected; applying voltage between the working electrode and one of the other electrodes and re-detecting the amount of current flowing through the working electrode; and acquiring and displaying a concentration value as a sample reaction result corresponding to the amount of detected current.