Abstract: The present invention provides a biosensor which enables quick measurement and is excellent in storage characteristic. This biosensor comprises an electrically insulating base plate on which an electrode system having at least a measuring electrode and a counter electrode is formed, a cover member which is integrated to the base plate so as to form a sample solution supply path for supplying a sample solution to the electrode system between the cover member and the base plate, and a carrier composed of fiber supporting a reagent containing at least an oxidoreductase, and the carrier is placed in the sample solution supply path. Preferably, the carrier is constituted at least of two carrier pieces and each carrier piece supports a different reagent.

Abstract: Humectants are applied to cathodic protection systems which utilize thermally-sprayed zinc or zinc alloy anodes applied to the surface of reinforced concrete structures. The humectants are deliquescent or hygroscopic organic or inorganic salts, hydrophilic polymers or colloids, or organic liquid desiccants. The humectants are positioned at or near the interface between the anodes and the concrete and increase the moisture content at the interface. This increases the ability of the anode to deliver cathodic protection current to steel embedded in the concrete. The humectants may be applied to the concrete surface prior to application of the anode, or may be applied subsequent to installation of the anode.

Abstract: The present invention generally provides methods for enhancing transport and direction of materials in fluidic systems, which systems utilize electroosmotic (E/O) flow systems, to affect that transport and direction. The methods generally comprise providing an effective concentration of at least one zwitterionic compound in the fluid containing the material that is to be transported or directed.

Abstract: A combined gas sensor of the invention is equipped with a second oxygen sensing electrode 5 active only to oxygen, which is disposed on a solid electrolyte substrate 3a such that it is directly exposed to detection gases. Sensor disorder is detected by measuring an electromotive force (signal output 2) generated between a reference electrode 7 and the second oxygen sensing electrode 5 as an oxygen concentration in an exhaust gas atmosphere, and comparing and judging the detected result with a signal output 1 corresponding to an electromotive force between a first oxygen sensing electrode 4 and the sit reference electrode 7, or with a signal output of an oxygen pump current.

Abstract: A measuring device (1), for examining a medium (2) that is liquid or free-flowing, has at least two electrically and/or optically conducting layers or layer areas (5a, 5b, 5c, 6a, 6b, 7a, 7b) located on a substrate layer (3), wherein these layers or layer areas are electrically and/or optically insulated from each other. At least one of these layers or layer areas (5a, 5b, 5c, 6a, 6b, 7a, 7b) is part of a layer stack (4), which has several layers arranged on top of each other on the substrate layer (3). The layer stack has, on its side facing away from the substrate layer (3), a recess that adjoins the electrically and/or optically conducting layers or layer areas (5a, 5b, 6a, 6b, 7a, 7b). At least one electrically and/or optically conducting layer or layer area (5a, 5b, 6a, 6b, 7a, 7b) located in the layer stack (4) is spaced at a distance from the bottom (11) of the recess (10).

Abstract: The invention relates to a polymeric electrolyte which is part of an electrochemical reference electrode and which is used in potentiometric and amperometric sensors. The polymeric electrolyte is a hydrogel which is stable in a large pH-range and stable against organic solvents.

Abstract: An L-phenylalanine sensor wherein all of the reagents required in determining L-phenylalanine are integrated together, thereby enabling quick and convenient quantification without resort to any special equipment, devices or techniques. This sensor is fabricated by integrating L-phenylalanine dehydrogenase, oxidized nicotinamide adenine dinucleotide (NAD+) or oxidized nicotinamide adenine dinucleotide phosphate (NADP+) as a coenzyme and an electron mediator, which are employed as reagents, with an electrode system comprising at least a working electrode and a counter electrode. Also, a method of determining L-phenylalanine which comprises adding a sample containing L-phenylalanine to the above-described sensor and electrochemically quantitating L-phenylalanine is provided.

Abstract: On an insulating substrate 1 is formed an electrode 2, on which is then formed a protection layer 3 consisting of a methacrylate-resin polyfluoroalcohol ester layer.

Abstract: The present invention provides a biosensor having a high current response sensitivity, a low blank response and a high storage stability. This sensor comprises an electrode system including a working electrode and a counter electrode, for forming an electrochemical measurement system by coming in contact with a supplied solution; an insulating supporting member for supporting the electrode system; a first reagent layer formed on the working electrode; and a second reagent layer formed on the counter electrode, wherein the first reagent layer does not contain an enzyme, but it contains at least an electron mediator, and the second reagent layer does not contain an electron mediator, but it contains at least an enzyme.

Abstract: A gas sensor is described which is particularly well suited as a carbon monoxide (CO) sensor in a self test gas sensor. The sensor includes a number of aspects which may or may not be used in conjunction with one another. A first aspect is an embodiment which reduces electrical interference (or cross-talk) between a test or gas generating cell and a sensing cell. In one embodiment, baffles are provided to prevent cross-talk. In another embodiment a switching circuit ensures that a test gas generator is operational only when the gas sensor is disconnected from a current source. A second aspect is an embodiment which includes an improved wick which is in close proximity with an electrode and ensures electrolyte is always in contact with the electrode. In an alternate embodiment a solid polymer electrolyte is used between the electrodes. A third aspect is an improved catalyst which reduces the reaction energy and thereby renders the sensor more sensitive. The catalyst is also cheaper than platinum.

