Abstract: Systems and methods are disclosed that use a nebulizer for remote aerosol generation and then transport the aerosol by way of, for example, an argon gas stream through tubing. By transporting the chemical to be analyzed in aerosol form, transport time is reduced from about 30 minutes to less than one minute, using a relatively small amount of sample, and enabling the accurate, remote analysis of a variety of chemicals, including relatively high pH chemicals.

Abstract: A process and system for purifying an impure gas to produce a purified gas in a gas purification system and protecting the system from damage by a) passing a portion of a first gas stream into a reactor vessel, which exits as a second purified gas stream; b) combining a portion of the second purified gas stream with another portion of the first gas stream to form a combined gas stream; and c) passing the combined gas stream into a sensing device to regulate the flow of the first and second gas streams into the reactor vessel.

Abstract: A flow-through monitor for detecting molecular contamination (MC) within a fluid flow. The monitor has a diffusion chamber having an inlet port and an outlet port, and a structure for supporting a fluid flow from the inlet port to the outlet port. The structure includes a flow gap causing a diffusion of molecular contaminants into the diffusion chamber, while substantially preventing, for a rate of the fluid flow above a predetermined magnitude, particulate contaminants within the fluid from entering the diffusion chamber. A SAW device detects molecular contamination interior to the diffusion chamber. Fluid input to the flow-through monitor may be diluted by a pure fluid for extended monitor life. A system for aggregate sampling connects an ensemble manifold upstream of the flow-through monitor. A system for triggered sampling connects a sample preconcentrator downstream of the flow-through monitor. A chemically selective membrane may be located between the flow gap and the SAW.

Abstract: A method for determining the quantity of phenol extracted into an aqueous solution of an alkali metal hydroxide uses a measurement of the pH of the solution, from which the equivalents of phenol relative to alkali metal hydroxide in solution is determined. A method for optimizing the use of an aqueous solution of an alkali metal hydroxide in a phenol recovery process uses pH measured to regulate the feed rate of the aqueous solution.

Abstract: A method involving the automatic, online dilution of polymer and/or colloid solutions, such that, when the diluted polymer stream flows through suitable detectors, non-equilibrium processes, such as polymerization, degradation and aggregation, can be monitored. The dilution involves a reacting or stock solution of polymer and/or colloid, and at least one solvent. The online dilution technique can also be used to assess the effects of solvent quality and other solutes on polymer/colloid characteristics and reactions, and also permits equilibrium characterization of polymers/colloids by making a single stock solution of the polymer/colloid.

Abstract: Elemental analysis of a sample is carried out in an oxygen atmosphere in a combustion reactor and the volume of oxygen required for analysis is determined by means of the algorithm Qo=&Dgr;(Qc)  [1] where Qo is the volume of oxygen required and Qc is the weight of the sample to be analyzed and &Dgr;=Qo1/Qc1 where Qo1 is the volume of oxygen necessary for the combustion of a predetermined quantity Qc1 of the sample to be analyzed, the volume of oxygen Qo is then fed in pulsed mode to the combustion reactor, by means of a flow detector.

Abstract: An analytical method for monitoring the desorption of a sorbate from a particulate sample, the method comprising the steps of: introducing the particulate sample into a control container, mixing the sample; passing a carrier gas through the container such that it permeates the sample; repeatedly measuring the concentration of the sorbate in the outlet gas as it leaves the container; and analysing the readings from the measuring step.

Abstract: The presence of carcinogens in air, soils, and other areas is detected by combining liquid-assisted air sampling with means for testing liquid samples for mutagenicity. Hazardous or illicit substances or pathogens which may be buried in the ground or otherwise concealed or present in contaminated food at various stages of food processing are detected using a two-line probe such that one of the lines directs exhaust air from the sampler onto suspect surfaces so as to dislodge and blow off droplets, particles or insects therefrom while the other line draws some of them into the sampler. Variants of said two-line probe can also serve to collect lead, hexavalent chromium or other harmful substances and bacterial, fungal or viral pathogens from crumbling walls or floors. Liquid-assisted air sampling can also serve to capture disease-transmitting insects and detect and identify insect-borne pathogens.

