Abstract: A closure cap system for glass chromatography columns includes a glass cylinder with unfinished shaping or work on each end, and two sealing caps. The caps have a circumference shoulder with O-rings. The O-rings having the same diameter as the diameter of the glass cylinder unfinished ends. A base and top parts, both containing openings for receiving sealing caps and the glass cylinder. Threaded rods are received by additional openings in said top and base parts. Nuts are affixed at the end of each threaded rod. The combined action of the nuts and threaded rods apply compression forces to the caps and glass cylinder for sealing in a simple and economic manner defining the system as a disposable apparatus.

Abstract: To economically perform preparatory chromatography, a plurality of pumps each having a corresponding one of a plurality of pistons and a corresponding one of a plurality of cylinders are driven by one motor to draw and pump solvent simultaneously into corresponding columns. To form a gradient, the pumps are connected to two-way valves that are connected alternately to a first solvent and a second solvent, whereby the time said valve is in a first position controls the amount of solvent drawn from the first reservoir into said pumps and the amount of time in said second position controls the amount of said second solvent drawn from the second reservoir into said pumps and the solvent is mixed in the pumping systems. The detectors are photodiodes mounted to light guides in the flow cells that generate signals related to light absorbance and communicate with a controller, whereby the controller receives signals indicating solute between the light guides and causes collection of solute.

Abstract: Gradient performance with high pressure gradient solvent delivery system is optimized by approximation of infinite stroke volume of high pressure pumps by the addition of pulse dampening with backflow prevention to each high pressure pump. The backflow prevention adds sufficient minimum flow resistance, thereby enhancing the performance of the pulse dampening over a wider range of flow rates resulting in consistent gradient performance.

Abstract: An installation for treating samples by chromatographic separation comprises: i) means (1, 2, 4) for feeding moving phase, means (14) for supplying samples, and a multiplicity of injector means (10-i), each comprising a first inlet (11-i) for receiving a sample, a second inlet (8-i) connected to the feed means, and an outlet (13-i) for delivering the moving phase and/or the sample; ii) a stationary phase (3) defining a multiplicity of sample treatment channels (12-i), each starting at a first selected location (19-i) and terminating at a second selected location (20-i); and iii) a chamber (17) housing the stationary phase (3) and including pressurizing means for applying an external pressure to one face of the stationary phase, a multiplicity of inlets, each connected to the outlet (13-i) of an injector (10-i) to deliver the moving phase and/or the samples to the first locations (19-i), and a multiplicity of outlets (18-i) for discharging the multiplicity of samples treated in the channels (12-i) that have re

Abstract: The invention concerns a method supplying volume streams of fluids in channels or capillaries of small stream cross sections, more particularly chromatographic separating columns for the analytical fluid metrology, wherein a delivery device for delivering a volume stream of the fluid through an operating channel and a pressure measuring device for measuring the pressure in the operating channel is provided, wherein a measurement of the volume stream is possible, characterized by the following steps: a) Recording a time reference pressure course using the pressure measuring device in the operating channel, while the delivery device delivers an essentially constant, pre-determinable reference volume stream through the operating channel of a fluid with properties, more particularly flow properties, varying over time; b) Calculation of a time development of the operating pressure, which corresponds to the essentially constant and preferably small operating volume stream through the operating channel, which is d

Abstract: Method and apparatus for generating an acid or base, e.g. for chromatographic analysis of anions. For generating a base the method includes the steps of providing a cation source in a cation source reservoir, flowing an aqueous liquid stream through a base generation chamber separated from the cation source reservoir by a barrier (e.g. a charged membrane) substantially preventing liquid flow while providing a cation transport bridge, applying an electric potential between an anode cation source reservoir and a cathode in the base generation chamber to electrolytically generate hydroxide ions therein and to cause cations in the cation source reservoir to electromigrate and to be transported across the barrier toward the cathode to combine with the transported cations to form cation hydroxide, and removing the cation hydroxide in an aqueous liquid stream as an effluent from the first base generation chamber. Suitable cation sources include a salt solution, a cation hydroxide solution or cation exchange resin.

