Abstract: A fluid content monitor including a cuvette, a colorimeter adapted to generate a signal indicative of contents of a fluid sample contained in the cuvette, a container for holding a reagent, and a pump assembly for delivering reagent from the container to the cuvette. The pump assembly includes a tube extending from the container to the cuvette, check valves preventing reverse flow in the tube, and a hammer driven by a solenoid for repetitively compressing the tube to pump reagent to the cuvette. The cuvette can be removed for cleaning and replacement.

Abstract: Methods and devices are provided for overcoming detrimental diffusive effects in a sample liquid stream by forming segmented liquid bodies (e.g., droplets) from a sample liquid stream in an immiscible liquid stream. The liquid bodies are formed at the intersection of a channel providing the sample liquid stream and a channel providing the immiscible liquid stream. The formed liquid bodies compartmentalize the portion of the sample liquid stream from which the liquid bodies are formed, thus minimizing the detrimental effects of diffusion that occur in a continuous liquid stream.

Abstract: A method is provided for pumping fluid through a channel of a microfluidic device. The channel has an input port and an output port. The channel is filled with fluid and a pressure gradient is generated between the fluid at the input port and the fluid at the output port. As a result, fluid flows through the channel towards the output port.

Abstract: The invention features devices for mixing fluids, e.g., for lysing cells, and methods of use thereof. One device is based on the ability to control the flow of fluids, e.g., by contact angle and channel size. Fluids in this device can be divided to form segments of controlled volume, which are then brought together to initiate mixing. An exemplary use of the device is for the lysis of single cells. Another device is based on the ability to two mix two fluids in a channel and affinity capture of analytes. The devices can be integrated on the same chip with other devices, for example, for cell handling or analysis of DNA, mRNA, and proteins released from the lysis of a cell.

Abstract: The present invention, provides a flow cytometry apparatus for the detection of particles from a plurality of samples comprising: means for moving a plurality of samples comprising particles from a plurality of respective source wells into a fluid flow stream; means for introducing a separation gas between each of the plurality of samples in the fluid flow stream; and means for selectively analyzing each of the plurality of samples for the particles. The present invention also provides a flow cytometry method employing such an apparatus.

Abstract: A device and method for enhancing rapid confirmatory immunological testing (“RCIT”) in chromatography strip-type rapid IVD devices useful in, for example, clinical, point-of-care, laboratory or over-the-counter settings. The device drives a flow fluid, primarily under the force of gravity alone, through a first chamber having a porous dam structure to enhance and substantially complete the first affinity binding reaction between a source of mobilizable labeled binding members and an analyte in the fluid. Flow through the dam causes a delay, mixing and trapping of the typically chemically disuniform initial fluid front so that fluid exiting the dam exhibits a more uniformly high degree of first affinity binding and decreased non-affinity binding.

Abstract: Disclosed is an apparatus and method for ejecting droplets using charge concentration and liquid bridge breakup. The droplet ejection apparatus includes a reservoir storing a liquid; a capillary nozzle having a lower end submerged in the liquid stored in the reservoir and an upper end exposed outside the surface of the liquid, the capillary nozzle transferring the liquid to the upper end using capillary force; a potentiostat for applying a voltage to the liquid; a substrate mount on which a substrate is disposed to face the upper end of the capillary nozzle; and a distance adjusting unit for reciprocatingly moving the substrate between first and second positions with respect to the capillary nozzle, wherein the first position denotes a position where a distance between the upper end of the capillary nozzle and the surface of the substrate is less than a effective distance.

Abstract: An apparatus and method are disclosed for measuring the kinetic parameters of a catalyst powder, which include the reaction rate constants, active site concentration and intraparticle diffusivity. The measurement of the active site concentration selectively measures just the active sites and not the entire exposed atom concentration. The apparatus and method use surface concentrations less than 50% and larger than 1% the total active site concentration and a dynamic pulsed flow to avoid including weak adsorption sites not involved in the catalysis. The measurement is more accurate because (1) it uses a reactant gas and non-steady state adsorption at temperatures near to reaction temperatures, and (2) it uses the chemical kinetics expressions to extract the measured active site concentration to perform the measurement so as to count just those sites actually active for that reactant.

