Abstract: A method for analyzing multiple analyte specimens using an analytical column containing a selective adsorbent media. A carrier fluid flows through the column. The method involves introducing a first analyte specimen into the analytical column at an initial temperature. The analytical column is then heated to an intermediate temperature to cause the first analyte specimen to partially travel into the column. The analytical column is then cooled back to the initial temperature, followed by introduction of a second analyte specimen into the analytical column. The analytical column is then heated to a final temperature greater than the intermediate temperature, during which heating analytes from the first and second analyte specimen concurrently and discretely travels through, and sequentially elutes from, the analytical column. The method results in discrete bands of analyte being loaded at spaced intervals within the column, and can be used to load a multiplicity of samples for concurrent analysis.

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: 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.

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: The invention is an apparatus and method for preparing volatiles collected from a sample for gas chromatographic analysis. Volatiles are collected from the sample in a volatile trap, such as a porous polymer trap. The volatile trap is then connected to a transfer line. The trap is heated to thermally desorb the volatiles, and an inert gas, such as helium, flows through the heated trap to transport volatiles through the transfer line into a capillary column located in a gas chromatograph oven. Inside of the oven, a portion of the capillary column is cooled with a cooling fluid such as liquid nitrogen to form a cold trap. When the cold trap is cooled, the desorbed volatiles are trapped in the cold trap. Then the cold trap is heated to allow the volatiles to be released and the volatiles are carried to the remainder of the capillary column for chromatographic analysis by an inert carrier gas.

Abstract: An on-line multidimensional system which includes a liquid chromatograph having an on-line connection to a pyrolysis probe, which in turn has on-line connection to a gas chromatograph. Preferred applications use a size-exclusion chromatograph coupled to a pyrolysis probe coupled to a gas chromatograph to simultaneously produce composition as a function of molecular weight/size information for polymeric materials.

Abstract: An injector with a vaporization chamber for gas chromatographic apparatus includes a heater to heat the chamber and a pierceable septum to seal an end of the chamber. At least a heat conducting element is removably mounted between the septum and the heater. One or more elements are positioned adjacent to the septum and are in fluid communication with a source of carrier gas and a discharge outlet. The elements define paths with forced run for washing the septum and for feeding the vaporization chamber.

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: Apparatus and methods are provided for using a detector designed for use with liquids to detect resolved analytes in an effluent stream from a gas chromatography instrument. The gaseous stream is entrained by a flowing liquid solvent, and at least a portion of the analytes are transferred from the gas phase to the liquid phase. The liquid solvent containing the analytes is then conveyed to a detector designed for liquid analysis. Thus, the present invention gives the analyst more options for detecting an analyte or a group of analytes, thereby providing greater flexibility in optimizing the sensitivity or selectivity of the analysis. Furthermore, the present invention allows gaseous effluents to be analyzed by detectors which more readily permit sample recovery than the detectors currently being used to analyze gaseous effluents.

Abstract: Apparatus and method for on-line coupled liquid chromatography and gas chromatography analysis. The system includes a high-volume, liquid vaporizing chamber, or interface capillary tube which allows injection of a substantial volume of sample-carrying eluent and concentrates bands, obviating adverse effects on the resolution or peak shape of the components of interest. The vaporizing chamber is interposed between a packed or wall-coated open tubular capillary liquid chromatographic column and a capillary gas chromatographic column. The capillary liquid chromatographic column permits the use of small volumes of eluent and reduced flow rates.