Abstract: A pumping arrangement, for example for liquid chromatography, comprises a first liquid reservoir at a first height level, connected via a first hydraulic path to a pumping means; a second liquid reservoir at a second height level, connected via a second hydraulic path to the pumping means; and filtration devices arranged in the first and in the second hydraulic path. Each filtration device comprises an outer member (1) forming a first chamber (6), and an inner member (2) arranged within the outer member and forming a second chamber (5). The inner member (2) is porous and acts as a filter for liquid flowing from the first chamber to the second chamber. The arrangement ensures efficient filtering and prevents undesired backflow of liquid.

Abstract: A method and an apparatus for efficiently analyzing an organic macromolecular component contained in a sample with high precision are provided. The method and the apparatus for analyzing the organic macromolecular component are based on a flow analysis method with a measuring system including a sample introduction section, a preparation section, and a measuring section, and include the steps of supplying a sample together with a carrier solution into the measurement system through the introduction section, leading the sample to the preparation section and separating an organic macromolecular component from the sample, and leading the separated organic macromolecular component to the measuring section for analysis.

Abstract: A method and apparatus for efficiently analyzing an organic macromolecular component contained in a sample with high precision are provided. The method and apparatus for analyzing the organic macromolecular component are based on a flow analysis method with a measuring system including a sample introducing section, a preparing section, and a measuring section, composed of steps of supplying a sample with a carrier solution into the measurement system through the introducing section, leading the sample to the preparing section and separating an organic macromolecular component in the sample, and leading the separated organic macromolecular component to the measuring section and analyzing. Herein, the step of separating the organic macromolecular component includes steps of the organic macromolecular component in the sample being adsorbed on a resin and introducing an eluant into the preparing section and eluting the organic macromolecular component adsorbed on the resin.

Abstract: A chromatography system including a chromatography column connected to receive a sample and separate different compounds in the sample, a flow-through detector that outputs a signal indicating the presence of compounds in the sample leaving the column, a fraction collector that directs fractions of the sample from the column to separate fraction wells, and an electronic controller that receives inputs from the detector and controls the fraction collector. The electronic controller monitors the signal from the detector over time and initiates a cut from one well to another at the fraction collector when the signal over time experiences a shoulder where the slope of the signal over time does not change in sign but does change by more than a predetermined amount.

Abstract: The present invention relates to an autosampler device useful in high pressure liquid chromatography (HPLC), and more particularly to a device useful for the automated introduction of small sample volumes into a HPLC system. Methods of analyzing low abundant protein samples using such a device are also included.

Abstract: The invention is a device and method in a high-pressure chromatography system, such as a supercritical fluid chromatography (SFC) system, that uses a pump as a pressure source for precision pumping of a compressible fluid. The preferred exemplary embodiment comprises a pressure regulation assembly installed downstream from a compressible fluid pump but prior to combining the compressible flow with a relatively incompressible modifier flow stream. The present invention allows the replacement of an high-grade SFC pump in the compressible fluid flow stream with an inexpensive and imprecise pump. The imprecise pump becomes capable of moving the compressible fluid flow stream in a precise flow rate and pattern. The assembly dampens the damaging effects of an imprecise pump, such as large pressure oscillations caused by flow ripples and noisy pressure signals that do not meet precise SFC pumping requirements.

Abstract: An apparatus for monitoring a fluid system particularly suited for use with high pressure liquid chromatography systems. The apparatus monitors seal leakage as well as the general wellness of the apparatus and can thus be used to provide preventive maintenance feedback. The apparatus includes a liquid chamber, a wash chamber, a reservoir, a supply pump, a return line, and a detector. The liquid chamber includes a seal for sealing a fluid within the liquid chamber. The wash chamber is located adjacent the seal. The reservoir supplies a wash solution to the wash chamber. The supply pump supplies a unidirectional flow of wash solution from the reservoir to the wash chamber. The return line conveys a return flow from the wash chamber to the reservoir, in which the return flow includes any leakage of the fluid from the liquid chamber into the wash chamber and the portion of the wash solution that returns from the wash chamber to the reservoir.

