Abstract: A method of measuring the effective temperature inside a sealed container having a headspace is provided. A liquid solvent is added to the container, and a solid compound is added to the liquid solvent to create a saturated solution. Vapor of the saturated solution is allowed to equilibrate in the headspace of the sealed container, and a volume thereof is transferred to a chromatographic column, where chromatographic readings of the equilibrated vapor are taken. A temperature within the sealed container is then calculated based upon the chromatographic readings of the equilibrated vapor, wherein the temperature calculation is based upon the concentrations of the liquid solvent and the solid compound in the equilibrated vapor.

Abstract: Disclosed are systems and methods that include providing a vessel having an inlet and an outlet for communicating a carrier gas through the vessel; determining a differential pressure between the inlet and the outlet for a known flow rate at the outlet; and, determining a unit flow per unit pressure based on a ratio of the flow rate and the differential pressure. In certain embodiments, the flow rate at the outlet is established by controlling the flow rate of the gas. In some embodiments, the methods and systems can include a viscosity in the ratio, determining a flow rate at ambient pressure using a factor based on a ratio of a gas pressure at the output and ambient pressure, and/or, determining a flow rate at ambient temperature using a factor based on a ratio of a temperature at the output and ambient temperature.

Abstract: A gas chromatography system comprising a sample introduction device, an oven coupled to the sample introduction device and a detector coupled to the oven is disclosed. In certain examples, the oven may be configured to receive a chromatography column in a space in the oven. In some examples, the oven may be constructed and arranged to provide a substantially constant temperature to the space during an analysis stage of the gas chromatography system.

Abstract: An analyte pre-concentrator for gas chromatography is disclosed generally comprising a tube packed with an adsorbent, wherein the tube may serve as the liner of a chromatographic injector, as an adsorbent trap coupled to a chromatographic column, and/or as an adsorbent trap coupled to a headspace sampler. Preferably, a heating device allows the tube to be heated. In a preferred embodiment, the analyte pre-concentrator further comprises a column isolating accessory so that a chromatographic column can be temporarily isolated from substances flowing through the tube.

Abstract: Disclosed are systems and methods that include a thermal desorption unit, a chromatographic column, and an interface device between the unit and the column. The interface device controls the fluid flowing into the column, such as by providing additional carrier gas to maintain a substantially constant gas flow or velocity, by proving a controlled temperature increase, or by venting a portion of the gas received from the thermal desorption unit, thereby removing the dependence on the thermal desorption unit for such control. In some embodiments, the interface is a chromatographic injector. In certain embodiments, a transfer line from the desorption unit is coupled to the same port of the interface device as the chromatographic column. In some of these embodiments, this is accomplished by employing a special adaptor.

Abstract: Disclosed are systems and methods that include providing a vessel having an inlet and an outlet for communicating a carrier gas through the vessel; determining a differential pressure between the inlet and the outlet for a known flow rate at the outlet; and, determining a unit flow per unit pressure based on a ratio of the flow rate and the differential pressure. In certain embodiments, the flow rate at the outlet is established by controlling the flow rate of the gas. In some embodiments, the methods and systems can include a viscosity in the ratio, determining a flow rate at ambient pressure using a factor based on a ratio of a gas pressure at the output and ambient pressure, and/or, determining a flow rate at ambient temperature using a factor based on a ratio of a temperature at the output and ambient temperature.

Abstract: An analyte pre-concentrator for gas chromatography is disclosed generally comprising a tube having a restricted outlet and packed with an adsorbent, wherein the tube serves as the liner of a chromatographic injector, as an adsorbent trap coupled to a chromatographic column, and/or as an adsorbent trap coupled to a headspace sampler. Preferably, a heating device allows the tube to be heated. In a preferred embodiment, the analyte pre-concentrator further comprises a column isolating accessory so that a chromatographic column can be temporarily isolated from substances flowing through the tube.

