Abstract: In a method for the manufacture of a microarray, surface areas of a chip are brought into contact with different aqueous solutions that contain at least one coating substance. For each of the individual surface areas, an absorbent substrate is provided and is filled with the solution that is to be brought into contact with the surface area in question. Then, for the printing of the surface area with the at least one coating substance contained in the solution, each substrate is brought into contact with the surface area in question.

Abstract: An apparatus for airborne particle sorting is provided comprising a charging system adapted for applying an electrostatic charge to the particles, such that particles of at least a first group are deflected to a greater extent than particles of a second group are deflected. A focusing system is adapted for electrostatically focusing substantially at least the particles of the first group into a focused stream that is narrower than the input air stream. A deposition system is adapted for substantially depositing the particles of the first group from the focused stream upon a target surface, where the target surface may be transported to an analysis system capable of analyzing the particles deposited thereon.

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: A sensor system having an analyte modulator, detector and a pump. The concentration of an analyte sample may be modulated at one time constant. The detector may have an output with a drift at another time constant. The one time constant may be shorter than the latter time constant. The latter time constant may be substantially removed from the detector output with a discriminator. A reservoir may receive high concentrations of analyte from the modulator, before analyte is forwarded to the detector and pump via analyte conveyance lines and valving. The modulation or pre-concentration of analyte in the sensor system may entail shorter times and smaller volumes than those needed by the detector. Such mismatches may be alleviated via accumulation of analyte in the reservoir prior to being forwarded to the detector.

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 by constricting flow, and wherein the fluid is recirculated through the measuring region. A mixing region can be created separate from the measuring region sufficient to substantially mix the fluid. Free stream particulates in the fluid can be measured 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 as well as undesirable agglomeration on device surfaces is minimized.

Abstract: A method and an apparatus for detecting, locating, and quantifying contamination in a fluid flow system like a pipe or duct. This characterization technique uses a conservative and one or more interactive tracers that are injected into the fluid flow system and then monitored at another location in the system. Detection, location, and quantification are accomplished by analysis of the characteristic features of measured curves of tracer concentration.

Abstract: An oxidation reactor includes a reactor body, a manhole nozzle projecting from the reactor body, and a partition plate separating an inside of the manhole nozzle and an inside of the reactor body from each other. In an oxidation reactor including the reactor body and a nozzle projecting from the reactor body, there is provided a means for feeding an inert gas into the nozzle. In a process for producing (meth)acrylic acids by subjecting propane, propylene or isobutylene to catalytic gas-phase oxidation reaction in an oxidation reactor for producing (meth)acrolein or (meth)acrylic acid, the above oxidation reactor is used as the oxidation reactor. In a method for analyzing an easily-polymerizable compound by introducing a gas containing the easily-polymerizable compound into an analyzing apparatus through a sampling tube, a double tube is used as the sampling tube, and a heating medium is fed into an outer tube of the double tube.

Abstract: A method and an apparatus for detecting, locating, and quantifying explosive materials and devices, and naturally occurring and man-made dangerous or hazardous biological and chemical materials and devices in ducts or piping systems, or other fluid flow systems in buildings such as residential, office, industrial, and power plants, transportation systems such as ships, airplanes, subways, and trains, and various types of infrastructure such as dams, tunnels, or bridges, and in the rooms, compartments, enclosures, containers, or difficult to access areas in these buildings, transportation systems, and structures. The preferred embodiment of this detection and location method uses a conservative tracer and one or more interactive tracers that are injected into the duct or area to be searched at one location and then monitored at the same or another location in the duct or area.

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: An analytical system is provided for determining nitrogen monoxide, nitrogen dioxide and ozone concentrations in air samples. An ultraviolet light source 4 is used to alter the equilibrium between nitrogen dioxide and oxygen on the one hand and nitrogen monoxide and ozone on the other. Dynamic measurement of ozone concentration with time while ultraviolet irradiation is pulsed enables each gas concentration to be calculated without requiring input gases to be scrubbed. An aApparatus 101 is further provided to provide a controlled flow of gas to a sensor 103 attached to a high altitude balloon while sheltering it from the elements and allowing for affects of temperature, said apparatus comprising a shield 104 and a gas conducting means which uses the venturi effect to control air flow or has a hole to allow water to drain without affecting air flow past the sensor.

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: 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: 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: A system and method are described herein for self-referencing a sensor that is used to detect a biomolecular binding event and/or kinetics which occur in a sample solution flowing along side a reference solution in a micron-sized deep flow channel.

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: A process and an assembly for simultaneously evaluating a plurality of catalysts is provided wherein the flow rate of a reactive fluid to each of a plurality of reactors is automatically adjusted based on the measured amount of catalyst sample in each reactor to concurrently obtain a substantially identical fluid space velocity in each of the reactors.

