Abstract: Methods and sensors for the detection, identification, and quantification of one or more gas species, including volatile organic compounds, in a test sample are described. Methods employ gas sensors comprising a diffusion matrix present on the sensor surface. A gas analyte in a test sample diffuses through the matrix and is detected upon interaction of the analyte with the sensor. A response profile of a gas sensor to a gas analyte in the test sample is compared to a control gas sensor response profile determined in a similar manner for a known gas species. Comparisons of test sample and control sample sensor response profiles enable detection, identification, and quantification of a gas species analyte in a test sample.

Abstract: The present disclosure discloses a novel omniphobic, paper-based, smart bandage (OPSB) devices, and the methods to make and use the omniphobic, paper-based, smart bandage devices. The OPSB device of the present disclosure provides a simple, low-cost, and non-invasive strategy to monitor open wound status wirelessly. This disclosure also provides the demonstration of in-vivo early detection and monitoring of pressure ulcers using wireless smart bandages.

Abstract: An apparatus for measuring a concentration of a target gas includes: a gas sensor including a sensing layer having an electric resistance that changes by an oxidation reaction or a reduction reaction between gas molecules and the sensing layer; and a processor configured to, in response to the target gas being introduced along with air into the gas sensor, monitor a change of the electric resistance of the sensing layer and determine the concentration of the target gas by analyzing a shape of the change of the electric resistance.

Abstract: Methods and apparatus for detecting electrical short circuits in fuel cell stacks are provided. The methods involve supplying a reactant and an inert gas to a fuel cell stack and measuring the open circuit voltage of fuel cell assemblies in the fuel cell stack. The sensitivity of the methods can be adjusted to detect an electrical short circuit having a resistance at or below a particular threshold short-circuit resistance value, by using a suitable reactant concentration in the method. The methods can include determining a set-point reactant concentration that can be used to detect an electrical short circuit having a resistance at or below a particular threshold short-circuit resistance value.

Abstract: A microfluidic flow restrictor that uses micron-sized beads to impede flow is described. The flow rate can be adjusted by adding or removing the beads using injection needles through self-sealing ports, one injection needle injecting or aspirating beads and another injection needle pushing or pulling fluid from outside of a bead trap within the flow restrictor. In alternative embodiments, the beads or other filler material can be trapped in a manifold bead trap such that they block a subset of fluid channels of the flow restrictor, allowing fluid to flow freely through the rest of the fluid channels. The flow restrictor can be integrated with a contact lens or implantable medical device for use in dispensing liquid therapeutic agents at flow rates of microliters per minute or moving body fluids at a controlled rate from one part of the body to another.

Abstract: Methods for in situ measurement of an oxidation reduction potential (ORP) and pH of a solution comprising iron are provided. The methods comprise measuring a kinetic parameter at an electrode surface of an electrode system comprising a working electrode, a counter electrode and a pseudo-reference electrode, wherein the kinetic parameter is associated with ferric reduction or both ferric reduction and ferrous oxidation and comparing the kinetic parameter to calibration data for the electrode system to determine the ORP and pH of the solution. Also provided are apparatus and systems for in situ measurement of an ORP and pH of a solution comprising iron. The apparatus and systems comprise an electrode system comprising a working electrode, a counter electrode and a pseudo-reference electrode and a detector for measuring a kinetic parameter at an electrode surface of the electrode system.

Abstract: A system includes a fluidic device, a flow control valve, a first reagent fluid reservoir fluidly connectable to the fluidic device by the flow control valve, a first fluid buffer reservoir fluidly connectable to the fluidic device by the flow control valve, and a common fluid buffer source fluidly connectable to the fluidic device by the flow control valve. The flow control valve permits flow comprising: (i) flow from the first reagent fluid reservoir to the fluidic device, (ii) flow from the common fluid buffer source to the fluidic device, (iii) flow from the fluidic device to the first fluid buffer reservoir, (iv) flow from the first reagent fluid reservoir to the fluidic device, and (v) flow from the first fluid buffer reservoir to the fluidic device.

Abstract: The disclosure relates to electrochemical sensors for measuring creatinine and creatine in a patient's blood. More particularly, the disclosure relates to compositions and methods for improving measurement accuracy of electrochemical sensors used for measuring creatinine and creatine.

