Abstract: A multiple parallel hand-held gas chromatograph (GC) system which includes several independent GCs. Each independent GC has its own injector, separation column, detector and oven and the GCs are mounted in a light weight hand-held assembly. Each GC operates independently and simultaneously. Because of different coatings in different separation columns, different retention times for the same gas will be measured. Thus, for a GC system with multiple parallel GCs, the system can measure, in a short period, different retention times and provide a cross-reference in the determination of the measured gas and to become a two-dimensional system for direct field use.

Abstract: The invention concerns a method and an apparatus for the direct injection of large volumes (>3 &mgr;l) of samples into the column in a gas chromatography analysis apparatus comprising an oven, a gas chromatography column lodged in the oven, a means for the direct transfer into the column of the sample and a source of carrier gas upstream the column, as well as a detector downstream the column. According to the invention two or more of the parameters: nature of the solvent injection rate flow-rate and/or pressure of the carrier gas temperature at least of an initial length of the column during the injection are correlated and/or controlled to achieve a control of the length of the zone wetted by the sample during its introduction.

Abstract: To enable the mass injection of a sample in a gas chromatography and prevent occurrence of residue or decomposition of a desired constituent during analysis. The invention calls for providing the injection port with a liner, connecting the column and the liner to a press-fit, evaporating the solvent introduced into the liner, and discharging the evaporated solvent from a discharge port formed at the upper part of the liner.

Abstract: A sample concentration device is provided in which a gaseous sample is concentrated by cooling a portion of a gas transfer line through which the sample is introduced into a detecting apparatus, such as a gas chromatograph or the like. The device is characterized by a cooling device for cooling a portion of the gas transfer line, which is housed in a constant temperature chamber, by spraying a coolant from a nozzle facing the portion of the gas transfer line, and by a gas flow device for creating a substantially dry gas flow through the nozzle to prevent the nozzle from becoming plugged with ice formed by freezing of moisture in the air inside the constant temperature chamber when the coolant spray is stopped. An outer jacket surrounding a portion of the gas transfer line which is subjected to cooling is also disclosed.

Abstract: The invention relates to a method and device for preparing samples for gas chromatography, the sample material being guided through a liquid chromatograph (1) by means of a solvent and being monitoring by means of a detector (2), and, on the basis of the detector (2) recognizing a chromatographic region of interest, the sample material of this region being removed from the stream of sample material leaving the liquid chromatograph (1) and being analyzed by gas chromatography. In this case, the stream of sample material leaving the liquid chromatograph (1) is guided through a flow-through cuvette (4), and the removal is carried out, until the end of the chromatographic region of interest, via a syringe (18) which, when the sample material of the region of interest reaches the flow-through cuvette (4), is introduced into the stream of sample material guided through the flow-through cuvette (4) and is drawn upwards at a predetermined ratio to the transport rate of the stream of sample material.

Abstract: Apparatus and method for periodic analysis of trace amounts of volatile organic compounds in a waste gas provide for feeding of a sample of a waste gas first to an organics concentrator which isolates the volatile organic compounds from the waste gas sample and prepares a concentrated sample for feed to a gas chromatograph. In normal operation, a waste gas is continuously sampled from the waste gas source to produce a continuous waste gas flow through a switching valve and out a vent. A portion of that waste gas flow is periodically diverted by the switching valve and routed to the organics concentrator. The switching valve also receives calibration samples containing known concentrations of the volatile organic compounds prepared in a gas blender. It periodically feeds the calibration samples to the organics concentrator and the gas chromatograph for calibration of the system.

Abstract: A chromatography sample module including a flow-through member having an inlet and an outlet, chromatography media within the flow-through member, and a sample carried on the media. The module can fit within a chromatography column, and a plurality of modules can be arranged in an array in a rack to facilitate processing of multiple samples.