Abstract: This invention provides an online polymer monitoring apparatus for rapid determination of molecular weight and/or size, and/or other properties of importance to the polymer quality. The apparatus uses fast sample extraction, preparation and delivery techniques to convert complex polymer sample solution into the diluted polymer analyte solution. This analyte solution is then passed through the flow-through detectors for measurement of the polymer molecular weight, the polymer concentration and/or the identification and concentrations of the selected species of importance to the polymer quality. The continuous stream of the above measurement data, thus, allows accurate determination the status of the polymer for many polymer containing process streams, such as an ongoing polymerization reaction mixture, polymer resin fluid, melt or solid polymer flow.

Abstract: Oil aging and particulate building in a lubricant other than one exposed to combustion products is monitored by detecting light transmitted through the lubricant at least one, and preferably, two or more preselected wavelengths over a pathlength greater than about 0.5 cm wherein one wavelength is in the near infra-red spectrum and/or one wavelength is in the visible or near infra-red spectrum. The detected light when compared to predetermined values provides an indication of the condition of the lubricant.

Abstract: A system for analyzing samples using purge and trap concentration is provided. The system includes a plurality of purge and trap concentration units, each adapted to receive a sample and provide a focused analytic sample slug to an analyzer. An analyzer is coupled to each of the plurality of concentrators and receives the focused analytic slugs therefrom. The concentrators are operated in phases from one another.

Abstract: A method and system for detecting chemical or biological hazards in items is provided. An incoming mail mailbox includes a sampler to sample air from a letter that is tested using a first sensor and then placed in a receptacle having an environment that is tested using a second sensor.

Abstract: Apparatus and method for sequential injection liquid-liquid extraction analysis. Under the control of a bidirectional precision pump, a stream-selection valve, and a microprocessor, a series of liquid zones is built up in a holding/mixing coil. The liquid zones are transferred from the holding/mixing coil to a separation cell. After phase separation into an extract and a raffinate, the extract is withdrawn from the separation cell and sent to a detector, which determines the amount of a component which was extracted from a sample by an extraction solvent. The principal advantages of this automated technology are elimination of the need for dynamic phase separation; on-line pre-extraction chemical conditioning; a substantial reduction in solvent, reagent, and sample usage; and a similar substantial reduction in waste generation.

Abstract: The invention provides methods and devices for detecting the presence of one or more target analytes in a sample employing a channel having affixed therein one or more binding partners for each target analyte. Assays are carried out by transporting the sample through the channel to each successive binding partner so that target analyte present in said sample binds to the corresponding binding partner. The sample is then transported beyond the binding partner(s), followed by detection of any target analyte bound to each binding partner. In one embodiment, binding efficiency is increased by the use of segmented transport, wherein a first bolus or bubble of a fluid that is immiscible with the sample precedes the sample during transport and a second bolus or bubble of a fluid that is immiscible with the sample follows the sample. Many configurations are possible for the device of the invention.

Abstract: The present invention is a method and an apparatus for identifying and quantifying components in an effluent stream from an ammoxidation reactor, the apparatus comprising a microprocessor; and a Fourier Transform infrared spectrometer having a sample cell through which may flow a portion of the effluent stream, an infrared source to emit infrared radiation and pass the infrared radiation through the effluent stream, an infrared detector to detect transmitted infrared radiation at the selected infrared wavelengths and to generate absorbance data due to absorbance of the infrared radiation by the components, wherein each of the components absorbs infrared radiation at one or more of the infrared wavelengths, and an output apparatus to provide the absorbance data to the microprocessor; wherein the microprocessor is programmed to identify and quantify each of the plurality of components based upon the absorbance data and calibration data, the calibration data being obtained from recovery run analyses and calibrat

Abstract: An ion-exchange membrane has a mesh structure with microscopic pores in which water can infiltrate. When the ion-exchange membrane is incorporated in the sensor body, the one side of the membrane comes in contact with the sample solution and the other side thereof comes in contact with the internal solution. The water in the internal solution gradually migrates to the side of the sample flow path permeating through the membrane. When the sensor is used for extended periods of time, therefore, the sensor performance often decreases due to a decrease in the electric conductivity between the internal electrode and the ion-exchange membrane.

Abstract: A reference T-sensor system is provided for detecting the presence and/or measuring the concentration of analyte particles in a sample stream. The system includes: a) a laminar flow channel; b) three or more inlets in fluid connection with the laminar flow channel for respectively conducting into the laminar flow channel (1) an indicator stream which may include an indicator substance which indicates the presence of analyte particles by a detectable change in property when contacted with the analyte particles, (2) the sample stream, and (3) a reference stream, which can be a control stream and/or an internal standard stream; c) wherein the laminar flow channel has a depth and/or width sufficiently small to allow laminar flow of the streams and a length sufficient to allow particles of the analyte to diffuse into the indicator stream to form a detection area; and (d) an outlet for conducting the streams out of the laminar flow channel preferably to form a single mixed stream.