Abstract: Spillage of liquid during switching of receptacles in a fraction collector is avoided by introducing a device in the flow path between an inlet tube and a dispensing means. The device includes an expandable chamber that accommodates liquid during the time interval for switching from one receptacle to the next receptacle.

Abstract: High pressure capillary liquid chromatography solvent delivery is effected at substantially low volume and atmospheric pressure. The low volume solvent composition is subsequently pressurized and expelled at high pressure into a receiving device such as a column. The solvent composition is expelled from a fluid metering system configured to deliver liquids at low pressures to a storage matrix via an isolation valve. The solvent composition is delivered to the storage matrix in reverse order such that the first volume of liquid delivered into the storage matrix is the last volume of liquid expelled out. Liquid pre-existing within the storage matrix is transferred into a fluid accumulator in fluid communication with the storage matrix. The fluid accumulator is enveloped in a pressure caisson which can be pressurized or depressurized in response to sensor signals obtained from a fluid volume displacement transducer and a pressure sensor, in accordance with solvent composition cycle formation.

Abstract: A fluid monitoring and control apparatus and method including providing a programmable and reprogrammable control unit comprising a display, user inputs, and input/output connections; placing a programmable logic controller in direct communication with the control unit, which programmable logic controller is programmable and reprogrammable through the control unit; and placing a plurality of fluid parameter sensors in direct communication with the control unit. The invention is also of a fluid control apparatus and method comprising providing a membrane and estimating salt rejection by the membrane.

Abstract: A closed &Dgr;Pstat-installation is disclosed for the potential-independent control of the pressure difference for continuous column tests under high hydrostatic pressure, as well as a pressure difference control process useful in particular for carrying out migration tests in pressure columns. By coupling two potential bottles into a closed vessel system, the gas or fluid pressure required to carry out the continuous column tests can be regulated at any desired height independently of outer influences. The pressure difference required to move the liquid is adjusted by setting the potential bottles at predeterminable heights.

Abstract: The present invention provides a device capable of simply formulating an arbitrary gradient pattern in a low flow gradient high performance liquid chromatography. That is, the present invention provides a split tubing apparatus for a gradient high performance liquid chromatography, which comprises a solvent inlet part, a split tubing part split into two or more plural tubes, and a solvent outlet part.

Abstract: This invention provides a RP-HPLC method, for the determination of logPoct values, which combines ease of operation and high accuracy, and which has been shown to work for a set of 36 molecules largely comprised of drugs. The general features of the method are: i) compound sparing (≦1 mL of a 30-50 &mgr;g/mL solution needed), ii) rapid determinations (20 minutes on average), iii) low sensitivity to impurities, iv) wide lipophilicity range (6 logPoct units), v) good accuracy, vi) excellent reproducibility. A linear free energy relationship (LFER) analysis, based on solvation parameters, shows that the method encodes the same information obtained from a shake-flask logPoct determination. The value generated via this method is referred to as ElogPoct.

Abstract: Methods for calculating Log P values for organic compounds are disclosed. The methods allow identification of compounds in a library with a desired Log P value. The method can be used to minimize the number of compounds in a given combinatorial or lead generation library which need to be further characterized and/or assayed. The Log P value is preferably obtained while the purity of the compounds is being determined. Preferably, the Log P value is correlated to the retention time on an HPLC column, such that the retention time equals the Log P value.

Abstract: Self-washing injection apparatus [101] for liquid chromatography injection valves utilizes an interior chamber [105] with a penetrable seal [109] at the top end of the chamber and a needle sleeve seal [113] at the bottom end of the interior chamber. A wash port [145] in the body [103] of the apparatus connects one or more sources of wash fluid to the interior chamber between the penetrable seal and the sleeve seal. The apparatus provides a simple and effective means to aspirate or pump wash fluids from one or more wash fluid reservoirs through the apparatus, the injection port of the injection valve, and associated components.