Abstract: The invention relates to a method for applying samples to be analyzed by gas chromatography using a sampling tube, which has a section which contains the adsorbing agent and narrows essentially conically towards a bore which is free of adsorbing agent and has a reduced diameter, in such a manner that the flow rate of a gas which is guided through towards the narrowed section on the outlet side is at least approximately equal to the inlet-side flow rate, liquid or gaseous starting sample material being guided through the sampling tube towards the narrowed section, so that substances to be analyzed are adsorbed on the adsorbing agent, the sampling tube being flushed with drying gas, which is guided through the sampling tube in the same direction as the starting sample material, until the liquid phase, which is contained in the sampling tube, or the starting sample material is essentially removed, and the adsorbed sample being desorbed by means of a carrier gas which is introduced through the sampling tube from

Abstract: A sample inlet liner includes a novel matrix that serves to retain an injected sample. The preferred inert matrix is polytetrafluoroethylene (PTFE) that serves to retain an injected sample and is provided in lieu of a conventional packing material. The contemplated inert matrix may be selected from a range of configurations of PTFE so as to provide a supporting material capable of retaining an ample quantity of injected sample in the sample inlet liner. The contemplated matrix nonetheless provides a tortuous path for the retained quantity of injected sample so as to facilitate known injection techniques such as split/splitless injection and large volume injections.

Abstract: A novel chromatograph is provided. The chromatograph includes an analytical column which is a channel with a rectangular cross-section. Integrated with the chromatograph are a sample collection channel and a restriction channel. The column, sample collection channel, and restriction are all part of a single unitary microstructure. The microstructure is manufactured by irradiating and etching a material subject to synchronized x-ray radiation. The device will either be made of the actual etched material, or the etched material will be used as a mold or model to fabricate the chromatograph. A method of using the device is also disclosed.

Abstract: A tubular insert with a small internal volume is disposed inside the vaporization chamber at the inlet of a capillary column of a gas chromatograph such that the sample with a solvent injected into the vaporization chamber is carried by a carrier gas through the insert into the column. The internal volume of the insert is such that the retention time of the carrier gas through the insert is less than 4 seconds. A heater is controlled to maintain the temperature inside the vaporization chamber within a specified range above the boiling point of the solvent as the sample is injected into the vaporization chamber, and this temperature is subsequently raised to a final temperature above the boiling points of the components to be analyzed. The carrier gas pressure is temporarily increased for better efficiency as the sample is injected.

Abstract: The invention relates to a method for applying samples to be analyzed by gas chromatography using a sampling tube, which has a section which contains the adsorbing agent and narrows essentially conically towards a bore which is free of adsorbing agent and has a reduced diameter, in such a manner that the flow rate of a gas which is guided through towards the narrowed section on the outlet side is at least approximately equal to the inlet-side flow rate, liquid or gaseous starting sample material being guided through the sampling tube towards the narrowed section, so that substances to be analyzed are adsorbed on the adsorbing agent, the sampling tube being flushed with drying gas, which is guided through the sampling tube in the same direction as the starting sample material, until the liquid phase, which is contained in the sampling tube, or the starting sample material is essentially removed, and the adsorbed sample being desorbed by means of a carrier gas which is introduced through the sampling tube from

Abstract: A device for carrying out solid phase microextraction is a tubular member having one closed end and one open end with an extracting surface within said tubular member. The extracting surface can be an extracting phase coating extending over a zone within the tubular member. The tubular member has a heater that can be used for either or both drawing fluid carrier into the tubular member or assisting in desorbing analytes into an injector of an analysis instrument. The tubular member can also be mounted in a housing with an airtight cavity and a plunger. A method of operation of the device is also provided. Previously, samples were analyzed using liquid-liquid extraction or using cartridges. Both of these methods are relatively expensive and time consuming. Both of these methods also require the use of solvents which can be difficult and expensive to dispose of.