Abstract: The present invention provides an apparatus and method for storing a particle-containing liquid. The storage apparatus comprises a microfluidic convoluted flow channel having a plurality of particle capture regions. The storage channel is preferably an isotropic spatially periodic channel. Sedimented particles can be resuspended following storage. This invention further provides a microfluidic analysis cartridge having a convoluted storage channel therein. The sample analysis can use optical, electrical, pressure sensitive, or flow sensitive detection. A plurality of analysis channels can be included in a single cartridge. The analysis channels can be joined to reagent inlets for diluents, indicators or lysing agents. A mixing channel can be positioned between the reagent inlet and the analysis region to allow mixing and reaction of the reagent. The cartridge can include additional valves and pumps for flow management.

Abstract: The presence of carcinogens in air, soils, and other areas is detected by combining liquid-assisted air sampling with means for testing liquid samples for mutagenicity. Hazardous or illicit substances or pathogens which may be buried in the ground or otherwise concealed or present in contaminated food at various stages of food processing are detected using a two-line probe such that one of the lines directs exhaust air from the sampler onto suspect surfaces so as to dislodge and blow off droplets, particles or insects therefrom while the other line draws some of them into the sampler. Variants of said two-line probe can also serve to collect lead, hexavalent chromium or other harmful substances and bacterial, fungal or viral pathogens from crumbling walls or floors. Liquid-assisted air sampling can also serve to capture disease-transmitting insects and detect and identify insect-borne pathogens.

Abstract: A dissolution system provides remote flow cells integrated into a manifold device. The manifold device communicates with liquid input and output lines associated with each flow cell, as well as fiber-optic input and output lines associated with each flow cell. Liquid samples are respectively drawn from dissolution vessels, optically-related measurements are taken, and the samples are thereafter returned their respective vessels. The manifold device can be adapted to receive probe-type instruments that incorporate the fiber-optics, wherein each probe-type instrument is associated with each flow cell. Alternatively, each corresponding pair of fiber-optic input and output lines are disposed in opposing, optically-aligned relation and probe-type instruments are not used. The gap between the ends of the opposing fiber-optic lines provides a light path across the corresponding flow cell.

Abstract: A single pass analyzer includes multiple infrared sensors, a catalytic converter, a scrubber and a thermal conductivity cell all coupled in series to provide a single pass (i.e., one sample) analyzer which allows for fast analysis, allows for the speciation of hydrogen samples, requires no purging between different sample types, utilizes a single carrier gas, and eliminates molecular sieves and Shutze converters. The resultant analyzer provides improved quicker results with less plumbing (i.e., gas conduits and valving) in a single instrument.

Abstract: For direct and on-line study of the physiological states of cell cultures, a robust flow injection system has been designed and interfaced with flow cytometry (FI-FCM). The core of the flow injection system includes a microchamber designed for sample processing. The design of the microchamber allows not only an accurate on-line dilution but also on-line cell fixation, staining, and washing. The flow injection part of the system was tested by monitoring the optical density of a growing E.coli culture on-line using a spectrophotometer. The entire growth curve, from lag phase to stationary phase, was obtained with frequent sampling. The system is thus particularly useful since it operates automatically without direct operator supervision for extended time periods.

Abstract: Microfluidic devices for performing integrated reaction and separation operations. The devices have a planar substrate having a first surface with an integrated channel network disposed therein. The reaction region in the integrated microscale channel network has a mixture of at least first and second reactants located therein, wherein the mixture interacts to produce one or more products. The reaction region is configured to maintain contact between the first and second reactants contained within it. The device also includes a separation region in the integrated channel network, where the separation region is configured to separate the first reactant from the product, when the first reactant and product are flowing through the separation region.

Abstract: Methods and apparatuses are provided for determining presence and concentration of analytes by exploiting molecular binding reactions and differential diffusion rates. Analyte particles and binding particles are allowed to diffuse toward each other, and slowing of the diffusion front is detected when they meet. From the position of the diffusion front, presence and concentration of analyte particles can be determined. One embodiment provides a competitive immunoassay in a microfluidic format. This diffusion immunoassay (DIA) relies on measuring the concentration of labeled antigen along one dimension of a microchannel after allowing it to diffuse for a short time into a region containing specific antibodies. A simple microfluidic device, the T-Sensor, was used to implement a DIA to measure the concentration of phenytoin, a small drug molecule. Concentrations of analyte over the range of 50 to 1600 nM can be measured in less than a minute.