Abstract: An operation portion reads an analyzing time and an analyzing flow rate from a storing portion for a next analysis to calculate a liquid delivery quantity per analysis for the next analysis, and transmits the liquid delivery quantity per analysis to a comparison portion. The comparison portion compares a pump capacity and the liquid delivery quantity per analysis, and when the comparison portion determines that the pump capacity is larger than the liquid delivery quantity per analysis, a control portion allows a mobile phase in the next analysis to be delivered by only one cycle discharging operation in a low flow rate mode. Thus, in a micro-liquid chromatography, influence of a pulsating flow can be suppressed.

Abstract: A high-performance liquid chromatography apparatus and a process for conversion of mobile phase, enabling a trace amount of sample for NMR analysis to be efficiently separated and prepared, includes steps of separating a target ingredient from the sample by the high-performance liquid chromatography, trapping the target ingredient in a trapping column using a different mobile phase, replacing water by deuterium oxide and eluting this target ingredient from the trapping column using deuterated solvent other than deuterium oxide.

Abstract: Method and apparatus for generating an acid or base, e.g. for chromatographic analysis of anions. For generating a base the method includes the steps of providing a cation source in a cation source reservoir, flowing an aqueous liquid stream through a base generation chamber separated from the cation source reservoir by a barrier (e.g. a charged membrane) substantially preventing liquid flow while providing a cation transport bridge, applying an electric potential between an anode cation source reservoir and a cathode in the base generation chamber to electrolytically generate hydroxide ions therein and to cause cations in the cation source reservoir to electromigrate and to be transported across the barrier toward the cathode to combine with the transported cations to form cation hydroxide, and removing the cation hydroxide in an aqueous liquid stream as an effluent from the first base generation chamber. Suitable cation sources include a salt solution, a cation hydroxide solution or cation exchange resin.

Abstract: Method and apparatus for generating an acid or base, e.g. for chromatographic analysis of anions. For generating a base the method includes the steps of providing a cation source in a cation source reservoir, flowing an aqueous liquid stream through a base generation chamber separated from the cation source reservoir by a barrier (e.g. a charged membrane) substantially preventing liquid flow while providing a cation transport bridge, applying an electric potential between an anode cation source reservoir and a cathode in the base generation chamber to electrolytically generate hydroxide ions therein and to cause cations in the cation source reservoir to electromigrate and to be transported across the barrier toward the cathode to combine with the transported cations to form cation hydroxide, and removing the cation hydroxide in an aqueous liquid stream as an effluent from the first base generation chamber. Suitable cation sources include a salt solution, a cation hydroxide solution or cation exchange resin.

Abstract: A thermal exchanger for a liquid chromatography system is provided. The tube-in-tube thermal exchanger comprises a first and a second sections of tubing, a first connector and a second connector. The first section of tubing carries sample solution from the packed chromatography column. The second tubing carries the sample solution from the detector out of the system, i.e., in an opposite direction to the direction of the first section of tubing. Both the first section of tubing and the second section of tubing connect to the first connector, which combines the two sections of tubing into a thermal exchange tubing. The thermal exchange tubing comprises the first section of tubing placed inside the second section of tubing such that waste fluid from the second tubing can optimally exchange thermal energy with fluid from the chromatography column. The thermal exchange tubing is configured into a plurality of coils.

Abstract: A method is disclosed for characterizing a plurality of non-biological polymer samples. The method includes the steps of injecting four or more non-biological polymer samples into a mobile-phase of a liquid chromatography system, chromatographically separating at least one sample component or polymer molecule of each of the four or more injected polymer samples from other sample components or polymer molecules thereof in a chromatographic column, and serially detecting a property of the four or more non-biological polymer samples or of components or polymer molecules thereof with a flow-through detector at an average sample throughput of not more than about 10 minutes per sample.

Abstract: The present invention is directed to a microfluidic chromatography apparatus comprising a microfabricated fluid delivery system and a chromatography column which is in fluid communication with the fluid delivery system, and a method for producing and using the same. Preferably, the chromatography column comprises an OTLC, PCLC, or combinations thereof.