Abstract: Device for connecting a first duct of a very small diameter, such as for instance a needle or a capillary column, to a second duct, wherein the device comprises a receiving part and a sealing element, wherein the receiving part is provided with a duct bore in which the first duct is slidably receivable, wherein the receiving part is also provided with a sealing-element bore which intersects the duct bore and in which the sealing element is slidably received, wherein the sealing element is provided with a recess, wherein the sealing element is adapted to assume a sealing position in which the duct bore is sealed, and is adapted to assume a connecting position in which the two duct bore parts on either side of the sealing-element bore are in fluid connection with each other via the recess, wherein the sealing element is biased in the sealing position by a spring under spring action.

Abstract: A gas chromatograph includes a manifold having a plurality of gas conduits formed therein. A valve module includes a support, a first valve mounted to the support and having a plurality of ports, and a column coupled to the support and being in communication with a port in the first valve. The valve module is pluggably engagable with the manifold. A detector is coupled relative to the column to detect gasses expelled from the column.

Abstract: An apparatus and a method are described for forming a chemical modulation of a substance present in a fluid stream, which utilize a movable device, such as a movable heater, to induce changes in the retention of a chemical substance flowing through the modulator tube. The modulator tube has an inlet, a first portion in communication with the inlet, a second portion in communication with said first portion, and an outlet in communication with said second portion. The method involves causing a chemical modulation by moving retention alteration device relative to a modulator tube.

Abstract: A gas chromatograph includes a heating enclosure, an injection port extending through a wall of the enclosure, a capillary column within the heating enclosure and connected at a distal end thereof to a detector. The injection port is arranged to accept a carrier gas for gaseous components an analyte solution through the capillary column to the detector. An expansion chamber is located within the heating enclosure between the injection port and the capillary column. The expansion chamber is arranged such that it provides fluid communication between the injection port and the capillary column. First and second conduits are attached to the expansion chamber in fluid communication therewith. The first conduit is arranged to accept the carrier gas from outside the heating enclosure and the second conduit is arranged to vent excess vapor from the chamber to a point outside the heating enclosure.

Abstract: The invention relates to a method for the quantitative determination of deuterium in samples containing hydrogen, and to a reduction oven for reducing gaseous or liquid substances containing hydrogen, which may be coupled directly to an isotope ratio mass spectrometer (IRMS), thereby permitting an online-coupled, reliable deuterium determination which can be automatized.

Abstract: An injector for a gas chromatography system resistively heats an included cold trap by magnetically inducing a high-frequency current therethrough to inject absorbed analyte into a gas chromatography separation column. The injector includes a flow controller that is set initially to load analyte into the trap. A heater and a two-stage Peltier cooler are used to establish a sharp trough-shaped temperature gradient along the cold trap so that analyte loaded into the cold trap is absorbed only at a relatively cold "focussing" zone of the trap. Once the analyte is focussed, the flow controller is set to direct released analyte into the column. The magnetic-field generator includes a capacitor that is discharged to initiate cold-trap heating. An inverter converts the discharge to a 100,000 Hz waveform through a transformer primary coil. A magnetic core delivers the resulting alternating magnetic field through the cold trap.

Abstract: A gas chromatograph has a sample vaporization chamber connected to a column for vaporizing a liquid sample injected therein and introducing this vaporized liquid sample with a carrier gas into the column. There is also a flow rate control device for controlling the flow rate of the carrier gas either as it is being supplied into the vaporization chamber or as it is being discharged from the vaporization chamber through a discharge route other than the column for keeping the gas pressure approximately constant inside the vaporization chamber. A leakage detector detects a leakage of gas from the vaporization chamber on the basis of either a target value set for the flow rate control device or a monitored value of the flow rate. A warning device outputs a warning when a gas leakage is detected by the leakage detecting device.

Abstract: An apparatus and process for the continuous, near real-time monitoring of low-level concentrations of organic compounds in a liquid, and, more particularly, a water stream. A small liquid volume of flow from a liquid process stream containing organic compounds is diverted by an automated process to a heated vaporization capillary where the liquid volume is vaporized to a gas that flows to an automated gas chromatograph separation column to chromatographically separate the organic compounds. Organic compounds are detected and the information transmitted to a control system for use in process control. Concentrations of organic compounds less than one part per million are detected in less than one minute.

