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: 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: A process for determining the amount of argon contamination present in high purity oxygen employing a combination apparatus including a gas chromatography apparatus, a pressure swing adsorption apparatus, and a conduit connecting the two apparatus to each other. The gas chromatography apparatus can be run with its column at about 70.degree. F. (21.1.degree. C.) or higher. A sample of the high purity oxygen is fed to the pressure swing adsorption apparatus, where a portion of the oxygen is removed, and then the thus modified sample is fed through the conduit to the gas chromatography apparatus. Since some of the oxygen has been removed with the pressure swing adsorption apparatus, the graph generated by the gas chromatography apparatus shows 2 resolved peaks, namely a small argon peak preceding a large oxygen peak, even though the column of the gas chromatography apparatus is not being cooled to cryogenic temperatures with a cryogen.

Abstract: A device and method are described for the gas chromatographic separation of a sample, aimed in particular at the analysis of large volume samples. Provision is made for the use of calculating and memorizing a plurality of reference values corresponding to the evaporation rates of solvents combined with a carrier gas for a corresponding plurality of discrete values representing the conditions of pressure, temperature, injected sample volume and sample injection rate. The effective solvent evaporation rate is then calculated in correspondence to the effective conditions in which the process is carried out to determine the volumetric fraction of the sample which is transferred through the capillary column in relation to its characteristics and geometrical dimensions.

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: 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: A method for determining the efficiency of a carbon filter to absorb hydrocarbons from an organic amine solvent. After the solvent has passed through the filter, a sample is taken and passed through a standard gas chromatograph (GC) to measure the area counts for the hydrocarbons and the solvent. The sample does not have to have an internal standard added thereto nor does it have to be measured before it is run through the GC. The area counts are converted into actual amounts by using Reduction Factors taken from a specially-prepared calibration table. These amounts are normalized and added to give the total amount of hydrocarbons present in the solvent after it has passed through the carbon filter.

Abstract: A chromatograph system with improved automation is provided. In the chromatograph system of one embodiment, a regression line is set between retention times of predetermined peaks measured at each run in the past for a standard sample having known components. Referring to this regression line, the peak identifying condition, i.e., time window, is corrected. In another embodiment, there is provided a chromatograph apparatus having a function of estimating a limited life time of a system component. The analyzed results of the chromatograph system can thus be improved.

Abstract: Miniaturized planar column devices are described for use in liquid phase analysis, the devices comprising microstructures fabricated by laser ablation in a variety of novel support substrates. Devices formed according to the invention include associated laser-ablated features required for function, such as analyte detection means and fluid communication means. Miniaturized columns constructed under the invention find use in any analysis system performed on either small and/or macromolecular solutes in the liquid phase and may employ chromatographic, electrophoretic, electrochromatographic separation means, or any combination thereof.

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: A method for sampling and analyzing landfill gas, in which the landfill gas, which consists primarily of methane and contains volatile organic components, is passed through a quantity of liquid tetraglyme to cause the volatile organic components to be absorbed in the tetraglyme. The tetraglyme containing the absorbed volatile organic components, is then disposed in a sealed container with zero headspace and transported to a laboratory testing facility. At the testing facility, at least a portion of the tetraglyme is withdrawn from the container, dispersed in water, and subjected to a gas chromatography/mass spectrometry procedure to analyze the volatile organic components.

Abstract: A process for producing a resin for the chromatographic extraction of metal ions is provided, the process involving:treating an acidic bidentate organic phosphonate metal complexing agent with an alcohol or ketone solvent containing an aqueous alkaline solution, thereby forming the corresponding salt of the phosphonate compound;mixing the bidentate organic phosphonate salt with an absorbent resin in an alcohol or ketone solvent containing an aqueous alkaline solution, thereby absorbing the phosphonate salt in the resin;washing the resin containing bidentate complexing agent with an aqueous alcohol or ketone solution; anddrying the washed resin, wherein the process provides improved chromatographic extraction of metal ions.