Abstract: The present invention concerns a detector arrangement that is adapted to measure radiation from detector areas in the surface of a microfluidic device. The arrangement comprises a detector unit with a detector head and other units enabling for the detector unit to collect radiation from the detection areas.

Abstract: The invention relates to methods and devices for conducting multiplex assays for determining absorption, distribution, metabolism, and/or excretion (ADME) properties of an analyte. The method and device provide the ability to study analytes by controllably flowing, in laminar flow, an analyte in an analyte stream over a substrate having a plurality of substantially parallel individual test lanes on the surface thereof, wherein each test lane comprises a plurality of living cells immobilized therein. Changes, when present, in the analyte, the cells, or both, are detected and thereafter correlated to an ADME property of the analyte.

Abstract: An apparatus and method for handling flowing liquids for analytical purposes such as for introduction of liquid samples in atomic spectroscopy and carrying out a continuous flow digestion process at high temperture and pressure. The appaartus comprises a high-pressure pump for conveying a liquid from a reservoir into a tube having an elongate cavity connected to the high-pressure pump outlet. A heating device is arranged so as to heat the liquid in the cavity to a predetermined temperature and a restrictor is arranged downstream of the cavity at the opposite end of the tube. The restrictor is dimensioned relative to the conveying capacity of the high-pressure pump so that liquid in the cavity is maintained at a pressure which is higher than the saturated vapor pressure of the liquid at the predetermined temperture such that no vapor forms within the cavity.

Abstract: An apparatus provides for the detection, the determination of the location or the spatial distribution, and/or the quantification of an amount of a chemical species by allowing the chemical species to come into contact with a fluid medium contained in a permeable capillary, transferring the content of the capillary after the contact to a detector, and detecting the chemical species as the content of the capillary is transferred to a detector. The fluid medium can contain a selected reagent that selectively interacts with the chemical species to produce an optically detectable interaction product. The location and amount of the chemical species are determined from a characteristic of the chemical species or its interaction product measured on the content of the capillary and the time at which the characteristic is detected.

Abstract: An improved instrument for measuring the total organic carbon content of water provides substantially instantaneous TOC measurements that are repetitively calibrated, provides substantially improved accuracy of results in a circuit providing improved noise rejection, allowing faster response, and provides controlled dilution of the sample stream to extent the useful range of the instrument.

Abstract: A self-adjusting, free-flowing pneumatic nebulizer interface is described for coupling fluid phase separation apparatus such as capillary electrophoresis apparatus or fluid-phase analyte delivery apparatus such as flow-injection analysis apparatus to gas phase, post-separation detection apparatus such as mass spectrometers, chemiluminescence detectors, or other similar gas phase detection apparatus. The interface combines the analytes with only the needed amount of sheath fluid to produce a combined flow whose magnitude automatically matches the self-aspiration rate of the pneumatic nebulizer interface, and which is combined with a gas flow to produce an aerosol. The resulting aerosol can then be either deposited directly on a surface, forwarded directly to a detection system or forwarded first to a conversion apparatus such as an oxidizer and the oxidized sample components are then forwarded to a detector.

Abstract: Provided is a sample clean-up apparatus for removing low-molecular weight substances such as salts from high-molecular weight biological samples such as proteins by simple molecular diffusion in a laminar flow channel and enabling solvent exchange for samples to be suitable for mass spectrometry.

Abstract: The liquid sample take-up device comprises two layers of concentric tubing. An outer tube has a fluid take-up end for selective immersion in a liquid to be sampled, and a liquid connection spaced from the fluid take-up end adapted to receive a chemical reagent under pressure, creating a reagent flow toward the take-up end. An inner tube is disposed within the outer tube and has an open end adjacent to the outer tube take-up end. The inner tube is adapted to fluid connect to a negative pressure source, higher than the reagent pressure, to create a fluid flow within the inner tube in a direction away from the open end, whereby sampled liquid and reagent are mixed adjacent the inner tube open end and within the outer tube take-up end. When the outer tube take-up end is not immersed in a liquid to be sampled, air is drawn into the outer tube take-up end and into the inner tube open end, creating a series of air bubbles, each bubble separated by a volume of reagent.