Abstract: Device for connecting a first duct of a very small diameter, such as for instance a needle or a capillary column, to a second duct, wherein the device comprises a receiving part and a sealing element, wherein the receiving part is provided with a duct bore in which the first duct is slidably receivable, wherein the receiving part is also provided with a sealing-element bore which intersects the duct bore and in which the sealing element is slidably received, wherein the sealing element is provided with a recess, wherein the sealing element is adapted to assume a sealing position in which the duct bore is sealed, and is adapted to assume a connecting position in which the two duct bore parts on either side of the sealing-element bore are in fluid connection with each other via the recess, wherein the sealing element is biased in the sealing position by a spring under spring action.

Abstract: An automatic sample injector for injecting a liquid sample into a vaporization chamber of a gas chromatograph includes a syringe, a plunger adapted to move inside the barrel of this syringe, a stepping motor having a plurality of magnetic poles for moving the plunger up and down inside the barrel, a power source for supplying excitation currents to these magnetic poles, switches for these magnetic poles, and a control unit for controlling the switches or the power source such that the excitation current to one of a pair of the magnetic poles corresponding to a rotary angular position is increased and the excitation current to the other of the pair is simultaneously decreased.

Abstract: A gas chromatography oven is endowed with a shutter for the influx of air from the outside and a pair of shutters for the controlled outflow of air from the oven, the shutters being positioned on the rear wall of the oven, near the corners of the rear wall. On the upper wall of the oven, at least one injector of the sample to be analyzed and at least one detector are lodged in a removable drawer.

Abstract: A device for performing sample acquisition and introduction of a selectable quantity of the acquired sample to associated device such as an analytical instrument.

Abstract: A gas flow distribution system accumulates a sample from a sample bearing carrier gas in a micro-accumulator, delivers it using a carrier gas to a gas chromatography column, and supplies a carrier gas to the gas chromatography column to facilitate separation of the sample into sample components and transport the sample components to a mass spectrometer for trace vapor detection and analysis or testing in real time. The system is made of inert components and configured to have low dead volume for improved performance and accuracy of detection. External valves are employed for easy management and balance of the flow in the system to minimize operation time and facilitate continuous accumulation, delivery, and testing of the sample. The delivery of the sample to the gas chromatography column using an electrically heated cold trap as the micro-accumulator can be performed extremely fast.

Abstract: A gas chromatograph includes a manifold having a plurality of gas conduits formed therein. A valve module includes a support, a first valve mounted to the support and having a plurality of ports, and a column coupled to the support and being in communication with a port in the first valve. The valve module is pluggably engagable with the manifold. A detector is coupled relative to the column to detect gasses expelled from the column.

Abstract: An analytical instrument includes a control system, including a computer and a pneumatic controller responsive to the computer, and a planar chromatographic assembly. The planar chromatographic assembly includes a planar pneumatic manifold, a heater/fan assembly for establishing a temperature-controlled zone, an insulating enclosure for confining the temperature-controlled zone to an oven cavity and certain zones of the planar pneumatic manifold, a separation column having inlet and outlet ends attached to couplers at selected internal fluid-bearing conduits in the pneumatic manifold and located closely adjacent the planar manifold and within the temperature-controlled zone, and one or more fluid-handling functional devices attached to the pneumatic manifold for fluid-tight communication with respective internal etched channels provided within in the planar pneumatic manifold.

Abstract: A gas chromatograph has a control unit which normally carries out a pressure control so as to keep the pressure inside the vaporization chamber at a specified target level while the flow rate of a carrier gas into the vaporization chamber is kept constant. When a liquid sample is injected to cause a sudden rise in the pressure, the normal pressure control is temporarily stopped, say, for keeping the split ratio unchanged. In order to keep unchanged the retention time for components being analyzed although the pressure inside the vaporization chamber rises, the target value for the pressure control is reduced for an appropriate length of time after the temporary stopping of pressure control is discontinued.

