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: 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: Improved dry-operative ion-selective electrodes and their use are described. The dry-operative ion-selective electrodes include an internal reference electrode comprising a water-soluble salt dispersed in a polymer binder consisting essentially of a monomer having at least one carboxyl group and a hydrophobic monomer. The polymer provides reduced brittleness, good interlayer adhesion and high salt tolerance.

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: 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 linker lipid for use in attaching a membrane including a plurality of ionophores to an electrode and providing a space between the membrane and the electrode in which the membrane is either in part or totally made up of the linker lipid. The linker lipid has within the same molecule a hydrophobic region capable of spanning the membrane, an attachment group used to attach the molecule to an electrode surface, a hydrophilic region intermediate the hydrophobic region and the attachment group, and a polar head group region attached to the hydrophobic region at a site remote from the hydrophilic region. The attachment group has a cross sectional area greater than the cross sectional area of the hydrophilic region, and has the structure recited in the specification.

Abstract: A sensor is provided that includes at least one functional coating layer that includes a UV-absorbing polymer. Methods for making the inventive sensors are also provided.

Abstract: An implantable analyte sensor includes a substrate, electrodes on the substrate, and a membrane on the electrodes. The membrane can comprise elemental silicon and has a glucose diffusion test result of at least 1 mg/dl in 330 min., and an albumin diffusion test result of at most 0.1 g/dl in 420 min.

Abstract: Sensor for measuring the partial pressure of a gas in a gaseous medium, comprising an electrochemical cell (2) and a diffusion barrier comprising a porous membrane (10) situated above an orifice (7) made in a component surmounting a casing (1) enclosing said electrochemical cell (2).

Abstract: An ion exchange membrane for use in sensors which measure dissolved gases. Disclosed is a method for using ion exchangers in gas permeable membranes to maintain optimal conditions in the electrolyte contained within the sensor. This can greatly extend the lifetime and improve the stability relative to sensors of similar size and electrolyte volume that have been constructed using prior art.

Abstract: An electrochemical measuring cell for detecting hydrocyanic acid is improved in such a manner that a stable measurement signal is provided after a short time. The measuring cell includes a measuring electrode (1) of sintered gold and a counter electrode (2). A measuring cell housing (4) accommodates the measuring electrode (1) and the counter electrode (2). An electrolyte is in the measuring cell housing (4) and includes sulphuric acid with an additive of silver sulphate. A diffusion membrane (5) is disposed between the measuring electrode (1) and the substance to be detected.

Abstract: A combined toxic gas sensor and an oxygen sensor includes a sensor body 1 with a top plate 2 provided with a toxic gas diffusion barrier 3 leading to a chamber 7 from having an outlet aperture 5 registering with the diffusion barrier 6 of the oxygen sensor.

Abstract: The invention relates to novel methods and compositions for the detection of analytes using the nuclear reorganization energy, &lgr;, of an electron transfer process

Abstract: An electrochemical gas sensor has at least one measuring electrode (5), a reference electrode (11) and an auxiliary electrode (7) in an electrolyte (3) and a diffusion membrane. The diffusion membrane (4) is formed from a polymer (Teflon® AF) containing bis-2,2-trifluoromethyl-4,5-difluoro-1,3-dioxol. The diffusion membrane (4) faces the ambient atmosphere.

Abstract: A fuel cell gas sensor for detecting gases such as Hydrogen (H2) and Carbon Monoxide (CO) comprises a main body (10) in which are mounted a protection membrane (11), a working electrode (12), electrolyte (13), a counter electrode (14), a protection membrane (15) and respective contacts (16). A catalyst disk (17a) or a very low impedance fuel cell (17b) is placed between the counter electrode (14) and the protection membrane (15). The membrane (15) slows down the flux of gases onto the counter electrode (14). The catalyst disk (17a) eliminates chemically while the fuel cell (17b) eliminates electrochemically the gases to be detected that permeate through the protection membrane (15). This arrangement makes it possible to detect the gases in places where the gases to be detected are able to reach both the working electrode (12) and the counter electrode (14).

