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: In a chemical analysis apparatus for extracting a specific substance, such as nucleic acid, from a sample containing a plurality of chemical substances, solutions remaining in valves are prevented so that a reagent in an earlier step does not contaminate the subsequent steps. Predetermined quantities of solutions are carried and supplied by centrifugal force without providing valves for controlling the flow of the solutions. After perforating the lids of ventilation holes 272, 273, 274 communicated with a detection container 450 and disposal containers 460 and 470 in an analysis disc 2, the analysis disc 2 is rotated to supply and carry a predetermined quantity of the sample.

Abstract: An apparatus and method for capturing a target substance in a sample. The method includes the steps of preparing particles capable of capturing the target substance in a dispersed state in a fluid, aggregating the particles, and allowing the particles to capture the target substance in the sample by bringing the sample into contact with the particles aggregated.

Abstract: A fluid dispenser useful in methods and apparatuses for automated biological reaction systems including a barrel, a coupler, a piston associated with the barrel, and a sealing surface that seals the inner diameter against fluid flow at the lower extent of the piston.

Abstract: The present invention provides microfluidic devices and methods for using the same. In particular, microfluidic devices of the present invention are useful in conducting a variety of assays and high throughput screening. Microfluidic devices of the present invention include elastomeric components and comprise a main flow channel; a plurality of branch flow channels; a plurality of control channels; and a plurality of valves. Preferably, each of the valves comprises one of the control channels and an elastomeric segment that is deflectable into or retractable from the main or branch flow channel upon which the valve operates in response to an actuation force applied to the control channel.

Abstract: The invention relates to a system for processing an analyte. The system includes a fluid reservoir, a plurality of sample reservoirs, a plurality of channels, a pump that synchronously draws from the fluid reservoir and the plurality of sample reservoirs to provide a plurality of samples through the plurality of channels and a processing device, for example, a flexural plate wave device, for processing the plurality of samples in the plurality of channels. A valve including a pin disposed beneath a dowel and a pusher pushes the pin toward a fastened dowel, which pinches a portion of the channel disposed therebetween. A socket provides electrical contact to the processing device.

Abstract: A flow cytometer is provided which includes an interrogation flow cell and a plurality of assay fluidic lines extending into the interrogation flow cell. A method of operating such a flow cytometer includes priming the interrogation flow cell with a sheath fluid and injecting different assay fluids into a flow of the sheath fluid through the plurality of fluidic lines. A fluidic line assembly is provided which includes a plurality of capillary tubes coupled to a base section configured for coupling to an interrogation flow cell assembly of a flow cytometer. The capillary tubes are dimensionally configured such that when the fluidic line assembly is arranged within the flow cytometer and fluid is dispensed from one or more of the capillary tubes at a given pressure differential with respect to an encompassing sheath fluid within the interrogation flow cell the fluid is substantially centrally aligned within the interrogation flow 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: The invention relates to a microfabricated device for the rapid detection of DNA, proteins or other molecules associated with a particular disease. The devices and methods of the invention can be used for the simultaneous diagnosis of multiple diseases by detecting molecules (e.g. amounts of molecules), such as polynucleotides (e.g., DNA) or proteins (e.g., antibodies), by measuring the signal of a detectable reporter associated with hybridized polynucleotides or antigen/antibody complex. In the microfabricated device according to the invention, detection of the presence of molecules (i.e., polynucleotides, proteins, or antigen/antibody complexes) are correlated to a hybridization signal from an optically-detectable (e.g. fluorescent) reporter associated with the bound molecules.

Abstract: The present embodiment describes a laminar-mixing embodiment that utilizes simple, three-dimensional injection. Also described is the use of the embodiment in combination with wide and shallow sections of channel to affect rapid mixing in microanalytical systems. The shallow channel sections are constructed using all planar micromachining techniques, including those based on isotropic etching. The planar construction enables design using minimum dispersion concepts that, in turn, enable simultaneous mixing and injection into subsequent chromatography channels.

Abstract: A vessel arrangement having a base and multiple vessels suited for simultaneously conducting a plurality of isolated experimental reactions or treatments at atmospheric process conditions or elevated temperatures and pressure condition has been developed. A component of a first material is introduced into one independent vessel through an opening in its top of the first vessel and another component of a second material is introduced into a different independent vessel through its top. Both vessels are removably located about a base at different first locations. Transformation of the components in the vessels then occurs to produce different materials therein. After completion of the experiments a displacement medium simultaneously urges the vessels from their respective locations about the base for discard or reuse after any necessary cleaning. Typically at least one property of the materials from the vessels is determined either within the vessel or after recovery of the materials.

