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: The present invention relates to the measurement of the progress of a chemical reaction that generates an electroactive reaction product that is subsequently detected at an electrode amperometrically or coulometrically. The method is useful in applications where it is desirable to follow the progress of a chemical reaction, particularly in sensor applications where the progress of the reaction of an analyte can be useful in determining the analyte concentration.

Abstract: The present invention concerns cartridges adapted to provide a solution for medical use such as a dyalysis solution by dissolving a plurality of substances in powder form in at least one liquid. The cartridge according to the invention comprises a container including a lateral wall, a bottom wall unitary with the lateral wall, the lateral and bottom walls delimiting a main volume, a central nucleus unitary with the bottom wall, the height of the central nucleus being substantially equal to that of the lateral wall to define an annular volume in the main volume, at least two separation walls imperviously unitary with the bottom wall, with the interior surface of the lateral wall and with the exterior surface of the central nucleus to delimit two secondary volumes in the annular volume, and at least two fluid connections adapted to connect the exterior of the container with the two secondary volumes.

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: An emission control system for determining a concentration of oxygen in a flow of gas which has a sensor. The sensor has a diffusion barrier, an electrolyte material, and a counter-electrode. The counter-electrode is configured to support the diffusion barrier, and the electrolyte material is disposed between the diffusion barrier and the counter-electrode.

Abstract: In a method for positioning or controlling the motion of an object in a multi-electrode arrangement for forming a field cage, the basic potentials for driving the electrodes are modulated with drive potentials in such a way that the object position in the field cage changes in relation to a predetermined position or path. A device for arranging objects at predetermined positions in a multi-electrode arrangement has a switching device by which basic potentials, produced by generator means, can be modulated according to predetermined drive potentials (FIG. 1).

Abstract: A biosensor is used for measuring principal metabolites in blood and other substances. The biosensor has a special structure formed of a two-layer enzymatic membrane with a considerably increased functionality compared with enzymatic membranes of the prior art.

Abstract: An electrochemical sensor for ascertaining a gas concentration of a measuring gas includes an electrochemical element, including a first solid electrolyte body having an electrochemical pump cell and a first and a second electrode, and having a gas compartment which is connected via a gas access opening to the measuring-gas compartment, and in which one of the two electrodes is arranged. The electrochemical element further includes a second solid electrolyte body having an electrochemical sensor cell (Nernst cell) and a third and a fourth electrode. The surface of the first solid electrolyte body faces the measuring-gas compartment, and the gas access opening is covered by a porous protective layer. The electrochemical sensor includes a layer that exhibits a higher density or a lower porosity compared to the protective layer and that is allocated to the porous protective layer.

Abstract: The present invention is an apparatus for laboratory and field use in detecting and measuring Hg+ and Hg2+ in sample. A selective mercury binding agent, such as a chelating agent or clathrating agent, is covalently bound in a copolymer and deposited as an electrode layer. To prepare the preferred apparatus of the invention, thiophene, or other, similar monomer, is derivatized by covalent attachment thereto of Kryptofix-21™ (1,4,10-trioxa-7,13-diazacyclopentadecane) in the 3-position. The thiophene monomer and Kryptofix-21™ are co-polymerized and electrodeposited by known techniques onto a conductive substrate, such as platinum or glassy carbon, to obtain a multi-layer polymer coating of desired thickness. The resulting coated electrode has selective coordination sites for mercury of the order of Kf=1016, compared to Kf=103 for cadmium, Kf=105 for lead and Kf=105 for silver.

Abstract: A galvanic-cell gas sensor includes casings containing a diaphragm permitting the permeation of gas to be detected but having a water-repelling property, a cathode provided on the back side of the diaphragm, an anode formed by electrolytically coating a layer of lead (Pb) on an electrically conductive material having a corrosion resistance to electrolyte so as to leave a portion thereof uncoated to serve as a lead, and a sheet impregnated with electrolyte before assembly and disposed between the cathode and anode, with the diaphragm positioned so as to be exposed to the atmosphere.

Abstract: The present invention provides a biosensor which enables prompt quantification by facilitating introduction of a sample solution even when the amount of the sample solution is small and improving dissolution of reagents. The biosensor comprises an insulating base plate; an electrode system including at least a measuring electrode and a counter electrode formed on the base plate; a cover member integrated into the base plate to form a sample solution supply pathway for supplying a sample solution to the electrode system between the cover member and the base plate; a reaction reagent system including at least an electron mediator and an oxidoreductase; and a carrier supporting at least the electron mediator or the oxidoreductase of the reaction reagent system, wherein the carrier is partially or wholly disposed outside the sample solution supply pathway.