Abstract: Electrochemical sensor for determining analyte in the presence of interferent, particularly carbon monoxide in the presence of hydrogen. An electrochemical cell is designed so that current flow resulting from reference electrode potential shift caused by interferent cancels out the current flow caused by interferent at the working electrode. Another electrochemical cell corrects for interferent concentration using the potential difference between a reference electrode in contact with interferent and a referent electrode not affected by inteferent.

Abstract: Method and apparatus for detecting and/or determining ethanol in fluid samples using a substantially non-porous barrier of un-plasticized polyvinyl chloride (PVC) interposed between the sample to be analyzed and a detecting means responsive to ethanol. The ethanol diffuses through the barrier membrane and then is measured at the detecting means. The PVC membrane can be made by solvent casting, and is usually 10 to 40 um thick. Measurement can be by any known means, but preferably electrochemically (amperometrically). The PVC membrane may be part of a multiple membrane system. The method and sensor are useful for analyzing alcoholic liquors or beverages (for example beer, wine and other fermentation products), in their final form or at intermediate stages of their manufacture or storage, and also for the monitoring of a wide range of process, waste and effluent liquids.

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

Abstract: The present invention relates to an apparatus to perform reagent-free assays, which apparatus utilizes an all solid probe having an enzyme label that acts on a substrate by obtaining electrons directly from the electrode by bioelectrocatalysis.

Abstract: There is provided a microchip-based differential-type carbon dioxide gas sensor for detecting dissolved carbon dioxide levels. It functions with at least one working electrode composed of an unbuffered hydrogel membrane containing a certain amount of sodium bicarbonate and a pH-sensitive gas-permeable membrane; and a reference electrode composed of a buffered hydrogel membrane and a pH-sensitive gas-permeable membrane. The unbuffered hydrogel membrane contains carbonic anhydrase, which reduces the time period for the hydration of carbon dioxide, thereby allowing the quick measurement of the level of carbon dioxide. In addition to being significantly improved in stabilization, sensing, and recovering time periods, the differential-type carbon dioxide gas sensor can be fabricated in small sizes and quickly measure levels of carbon dioxide dissolved in sample solution.

Abstract: Magnetic composites exhibit distinct flux properties due to gradient interfaces. The composites can be used to improve fuel cells and batteries and effect transport and separation of different species of materials, for example, transition metal species such as lanthanides and actinides. A variety of devices can be made utilizing the composites including a separator, an electrode for channeling flux of magnetic species, an electrode for effecting electrolysis of magnetic species, a system for channeling electrolyte species, a system for separating particles with different magnetic susceptibilities, improved fuel cells, batteries, and oxygen concentrators. Some composites can be used to make a separator for distinguishing between two species of materials and a flux switch to regulate the flow of a chemical species. Some composites can control chemical species transport and distribution. Other composites enable ambient pressure fuel cells having enhanced performance and reduced weight to be produced.

Abstract: Electrode membrane combinations for use in biosensors to detect analytes in a sample and methods for making and storing same are disclosed. In one aspect, a method is provided for producing a first layer electrode membrane comprising: (1) Forming a solution containing Linker Lipid A, the disulfide of mercaptoacetic acid (MAAD) or similar molecule, linker Gramicidin B, membrane spanning lipid C (MSL-C) and membrane spanning lipid D (MSL-D) or other suitable linker molecules and other ion channel combinations; (2) Contacting an electrode containing a clean gold surface with the solution, the disulfide containing components in the solution thus adsorbing onto the gold surface of the electrode; (3) Rinsing the electrode with a suitable organic solvent; and (4) Removing the excess organic solvent used for rinsing.