Abstract: A frequency response of a pneumatic system used to control a gas chromatograph may be determined by applying a loop-closed direct method. The loop-closed direct method can be used to describe a frequency response of a time-invariant, linear system and predicting the system stability for any input signal. The transfer function which describes the frequency response is used by a microprocessor to control the physical parameters of the pneumatic system in terms of pressure and flow.

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: Composite articles are useful for separating mercury from fluids. The composite articles can be porous supports comprising an inert substrate having immobilized thereon finely divided gold optionally in combination with a tin salt coating. The porous support can be a particulate or porous fibrous webs. Alternatively, the composite articles can comprise a porous fibrous membrane having enmeshed therein the aforementioned porous supports which can be in particulate or fibrous forms. The method for separating elemental, ionic, or organic mercury in fluids comprises the step of contacting and passing a fluid containing mercury through a support comprising a porous, high surface area, inert substrate on which is immobilized finely divided elemental gold at a controlled rate for a time sufficient for the mercury to sorb to the elemental gold and to provide an immobilized gold-mercury amalgam on the support. If a tin salt also is immobilized on the inert substrate, mercury-tin salt can also be formed.

Abstract: Close coupled momentum separator with integral removable source volume for particle beam liquid chromatography/mass spectrometry is provided. The inventive PB LC/MS system comprises a momentum separator wherein the skimmers are designed to accommodate the particle beam conical dispersion so as to minimize the number of particles lost in the separator. In addition, the exit of the momentum separator is closely coupled to the entrance of the MS source volume. The PB LC/MS system demonstrates improved linearity in signal and enhanced sensitivity.

Abstract: The present invention relates to a chromatography analysis method and a system employing the same which are capable of automatically determining an constituents to be detected contained in the unknown sample based on results on measuring a standard sample. The standard sample is first separated to obtain its chromatogram. The system extracts the necessary information from the chromatogram to identify the peaks corresponding to the constituents to be detected to set widths of time windows for the peaks. Then, the time windows thus set are applied to the chromatograms obtained by the separation of the unknown sample to identify the constituents contained in the unknown sample. By employing the present invention, it is unnecessary for an operator to input the retention time of each constituent to the system.

Abstract: A separation process includes producing low temperature glassy carbon from an aromatic oligomeric precursor with acetylene groups and using the resultant glassy carbon as the stationary phase in a separation process. Glassy carbon with preselected selectivity and retention characteristics can be generated by controlling the temperature of which the glassy carbon is processed.

Abstract: Chromatographic system includes a split/splitless injection port operatively connected to an inlet line for receiving the regulated carrier gas flow, a separation column for receiving at least a portion of the mixture as a column flow, and a split vent line and a septum purge line for outputting respectively a split flow and a septum purge flow. A forward device driver operatively connected to a respective fluid controller controls fluid flow in the inlet line and a back device driver operatively connected to a respective fluid controller controls fluid pressure in the split line. A setpoint controller provides first and second setpoint control output values to a configuration module, which selectably configures the provision of each of the first and second setpoint control output values to a selected one of the forward and back device drivers according to the selection of a split or splitless injection mode.

Abstract: The invention is a method for modifying a known chromatographic method without changing peak elution order and with little or no change in resolution. Column and operational parameters of a known method are systematically translated to ensure that a new chromatographic method having possibly different column and operational parameters has a chromatographic output with similar separation.

Abstract: A gas chromatograph for operation selectably in both split mode and splitless wide bore injection mode includes a capillary column, a sample injection chamber at the inlet of the column, a three-way valve, a first piping line connected between one of the two outlets of the three-way valve and the sample injection chamber, a split line connected to the sample injection chamber immediately upstream of the inlet of the column for discharging therethrough a portion of a gas being sent out from the sample injection chamber, a second piping line connected between the other of the outlets of the three-way valve and the split line, and a third piping line connected between the first and second piping lines. By properly controlling the total carrier gas flow rate and the column inlet pressure, the split ratio can be controlled easily. By varying the split ratio appropriately during an analysis, the amount of the carrier gas to be wasted in the case of a split mode of operation can be significantly reduced.