Abstract: Methods and systems for particle focusing to increase assay throughput in microscale systems are provided. The invention includes methods for providing substantially uniform flow velocity to flowing particles in microfluidic devices. Methods of sorting members of particle populations, such as cells and various subcellular components are also provided. Integrated systems in which particles are focused and/or sorted are additionally included.

Abstract: A method and apparatus for controlling a stream of liquid and air segments wherein the liquid and air segments are selectively aspirated into a first fluid conduit in a plurality of cycles, each cycle beginning with the aspiration of a first air segment and ending with the aspiration of a final air segment. The liquid and air segments are then transferred from the first fluid conduit to a second fluid conduit. The volume of the final air segment of each cycle is then adjusted after the final air segment has moved into the second fluid conduit. Next, the liquid segments and the air segments of each cycle are transferred from the second fluid conduit to a third fluid conduit. The volume of the first air segment of each cycle is then adjusted after the first air segment has moved into the third fluid conduit.

Abstract: A method and apparatus for Flow Injection Analysis (FIA) into Atmospheric Pressure Ion sources (API) including Electrospray (ES) and Atmospheric Pressure Chemical Ionization (APCI) sources whereby the sampling and spray needles are one and the same. The sampling and spray needle configured with an autoinjector apparatus or used in manual injection is introduced directly into a mating ES or APCI probe configured in an API source. Such a sampling and spray needle eliminates the need for injector valves, transfer lines or additional fluid delivery systems in FIA into API sources interfaced to mass spectrometers or other chemical analyzers. The use of a sampling and spray needle configuration reduces component costs, liquid dead volume, sample dilution effects, and minimizes cross contamination effects, solvent consumption and waste while increasing sample throughput.

Abstract: Microfluidic devices having predisposed assay components for increased throughput and prolonged shelf life are provided.

Abstract: The present invention is generally directed to methods, apparatus and systems for use in performing in situ dilution or concentration of a particular subject material in a microfluidic device or system. These methods and apparatus may generally be integrated with other microfluidic operations and/or systems, to perform a number of different manipulations, wherein dilution or concentration, carried out within the context of the microfluidic device or system, is just one part.

Abstract: A method for directly monitoring and controlling a continuous process stream for dechlorination residual is provided. A sample stream to which a dechlorination agent has been added to completely eliminate a residual disinfectant is continuously drawn off. An analyzing agent of iodine is provided by introducing an iodide solution, a chloramine-T solution, and an acetic acid buffer into the sample stream. The reagents quickly react to produce iodine that reacts with any residual disinfectant removal agent residual that may be present. Thereafter, the sample stream is continuously analyzed to determine the amount of unreacted iodine remaining in the process sample. Based on the amount of iodine added to the process sample and the amount of unreacted iodine remaining in the sample after reaction, the amount of dechlorination residual is continuously determined.

Abstract: A method for determining the concentration of a dihydric phenol in the presence of a monohydric phenol uses spectroscopic detection at at least two wavelengths. Because the method does not require a chemical separation of the dihydric phenol and monohydric phenol, it is very rapid and particularly suitable for the analysis of large numbers of samples, such as those derived from combinatorial libraries.

Abstract: The present invention relates to a microfluidic system for processing a cell-containing liquid. The system includes a microfabricated substrate having an enrichment channel to prepare an enriched cell sample from the cell-containing liquid. A flow through member is in liquid communication with the enrichment zone. The flow through member substantially prevents cells of the cell-containing fluid from exiting the enrichment zone while allowing liquid of the cell-containing liquid to exit the enrichment zone. A gas actuator associated with the enrichment zone provides a gas pressure sufficient to move the enriched cell sample from the enrichment zone.

Abstract: The present invention relates to a system and method for moving samples, such as fluid, within a microfluidic system using a plurality of gas actuators for applying pressure at different locations within the microfluidic. The system includes a substrate which forms a fluid network through which fluid flows, and a plurality of gas actuators integral with the substrate. One such gas actuator is coupled to the network at a first location for providing gas pressure to move a microfluidic sample within the network. Another gas actuator is coupled to the network at a second location for providing gas pressure to further move at least a portion of the microfluidic sample within the network. A valve is coupled to the microfluidic network so that, when the valve is closed, it substantially isolates the second gas actuator from the first gas actuator.

Abstract: The invention provides a method for measuring the amount of analyte in a sample of biological fluid using a simple low sample volume reagent test strip with a built in metering system. The test strip may comprise a microtitration zone to prevent oversampling and an integrated capillary to prevent problems associated with short sampling and act as means of absorbing the fluid sample. The test strip comprises a wicking layer and a reaction matrix embossed layer in the form of a pillow assembled into a microtitration pocket formed in the strip. The test strip is used in single use applications such as the determination of the concentration of glucose in blood.