Abstract: A microfluidic device for analysis of a sample. The microfluidic device includes a substrate portion that at least partially defines a chamber for receiving the sample. The substrate portion includes a substrate having a surface. The substrate portion also includes a plurality of thin-film layers formed on the substrate adjacent the surface. The thin-film layers form a plurality of electronic devices. Each of at least two of the electronic devices is formed by a different set of the thin-film layers. The at least two electronic devices may include 1) a temperature control device for controlling the temperature of fluid in the chamber, and 2) an other electronic device configured to sense or modify a property of fluid in the chamber.

Abstract: Provided is a method for determining a zeta potential generated between a solid wall and a solution. The method includes (a) injecting an electrolyte solution into a first inlet of a T channel, which is provided with first and second inlet electrodes and a grounded outlet electrode, and a mixed solution of the electrolyte solution and a fluorescent dye into a second channel of the T channel and maintaining a steady-state of the two solutions; (b) applying a direct current electric field from the first and second electrodes to the outlet electrode to form an interface between the electrolyte solution and the mixed solution; (c) applying an alternating current electric field from one of the two inlet electrodes to the outlet electrode to oscillate the interface; and (d) measuring an amplitude of oscillation of the interface and determining the zeta potential from the standard relationship between the zeta potential and the amplitude.

Abstract: Disclosed is an apparatus and method for inserting one or several chemical or biological species into phospholipid containers that are controlled within a microfluidic network, wherein individual containers are tracked and manipulated by electric fields and wherein the contained species may be chemically processed.

Abstract: The present invention includes a method, apparatus and system for nanofabrication in which one or more target molecules are identified for manipulation with an electron beam and the one or more target molecules are manipulated with the electron beam to produce new useful materials.

Abstract: Provided are an apparatus for circulating a carrier fluid having two or more chambers or sections, an apparatus for amplifying a nucleic acid using the same, and a chip containing the same. The apparatus for circulating a carrier fluid includes two or more chambers maintained at different temperatures, each chamber having an inlet valve containing a pneumatic air pressure port for controlling inflow of the carrier fluid to the chamber (inlet pneumatic air pressure port), and an outlet valve containing a pneumatic air pressure for controlling outflow of the carrier fluid from the chamber (outlet pneumatic air pressure port), wherein the chambers are sequentially connected such that the outlet valve of one chamber is connected to the inlet valve of an adjacent chamber in a direction the fluid flows.

Abstract: An electrophoresis apparatus is generally disclosed for sequentially analyzing a single sample or multiple samples having one or more analytes in high or low concentrations. The apparatus comprises a relatively large-bore transport capillary which intersects with a plurality of small-bore separation capillaries and includes a valve system. Analyte concentrators, having antibody-specific (or related affinity) chemistries, are stationed at the respective intersections of the transport capillary and separation capillaries to bind one or more analytes of interest. The apparatus allows the performance of two or more dimensions for the optimal separation of analytes. The apparatus may also include a plurality of valves surrounding each of the analyte concentrators to localize each of the concentrators to improve the binding of one or more analytes of interest.

Abstract: Microfluidic devices for manipulating relatively dense materials, such as colloidal rod particles, are provided. Microfluidic devices for separating a denser first material from a less-dense second material are provided. Methods of manipulating a relatively dense first material, for example, colloidal rod particles, and separating the first material from a less-dense second material, are provided. Methods of marking samples or sample components with relatively dense materials, are also provided.

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: The present invention provides, in certain embodiments, improved microfluidic systems and methods for fabricating improved microfluidic systems, which contain one or more levels of microfluidic channels. The inventive methods can provide a convenient route to topologically complex and improved microfluidic systems. The microfluidic systems provided according to the invention can include three-dimensionally arrayed networks of fluid flow paths therein including channels that cross over or under other channels of the network without physical intersection at the points of cross over. The microfluidic networks of the invention can be fabricated via replica molding processes, also provided by the invention, utilizing mold masters including surfaces having topological features formed by photolithography.

Abstract: There is provided a flow cell assembly in which a shuttle supports and positions a capillary with its end extending beyond the shuttle. The flow cell assembly facilitates the replacement of a flow cell which is damaged or with flow cells having capillaries of different size or shape.

Abstract: Integrated nanotube sensors are adapted for detecting various chemical and biological molecules. In one implementation, nanotube sensor arrays are formed as nano-electronic noses capable of such detection, and can be implemented in devices including carbon nanotube-based electronic noses and biochips. Various implementations of the present invention are also directed to nanoscience and nanotechnology applications, such as medical, military and biological applications. In a more particular implementation, nanotubes are produced on full-scale wafers and functionalized. In another more particular implementation, functionalized nanotubes are integrated into addressable devices. With these approaches, various aspects of the present invention have been found to be useful in sensor applications having small size, high density and extreme sensitivity. Such sensor applications are applicable to many aspects of society, and can be implemented for making human lives more safe, secure and healthy.