Abstract: A method is disclosed for characterizing non-biological polymers using liquid chromatography that is particularly useful in polymer research programs. The method includes the steps of providing a library of four or more non-biological polymer samples, with each of the four or more polymer samples being polymerization product mixtures that result from polymerization reactions that are varied with respect to a factor affecting polymerization. Each of the four or more polymer samples resides in the reaction vessel in which they were formed.

Abstract: A method and an apparatus for efficiently analyzing an organic macromolecular component contained in a sample with high precision are provided. The method and the apparatus for analyzing the organic macromolecular component are based on a flow analysis method with a measuring system including a sample introduction section, a preparation section, and a measuring section, and include the steps of supplying a sample together with a carrier solution into the measurement system through the introduction section, leading the sample to the preparation section and separating an organic macromolecular component from the sample, and leading the separated organic macromolecular component to the measuring section for analysis.

Abstract: A method is disclosed for characterizing a plurality of non-biological polymer samples. The method includes the steps of injecting a first non-biological polymer sample into a mobile-phase of a liquid chromatography system, chromatographically separating at least one sample component of the injected first sample from other sample components thereof in a chromatographic column, detecting at least one property of the separated sample component of the first sample, injecting a second non-biological polymer sample into the mobile-phase of the liquid chromatography system while advancing the first sample to the chromatographic column, chromatographically separating at least one sample component of the injected second sample from other sample components thereof, and detecting at least one property of the separated sample component of the second sample.

Abstract: In obtaining an accurate mixing ratio of a liquid mixture, an actual mixing ratio of at least two different liquids mixed together is obtained, wherein the two kinds of liquids have a predetermined mixing ratio and are mixed by setting switching valves for the liquids. A mixing ratio error is calculated as a difference between the actual mixing ratio and the predetermined mixing ratio, and is stored. A switching timing of the switch valves is corrected based on the stored mixing ratio error.

Abstract: A method of chromatographically separating ionic species in an aqueous electrolyte-containing eluent to form an effluent, suppressing the effluent, detecting the suppressed effluent and passing the detected effluent to a regenerant reservoir, thereby displacing the regenerant to flow to the suppressor, wherein the regenerant and effluent are of different chemical compositions.

Abstract: An improved method and apparatus for safely introducing sample into a flow stream of a supercritical fluid chromatography system is described. The sample injection method improves safety of injection by eliminating the risk of injecting sample into a high-pressure system containing liquids and gasses at or near supercritical ranges. The method improves the efficiency and significantly shortens the time of the injection process by using a check valve placed between a fill port on an injection valve and sample port where sample is injected by a syringe. After sample injection from a sample loop into a high-pressure flow stream, an injection valve is reset to receive a subsequent sample. High-pressure flow stream mixtures become trapped within the sample loop when the valve is reset. The check valve prevents the mixtures from expanding into the sample port and blowing out a syringe and flow stream mixtures from the fill lines.

Abstract: An injection apparatus of the present invention includes a first switching valve RV1 which is selectively connected to any of a plurality of injectors 21-30 at one end sides thereof; a second switching valve RV2 which is selectively connected to any of the plurality of injectors at the other end sides thereof; a third switching valve RV4 which is connected to the second switching valve and is selectively connected to any of a plurality of columns 31-40 at one end sides thereof; and a fourth switching valve RV5 which is selectively connected to any of the plurality of columns at the other end sides thereof A sequential switching of these four switching valves can permit the sample liquids in the injectors 21-30 to be delivered in sequence into any selected column 31-40, and as such can allow the sample liquids packed in the plurality of injectors to be efficiently dispensed or analyzed by a chromatograph.

Abstract: A device for feeding a chromatography flow coming from a flow source, in particular from a liquid chromatography (LC) separating unit or a peak sampling or trapping unit, in part to at least a first decision detector unit and/or at least a first destination detector unit, and in part to at least a second destination detector unit is disclosed, including a first capillary line coming from the flow source, a second capillary line leading to the first decision detector unit, and/or to the first destination detector unit, and a third capillary line leading to the second destination detector unit, the first, second and third capillary line being connected with one another by means of a flow splitter splitting the flow coming from the first capillary line into two parts, a first part being fed into the second capillary line and the second part being fed into the third capillary line.