Abstract: A combined portable fishing rod holder and storage stand includes a base and a plurality of holder units. The base includes anchoring apertures defined therein that are configured to receive anchoring mechanisms therethrough, such as stakes, pins, and other earth anchors that can secure within a ground surface. As such, the base of the combined apparatus is securable to a ground surface. In addition, the base includes a plurality of holder receipts that receive and retain the holder units. Each holder unit is designed to receive and retain an object, such as an assembled or disassembled fishing rod, therein. In addition, the holder units are designed to be secured to each other via cable ties. As such, one or more fishing rods can be secured within the combined holder and stand during storage, transportation, and use during fishing activities, without the need to use different products for each application.

Abstract: An electric conductivity detector includes at least a cell part having a cell through which liquid flows therein and measurement electrodes measuring a current of liquid flowing through the liquid in the cell, a detection circuit electrically connected to the measurement electrodes and configured to detect a current value flowing between the measurement electrodes, and to output a signal based on the detected value, and a processing unit configured to take in a signal output from the detection circuit and perform signal processing, in which the cell part and the detection circuit are configured to be accommodated in a column oven regulating a temperature of an analytical column of an ion chromatograph.

Abstract: A urine analyzer device, configured to be installed in a toilet bowl, to be used several times, the device comprising a holder member, to attach the device to the rim of the toilet bowl, an electronic unit, enclosed in a housing, a urine reception area, with at least one electro-chemical sensor, configured to measure a quantity of at least one substance contained in urine, such as physiological compound or chemical component, a wireless coupler to send resulting data to a remote computing device, wherein the electro-chemical sensor comprises at least a ion selective Field Effect Transistor (ISFET), configured to sense levels of one or more physiological ions, thereby providing a urine analyzer device, readily available at home, simply installed in a toilet bowl, and that can be used several times subsequently.

Abstract: A reflective color display that can be addressed from the front (viewing surface side) of the display with a light source, such as a projector, LED, or laser. The display comprises (in order) a color filter array, a transparent electrode, an electro-optic medium, a photoconductive material, and a rear electrode. The color displays of the invention are useful for large format color signage, such as billboards and wayfinding.

Abstract: A corrosion sensor includes an inner electrode formed of a conductive material, the inner electrode including a columnar portion around an axial line as a center thereof and of which an outer circumferential surface is tapered, wherein a diameter of the outer circumferential surface decreases toward one side in an axial direction, an outer electrode formed of a conductive material, the outer electrode including a cylindrical portion around the axial line and of which an inner circumferential surface is tapered, wherein a diameter of the inner circumferential surface decreases toward the one side in the axial direction, and the cylindrical portion is positioned such that the inner circumferential surface radially faces the outer circumferential surface, and an insulation layer formed of an insulation material and in a position across which the outer circumferential surface faces the inner circumferential surface.

Abstract: An air data probe includes an air data probe body and an additively manufactured heater on the air data probe body, the heater including a first heater layer and a first dielectric layer on the first heater layer. The first dielectric layer makes up an exterior surface of the heater.

Abstract: A chromatography system comprising a mixing circuit or a mixing chamber, a bubble trap, a concentration detector and one or more pumps, characterized in that the bubble trap has a permanent opening at its highest point is described herein. Furthermore, a chromatography system is described, characterized in that it contains two concentration detectors the first of which is located in the mixing circuit or the mixing chamber and the second is located downstream of the main pump.

Abstract: A method for detecting an analyte in a sample includes the steps of obtaining a nanopore sensor comprising a nanopore and a protein adaptor internalized in the lumen of the nanopore, adding a sample comprising an analyte to the cis side or the trans side of the nanopore, and measuring conductance across the nanopore. A change in conductance after adding the sample indicates the analyte is present in the sample and has bound to the protein adaptor. Nanopore sensors comprise a nanopore and a protein adaptor internalized in the lumen of the nanopore. The protein adaptor is a functional enzyme or ligand-binding protein.

Abstract: A method of operating a gas detection device including a capillary-limited, electrochemical gas sensor includes operating the gas sensor in a sensing mode during which a signal from the gas sensor is representative of a concentration of the analyte gas measured by the gas sensor and in an interrogation mode during which the gas sensor is electronically interrogated by applying an electric signal to the gas sensor to generate a non-faradaic current flow between a working electrode and a counter electrode without the application of a test gas, periodically entering the interrogation mode, measuring a parameter of a gas sensor output during the interrogation mode, comparing the measured parameter to one or more previously measured parameters, determining an operational state from the comparison, and returning the gas sensor to the sensing mode if the operational state is determined to be within a predetermined range.