Abstract: The present invention is a flow cell and method for use in microfluidic analyses that presents highly discrete and small volumes of fluid to isolated locations on a two-dimensional surface contained within an open fluidic chamber defined by the flow cell that has physical dimensions such that laminar style flow occurs for fluids flowing through the chamber. This process of location specific fluid addressing within the flow cell is facilitated by combining components of hydrodynamic focusing with site specific cell evacuation. The process does not require the use of physical barriers within the flow cell or mechanical valves to control the paths of fluid movement.

Abstract: An electrochemical plating system, which includes one or more plating cell reservoirs for storing plating solution and a chemical analyzer in fluidic communication with the one or more plating cell reservoirs. The chemical analyzer is configured to measure chemical concentrations of the plating solution. The plating system further includes a plumbing system configured to facilitate the fluidic communication between the one or more plating cell reservoirs and the chemical analyzer and to substantially isolate the chemical analyzer from electrical noise generated by one or more plating cells of the one or more plating cell reservoirs.

Abstract: The present invention, provides a flow cytometry apparatus for the detection of particles from a plurality of samples comprising: means for moving a plurality of samples comprising particles from a plurality of respective source wells into a fluid flow stream; means for introducing a separation gas between each of the plurality of samples in the fluid flow stream; and means for selectively analyzing each of the plurality of samples for the particles. The present invention also provides a flow cytometry method employing such an apparatus.

Abstract: Microfluidic devices and systems for affecting the serial to parallel conversion of materials introduced into the device or system. Material or materials to be converted from a serial orientation, e.g., a single channel, into a parallel orientation, e.g., multiple channels, are introduced into an open chamber or field in which containing flows of materials maintain the cohesiveness of the sample material plugs serially introduced into the open chamber. The sample material or materials are then redirected in the chamber toward and into a plurality of parallel channels that also communicate with the chamber.

Abstract: A testing microchip includes a specimen storage section; a reagent storage section; a reaction section; a testing section for a test of a reaction product obtained from the reaction; a liquid feed control section; and a gas bubble trapping structure. The sections are connected continuously by a series of flow channels. The liquid feed control section stops passing of liquid until a liquid feeding pressure reaches a predetermined pressure, and passes the liquid when the liquid feeding pressure becomes higher than the predetermined pressure; and the gas bubble trapping structure traps a gas bubble in the liquid that flows in the flow channel so that the gas bubble does not flow to the downstream side and only the liquid passes to the downstream side. A testing apparatus that performs testing in the testing section of the testing microchip, wherein the testing microchip is attachably and detachably mounted to the apparatus.

Abstract: Particles are removed from a fluid stream, such as air, and are deposited on one or more collection surfaces. A pre-filter can be employed to reject oversized particles and contaminants, such as rain and insects. A concentrator is employed to increase a concentration of particles larger than a pre-defined particle size in at least a portion of the fluid, producing a concentrated volume of fluid. The concentrator and pre-filter can, for example, be virtual impactors. The concentrated volume of fluid/air is directed to the collection surface(s), where particles in the concentrated volume of air are deposited. In at least one embodiment, the collection surface is a bed of beads, reducing loss of particles that might occur due to particles bouncing from a single collection surface. A sampling component removes a portion of the deposited particles to generate a sample, which is analyzed by an analytical component.

Abstract: Methods for using semiconductor nanocrystals for determining fluid movement, fluid dilution and fluid removal are described. Methods for using semiconductor nanocrystals for monitoring and quantifying the amounts of solid materials dissolved in a liquid are also described.

Abstract: Methods for performing microfluidic sampling are provided. The method includes providing a substrate including an arrangement of first, second and third electrodes, wherein the second electrode is interposed between the first and third electrodes. The method additionally includes causing a fluid input to continuously flow to the first electrode and biasing the first, second and third electrodes to a first voltage to cause a portion of the fluid input to spread across the second and third electrodes. The method further includes biasing the second electrode to a second voltage different from the first voltage to form a droplet on the third electrode, the droplet being separate from the fluid input.

Abstract: A method and apparatus for removing concentrated spots of collected particulates from an impact collection surface, and transferring those particulates into a container suitable for preparing a liquid sample. A jet of fluid can be utilized to remove and transfer the particulates. If a liquid jet is employed, care is taken to minimize the quantity of liquid to avoid unnecessarily diluting the sample. A mechanical scraper can alternatively be employed to remove and transfer the particulates into the container. The scraper can be rinsed with liquid or vibrated to remove the particulates. Alternatively, the portion of the surface containing a specific spot of particulates can be removed and placed into a container.