Abstract: An electrochemical sensor for detection of a gas in an atmosphere containing the gas. The sensor has a housing having an electrochemical gas sensor with an electrolyte and at least two electrodes, one electrode being a gas sensing electrode. The housing has an orifice between the sensing electrode and the atmosphere for transmission of gas from the atmosphere to the sensing electrode, the orifice being protected by a hydrophobic membrane, and connected to at least two radial channels extending from the orifice. Each of the radial channels is connected to a common channel, such that gas communication from the atmosphere through the orifice to the sensing electrode is through the common channel and the radial channels, in addition to the covering membrane if the membrane is gas permeable.

Abstract: The present invention relates to a device for generating an oscillating electrical current, where the device incorporates an ion channel. In particular, the ion channel is incorporated into an integrated electronic device having nanoscale dimensions. Thus, this device can transform biological processes into an electrical output. The present invention also describes a sensor for detecting biological or chemical analytes with the ion channel device. Methods for generating the oscillating currents and detecting the analytes are also disclosed.

Abstract: In an electrode system, particularly for electrochemical sensors, which comprises a working electrode, a counterelectrode and an electrolyte, the counterelectrode is constituted by a material containing an elementary carbon, whereby the long-term stability of the electrode system is considerably increased.

Abstract: Magnetic composites exhibit distinct flux properties due to gradient interfaces. The composites can be used to improve fuel cells and effect transport and separation of different species of materials. A variety of devices can be made utilizing the composites including a separator, a cell, an electrode for channeling flux of magnetic species, an electrode for effecting electrolysis of magnetic species, a system for channeling electrolyte species, a system for separating particles with different magnetic susceptibilities. Some composites can be used to make a dual sensor for distinguishing between two species of materials and a flux switch to regulate the flow of a redox species and a flux switch to regulate the flow of a chemical species. Some composites can control chemical species transport and distribution.

Abstract: An implantable enzyme-based monitoring system suitable for long term in vivo use to measure the concentration of prescribed substances such as glucose is provided. In one embodiment, the implantable enzyme-based monitoring system includes at least one sensor assembly, an outer membrane surrounding the sensor assembly and having a window therein, and a polymeric window cover affixed to the outer membrane and covering the window. Preferably, the outer membrane of the monitoring system is silicone and the window cover is a polymer of 2-hydroxyethyl methacrylate (HEMA), N,N,-dimethylaminoethyl methacrylate (DMAEMA) and methacrylic acid (MA). Also provided herein is an implantable enzyme-based monitoring system having at least one sensor assembly, an outer membrane surrounding the sensor assembly and a coating affixed to the exterior surface of the outer membrane, wherein the coating resists blood coagulation and protein binding to the exterior surface of the outer membrane.

Abstract: The invention provides a mechanically stable substrate having at least one through-opening, a perforated membrane which is integral or fluid-tightly connected with the substrate and which extends across the through-opening, and at least one semi-permeable layer which is applied in firmly adhering manner to one or both sides of the membrane, at least in the perforated region thereof, in that the semi-permeable layer or semi-permeable layers is/are secured mechanically in the adjacent perforations and/or by chemical-structural and/or physical adhesion and/or adhesive intermediate layers and/or covalent surface bonding to the adjacent surfaces of the membrane, optionally of the substrate, or of a metallic film optionally additionally applied to one or both sides of the membrane. The invention further provides a process for the production of this sensor- and/or separating element and the use thereof.

Abstract: A gas sensor assembly is provided with a non-conductive housing portion and a plurality of conductive housing portions, each of which are conductively separated from each other, and the conductive housing portions are composed of a conductive plastic material. A gas-sensing agent is disposed in a receptacle formed in the housing, and a plurality of electrodes are disposed in conductive contact with the gas-sensing agent. The gas sensor has an electrode support sheet with a plurality of electrodes formed thereon, and a seal is formed between the electrode support sheet and the housing, the seal being formed by the sealing of a portion of one of the electrodes to a portion of the housing.