Abstract: A arrangement for calibrating at least two sensors in parallel, including a data processing unit, especially a measurement transmitter for a multisensor system or a computer, wherein the data processing unit has an interface, via which the at least two sensors are connected via separate transmission lines for transmission of data, and wherein the data processing unit is embodied to perform calibrations of the at least two sensors in parallel and independently of one another.

Abstract: The present invention provides a device for measuring a particle size at a low temperature, specifically, which includes a refrigerant tank containing a refrigerant; a heat conduction plate thermally connected to the refrigerant tank; and a nanoantenna located on the heat conduction plate, thereby it is possible to determine a degree of light transmission to the sample to be measured located on an upper portion of the nanoantenna, and predict the physical properties of the sample.

Abstract: A guide member for a fishing line including an alumina ceramic including Ti and Al, a content of Ti being not less than 0.5 mass % in terms of TiO2, a content of Al being not less than 92 mass % in terms of Al2O3, and a main phase of the alumina ceramic being alumina crystals, wherein a content ratio of aluminas crystal with an aspect ratio of not less than 2 within the alumina crystals is not less than 15%.

Abstract: Embodiments of the present disclosure are directed to thin conductive composites, such as biosensor electrodes, containing a polymeric film substrate a conductive layer disposed adjacent the substrate. The conductive layer includes Krypton and a conductive material. The conductive layer has an average thickness of no greater than about 150 nanometers. The conductive layer has a normalized thickness (t/?) of no greater than about 3.0. Further, the composite has a sheet resistance of no greater than about 97.077t?1.071 ohm/sq, where t represents the thickness of the conductive layer in nanometers.

Abstract: A method of monitoring a protective fluid of a wellbore tool includes flowing, by a sensor or a fluid moving device secured to a wellbore tool disposed at a downhole location within a wellbore, a portion of a protective fluid of the wellbore tool through a body of the sensor. The portion of the protective fluid is exposed to the body of the sensor responsive to the flowing. The protective fluid degrades over time responsive to the wellbore tool performing operations in the wellbore. The method also includes, in response to the protective fluid being exposed to the body of the sensor, determining, at least in part by the sensor, a degradation level of the protective fluid. The method also includes transmitting, by the sensor or a device communicatively coupled to the sensor, the determined degradation level to a surface of the wellbore.

Abstract: On-body units are provided and include a transcutaneous analyte sensor, electronic circuitry electrically coupled to the sensor, and an on-body housing having electrical contacts disposed thereon. The on-body housing comprises a substantially flat surface and a curved and convex surface opposite the substantially flat surface. Systems and methods including the on-body units are also provided. Methods for performing continuity measurements using on-body units are also provided. The methods include positioning an on-body unit (OBU) on a skin of a subject, contacting a continuity test instrument to the OBU; and performing a continuity measurement with the continuity test instrument. An AC signal may be provided across two electrical contacts, or a DC signal may be provided across two electrical contacts in opposite directions for the same amount of time. The measurement may be performed with one electrical contact, or with isolated electrical contacts.

Abstract: A PCB based electrochemical sensor includes a PCB having a first electrode on a first surface of the PCB, and a second electrode on a second surface. A sensing element, such as a conductive wire, is attached to the first electrode. The PCB includes one or more through holes, and the conductive wire is positioned proximate one or more of the one or more through holes. When the PCB based electrochemical sensor is positioned in a solution to be sensed, the solution fills the through holes. The ions within the solution provide a current pathway between the conductive wire and the second electrode through the through holes. A voltage potential between the two electrodes is measured. The measured voltage potential is used to determine a value associated with the solution, such as a pH value.

Abstract: Systems and methods for measuring corrosion rate of an equipment material are provided. A system may comprise a corrosion probe body for insertion within an interior of the equipment through which corrodant fluid flows. At least one sensor on the corrosion probe body includes an ultrasonic source configured to provide an ultrasonic signal into the probe body material, and a receiver configured to receive reflections of the ultrasonic signal from the probe body material and generate electrical response signals indicative of the travel time of the ultrasonic signal. A heat exchanger may be placed in fluid communication with the probe body to deliver heated or cooled fluids to the probe body. A processor is configured to process the electrical response signals and produce corresponding corrosion data.