Abstract: Laser-induced phase-separation polymerization of a porous acrylate polymer is used for in-situ fabrication of dialysis membranes inside glass microchannels. A shaped 355 nm laser beam is used to produce a porous polymer membrane with a thickness of about 15 ?m, which bonds to the glass microchannel and forms a semi-permeable membrane. Differential permeation through a membrane formed with pentaerythritol triacrylate was observed and quantified by comparing the response of the membrane to fluorescein and fluorescently tagging 200 nm latex microspheres. Differential permeation was observed and quantified by comparing the response to rhodamine 560 and lactalbumin protein in a membrane formed with SPE-methylene bisacrylamide. The porous membranes illustrate the capability for the present technique to integrate sample cleanup into chip-based analysis systems.

Abstract: An assay method is described, which comprises the steps of immobilizing a binding partner (e.g., an antigen or antibody) for an analyte to be detected (e.g., an antibody or antigen) on a portion (140) of a surface (130) of a microfluidic chamber (120,122,124); passing a fluid sample over the surface and allowing the analyte to bind to the binding partner; allowing a metal colloid, e.g., a gold-conjugated antibody, to associate with the bound analyte; flowing a metal solution, e.g., a silver solution, over the surface such as to form an opaque metallic layer; and detecting the presence of said metallic layer, e.g., by visual inspection or by measuring light transmission through the layer, conductivity or resistance of the layer, or metal concentration in the metal solution after flowing the metal solution over the surface.

Abstract: A cassette for preparing a sample is disclosed herein. The cassette includes a housing, which encloses the structures and the processes used to prepare the sample.

Abstract: A closed and yet flexible and easily adaptable reaction vessel system for performing liquid handling operations, such as sampling, incubating, homogenizing and/or metering fluids, can be constructed in a modular fashion, comprising a first container, to which at least two second containers are connected, wherein the contents of said second containers can be transferred from one of said second containers into said first container and back, or into another second container.

Abstract: The present invention provides a series of methods, compositions, and articles for altering a property of a surface (for example, the cytophilicity and/or the hydrophilicity), by exposing at least a portion of the surface to a non-chemical, force-creating field and/or force, such as an electric field. The field/force may be created by any suitable technique. For instance, the field can be created by applying a voltage across the surface, by electrical induction, etc. In certain embodiments, the surface includes molecules attached thereto that can be detached when exposed to non-chemical, force-creating fields and/or forces, thereby altering the chemical composition of at least a portion of the surface. In one set of embodiments, the molecules attached to the surface may include molecules forming a self-assembled monolayer on the surface. In some embodiments, the molecules attached to the surface may include thiol moieties (e.g., as in an alkanethiol), by which the molecule can become attached to the surface.

Abstract: This invention is a method and device for use with multi-dimensional chromatography that utilizes partial modulation. An analyte-bearing sample is subjected to a first dimension of chromatography. Thereafter the separated analyte-bearing sample is diluted with a modulated second carrier such at the analyte-bearing sample is not stopped or its temperature altered. The partially modulated analyte-bearing sample then feeds into a secondary column where the analyte-bearing sample is further separated.

Abstract: An improved microscale diffusion immunoassay utilizing multivalent reactants is disclosed. In particular, a method for detecting the presence of analyte particles in an analyte fluid is disclosed, the method comprising: (a) providing the analyte fluid comprising the analyte particles; (b) providing a diffusion fluid comprising binding particles capable of binding with the analyte particles; (c) flowing the analyte fluid and the diffusion fluid in adjacent laminar flow through a microfluidic channel; (d) allowing the analyte particles to diffuse into the diffusion fluid and bind with the binding particles to form analyte/binding particle complexes; and (e) detecting the presence of the analyte particles and the analyte/binding particle complexes, wherein each of the binding particles is capable of binding with more than one analyte particle, and wherein each of the analyte particles is capable of binding with more than one binding particle.

Abstract: A method of directed automated analysis of a plurality of analytes of a process solution includes providing a sample of the process solution containing a plurality of the analytes, admixing an enriched isotope spike for each of the plurality of analytes to be analyzed with the process solution sample thereby effecting admixture of the enriched ratio of isotopes with the naturally occurring ratio of each analyte to be analyzed, creating ions from the spikes, introducing the ions into a mass spectrometer for determination of the identity and quantity of each analyte and delivering the information to a microprocessor. If desired, the process solution sample may be diluted and/or subjected to the addition of reagents or standards prior to initiation of the analysis. The ions may be created by an atmospheric pressure ionization interface. The information obtained is processed in a computer which serves to control other portions of the practice of the method.