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: 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 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: A compound linked to a solid support (R) through a divalent linker moiety (X) and which is represented by the following formula: is disclosed. In particular, the 1-hydroxybenzotriazole-6-carboxylic acid is directly linked to the support under mild conditions (i.e., in aqueous or organic solvents at neutral pH and at room temperature). The polymer bound 1-hydroxybenzotriazole-6-carboxylic acid can be used for the derivatization of amines as well as for single step amino group modification of proteins, peptides, and amines via acylation or sulfonylation reactions. A flow through device and method for the single step amino group modifications of proteins, peptides, and amines is disclosed. Also disclosed is a flow through device for the detection of amines in a sample. Additionally, a device and method for the detection of amines in a sample using 1-hydroxybenzotriazole-6-carboxylic acid is disclosed. In a preferred embodiment, the device is used to detect the presence of amines in a spoiled meat product.

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.

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: A biological suspension processing system is disclosed that may include a suspension treatment device for treating one or more components of a biological suspension, a first fluid flow path for introducing a suspension into the treatment device and a second fluid flow path for withdrawing a constituent of the suspension from the device. At least one microelectromechanical (MEM) sensor communicates with one of the fluid flow paths for sensing a selected characteristic of the fluid therewith. The MEM sensor may be located elsewhere, such as on a container or bag and communicate with the interior for sensing a characteristic of the fluid contained therein. A wide variety of characteristics may be sensed, such as flow rate, pH, cell type, cell antigenicity, DNA, viral or bacterial presence, cholesterol, hematocrit, cell concentration, cell count, partial pressure, pathogen presence, or viscosity.

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 multicomponent fluid composition monitoring and compositional control system, in which a component analysis is effected by titration or other analytical procedure, for one or more components of interest, and a computational means then is employed to determine and responsively adjust the relative amount or proportion of the one or more components in the multicomponent fluid composition, to maintain a predetermined compositional character of the multicomponent fluid composition. The system is usefully employed in semiconductor manufacturing photoresist and post-etch residue removal, in which the cleaning medium is a semi-aqueous solvent composition, and water is the monitored and responsively adjusted component.

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: The present invention relates to a method of saturating ethylene-containing gases with acetic acid before they are fed into a vinyl acetate reactor, in which the acetic acid recovered in the vinyl acetate process is introduced into a column having a countercurrent stripping section and a rectification section and ethylene-containing gas is supplied via the bottom, wherein the liquid taken off at the bottom of the column is divided into two substreams and one substream is pumped back into the column with maintenance of a minimum pumped circulation required for sufficient saturation with acetic acid.

Abstract: A biological material detection apparatus which detects a charged biological material such as a gene or protein contained in a sample liquid is disclosed. A biological material detection element includes a substrate, at least one first electrode formed on the substrate, and a plurality of second electrodes which are arrayed at predetermined intervals around the first electrode on the substrate along the circumferential direction and to which ligands that react with predetermined biological materials are respectively immobilized. A sample liquid is introduced toward the first electrode on the substrate. The introduced sample liquid is moved radially toward the second electrodes by electrical control.

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 process. The apparatus may have additional light source so that the photo sensor may monitor the test process by detecting the absorption light beam or fluorescent light beam from the flow cell at different phases of the test process.

Abstract: A method is provided of obtaining a sample concentration of a solution in a microfluidic device. The microfluidic device includes a channel having a reservoir and a collection port. The channel is filled with a solution having particles therein. A reservoir drop is deposited over the reservoir of the channel such that the solution of the channel flows towards the collection port in response to evaporation of the solution at the collection port. The particles at the collection port are collected to obtain the sample concentration.

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

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: This invention provides a method and system capable of the continuous, real-time measurement of low concentrations of aqueous free cyanide (CN) using an on-line, flow through system. The system is based on the selective reactivity of cyanide anions and the characteristically nonreactive nature of metallic gold films, wherein this selective reactivity is exploited as an indirect measurement for aqueous cyanide. In the present invention the dissolution of gold, due to the solubilization reaction with the analyte cyanide anion, is monitored using a piezoelectric microbalance contained within a flow cell.

Abstract: A supply apparatus for preparing a mixed chemical solution of a predetermined mixing ratio at a low cost and for supplying the mixed chemical solution stably. The supply apparatus includes a measuring apparatus located on an intermediate portion of a flow channel through which the chemical solution flows upward for measuring properties of the mixed chemical solution. In the lower portion of the measuring apparatus, disposed is a nozzle for spouting the chemical solution upward.

Abstract: A particle sorter/dispenser wherein particles that are suspended in a liquid are flowed through a conduit and selectively dispensed through a dispensing orifice. The conduit includes a sensing zone wherein the liquid-suspended particles are interrogated by a sensor. Data from the sensor is received by processing electronics that analyzes the data from the sensor and makes a decision whether or not to dispense a particle. The particle sorter/dispenser further includes a switch that, responsive to a signal from the processing electronics, controls whether or not a given particle is dispensed through the dispensing orifice. The switch has one or two valves that introduce relatively high-pressure liquid into the conduit. The flow streamlines of the high-pressure liquid controls the flow of the relatively low-pressure liquid-suspended particles in the conduit. Particles that are not dispensed are flowed past the dispensing orifice to a recycle reservoir that depends from the downstream end of the conduit.