Abstract: A microtrap sample concentrator useful for concentrating a sample of purged gas containing analytes for delivery to an analytical instrument, including: a tube containing at least one sorbent material which retains or traps analytes; where greater than 30% of all trapped analytes are directly delivered to an analytical instrument at a desorption flow rate of one to three cc/min, without splitting or cryogenic focusing the trapped analytes; where delivery of the trapped analytes to the analytical instrument is achieved by passing the trapped analytes through a passage being selectively connectable between the microtrap and the analytical instrument, the passage connected to a vent; where the temperature of the passage is not lower than ambient room temperature; and where the passage is heated to a temperature sufficient to vaporize water in the passage and to expel the vaporized water out of the vent.

Abstract: To inject a liquid sample with large volume into a GC column of a gas chromatograph, its volatile portion is evaporated by heat, in a non-selective way, in a vaporization chamber, the vapors thus generated being fed to pre-column located upstream of the GC column and maintained at a lower temperature to that of the vaporization chamber, where such compounds are separated from the solvent vapors, which are unloaded into the atmosphere while the compounds to be analyzed are sent to the GC column.

Abstract: The invention relates to a method and a device to control the physical conditions of the solvent within a pre-column, in a gas chromatography analysis apparatus. To achieve desired and controlled conditions of recondensation in the pre-column with vaporization injectors or of vaporation with "on-column" injectors, the dew-point of the solvent in the pre-column is calculated and the factors which influence this dew-point are varied and/or the temperature of the pre-column is varied, in order to set such temperatures in a desired correlation.

Abstract: A method and apparatus for non-liquid solvent introduction of analyte into an analytical instrument and, more particularly, to a bonded liquid phase analyte trap with integral flow switching that may include a rapid solid-state heating and cooling device. The analyte trap includes a first wafer having a flow channel formed on its bottom side such that a second wafer attached to the bottom side of the first wafer encloses the flow channel and a stationary phase coating is chemically bonded to the walls of the flow channel to provide a mechanism for trapping analytes of interest.

Abstract: The invention concerns a device for automatically injecting substances solubilised or diluted in a solvent for a gaseous phase chromatographic analysis column (14), wherein it includes a concentration/calcination chamber (10), a vaporization chamber (12) in contact with the chromatographic column (14), a sample support (16) moving in the concentration/calcination chamber between a first position in which the sample is in the concentration/calcination chamber and a second position in which the sample is in the vaporization chamber, as well as a system (18) for scavenging the two chambers with a vector gas.

Abstract: In a gas chromatographic system that includes a column and an injector with a chamber, a carrier gas normally flows into the chamber at a constant rate, and a constant primary pressure is maintained at the column inlet. A sampling receptacle selectively communicates a sample vessel with a source of transfer gas or the chamber. The vessel is pressurized with the transfer gas to a starting pressure greater than the primary pressure. Analyte sample in transfer gas is then tranferred from the vessel to the chamber by the vessel pressure while the vessel pressure remains greater than the primary pressure. Carrier gas flow is discontinued during transfer, so that analyte sample transfers through the chamber into the column by the primary pressure linearly with time. Standby and venting states are provided.

Abstract: The invention relates to a gas chromatography transfer line, having a glass tube (12), a steel tube (13) enclosing this glass tube and a heating coil (17) enclosing the steel tube, in which a tube (15) made of a material with high thermal conductivity is arranged between the steel tube (13) and the heating coil (17), the tube (15) being provided with a series of bores (16) in the axial and in the circumferential direction and being soldered to the heating coil (17) and to the steel tube (13), the solder (20) filling the bores (16) and intermediate spaces between the steel tube (13) and the tube (15).