Abstract: A method and a device for separating a small defined volume of a liquid sample from a relatively large undefined volume of the sample. In a surface of a first body (10) at least one cavity (12) having said small defined volume is provided. The relatively large volume of sample is applied onto the surface and into the cavity. A scraping edge (15) is moved relative to the surface and the cavity, thereby scraping a volume of the relatively large volume from the surface and leaving said small defined volume in the cavity.

Abstract: This invention is a method and device for use with multi-dimensional chromatography that utilizes partial modulation with multiple secondary retention times. An analyte-bearing sample is subjected to a first dimension of chromatography. Thereafter the separated analyte-bearing sample is diluted with a modulated second carrier such at the analyte-bearing sample is not stopped or its temperature altered. The secondary retention time period at which the modulator cycles is variable among multiple secondary retention time periods to prevent loss of resolution with less complex and/or low boiling point compounds and to prevent loss of data with more complex and/or higher boiling point compounds. The partially modulated analyte-bearing sample then feeds into a secondary column where the analyte-bearing sample is further separated.

Abstract: The present invention identifies biomarkers that are diagnostic of nerve cell injury, organ injury, and/or neuronal disorders. Detection of different biomarkers of the invention are also diagnostic of the degree of severity of nerve injury, the cell(s) involved in the injury, and the subcellular localization of the injury.

Abstract: Apparatus and Methods are provided for a microfabricated fluorescence activated cell sorter based on a switch for rapid, active control of cell routing through a microfluidic channel network. This sorter enables low-stress, highly efficient sorting of populations of small numbers of cells (i.e., 1000-100,000 cells). The invention includes packaging of the microfluidic channel network in a self-contained plastic cartridge that enables microfluidic channel network to macro-scale instrument interconnect, in a sterile, disposable format. Optical and/or fluidic switching forces are used alone or in combination to effect switching.

Abstract: Embodiments of the invention are directed to microfluidic devices. In one embodiment, a microanalysis chip comprises a body having at least one transfer-separation channel with a channel bottom that has a bottom opening. The transfer-separation channel terminates in a discharge aperture.

Abstract: A microfluidic device comprising one, two, three or more enclosed microchannel structures, each of which comprises a) an inlet arrangement with an inlet opening for liquid, b) a reaction microcavity (RM1) downstream to the inlet opening, and c) an upstream section that is located between the inlet opening and the reaction microcavity (RM1) and is defined between two planar substrates made of plastic material which substrates are common for said microchannel structures. The characteristic feature is that the inner wall in said upstream section exposes a hydrophilic surface area with an underlying base layer comprising metal oxide. In one aspect the microfluidic device as such is covered.

Abstract: The present invention provides methods and apparatus for mixing samples in-line in a microfluidic system, comprising methods of and means for introducing a first fluid sample into a flow-tube at a first end at a first velocity via a first conduit; methods of and means for introducing a second fluid sample into the flow-tube at the first end at a second velocity, the second velocity different from the first velocity, via a second conduit, wherein the first fluid sample and the second fluid sample converge in the flow tube to form an interface; whereby the first fluid sample and the second fluid sample mix at the interface within the flow-tube, wherein fluid flow at the first end of the flow-tube is laminar and fluid flow at a second end of the flow-tube is laminar, and wherein the flow-tube has a constant diameter between the first end and the second end of the flow-tube.

Abstract: A reaction apparatus comprises a first supply flow channel having a fine flow channel cross sectional area for a liquid pressurized by a pressurizing device, a gas supply flow channel having a fine flow channel cross sectional area for supplying a gas, a two-phase flow channel having a fine flow channel cross sectional area in communication with a joined portion for the first supply flow channel and the second supply flow channel for flowing a gas/liquid two-phase fluid, a gas bubble reaction flow channel in communication with the exit of the gas/liquid two-phase channel and having a flow channel cross sectional area larger than that of the gas/liquid two-phase flow channel, and a liquid discharge flow channel for discharging the liquid in the gas bubble reaction flow channel. Therefore, in the reaction apparatus, a stable mixing ratio of a gas to a liquid can be obtained and the mixing speed of the gas to the liquid is increased.

Abstract: Methods for using semiconductor nanocrystals for determining fluid movement, fluid dilution and fluid removal are described. Methods for using semiconductor nanocrystals for monitoring and quantifying the amounts of solid materials dissolved in a liquid are also described.