Abstract: A fluid interface port in a microfluidic system and a method of forming the fluid interface port is provided. The fluid interface port comprises an opening formed in the side wall of a microchannel sized and dimensioned to form a virtual wall when the microchannel is filled with a first liquid. The fluid interface port is utilized to fill the microchannel with a first liquid, to introduce a second liquid into the first liquid and to eject fluid from the microchannel.

Abstract: The present invention relates to an adhesive article which can be used as a layer in or a cover for various articles in which a hydrophilic or hydrophobic surface is desired. The adhesive article includes a base layer having a first surface and a second surface and a coating layer formed on the first surface of the base layer, where the coating layer contains at least one adhesive resin and at least one hydrophilic polymer; at least one adhesive resin (which can be a hydrophobic polymer) and at least one surfactant; or at least one adhesive resin, at least one hydrophilic polymer and at least one surfactant. Given the application, the coating layer can be formulated to provide either a hydrophilic or hydrophobic surface. The polymer portion of the coating provides the coating layer with sufficient hydrophilic properties to increase the rate fluid transport across (or in the area near) the coating layer.

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 method for determining a urea concentration in an aqueous solution containing urea, includes: hydrolyzing the urea in the aqueous solution, measuring an electric conductivity ? of the aqueous solution, and determining the urea concentration in the aqueous solution from the electric conductivity ? using a correlation between the urea concentration and an electric conductivity.

Abstract: Parallel flow reaction systems comprising four or more reaction channels are disclosed. Distribution systems, and parallel flow reaction systems comprising such distribution systems are also disclosed. Specifically, the distribution systems comprise one or more subsystems, including for example, a flow-partitioning subsystem for providing a different flow rate to each of the four or more reactors, a pressure-partitioning subsystem for providing a different reaction pressure in the reaction cavity of each of the four or more reactors, and a feed-composition subsystem for providing a different feed composition to each of the four or more reactors. In preferred embodiments, the one or more subsystems can comprise at least one set of four or more flow restrictors, each of the four or more flow restrictors having a flow resistance that varies relative to other flow restrictors in the set.

Abstract: This invention provides methods for using liquid junction potentials to control the transport of charged particles in fluid streams that are in laminar flow within microfluidic channels. Applications of the methods of this invention include sample preconditioning (removal of interfering substances), electrophoretic separation (fractionation) of charged particles, enhanced or delayed mixing of charged particles across a fluid interface relative to diffusion only, focusing charged particles in a fluid stream in one or two dimensions, and concentration of charged reactants at a fluid interface.

Abstract: A sample separation apparatus including a porous, or rough, capillary column. The porous capillary column includes a matrix which defines pores, and may be formed rough surface of hemispherical grain silicon. The capillary column is defined in a surface of a substrate, such as silicon. The sample separation apparatus may include a stationary phase or a capture substrate disposed on the surfaces thereof. The sample separation apparatus may also include a detector positioned proximate the capillary column. A variation of the sample separation apparatus includes an electrode proximate each end of the capillary column. The sample separation apparatus may be employed to effect various types of chromatographic separation, electrophoretic separation, and analyte identification.

Abstract: A method is provided for performing a gradient-based assay in a microfluidic device. The method includes the steps of passing first and second fluids through a channel in the microfluidic device. The first fluid has a predetermined concentration of particles therein such that the particles in the first fluid diffuse into the second fluid so as to cause a gradient of concentration of particles in the second fluid as the second fluid flows through the channel. The second fluid sequentially intersects a series of targets along the channel wall as the second fluid flows through the channel.

Abstract: Methods and devices are provided for controlling a fluid flow over a sensing surface within a flow cell The methods employ laminar flow techniques to position a fluid flow over one or more discrete sensing areas on the sensing surface of the flow cell. Such methods permit selective sensitization of the discrete sensing areas, and provide selective contact of the discrete sensing areas with a sample fluid flow. Immobilization of a ligand upon the discrete sensing area, followed by selective contact with an analyte contained within the sample fluid flow, allows analysis by a wide variety of techniques. Sensitized sensing surfaces, and sensor devices and systems are also provided.

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: Method and apparatus for measuring a water concentration in ammonia, comprising using ammonia having a water concentration of 10 ppm or less as a reference gas, introducing the ammonia at a constant flow rate into a multi-reflection long optical path gas cell, and measuring infrared absorption intensity of water at at least one measurement wave number in the range of from 3,500 to 4,000 cm?1, from 2,600 to 3,100 cm?1, or from 1,900 to 2,400 cm?1 at which infrared absorptions of ammonia and water do not overlap. According to the present invention, analysis of water in a low concentration range of 10 ppm or less in ammonia gas and liquefied ammonia can be performed in a simple and convenient manner.