Abstract: An aerosol can content analyzer workstation is disclosed which will make available the drug content of an aerosol can by a mechanical extraction process wherein the extraction is performed by isolating the bottom portion of the aerosol can in an extraction chamber. The aerosol can bottom is pierced by a metal punch after the aerosol can bottom is isolated. An extraction solvent is dispensed through spray holes in the metal punch in order to extract the contents from within the can. The extract is then collected in a collection flask and the extract is analyzed in order to determine the drug content.

Abstract: A system and method for measurement and control of suspended solids in a fluid includes a sensor, dosage supervisor and logic module. The sensor includes a measurement chamber with a piston. A diverter valve controls introduction of sample fluid into the measurement chamber in coordination with position of the piston. A measurement cycle includes the diverter valve allowing sample fluid into the measurement chamber as the piston retracts from the measurement chamber. The diverter valve prevents sample fluid from leaving the measurement chamber as the piston extends into the measurement chamber to compress the sample fluid. After a certain time of compression, light is transmitted across a portion of the sample fluid. The light received by a light detector is used as a measurement of suspended solids concentration in the fluid. This measurement is used to control introduction of polymers into a fluid source.

Abstract: A gas chromatograph or other analytical instrument requiring controlled fluid flow incorporates a manifold assembly that eliminates the need for many of the external fittings and connections required in the instrument. A manifold block has plural fluid flow paths formed therethrough to route fluids to selected components. A collar mates to the block and adapts to a rotary injection valve to provide the continued fluid paths from the block to the injector valve and the other components of the instrument.

Abstract: Rapid characterization and screening of polymer samples to determine average molecular weight, molecular weight distribution and other properties is disclosed. Rapid flow characterization systems and methods, including liquid chromatography and flow-injection analysis systems and methods are preferably employed. High throughput, automated sampling systems and methods, high-temperature characterization systems and methods, and rapid, indirect calibration compositions and methods are also disclosed. The described methods, systems, and devices have primary applications in combinatorial polymer research and in industrial process control.

Abstract: A high-throughput liquid chromatography system capable of parallel separations for increased sample throughput is described. The system comprises valves allowing for the use of multiple liquid chromatography columns and a single injector and pumping system while also minimizing extraneous plumbing and hardware. The system is capable of injecting individual samples and directing them to one of a multiplicity of columns followed by selective output to a detector. The system described allows for up to 16 columns, but the number may vary according to the application. The system may be run in an isocratic or gradient mode. Whereas currently available multi-probe systems incorporate a separate injector for each column, the invention described here uses only one injector and is independent of column number. This removes injector variability along with reducing the amount of pluming and mechanical parts in the system allowing for better separations while providing a more robust system.

Abstract: A method for generating high purity acid or base in an aqueous stream for use as an eluent for chromatography and, particularly, ion chromatography. For generating a base for anion chromatography, the aqueous stream is directed through a cation exchange bed having a first strongly acidic and a second weakly acidic portions. An electrical potential is applied to the bed. Cations on the bed electromigrate into the aqueous stream while hydroxide ions are electrolytically generated to form a base-containing eluent. Anions to be detected and the generated eluent flow through a chromatographic separator. The chromatographic effluent flows past a detector.

Abstract: High pressure capillary liquid chromatography solvent delivery is effected at substantially low volume and atmospheric pressure. The low volume solvent composition is subsequently pressurized and expelled at high pressure into a receiving device such as a column. The solvent composition is expelled from a fluid metering system configured to deliver liquids at low pressures to a storage matrix via an isolation valve. The solvent composition is delivered to the storage matrix in reverse order such that the first volume of liquid delivered into the storage matrix is the last volume of liquid expelled out. Liquid pre-existing within the storage matrix is transferred into a fluid accumulator in fluid communication with the storage matrix. The fluid accumulator is enveloped in a pressure caisson which can be pressurized or depressurized in response to sensor signals obtained from a fluid volume displacement transducer and a pressure sensor, in accordance with solvent composition cycle formation.