Abstract: A method for determining relative amounts of O2 and N2O in gas mixtures by quantitative electrochemical reaction including feeding a gas mixture containing O2 and N2O to a zinc-air cell having electrodes connected to a circuit consisting of a plurality of diodes and resistors, which circuit is set to have an electrochemical working range corresponding to each of the O2 and N2O; and measuring current flowing in the respective working range to determine the relative proportions of O2 and N2O in the gas mixture. An electrochemical cell including a casing capable of containing a gas mixture, including O2 and N2O a zinc-air cell in the casing, and a circuit connected to electrodes of the zinc-air cell, the circuit containing a plurality of diodes, resistors and tap points; means for measuring current to determine the relative proportions of O2 and N2O in the gas mixture.

Abstract: A chemical sensor (1) for selectively detecting an analyte in a solution as described. The sensor comprises a flow-through chamber (2), a selective membrane (3), a transducer means (4), an inlet (5) for a liquid flow containing a recognition element, and an outlet (6). There is also described a method of selectively detecting an analyte in a solution, wherein a recognition element is contacted with the solution containing the analyte via a selective membrane, said contact resulting in a response detectable by transducer means. The recognition element is injected into a flow, the flow is passed into a flow-through chamber comprising a transducer means and the selective membrane, where it is contacted with the analyte passing from the solution outside the selective membrane, whereby the recognition element and the analyte interact to provide a signal which is detected by the transducer means.

Abstract: A detector assembly for detecting a plurality of different properties at the same location at the same time is provided by integrating onto a single semiconductor substrate a first detector unit for measuring a first property and a second detector unit for measuring a second property. The first and second detector units can share, for example, a common element, such as a sensor device that can provide electrical output signals representative of, respectively, the first property and the second property. The common element can include a diaphragm with a pyroelectric element to provide a measurement of temperature and pressure.

Abstract: Nitric oxide-specific electrodes are useful for in situ detection of nitric oxide in biomedical applications and have at least a surface region thereof which is capable of forming complexes with nitric oxide, for example, nitrosyl complexes. The nitric oxide complexes formed at the surface of the electrodes apparently increase the concentration of nitric oxide available for detection, thereby leading to significantly improved relative responses as compared to other known nitric oxide electrode materials. Most preferably, the electrode has at least an exterior surface region which contains ruthenium and/or at least one oxide of ruthenium. The electrodes are advantageously conditioned in saline solution at +675 mV for about two hours.

Abstract: A method for determining the concentration of a reduced (or oxidised) form of a redox species in an electrochemical cell of the kind comprising a working electrode and a counter electrode spaced from the working electrode by a predetermined distance, said method comprising the steps of: (1) applying an electric potential difference between the electrodes; (2) selecting the potential of the working electrode such that the rate of electro-oxidation of the reduced form (or electro-reduction of the oxidised form) of the species is diffusion controlled, (3) selecting the spacing between the working electrode and the counter electrode so that reaction products from the counter electrode arrive at the working electrode; (4) determining current as a function of time after application of the potential and prior to achievement of a steady state; (5) estimating the magnitude of the steady state current, and (6) obtaining from the change in current with time and the magnitude of the steady state current, a value indicati

Abstract: Nitric oxide-specific electrodes are useful for in situ detection of nitric oxide in biomedical applications and have at least a surface region capable of forming complexes with nitric oxide. The nitric oxide complexes formed at the surface of the electrodes apparently increase the concentration of nitric oxide available for detection, leading to significantly improved relative responses as compared to other known nitric oxide electrode materials. The electrode has at least an exterior surface region which contains ruthenium and/or at least one oxide of ruthenium. The electrodes are pre-conditioned at a potential, or potentials, different than the working potential of the electrode, followed by further conditioning at the working potential. Direct response to nitric oxide has been observed for ruthenium electrodes at or below potentials about +675 mV vs. Ag/AgCl, while ruthenium electrodes paradoxical response to nitric oxide has been observed at potentials above +675 mV vs. Ag/Cl.