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: Chromatographic separations and resolutions of racemic mixtures and diastereoisomers are enhanced by simultaneously employing an enantiomeric, chiral stationary phase (CSP) and an enantiomeric, chiral mobile phase additive (CMPA) bearing a stereoisomeric relationship to the CSP but having the opposite chirality are enhanced relative to the use of either a CSP or a CMPA alone. Specific CMPA compositions having the structural formulas ##STR1## are also disclosed.

Abstract: A method and device are disclosed for performing supercritical fluid chromatography in packed columns of at least about 0.5 mm inside diameter. The column provides at least 50,000, preferably at least 100,000, theoretical plates with pressure drop across the column of at least 25 bar. The outlet pressure is controlled by the back pressure regulator. The column may comprise a plurality of individual columns in series. Separation is performed at a rate of at least 25 plates/min, preferably at least 100 plates/min.

Abstract: Methods and apparatus for extracting sample components from complex matrices using supercritical fluid as the principal extracting solvent are disclosed. The invention takes advantage of the fact that the solvent power of a supercritical fluid is stepwise settable by the parameters of density, modifier concentration, and temperature. Accordingly, methods and apparatus for extracting a component from a sample using fluid flow system having a variable and controllable flow restriction are disclosed. The methods of the present invention comprise the steps of inserting the sample into the sample container section, inputting temperature, pressure, flow rate and extraction time set points. Flow rate is controlled and system pressure regulated by the variable flow restriction. The output stream from the extraction is then expanded through a nozzle and into a trap. In certain embodiments, the trap is filled with chemically active packing material.

Abstract: A system (method and apparatus) for optimizing the relationship between resolution and time in chromatograms, especially chromatograms obtained by supercritical fluids (CSF) chromatography. The pressure or temperature or fluid density of the solution caring the material under analysis is varied dynamically under computer control to provide an optimum capacity factor for a particular transporting fluid in a particular chromatographic system to obtain the resolution of interest in the shortest period of time.

Abstract: A chromatography column having a media supply and product/buffer inlet assembly positioned at the inlet of a dispersion section at the top of the column and an outlet assembly positioned at the collection section at the bottom of the column for receiving and discharging product components and buffer liquid and for discharging liquefied spent media. The media and product inlet assembly includes a housing having a product and buffer inlet passage including a selectively movable media supply nozzle extending through the housing. The nozzle may be positioned through the dispersion section into the column housing for spraying media in the form of a slurry into the column housing, and may be withdrawn after the media bed is packed. The collection section of the column includes a hollow rod extending through a discharge conduit through which spent media may flow. The rod has a probe at the upper end for entering into the column, a point at the end of the probe being adapted to puncture and chip spent hardened media.

Abstract: A chromatographic column, which has for a stationary phase a polysiloxane containing pendant cyano-substituted biphenyls, is selective in the chromatographic separation of organic compounds including polycyclic aromatic hydrocarbon isomers.

Abstract: A filter for preventing foam and debris from accumulation on the trap used in sample concentration apparatus is disclosed. The filter is preferably a sintered metal frit removably inserted in the concentrator inlet on a sparge vessel. The filter also serves as a check valve for preventing water vapor or residual analytes in the sparge vessel from contaminating dry gas or other external samples which pass through the concentrator inlet.

Abstract: An on-line multidimensional chromatographic system and method which couples a liquid chromatograph to a supercritical fluid chromatograph. The system includes an inlet column for depositing a fraction of interest eluting from the liquid chromatograph, an interface interposed between the inlet column and the supercritical fluid chromatograph for receiving and trapping an analyte from the deposited fraction on an impactor surface, and a valve arrangement for controlling fluid flow throughout the system. After the fraction of interest has been deposited in the inlet column, the liquid chromatograph solvent is removed from the inlet column, and then the deposited fraction is extracted from the inlet column in a supercritical fluid stream. The supercritical fluid stream is directed into the interface, where the analyte is trapped while the supercritical fluid is decompressed and vented.