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: The invention provides systems, including apparatus, methods, and kits, for the microfluidic manipulation and/or detection of particles, such as cells and/or beads. The invention provides systems, including apparatus, methods, and kits, for the microfluidic manipulation and/or analysis of particles, such as cells, viruses, organelles, beads, and/or vesicles. The invention also provides microfluidic mechanisms for carrying out these manipulations and analyses. These mechanisms may enable controlled input, movement/positioning, retention/localization, treatment, measurement, release, and/or output of particles. Furthermore, these mechanisms may be combined in any suitable order and/or employed for any suitable number of times within a system.

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: An apparatus is provided for hematology testing, which has a sensing unit defining a counting orifice for the flow of a blood sample through the counting orifice to analyze the blood sample, and a pump unit having three syringes. A first syringe is coupled in fluid communication with the sensing unit on the inlet side of the counting orifice for injecting a stream of blood sample through the counting orifice. A second syringe is coupled in fluid communication with the sensing chamber on the inlet side of the counting orifice for simultaneously injecting a sheath of fluid surrounding the sample stream on the inlet side of the counting orifice. And a third syringe is coupled to the sensing chamber on the outlet side of the counting orifice for aspirating a sheath of fluid from the sensing chamber surrounding the sample stream on the outlet side of the counting orifice.

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: In a preferred embodiment, a pipettor head, including: a body; one or more solenoid valves disposed in the body; each one or more solenoid valves having an outlet at a lower end and an inlet at an upper end; each one or more solenoid valves having an outlet attached to a dispensing passageway; each one or more solenoid valves having its inlet attached to a standpipe; and the standpipe having an open top communicating with an interior of a closed vacuum/pressure chamber defined in the pipettor head, the closed vacuum/pressure chamber being arranged such that vacuum or pressure may be selectively applied to the closed vacuum/pressure chamber. A method of using the pipettor head is also provided.

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 is directed to devices and methods for carrying out and/or monitoring biological reactions in response to electrical stimuli. A programmable multiplexed active biologic array includes an array of electrodes coupled to sample-and-hold circuits. The programmable multiplexed active biologic array includes a digital interface that allows external control of the array using an external processor. The circuit may monitor, digitally control, and deliver electrical stimuli to the electrodes individually or in selected groups.

Abstract: A method for measuring properties of a fluid including placing a quantity of fluid in a container; inducing flow in the fluid wherein the flow is substantially streamlined in at least a measuring region of the container, and wherein the fluid is recirculated through the measuring region; creating a mixing region separate from the measuring region sufficient to substantially mix the fluid; and measuring a property of the fluid in the streamlined region. The invention is of particular interest in the assessment of blood platelet function. The method provides specific localized regions of thorough mixing that enable reproducible platelet aggregation, and also provides specific localized regions of streamlined flow that enable certain modalities of assessing aggregation. Both of these regions of flow are induced such that damage to platelet aggregates and other blood components is minimized.

Abstract: A solid state nanopore device including two or more materials and a method for fabricating the same. The device includes a solid state insulating membrane having an exposed surface, a conductive material disposed on at least a portion of the exposed surface of the solid state membrane, and a nanopore penetrating an area of the conductive material and at least a portion of the solid state membrane. During fabrication a conductive material is applied on a portion of a solid state membrane surface, and a nanopore of a first diameter is formed. When the surface is exposed to an ion beam, material from the membrane and conductive material flows to reduce the diameter of the nanopore. A method for evaluating a polymer molecule using the solid state nanopore device is also described. The device is contacted with the polymer molecule and the molecule is passed through the nanopore, allowing each monomer of the polymer molecule to be monitored.

Abstract: This invention provides a microfluidic device for use in the detection of one or more analytes in a fluid using solid-phase affinity binding assays. The device offers a practical, easy-to-use, portable, inexpensive, robust analytical system for the parallel and quantitative detection of multiple analytes. In addition, this invention provides methods and devices for the formation of concentration gradients of capture molecules immobilized on a solid phase.

Abstract: A system and method for detecting the presence of submicron sized particles in a sample taken from the environment includes a collecting a sample from the environment and purifying and concentrating the submicron particles in a sample based on the size of the particles. The purified and concentrated particles are detected with an apparatus which includes an electrospray assembly having an electrospray capillary, a differential mobility analyzer which receives the output from the capillary, and a condensation particle device for counting the number of particles that pass through the differential mobility analyzer.