Abstract: A modified universal exhaust gas oxygen sensor, referred to herein as a CEGA sensor, is provided which can be used to measure the concentration of a variety of components of a gaseous fuel emission including CO, CO2, O2, H2, and H2O. The CEGA sensor-employs at least one additional electrode on a ceramic substrate which possess a different catalytic activity relative to the electrodes that normally found on a UEGO sensor. The ceramic substrate may be made of any suitable ceramic and is preferably made of zirconia. The difference in catalytic activity between the additional electrode(s) and the electrodes native to the UEGO sensor create an oxygen gradient which enables a measure of combustion completeness to be calculated. In combination with an air/fuel ratio measured by the sensor, the concentrations of different components in the emission can be calculated.

Abstract: A corrosion test cell for evaluating corrosion resistance in fuel cell bipolar plates is described. The cell has a transparent or translucent cell body having a pair of identical cell body members that seal against opposite sides of a bipolar plate. The cell includes an anode chamber and an cathode chamber, each on opposite sides of the plate. Each chamber contains a pair of mesh platinum current collectors and a catalyst layer pressed between current collectors and the plate. Each chamber is filled with an electrolyte solution that is replenished with fluid from a much larger electrolyte reservoir. The cell includes gas inlets to each chamber for hydrogen gas and air. As the gases flow into a chamber, they pass along the platinum mesh, through the catalyst layer, and to the bipolar plate. The gas exits the chamber through passageways that provide fluid communication between the anode and cathode chambers and the reservoir, and exits the test cell through an exit port in the reservoir.

Abstract: The invention relates to an amperometric electrochemical cell having a first insulating substrate carrying a first electrode, a second insulting substrate carrying a second electrode, said electrodes being disposed to face each other and spaced apart by less than 500 &mgr;m, and defining a sample reservoir therebetween, and wherein at least one, and preferably both, insulating substrates and the electrode carried thereon include an electromagnetic radiation transmissive portion in registration with said reservoir. The walls of the electrochemical cell may be formed from a thin metallic portion on a transparent substrate. Such cells are useful in providing visual confirmation of the validity of the electrochemical measurement.

Abstract: An immersion sensor is provided for monitoring of aluminum electrolysis cells, together with a corresponding measurement arrangement and a measuring method. In order to obtain reproducible measurements, the bath electrode of the immersion sensor is arranged on a carrier.

Abstract: A detector for an air/fuel ratio sensor, which is comprised of a structure formed by stacking an oxygen reference electrode, a dense zirconia solid electrolyte, a negative electrode, a porous zirconia solid electrolyte, a positive electrode and a porous protection film on one another, is formed over a ceramic substrate having a heater built therein. Thus, a combined air/fuel ratio sensor can be obtained which is operated in a short time (about 5 seconds or less) after power-on so as to comply with emission control applied immediately after startup and provides low power consumption and a high degree of reliability.

Abstract: The present invention provides a biosensor that has a reaction reagent system easily dissolved even in a sample solution containing a high concentration of a substrate and ensures rapid and highly accurate measurement. The method of forming a target reaction layer according to the present invention dissolves a material constituting the target reaction layer in a solvent of a sublimable substance to prepare a solution, applies the solution in a desired area to form the target reaction layer, freezes the applied solution, and sublimates the solvent included in a solid matter of the frozen solution under reduced pressure for removal. The resultant reaction layer has a large surface area and is easily dissolved in the sample solution to enable rapid measurement.

Abstract: Methods, apparatus and systems are provided for introducing large numbers of different materials into a microfluidic analytical device rapidly, efficiently and reproducibly. In particular, improved integrated pipettor chip configurations, e.g. sippers or electropipettors, are described which are capable of sampling extremely small amounts of material for which analysis is desired, transporting material into a microfluidic analytical channel network, and performing the desired analysis on the material.

Abstract: A biosensor is provided that includes first and second plate elements, wherein each plate elements has first and second ends and first and second lateral borders. In addition, the biosensor includes a spacer positioned to lie between the first and second plate elements so that at least a portion of the first and second plate elements cooperate with one another to form opposite walls of a capillary space. Further, the first ends and at least a portion of the lateral borders define a fluid sample-receiving portion in communication with the capillary space. Electrodes are positioned in the capillary space of the biosensor.

Abstract: The present invention provides a membrane based biosensor. The biosensor includes an electrode and a passivating layer bound to the electrode. A lipid membrane incorporating ionophores, the conductivity of the membrane being dependent on the presence or absence of an analyte, is bound to the passivating layer in a manner such that an ionic reservoir exists between the membrane and the passivating layer. Reservoir spanning molecules spanning the ionic reservoir are also included. These molecules are covalently attached at one end to the membrane and at the other to the passivating layer. The incorporation of the passivating provides greater stability to the sensor.

Abstract: A circuit configuration for controlling a pump current includes a microcontroller, an analog circuit and a read-only memory. A pulse-width modulated signal, which is output by the micro-controller, is converted, by using the analog circuit, into the pump current for a pump cell of an exhaust probe which operates according to the principle of the galvanic oxygen concentration cell with a solid electrolyte. A pump current actual value is determined from a voltage drop across a measuring resistor, and a pump current setpoint value is determined from a voltage difference between an actual value of a Nernst voltage in the corresponding measuring cell and a predefined setpoint value. An exhaust probe configuration is also provided.