Abstract: Apparatus and method for driving a sample, having a well-defined volume, under pressure into a chromatography column. A conventional high pressure sampling valve is replaced by a sample injector composed of a pair of injector components connected in series to a common junction. The injector components are containers of porous dielectric material constructed so as to provide for electroosmotic flow of a sample into the junction. At an appropriate time, a pressure pulse from a high pressure source, that can be an electrokinetic pump, connected to the common junction, drives a portion of the sample, whose size is determined by the dead volume of the common junction, into the chromatographic column for subsequent separation and analysis. The apparatus can be fabricated on a substrate for microanalytical applications.

Abstract: A fraction collecting device for a liquid chromatograph has a splitter disposed downstream to a chromatographic column and serving to split the flow from the column into two flow routes individually connected to a mass analyzer serving as a detector and a fraction collector. A plurality of pipes each having a different flow resistance and being connected in parallel with respect to one other are inserted in either of these two flow routes. A control unit serves to select one of these pipes according to inputted parameters indicating the conditions of liquid chromatography to be carried out and controls valves so as to connect this selected one of the pipes to the column through the splitter.

Abstract: A method and apparatus for measuring the viscosity of a sample solution which comprises an input tube for transporting a sample solution flow towards a splitter for diverting input flow into two distinct flow streams where three capillary tubes are located in the two flow streams placed downstream from the flow splitter, where each flow stream has one or two capillary tubes a delay volume, and a flow through transducer having hydraulic connections placed in one stream or in two streams used for measuring the pressure difference across the capillary tubes.

Abstract: The disclosed syringe pump and valve assembly utilizes a cylindrical housing having a piston axially moved therein for defining a pump chamber, where the housing is mounted to rotate about its longitudinal axis. A port seat is disposed concentrically of this axis spaced from one housing end, and a seal/valving member has one face seated slidably on the port seat and has its opposite face exposed to the pump chamber. Connectors serve to communicate separate liquid lines to separate respective ports on the port seat, which the seal/valving member first face overlies. The seal/valving member has through opening and/or radial or arcuate channels operable in different rotational member positions to selectively isolate or communicate the lines relative to one another and/or the pump chamber. The seal/valving member is designed to rotate in unison with the housing, and mechanism rotates the housing to locate the seal/valving member as required.

Abstract: A gas chromatograph with multiple valves is disclosed. An embodiment of the multi-valve gas chromatograph includes multiple valves and multiple thermal conductivity detectors (TCD's). This allows separation and measurement of a gas sample in one compact integrated unit. Other features may also be present. For example, a first heating zone may include a band heater placed around the multi-valve block to heat the carrier gas and to keep the multi-valve block at a desired temperature. A second heating zone may include a spool and a cartridge heater to heat the columns through which the gas sample flows. Two sets of screws, one through the top of the multi-valve and one through the bottom, may be included to simplify maintenance of the multi-valve system. Insulation defining an oven can be placed around the assembly to stabilize the temperature of the multi-valve assembly.

Abstract: The process is disclosed for transforming a liquid mixture sample in a pressurized container to a vapor phase sample of substantially the same concentration as in the liquid mixture which includes the combination of a coarse filter, a first orifice or pressure regulator device, a pressure cut-off switch or second pressure regulator, a coalescing filter, and a fitting for linking the device to an analytical device.

Abstract: Method and apparatus for generating an acid or base, e.g. for chromatographic analysis of anions. For generating a base the method includes the steps of providing a cation source in a cation source reservoir, flowing an aqueous liquid stream through a base generation chamber separated from the cation source reservoir by a barrier (e.g. a charged membrane) substantially preventing liquid flow while providing a cation transport bridge, applying an electric potential between an anode cation source reservoir and a cathode in the base generation chamber to electrolytically generate hydroxide ions therein and to cause cations in the cation source reservoir to electromigrate and to be transported across the barrier toward the cathode to combine with the transported cations to form cation hydroxide, and removing the cation hydroxide in an aqueous liquid stream as an effluent from the first base generation chamber. Suitable cation sources include a salt solution, a cation hydroxide solution or cation exchange resin.