Abstract: A cell holding an electrolyte solution of not less than 0.5 mole and not more than 2.0 moles lithium chloride, having a window sealed with a gas-permeable diaphragm holding a working electrode attached to that side thereof which faces the electrolyte solution, and also holding a counter electrode permits improving response speed in accordance with the concentration of lithium chloride.

Abstract: One electrode is provided in association with the object to be coated, the other electrode. A pre-stretched ion-exchange membrane in a thin tubular form is sandwiched inbetween two nonconductive water permeable screen tubular housings. The assembly contains a supply line that provides a water way for the electrolyte to flow from the top of the device into a lower cap, then to the lower cap reservoir that allows stabilization and disbursement of electrolyte through the rifled housing Inertia developed through this defined pattern creates a swirling action that scrubs the impurities away from the anode, and to the top of the device to be carried out top. The location of the supply line is just inside the inner screen inserted through both the upper housing and lower cap. The tubular electrode is provided to the inside of membrane housing completing the inner portion of the waterway return chamber.

Abstract: The present invention relates to a non-enzymatic disposable uric acid detecting electrode strip which directly detects the concentration of uric acid in liquid sample under a low operation voltage of below 400 mV and pH value from 7.0 to 10.0. When the electrode strip is applied to detect the concentration of uric acid in human body, it avoids interference signals caused from any other components in blood and will not be interfered by ascorbic acid unless the concentration of ascorbic acid increases to 15 times of its normal concentration in blood. Not only serum but also whole-blood can be taken as a sample for detecting the uric acid concentration thereof. The uric acid detecting electrode strip is modified by a water soluble redox electron mediator. The electrode strip is easy to carry and can be easily made, particularly mass-produced.

Abstract: A method and apparatus for the manipulation of colloidal particles and biomolecules at the interface between an insulating electrode such as silicon oxide and an electrolyte solution. Light-controlled electrokinetic assembly of particles near surfaces relies on the combination of three functional elements: the AC electric field-induced assembly of planar aggregates; the patterning of the electrolyte/silicon oxide/silicon interface to exert spatial control over the assembly process; and the real-time control of the assembly process via external illumination. The present invention provides a set of fundamental operations enabling interactive control over the creation and placement of planar arrays of several types of particles and biomolecules and the manipulation of array shape and size. The present invention enables sample preparation and handling for diagnostic assays and biochemical analysis in an array format, and the functional integration of these operations.

Abstract: An operational amplifier (34) has its inverting input connected to a electrochemical gas sensor (38) for amplifying the current produced thereby in response to presence of a predetermined gas. In order to determine whether a sensor (38) is indeed present and that a sensor present is serviceable, a transient is applied to the non-inverting input of the operation amplifier (34). The presence or absence of the sensor (38) alters the transfer function of the operational amplifier (34) in respect of the test signal. If a serviceable sensor (38) is present, the gain of the operational amplifier (34) is high for the transient resulting at square pulse output. However, if a serviceable sensor (38) is not present, the gain of the operational amplifier (34) is relatively low and the transient retains its original form. Consequently the presence of a serviceable sensor (38) can be determined from the output of the operational amplifier (34) in response to the transient test signal.

Abstract: The invention is directed to an electrochemical measuring cell for detecting hydride gases, preferably arsine and phosphine. The measuring cell includes at least one working electrode (3) made of a catalytically inactive material and a reference electrode (4) in an electrolyte chamber (6) filled with an electrolyte containing sulphuric acid. The measuring cell is improved as to the cross sensitivity with respect to other toxic gases. The working electrode is configured as a carbon electrode (3) and an electrolyte additive of silver sulphate is provided in saturated solution in the electrode (9).