Abstract: A method for optical measuring of the solid substance content in a fluid uses periodical flushing of an optical sensor (1) with a combination of pressurized air and water in the form of a jet. The jet exerts a very powerful cleaning effect without causing scratches on measuring surfaces of glass or similar materials. The invention also relates to a system for performing such flushing in connection with measuring.

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 present invention provides novel microfluidic devices and methods for preventing/ameliorating formation of precipitate blockages in microfluidic devices. In particular the devices and methods of the invention utilize microchannels of specific cross-sectional configuration and of specific arrangement as well as application of AC current orthogonal to the direction of fluid flow, in order to preventing/ameliorating formation of precipitate blockages in microfluidic devices.

Abstract: The present invention provides a method for combining a fluid delivery system with an analysis system for performing immunological, chemical, or biological assays. The method provides a miniature plastic fluidic cartridge containing a reaction chamber with a plurality of immobilized species, a capillary channel, and a pump structure along with an external linear actuator corresponding to the pump structure to provide force for the fluid delivery. The plastic fluidic cartridge can be configured in a variety of ways to affect the performance and complexity of the assay performed.

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 present invention is directed to a method for determining the molecular weight and diffusivity of a sample solute by providing a plus shaped microchannel network on a microfluidic chip, having at least four microchannels intersecting at a cross point; flowing a sample stream comprising a sample solute of unknown diffusivity and a blank stream from separate microchannels through the cross point and out to separate microchannels; creating a sample curve measuring the concentration of the sample solute that diffuses from the sample stream to the blank stream at the cross point while altering the flowrate of one of the blank stream or the sample stream; and determining a diffusion coefficient of the sample solute by extrapolating data from similar curves of at least two solutes having known molecular weights and/or diffusion coefficients created under similar conditions as those generated by the sample solute.

Abstract: A process and apparatus for rapidly screening materials using, for example, mass spectrometry has been developed. More specifically, an array of materials on a fluid permeable support contained within a reaction cell having a semipermeable membrane can be rapidly screened for characteristics such as catalytic activity, selectivity, and adsorption and desorption properties.

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: In the case of a method for producing a fluid device with a fluid structure having an active height, a basic wafer is provided, which comprises a supporting substrate, an insulating layer on the supporting substrate and a patterned layer on the supporting substrate, the thickness of the patterned layer determining the active height of the fluid structure. Following this, the fluid structure is produced in the patterned layer of the basic wafer, said fluid structure extending through the semiconductor layer. A transparent wafer is then applied so that the fluid structure is covered. Subsequently, the supporting substrate and the insulating layer are removed from the back so that the fluid structure is exposed at a second surface of the patterned layer. Finally, a second transparent wafer is attached to the exposed second surface of the semiconductor layer so that the fluid structure is covered. The essential parameter of the fluid device, viz.

Abstract: Described herein is microfluidic device for joining fluids and a related method for doing the same. The device according to the present invention includes a microfluidic junction, an outlet channel, and a plurality of circuit units. A microfluidic junction is an area for converging multiple fluids. An outlet channel is capable of receiving fluid from the microfluidic junction. An outlet channel includes a first end connected with the microfluidic junction, a second end connected with a waste reservoir, and an analysis region positioned between the first end and the second end of the outlet channel. The device also includes a plurality of circuit units.

Abstract: A system for simultaneously processing a plurality of particles, e.g. beads or cells. A liquid sample containing the particles is delivered to a processing chamber in which the particles are positioned on particle retainers which lie in a plane. The particle retainers are sized to receive only one particle, so that the particles do not overlap. The system can make use of positioning fluid for forcing the particles into the particle retainers. The positioned particles can, for example, be processed by interrogating the particles with a light of a preselected wavelength, and analyzing signals received from the particles.

Abstract: An analytical apparatus to monitor fluid systems has at least one extraction module having a raw-sample reservoir connected by input fluid conduit to individual ones of said fluid systems, to extract raw samples for analysis from said fluid systems, one or more modification modules comprising additive materials to modify the extracted raw samples prior to analysis, an analytical device to receive at least a portion of said raw samples in an ordered sequence, and to determine concentration of at least one constituent of said sample portion, fluid-handling apparatus for transferring fluid through the analytical apparatus, and a computerized control and management system to manage operations of component modules and devices, and to report analytical results.

Abstract: An apparatus is provided for testing fluid samples includes a sensor, which can be light source, directed to a flow cell and a photo sensor for detecting a light beam reflected from the flow cell. The photo sensor monitors the fluid in the flow cell by sensing the reflected light beam from the flow cell, thereby monitoring the test.

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.