Abstract: A cytometer having two or more chambers or regions in a containment structure of sheathing fluid that may be used to provide hydrodynamic focusing of another fluid having particles to be observed. The latter fluid may be a core stream which may have its lateral position in a flow or measurement channel affected by control of at least one of the parameters of the several segments of the sheathing fluid. The lateral position of the core stream may be aligned with a light source and detector for a count and observation of the particles. Electrical signals from the detector may be fed back to a processor which may control one or more parameters of the sheathing fluid in the various chambers or regions via pumps, valves, and flow and pressure sensors. This control of parameters may provide for the positioning of the core stream. This cytometer may be miniaturized.

Abstract: The invention relates to a method for selecting charged particles possessing a predetermined property from a population of a multiplicity of different particles, and also to a device which is suitable for implementing the method.

Abstract: The present invention, provides a flow cytometry apparatus for the detection of particles from a plurality of samples comprising: means for moving a plurality of samples comprising particles from a plurality of respective source wells into a fluid flow stream; means for introducing a separation gas between each of the plurality of samples in the fluid flow stream; and means for selectively analyzing each of the plurality of samples for the particles. The present invention also provides a flow cytometry method employing such an apparatus.

Abstract: This invention significantly reduces the frequency of hydraulic failure in the analytical line of a capsule chemistry sample liquid analysis system which can occur when the reagents required for the specific analytical test have an imperfect merger with the sample aliquot reagent in the vanish zone of the analytical line. It has been found that the dynamic surface tension of the sample aliquot reagent and the analytical reagent influence the merging process. It has also been found that optimum merging of these reagent capsules in the vanish zone can be obtained when the dynamic surface tension of the sample aliquot reagent and analytical reagent is different.

Abstract: A sample testing system may include a housing, a cavity in the housing to receive a chamber, two contact members, and a sensor. The contact members may be positioned to be engageable with respective portions of the chamber inserted in the cavity, and to compress those respective portions, thereby driving fluid flow. A sample testing system may include a housing, a cavity in the housing to receive a chamber, at least one contact member, and a sensor. The at least one contact member may be positioned to be engageable with a first segment of the chamber when the chamber is in the cavity, and to compress the first segment, thereby defining a gap of the first segment of the chamber and a reservoir in at least a second segment of the chamber.

Abstract: In a method for sampling a continuous liquid flow, the liquid flow is supplied to a surface along an input flow path. The liquid flow is sampled by forming a sample droplet from a portion of the liquid flow. The sample droplet is moved along an analysis flow path to a processing area of the surface, where the sample droplet is processed. Discrete sample droplets are formed and moved using an electrowetting technique. A binary mixing apparatus and method are also provided. The apparatus comprises an array of electrodes, an electronic controller communicating with the electrodes, a sample droplet supply area communicating with the array, and an additive droplet supply area communicating with the array. The electronic controller alternately energizes and de-energizes selected electrodes to carry out droplet-to-droplet binary mixing operations to obtain one or more droplets having a target mixing ratio.

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: Microfluidic devices capable of combining discrete fluid volumes generally include channels for supplying different fluids toward a sample chamber and means for establishing fluid communication between the fluids within the chamber. Discrete fluid plugs are defined from larger fluid volumes before being combined. Certain embodiments utilize adjacent chambers or subchambers divided by a rupture region such as a frangible seal. Further embodiments utilize one or more deformable membranes and/or porous regions to direct fluid flow. Certain devices may be pneumatically or magnetically actuated.

Abstract: A fluidic micro electro-mechanical system (MEMS) device is described. In one aspect, at least one at least partially covered fluidic channel is formed between a polymer layer and a polymer substrate as the polymer layer is deposited on the substrate. The partially covered fluidic channel is fabricated as a unitary polymer layer structure. In one implementation, a strong exposure process is applied to the polymer layer to create a deep cross-linked polymer region. A weak exposure process is applied to the polymer layer to create a shallow cross-linked polymer region.

Abstract: Methods and apparatus for delivering fluidic materials to sample destinations, including mass spectrometers for analysis are provided. In preferred embodiments, sample aliquots are electrosprayed from tapered spray tips of capillary elements into the orifices of mass spectrometric inlet systems. In certain embodiments, fluidic samples are orthogonally sprayed from capillary elements or other fluid conduits, whereas in other embodiments samples are sprayed after devices are rotated or otherwise translocated from sample sources to sample destinations. In still other embodiments, samples are sprayed from flexed or deflected capillary elements at selected sample destinations.