Abstract: The present invention describes a fixed volume, vertical flow chromatographic column. The column comprises a column member having an inner chamber for containing the particulate sorbent in a space surrounded by sidewalls and two flat frits, one on the top and one on the bottom. The sidewall has at least one dedicated packing port formed therein through which the sorbent may be packed into and unpacked from the column member. Upon the completion of the packing process, a plug is placed into the packing port flush with the inside surface of the sidewall. The frits are covered and supported by two lids. The lids have plumbing ports formed therein through which a liquid sample enters and exits the column member. The plumbing posts are horizontal disposed on opposite sides of the lids so that the flow of liquid sample is the same.

Abstract: To avoid deposits on the restrictor that channels extractant into a collector, a heated capillary tube pressure release restrictor, has a thermally insulated outlet end in a collecting trap substantially colder than the capillary tube. The restrictor is heated between the insulation and the capillary tube by Joulean heating. The solvent in the trap is at a pressure of 5 to 200 psi above atmospheric pressure. The thermal resistance of the insulation is selected to reduce the heat added to the extractant to a minimum and yet cause the temperature of the extractant to be in a range within which it is sufficiently hot so it does not freeze when added to the collection solvent but not so hot as to reduce partitioning of the extract and extractant before the extractant leaves the collection solvent. It has a thermal conductivity no greater than 60 BTU's per hour, per square foot, per inch for a one degree Fahrenheit difference.

Abstract: Gas chromatographs are disclosed that may be constructed to be portable, light, rugged, fast, sensitive, and to use only utilities (compressed gas and electricity) that are readily available in the field. The gas chromatographs can also perform novel extractions of analytes from gaseous, liquid, or solid samples. The chromatographs can be truly portable; they can operate with approximately 100 watts of power (at peak power consumption); and they are extremely fast. The chromatographs are not limited just to portable applications, but will also find many uses within laboratories, because they require minimal laboratory bench or other space, because they can operate at high speed, and because they can operate with minimal consumption of utilities (compressed gases, air conditioning, etc.).

Abstract: The invention relates to a thermal desorption device for a gas chromatograph, having a thermostatically controlled oven (1) provided with a carrier gas connection and having an evaporator tube. In this case, the evaporator tube is an interchangeable sample holder tube (5) which can be held by a holding chamber (2) in the oven (1), which sample holder tube can be fitted into a holder piece (6) with one end externally sealed by a seal (8), the holder piece (6) having two seals (9) arranged separated in the region of its casing and being capable of being fitted into a correspondingly designed holder (10), the carrier gas connection (14) opening in the region (12) of an annular gap (13) between the holder (10) and the holder piece (6) between the two seals (9) located on the casing, which annular gap (13) is, for its part, connected to an annular gap (15) surrounding the inserted end of the sample holder tube (5), a trap (18) being connected downstream.

Abstract: A water management system removes water vapor from the analyte slug that is desorbed from the trap. The water management system includes a device having a passage through which the volatile organic chemicals and water pass, the passage being designed to remove water vapor by swirling action on the stream. The amount of water removed is more than can be accounted for by simple condensation. The invention also includes the adjustment of the temperature of the water management device during the sample concentration cycle to prevent undesired condensation prior to desorption.

Abstract: Methods and apparatus for extracting an analyte from a sample using a field-portable extraction instrument. The preferred embodiment of the extraction instrument includes an extraction fluid source, a sample container, a valve element, a nozzle, and a collection trap vessel. The methods of the present invention include the steps of inserting the sample into the sample container, attaching the sample container to the instrument, and providing a quantity of pressurized extraction fluid from the pressurized extraction fluid source into the sample container to initiate the extraction process. Extraction is facilitated by directing the extraction fluid into the sample at a rapid flow rate such that the sample and extraction fluid are vigorously mixed and a sample/solvent mixture is created. The valve element is then operated to isolate the extraction fluid source and to fully close the sample container.