Abstract: An improved disposable glucose test strip for use in a test meter of the type which receives a disposable test strip and a sample of blood from a patient and performs an electrochemical analysis is made using a non-conductive integrated reagent/blood separation layer containing a filler, an enzyme effective to oxidize glucose, e.g., glucose oxidase, and a mediator effective to transfer electrons from the enzyme. The integrated layer formulation is printed over a conductive carbon element to form a working electrode. The filler, for example a silica filler, is selected to have a balance of hydrophobicity and hydrophilicity such that one drying it forms a two-dimensional network on the surface of the conductive element. The response of this test strip is essentially temperature independent over relevant temperature ranges and is substantially insensitive to the hematocrit of the patient.

Abstract: Hybrid membrane electrode assemblies (MEAs) are presented, having an anode comprising a dense distribution of catalyst that may be borne on small, high-aspect ratio supports, such as nanostructured elements, and a cathode comprising a less dense distribution of catalyst that may be borne on lower-aspect ratio supports, such as carbon particle supported catalyst.

Abstract: A method and corresponding apparatus useful for the in situ measurement of atomic hydrogen permeation into carbon steel from process streams under operating conditions of up to 3000 psi and temperatures up to 300° F.

Abstract: A method for monitoring changes in the level of an osmotically active component, such as for instance glucose, or in healthy humans, such as athletes for monitoring the level of lactic acid in the muscles is described. The key feature of the method is that the osmotic movement back and forth over a membrane is used to activate a sensing device, whereby the physical changes that take place in the fluid may be recorded by a receiver situated outside the body. A device for carrying out said method is likewise described.

Abstract: The invention relates to a microsensor for the measurement of the presence and the concentration of a primary medium, for example nitrate, in an environment where the microsensor is placed. The microsensor has a casing which surrounds a transducer and a reservoir containing nutrients. The transducer has a tip placed at a distance from the opening of the casing. Between the transducer tip and the opening is a reaction chamber with bacteria. The bacteria metabolises the primary medium (nitrate) into a secondary medium (nitrous oxide) which is detected by the transducer. The casing has a passage that stretches to the reservoir behind the transducer tip. Through the passage nutrients are fed to the bacteria whereby their activity can be maintained.

Abstract: The invention is concerned with a sensor for the determination of the concentration and the detection of an enzyme substrate in a liquid sample, the sensor comprising an enzyme capable of reacting with the enzyme substrate while producing a substance directly or indirectly detectable, a detection device for this substance and a cover membrane from a polymer permeable to the enzyme substrate, characterized in that the polymer is a polyvinyl chloride copolymer, i.e. a copolymer from vinyl chloride and a further monomer, the copolymer comprising hydrophilic groups. The sensor according to the invention may be provided as an optical sensor or as an amperometric sensor.

Abstract: A chemical sensor (1) for selectively detecting an analyte in a solution as described. The sensor comprises a flow-through chamber (2), a selective membrane (3), a transducer means (4), an inlet (5) for a liquid flow containing a recognition element, and an outlet (6). There is also described a method of selectively detecting an analyte in a solution, wherein a recognition element is contacted with the solution containing the analyte via a selective membrane, said contact resulting in a response detectable by transducer means. The recognition element is injected into a flow, the flow is passed into a flow-through chamber comprising a transducer means and the selective membrane, where it is contacted with the analyte passing from the solution outside the selective membrane, whereby the recognition element and the analyte interact to provide a signal which is detected by the transducer means.

Abstract: The present invention provides a biosensor comprising an electrode and a membrane in which the biosensor includes at least two zones each zone differing from each other zone in a property. The membrane includes a plurality of ionophores, at least a proportion of which are capable of lateral diffusion within the membrane. A plurality of first binding partner molecules are attached to membrane elements positioned within a first zone such that the first binding partner molecules are prevented from diffusing laterally into a second zone. Second binding partner molecules are attached to the ionophores and the rate of lateral diffusion within the membrane of the first binding partner molecules and second binding partner molecules is different.

Abstract: A method and apparatus for detecting ethanol content of a sample wherein a membrane barrier comprising unplasticized PVC is interposed between the sample and detecting means.