Abstract: A fuel cell for generating a current in response to the presence of acetylene in a fluid. The fuel cell comprises first and second gas porous electrode means, and acidic electrolyte means interconnecting the first and second electrode means for facilitating the electrochemical oxidation of the acetylene at the first electrode means and the electrochemical reduction of oxygen in an oxygen-containing gas at the second electrode means so as to generate the current, the first electrode means being a gas porous gold electrode means.

Abstract: An oxygen concentration detector comprises a solid electrolyte 21, a sensing element 2 which consists of the solid electrolyte 21 coated on the surface with an outer electrode 23, a heater 3 provided inside the solid electrolyte 21, and a protecting cover 16 which protects the sensing element 2. The protecting cover 16 has two levels of openings 161, 162, the outer electrode 23 is constructed within the range defined by the length of the heat-generating part 31 of the heater 3, and the relationship between the length L1 of the heat-generating part 31 and the distance between the openings L2 of the two levels of openings 161, 162 in the axial direction is such that L1/L2=0.9 to 1.3.

Abstract: The present invention provides an on-chip packed reactor bed design that allows for an effective exchange of packing materials such as beads at a miniaturized level. The present invention extends the function of microfluidic analysis systems to new applications including on-chip solid phase extraction (SPE) and on-chip capillary electrochromatography (CEC). The design can be further extended to include integrated packed bed immuno- or enzyme reactors.

Abstract: A biosensor is provided in accordance with this invention. The biosensor includes a bottom section with an edge and a flange extending from the edge, a top section supported on the bottom section and having an edge and flange extending from the edge in alignment with the flange of the bottom section. The flanges of the top and bottom sections cooperate to form a capillary channel, and first and second electrodes. Additionally, the first electrode is positioned on the flange of the bottom section in the capillary channel and the second electrode is positioned on the flange of the top section in the capillary channel.

Abstract: A method for separating and concentrating charged species from uncharged or neutral species regardless of size differential. The method uses reversible electric field induced retention of charged species, that can include molecules and molecular aggregates such as dimers, polymers, multimers, colloids, micelles, and liposomes, in volumes and on surfaces of porous materials. The retained charged species are subsequently quantitatively removed from the porous material by a pressure driven flow that passes through the retention volume and is independent of direction thus, a multi-directional flow field is not required. Uncharged species pass through the system unimpeded thus effecting a complete separation of charged and uncharged species and making possible concentration factors greater than 1000-fold.

Abstract: An electrochemical gas sensor has a first gas diffusion electrode for a first reaction gas, which is inactive with respect to a second reaction gas at least in a first potential window, and a second gas diffusion electrode for the second reaction gas, which is active with respect to the second reaction gas at least in a second potential window for measuring two different gases in gas mixtures in a casing. The two gas diffusion electrodes are electronically isolated from one another, but electrically connected electrolytically to a reversibly loadable electrode and have contacts for connecting external closing circuits for adjusting the cell currents. The gas mixture is fed to the gas diffusion electrodes in series or parallel. The casing containing the electrodes is, in particular, in the form of a button cell. The reversibly loadable electrode is a Cu/CuO, Zn/ZnO or hydrogen electrode. The gas diffusion electrodes have a porous structure based on carbon or have a porous silver structure.

Abstract: The invention provides a sensor with a reference electrode and a flowing electrolyte which is particularly useful for measuring the ion concentration of a process solution. The invention includes a sensor having a pressurized reservoir which provides flow of an electrolyte, a non-metallic solution ground and a resistance temperature device bonded to a non-metallic solution ground. The invention provides sensors with greater accuracy and stability by minimizing or eliminating ingress of contaminants from a process solution through the external junction of the sensor.

Abstract: A electrochemical sensor for the detection of traces of HF and/or other acid gases in air, comprising a measuring electrode of an electrochemically active metal oxide powder, a reference electrode for fixing the potential of the measuring electrode close to the equilibrium potential of the oxidation/reduction system of MeOn/Mem+, and a counter electrode. The electrodes are in communicative contact with a hygroscopic electrolyte. The measured gas component changes the pH of the electrolyte, and thus the electrochemical equilibrium of the measuring electrode, to produce a measurable electrical current that is proportional to the concentration of the detected acid gas.

Abstract: A sensor housing for accommodating at least one electrode which can be brought into contact with a process fluid, the sensor housing being sealable by means of a porous seal by which an inner chamber is formed between an inner surface of the sensor housing, the external surface of the at least one electrode and the surface of the porous seal, with the inner chamber being filled with a first electrolyte, wherein the sensor housing further comprises a deformable section which enables the inner chamber volume to be variable. The sensor housing may be used in a sensor which is temperature and pressure resistant over a wide range of values.