Abstract: A gas chromatograph system including a cold trap having two portions, a capillary tube and a porous layer open tubular (PLOT) column, for substantially simultaneously trapping lower and higher boiling point gasses. The capillary tube enables cold trapping of lower boiling point gasses while the PLOT column enables cold trapping of higher boiling point gasses. The capillary tube interconnects at one end to an analytical column and a sample gas source and interconnects at its other end to a first end of the PLOT column. The other end of the PLOT column interconnects to a carrier gas source and a vacuum source. The capillary tube and PLOT column are both positioned within a temperature controlled environment of the cold trap. During the collection mode, the temperature control device maintains a relatively low temperature to condense the sample components.

Abstract: A gas chromatographic system includes a column and an injector for delivering into the column a test portion of flow. The injector has an exit passage for discharging a split portion of carrier flow. A flow controller for regulating the inlet flow rate includes a variable outlet restrictor for the split portion, a flow rate detector disposed to detect inlet flow rate, and a feedback flow controller to regulate the outlet restrictor to maintain the inlet flow rate substantially constant. Pressure at the inlet to the injector is regulated by detecting pressure at an outlet and providing feedback control to an inlet restrictor. An integral module for the gas components is used on each side of the injector. Calibration and correction for gas characteristics are provided in the feedback for a chromatographic system and for other flow controller regulation.

Abstract: A cap assembly for a gas chromatography injection port includes a two-piece septum. The two-piece septum includes a syringe seal for sealing an injection needle and a duckbill seal for sealing the injection port when the needle is not inserted. The syringe seal includes three annular ribs in its aperture. At the aperture base is a sealing rib that provides the main sealing function for the syringe seal. Just above the sealing rib is a stress-relief rib. At the top of the aperture is a wiping rib. The wiping rib wipes dust on the needle exterior so that it does not enter the aperture. Dust entering the aperture can be retained in the relatively large dust pocket between the wiping rib and the strain-relief rib. The septum is held in place by a septum nut that has a recess above the wiping rib for holding dust removed from the needle by the wiping rib. A washer in the recess prevents the syringe seal from deforming into the recess.

Abstract: Gas chromatography systems which provide for high speed separation of polar compounds of interest from samples which also include non-polar compounds. Efficient separation is achieved through the use of a tandem series connected combination of analytical columns, one of which having a polar stationary phase material and another having a non-polar stationary phase material. In two embodiments of the invention the order of the analytical columns is reversed. Fluid flow conduits, valves and vents are provided in a manner which eliminates mechanical valves in a sample stream.

Abstract: A multidimensional gas chromatograph (GC) system having wide bore capillary and narrow bore capillary GC columns in series and having a novel system interface. Heart cuts from a high flow rate sample, separated by a wide bore GC column, are collected and directed to a narrow bore GC column with carrier gas injected at a lower flow compatible with a mass spectrometer. A bimodal six-way valve is connected with the wide bore GC column outlet and a bimodal four-way valve is connected with the narrow bore GC column inlet. A trapping and retaining circuit with a cold trap is connected with the six-way valve and a transfer circuit interconnects the two valves.

Abstract: A supercritical fluid extraction system and method for extracting a sample from a matrix by use of supercritical fluid and collecting components of the matrix in a solid phase extraction collection column. This system includes a variable restriction valve for depressurizing the fluid with entrained sample and an integral adapter directly connected at a first end with the valve and directly sealingly engaging the collector column and having a second end for passage of the depressurized fluid and sample with matrix components into the collector column.

Abstract: A water management system removes water vapor from the analyte slug that is desorbed from the trap. The water management system includes a device having a passage through which the volatile organic chemicals and water pass, the passage being designed to remove water vapor by swirling action on the stream. The amount of water removed is more than can be accounted for by simple condensation. The invention also includes the adjustment of the temperature of the water management device during the sample concentration cycle to prevent undesired condensation prior to desorption.

Abstract: An apparatus for sample concentration for gas chromatography and mass spectrometry for analysis for volatile organic compounds, including a hollow differential pressure switch to switch sample flow non-mechanically, and so that the gas chromatograph and apparatus may be used with different sample levels of volatile organic compounds by changing the timing and temperature parameters by changing the flow non-mechanically.