Abstract: An automated device that couples a pair of differently sized sample loops with a syringe pump and a source of degassed water. A fluid sample is mounted at an inlet port and delivered to the sample loops. A selected sample from the sample loops is diluted in the syringe pump with the degassed water and fed to a flow through detector for analysis. The sample inlet is also directly connected to the syringe pump to selectively perform analysis without dilution. The device is airtight and used to detect oxygen-sensitive species, such as dithionite in groundwater following a remedial injection to treat soil contamination.

Abstract: A modular vial autosampler has a storage area for vials containing samples to be analyzed and at least one modular sampling station. A vial transfer mechanism includes an arm having a gripper that lifts a sample vial from the storage section, and the arm moves it to a station for identification and then to a sampling station, and under central control activates the sampling station for obtaining a sample for analysis. The vial transfer mechanism gripper is movable in X, Y, and Z directions to capture and move a selected vial and includes an alignment guide for the vials. Potentiometers are used for providing signals indicating arm position and the control is provided with updated information for calibration of the potentiometers and also updated position information for the arm relative to a fixed home position is obtained.

Abstract: A method of real time process control in a reaction system for the production of vinyl acetate from the oxidation of ethylene and acetic acid. Reaction system samples are collected from the reactor vessel feed and/or effluent and/or from columns and/or transfer lines downstream of the reactor vessel, and the concentration of one or more components in the sample is measured by an infrared analyzer. The concentration measurements are then used to make adjustments in the concentration of components in the reaction system, directly or indirectly, such as by adjusting the temperature profile in a particular column, the flow rate of solution in to or out of a column, or the addition or extraction of a component to or from the solution. For optimum process control, the measurements are transmitted to a control unit for real time analysis, and the adjustments are made almost instantly after the infrared analysis.

Abstract: A chromatogram analyzer is provided which analyzes a chromatogram obtained by applying a sample containing an analyte. The chromatogram analyzer can be used after peak detection, for example, based on predicted peak emergence times for respective analytes of interest and can determine proper baselines even in the presence of peaks attributable to components other than the analytes or ghost peaks. The chromatogram analyzer is used for an analysis of a chromatogram developed by chromatography, namely by separating and detecting analytes in a sample. Although chromatography is divided into various types of liquid chromatography and gas chromatography according to the principles for separation and development, a chromatogram obtained by any type of chromatography can be analyzed. For example, an electrophoretically obtained result stained with a proper dye can be analyzed by using the present invention after photometric scanning.

Abstract: A method for detection of human parvovirus B19, comprising the steps of: (1) bringing a sample into contact with fixed P-antigen positive red cells in a medium at pH 5.6±0.6; and (2) determining whether or not hemagglutination occurs; and a reagent for detecting human parvovirus B19, wherein the reagent comprises fixed P-antigen positive red cells.

Abstract: A method for determining the concentration of a dihydric phenol in the presence of a monohydric phenol uses spectroscopic detection at at least two wavelengths. Because the method does not require a chemical separation of the dihydric phenol and monohydric phenol, it is very rapid and particularly suitable for the analysis of large numbers of samples, such as those derived from combinatorial libraries.

Abstract: The invention relates to a method for determining an analyte in a solution. This method includes the following steps: a) fixing and immobilizing said analyte, for example via the presence of a ligand L, on the inner surface of a conduit (3) having a reduced cross section over all or part (9) of it, and b) determining the variation in load loss of a fluid circulating inside the conduit, due to the analyte P which has been fixed and immobilized at least in the reduced cross section part (9) of said conduit during step a).

Abstract: A disposable sampling device for an apparatus for counting particles contained in a liquid, including a solid block-shaped housing connectable in a defined position to the apparatus. The housing has a member for introducing a sample therein, a device for metering a defined volume of the sample, and a chamber for containing a defined volume (V) of a diluting liquid. A diluting chamber is provided together with a device for simultaneously directing the defined volume of a sample and the defined volume of diluting liquid to the diluting chamber for obtaining therein a diluted sample. A device is provided for directing at least a portion of the diluted sample past a particle detecting member, and a signal transmitting member connects the particle detecting member and terminal member located at an outer boundary of the housing in a position corresponding to a location of a terminal member of the apparatus when the housing is connected thereto in the defined position.