Abstract: A microfluidic device for analyzing and/or sorting biological materials (e.g., molecules such as polynucleotides and polypeptides, including proteins and enzymes; viruses and cells) and methods for its use are provided. The device and methods of the invention are useful for sorting particles, e.g. virions. The invention is also useful for high throughput screening, e.g. combinatorial screening. The microfluidic device comprises a main channel and an inlet region in communication with the main channel at a droplet extrusion region. Droplets of solution containing the biological material are deposited into the main channel through the droplet extrusion region. A fluid different from and incompatible with the solution containing the biological material flows through the main channel so that the droplets containing the biological material do not diffuse or mix.

Abstract: Laser-induced phase-separation polymerization of a porous acrylate polymer is used for in-situ fabrication of dialysis membranes inside glass microchannels. A shaped 355 nm laser beam is used to produce a porous polymer membrane with a thickness of about 15 ?m, which bonds to the glass microchannel and form a semi-permeable membrane. Differential permeation through a membrane formed with pentaerythritol triacrylate was observed and quantified by comparing the response of the membrane to fluorescein and fluorescently tagging 200 nm latex microspheres. Differential permeation was observed and quantified by comparing the response to rhodamine 560 and lactalbumin protein in a membrane formed with SPE-methylene bisacrylamide. The porous membranes illustrate the capability for the present technique to integrate sample cleanup into chip-based analysis systems.

Abstract: A method of transporting a desired fluid in a channel includes: providing a working fluid to transport the desired fluid, such as a sample; providing a first segment of a first buffer fluid which is immiscible with the working fluid and the desired fluid; providing a first segment of the desired fluid; providing a second segment of a second buffer fluid which is immiscible with the working fluid and the desired fluid; providing the desired fluid to be transported and further manipulated; and transporting the desired fluid in the channel by applying a motive force to the working fluid which in turn exerts force against the desired fluid through the first and second buffer fluid. The method prevents dilution of a sample in an apparatus such as a diagnostic analyzer or an apparatus for immunohematological testing of blood. A microfluidics handling system includes a microsystem platform that has: a substrate having: a first flat, planar surface; and a second flat planar surface opposite to the first surface.

Abstract: The invention relates to a device (1) for distribution of at least one liquid product, the device comprising at least one injection tube (2) supplied by a liquid product and being provided with an outlet orifice (4) capable of cooperating with an inlet orifice (12) of a reception tube (10) for reception of each liquid product. According to the invention, the outlet orifice (4) of each injection tube (2) and the inlet orifice (12) of the reception tube (10) open up into a sealed reservoir (6) full of an immiscible liquid (8), the outlet orifice (4) of each injection tube (2) being at a spacing from the inlet orifice (12) of the reception tube (10) and able to be located close to the reception tube (12), the device (1) also comprising means (14) for pressurizing the immiscible liquid (8).

Abstract: The invention provides a device for dispensing accurately-controlled small quantities of at least one liquid, comprising a liquid supply (L); a gas supply (G), arranged to selectively supply a gas pressure; and a capillary duct (20) adapted to be filled with liquid to be dispensed, and to eject the liquid. The device has a filling configuration wherein liquid from the supply is in contact with an end (20a) of the capillary duct to fill the capillary duct with liquid; and a liquid separation and ejection configuration, in which liquid remaining in the liquid supply is separated from liquid that fills the capillary duct to form a discrete quantity (V) of liquid filling the capillary duct (20) out of contact with the remaining liquid of the liquid supply. The capillary duct, filled with this discrete quantity (V) of liquid then has one end in contact with the gas supply and another end in contact with the atmosphere.

Abstract: An apparatus for measuring the effective vapor diffusion coefficient of a test vapor diffusing through a sample of porous media contained within a test chamber. A chemical sensor measures the time-varying concentration of vapor that has diffused a known distance through the porous media. A data processor contained within the apparatus compares the measured sensor data with analytical predictions of the response curve based on the transient diffusion equation using Fick's Law, iterating on the choice of an effective vapor diffusion coefficient until the difference between the predicted and measured curves is minimized. Optionally, a purge fluid can forced through the porous media, permitting the apparatus to also measure a gas-phase permeability. The apparatus can be made lightweight, self-powered, and portable for use in the field.