Abstract: Method and apparatus to test for volatile organic compounds (VOCs), including a cap configured to at least partially seal a container, and a plunger mechanism configured to form a passageway for air to flow from the container into a detection area. A sensor may be attached to the cap and positioned proximate the detection area. The sensor may be configured to detect data relating to a VOC and to generate a signal. A processor may be configured to receive the signal and to determine a result relating to the VOC.

Abstract: Embodiments of the disclosure relate to capillary controlled gas sensors comprising a top cap assembly, wherein the top cap assembly is operable to reduce the effects of condensation and pressure changes on the effectiveness of the gas sensor. The top cap assembly comprises a capillary controlled gas flow path, a bulk flow control assembly, and a raised boss surrounded by a moat.

Abstract: Techniques described herein can apply AC signals with different phases to different groups of nanopore cells in a nanopore sensor chip. When a first group of nanopore cells is in a dark period and is not sampled or minimally sampled by an analog-to-digital converter (ADC) to capture useful data, a second group of nanopore cells is in a bright period during which output signals from the second group of nanopore cells are sampled by the analog-to-digital converter. The reference level setting of the ADC is dynamically changed based on the applied AC signals to fully utilize the dynamic range of the ADC.

Abstract: A transfer template, a display substrate, a display panel, and a method for manufacturing the same are provided in the embodiments of the disclosure, the transfer template being configured to transfer a material to be transferred, including: a transfer substrate; and a plurality of transfer units arranged on the transfer substrate and spaced apart from one another; an adhesive force between the plurality of transfer units and the material to be transferred is configured to be larger than another adhesive force between the transfer substrate and the material to be transferred.

Abstract: A single crystal CVD diamond component comprising: a surface, wherein at least a portion of said surface is formed of as-grown growth face single crystal CVD diamond material which has not been polished or etched and which has a surface roughness Ra of no more than 100 nm; and a layer of NV? defects, said layer of NV? defects being disposed within 1 ?m of the surface, said layer of NV? defects having a thickness of no more than 500 nm, and said layer of NV? defects having a concentration of NV? defects of at least 105 NV?/cm2.

Abstract: A device and system for automatic handling of a sensor strip by a part of a meter that includes a sensor strip having a first section, a second section, and an intermediate section. The sensor strip includes at least a first opening about a first end thereof and a second opening about a second end thereof. A meter part includes a pair of pivoting catches configured to engage and grasp a sensor strip from a container containing a plurality of sensor strips. The sensor strip may thus be removed from a container for testing without need for manual handling of the strip by a user.

Abstract: A method for accurately measuring the conductivity of substances. This method incorporates two points of measurement that are isolated from each other. Each of these points is in contact with the substance to be measured. A continuous, constant electrical current is passed through the substance at the measurement points by means of an electrical force that is not constant but varies depending upon the amount of electrical force required to maintain the constant electrical current through the substance. This constant current is passed through the substance in two directions. This change in direction is achieved by reversing the polarity of the electrical force across the two measurement points. The time periods for each of the two directions of constant current flow are equal. The amount of electrical force or voltage that is required to maintain this constant amount of current is directly related to the resistance of the substance.

Abstract: The present invention relates to an ionic touch panel, and more particularly, to an ionic touch panel using hydrogel for a touch panel and having flexibility, stretchability, and biocompatibility. An ionic touch panel according to an embodiment of the present invention includes a hydrogel touch unit 100 containing salt, and electrodes connected to at least two parts of the hydrogel touch unit.

Abstract: An analyzer apparatus includes: an ionization unit that ionizes molecules to analyze; a filter unit that forms a field for selectively passing ions generated by the ionization unit; a detector unit that detects ions that have passed through the filter unit; an ion drive circuitry that electrically drives the ionization unit; a field drive circuitry that electrically drives the filter unit; a control unit that controls outputs of the ion drive circuitry and the field drive circuitry; a temperature detecting unit that detects the temperature of the ion drive circuitry and the field drive circuitry; and a correction unit that corrects output settings of the ion drive circuitry and the field drive circuitry based on the temperature detected by the temperature detecting unit.

Abstract: A method for manufacturing a palladium coated doped metal oxide conducting electrode including immersing a metal oxide conducting electrode into an aqueous solution having a palladium precursor salt to form the metal oxide conducting electrode having at least one surface coated with palladium precursor. To form a layer of palladium nanoparticles on the metal oxide conducting electrode the palladium precursor on the metal oxide conducting is reduced with a borohydride compound. The palladium nanoparticles on the metal oxide conducting electrode have an average diameter of 8 nm to 22 nm and are present on the surface of the metal oxide conducting electrode at a density from 1.5×10?3 Pd·nm?2 to 3.5×10?3 Pd·nm?2.

Abstract: A method for manufacturing a palladium coated doped metal oxide conducting electrode including immersing a metal oxide conducting electrode into an aqueous solution having a palladium precursor salt to form the metal oxide conducting electrode having at least one surface coated with palladium precursor. To form a layer of palladium nanoparticles on the metal oxide conducting electrode the palladium precursor on the metal oxide conducting is reduced with a borohydride compound. The palladium nanoparticles on the metal oxide conducting electrode have an average diameter of 8 nm to 22 nm and are present on the surface of the metal oxide conducting electrode at a density from 1.5×10?3 Pd·nm?2 to 3.5×10?3 Pd·nm?2.

Abstract: An air quality measurement system to monitor atmospheric properties at various locations, elevations, and times. The system includes an unmanned aerial vehicle having at least one carbon nanotube sensor for monitoring atmospheric air quality. Measurements of temperature, pressure, moisture, and gas species are obtained. A monitor mounted on the aerial vehicle is in communication with the sensor. A transmitter mounted on the aerial vehicle is in communication with the monitor for transmission of measurement data to a ground position controller.

Abstract: A low-cost and easy-to-fabricate mixed e? and CO32? conducting membrane for advanced high-flux and selective electrochemical CO2 separation from flue gas is provided. The membrane includes a CO32?-conducting molten carbonate phase and an e?-conducting lithiated Ni-oxide interphase that can be formed in situ during operation. The membrane exhibits a CO2 flux density greater than 0.8 mL/(minute·cm2) at 850° C. with a selectivity ranging from about 100 to about 500 and excellent stability for up to about 450 hours. Further, the self-formed interphase Li0.4Ni1.6O2 is highly electron conducting and can provide electrons to the co-reduction of CO2 and O2 into CO32?. Such a membrane is an alternative to the conventional “size-sieving” inorganic and “dissolution-diffusion” organic counterparts for CO2 capture from flue gas.

Abstract: The present disclosure relates to metal alloys for biosensors. An electrode is made from ruthenium metal or a ruthenium-based alloy. The resulting electrode has physical and electrical property advantages when compared with existing pure metal electrodes.

Abstract: In one aspect, a material system comprises a metal substrate and a first coating layer disposed on the metal substrate. A first electrode is directly disposed on the first coating layer, and a second electrode is disposed on the metal substrate. In one aspect, a method for determining material performance includes flexing a material system and detecting impedance of the material system with an electrochemical impedance spectrometer. The material system has a metal substrate, a first coating layer disposed on the metal substrate, a first electrode directly disposed on the first coating layer, and a second electrode disposed on the metal substrate.

Abstract: Techniques for generating a diagnostic waveform for a sensor are provided. In an example, a control circuit for an electrochemical sensor can include power supply inputs configured to receive a supply voltage, a first signal generator configured to receive control information and to generate a first signal on a first output using the supply voltage and the control information, a second signal generator configured to receive the control information and to provide a second signal on a second output, using the supply voltage and the control information. An output voltage between the first output and the second output, in a diagnostic mode of operation of the control circuit, can include a periodic signal having a peak-to-peak voltage greater than the supply voltage.

Abstract: Methods of detecting target nucleic acid is a sample are described. A first probe is attached to first beads, and the first beads are placed in the sample so that any target nucleic acid attaches to the first probe. A second probe also attaches to the target nucleic acid so that any of the target nucleic acid links or “tethers” the first and second probes. A capacitive sensor detects capacitance of the beads and processes capacitance data to quantify target nucleic acid presence in the sample. The second probe may be immobilised on the sensor surface. Alternatively the second beads are introduced into the sample with the second probe attached, and the extent of tethering of the first beads to the second beads is indicative of the extent of target NA present.

Abstract: A system, device and apparatus for measuring electrolytes, where an electrical charge is applied to a measurement portion to draw ions from a liquid to a gel-solution via at least one electric field. The gel-solution containing the extracted ions is excited with light of a predetermined wavelength from an emitter. A receiver detects the illumination of the ions as a result of the excited gel-solution, and a processor converts the detected intensities of the illumination to a biologically useful value representing ionic concentration.

Abstract: A biomolecule magnetic sensor configured to sense magnetic beads attached with biomolecules includes an adsorption pad, a magnetic field line generator and at least one magnetic sensor. The adsorption pad is configured to adsorb the magnetic beads. The magnetic field line generator is configured to generate a plurality of first magnetic field lines, and at least one of the first magnetic field lines passes through the magnetic beads along a first direction to induce a plurality of second magnetic field lines, wherein the magnetic field line generator is disposed between the adsorption pad and the magnetic sensor in the first direction. The magnetic sensor is configured to sense a magnetic field component of at least one of the second magnetic field lines in a second direction. A second shift is provided between the magnetic sensor and the adsorption pad in the second direction.

Abstract: An endoscope reprocessor includes: a concentration measurement chamber; a liquid concentrate supply unit; a diluent supply unit; a holding unit configured to hold a concentration sensor; a memory; and a processor configured to produce information on a temporary standard curve based on a first point at which a first concentration is associated with a sensor output value at measurement of concentration of liquid concentrate and a second point at which a second concentration is associated with a sensor output value at measurement of concentration of a practical use solution after dilution, calculate a deviation degree between a standard curve and the temporary standard curve, and determine whether the temporary standard curve is valid from the deviation degree.

Abstract: An electrochemical sensor may measure the flow of ions and/or electrochemical species in a solution passing the sensor because the electroactive species will continually come into contact with the electrode and an electric signal will be generated by the combination of diffusion and convection bringing the electroactive species to the electrode. The electric signal measured will vary by concentration of ions and/or electrochemical specie(s) and by flow rate. Flow rate may be measured if the concentration of ions and/or electrochemical specie(s) is known; conversely, the concentration of ions and/or electrochemical species may be measured if the flow rate is known. The sensor may also be used to confirm the delivery of a fluid containing ions and/or electrochemical specie(s).

Abstract: The present invention provides a surface acoustic wave sensor capable of suitably controlling the flow of a liquid sample onto IDT electrodes. A surface acoustic wave sensor has a piezoelectric substrate, a first IDT electrode and a second IDT electrode which are located on the upper surface of the piezoelectric substrate and are separated from each other while sandwiching a detection part on the piezoelectric substrate therebetween, and the cover which forms the space being on the first IDT electrode, second IDT electrode, and the detection part and straddling them. On the lower surface of the cover, the detection part-facing surface facing the detection part has a smaller contact angle to the liquid sample than that of a pair of electrode-facing surfaces facing the first IDT electrode and second IDT electrode.

Abstract: The invention relates to a closure for an electrochemical reaction vessel, in particular a potentiostat, the closure comprising: a holder for holding electrodes arranged at an inner side of the closure such that, when the closure is attached to a reaction vessel, electrodes held by the holder extend into an interior space of the reaction vessel and into an electrolyte contained in the reaction vessel; and a plurality of contacts arranged at an outer side of the closure for providing electrical contacts with the electrodes.

Abstract: A method for testing an electrochemical response of a sample, which is at least partially disposed within an electrolyte, includes macro scanning the sample. Macro scanning is applied across the entire sample and includes applying a first range of macro potential between the electrolyte and the sample, and measuring a first range of macro current between the electrolyte and the sample, while subject to the first range of macro potential. The macro scan is held at a first fixed macro potential within the first range of macro potential and the sample is micro scanned while held at the first fixed macro potential. Micro scanning is applied at individual points across a surface portion of the sample and includes measuring a plurality of first micro currents at each of the individual points of the surface portion of the sample. Each individual point is significantly smaller than the entire sample.

Abstract: A substrate treating apparatus includes a circulating line having a treating tank for storing a phosphoric acid aqueous solution, a circulating pump for feeding the phosphoric acid aqueous solution, a heater for circulation for heating the phosphoric acid aqueous solution, a filter for filtering the phosphoric acid aqueous solution, the circulating line causing the phosphoric acid aqueous solution discharged from the treating tank to flow in order of the circulating pump, the heater for circulation and the filter, and returning the phosphoric acid aqueous solution from the filter to the treating tank. The apparatus also includes a branch pipe branching from the circulating line between the heater for circulation and the filter for extracting the phosphoric acid aqueous solution from the circulating line, and a concentration measuring station connected to the branch pipe for measuring silicon concentration in the phosphoric acid aqueous solution by potentiometry.