Abstract: Disclosed are systems and methods that include a sampling device, a chromatographic column, and a transfer line through which a fluid containing analytes to be measured are communicated from the sampling device to the column. The pressure at which the fluid containing the analytes is applied at the inlet of the transfer line is adjusted as the temperature of the column increases in accordance with certain relationships in order to maintain a substantially constant flow rate or velocity for the fluid exiting the column. In this way, the system compensates for changes in the viscosity of the fluid flowing through the column that result from changes in the column temperature.

Abstract: Disclosed are systems and methods that include a thermal desorption unit, a chromatographic column, and an interface device between the unit and the column. The interface device controls the fluid flowing into the column, such as by providing additional carrier gas to maintain a substantially constant gas flow or velocity, by proving a controlled temperature increase, or by venting a portion of the gas received from the thermal desorption unit, thereby removing the dependence on the thermal desorption unit for such control. In some embodiments, the interface is a chromatographic injector. In certain embodiments, a transfer line from the desorption unit is coupled to the same port of the interface device as the chromatographic column. In some of these embodiments, this is accomplished by employing a special adaptor.

Abstract: Disclosed are systems and methods that include providing a vessel having an adsorbent disposed therein, the vessel having an inlet and an outlet for communicating a carrier gas through the vessel; determining a differential pressure between the inlet and the outlet for a known flow rate at the outlet; and, determining a geometric measure for the vessel based on a ratio of the known flow rate and the differential pressure. In some embodiments, the methods and systems can include a viscosity in the ratio, determining a flow rate at ambient pressure using a factor based on a ratio of a gas pressure at the output and ambient pressure, and/or, determining a flow rate at ambient temperature using a factor based on a ratio of a temperature at the output and ambient temperature.

Abstract: The invention includes a method and apparatus for a chromatography system having a chromatographic column for separating gases in a mixture from one another and an electrochemical gas sensor coupled to the chromatographic column for detecting a gas being emitted from the column. The electrochemical gas sensor further includes a substrate having a surface for depositing electrodes thereon, an ionomer membrane in contact with the surface, an electrode in contact with the surface, and an opening in the ionomer membrane in a location proximate to the electrode for permitting a gas to diffuse through the opening to simultaneously contact the electrode and the ionomer membrane within the opening.

Abstract: Disclosed are systems and methods that include a sampling device, a chromatographic column, and a transfer line through which a fluid containing analytes to be measured are communicated from the sampling device to the column. The pressure at which the fluid containing the analytes is applied at the inlet of the transfer line is adjusted as the temperature of the column increases in accordance with certain relationships in order to maintain a substantially constant flow rate or velocity for the fluid exiting the column. In this way, the system compensates for changes in the viscosity of the fluid flowing through the column that result from changes in the column temperature.

Abstract: Disclosed are systems and methods that include providing a vessel having an adsorbent disposed therein, the vessel having an inlet and an outlet for communicating a carrier gas through the vessel; determining a differential pressure between the inlet and the outlet for a known flow rate at the outlet; and, determining a geometric measure for the vessel based on a ratio of the known flow rate and the differential pressure. In some embodiments, the methods and systems can include a viscosity in the ratio, determining a flow rate at ambient pressure using a factor based on a ratio of a gas pressure at the output and ambient pressure, and/or, determining a flow rate at ambient temperature using a factor based on a ratio of a temperature at the output and ambient temperature.

Abstract: Disclosed are systems and methods that include providing a vessel having an adsorbent disposed therein, the vessel having an inlet and an outlet for communicating a carrier gas through the vessel; determining a differential pressure between the inlet and the outlet for a known flow rate at the outlet; and, determining a geometric measure for the vessel based on a ratio of the known flow rate and the differential pressure. In some embodiments, the methods and systems can include a viscosity in the ratio, determining a flow rate at ambient pressure using a factor based on a ratio of a gas pressure at the output and ambient pressure, and/or, determining a flow rate at ambient temperature using a factor based on a ratio of a temperature at the output and ambient temperature.

Abstract: Systems and methods for cooling a chromatographic column is disclosed generally, comprising heating a chromatographic column, supplying fluid into the column via the inlet end of the column at an inlet pressure, decreasing the temperature of the column, thereby causing the fluid in the column to contract, and controlling the fluid in the column such that the rate at which the fluid in the column contracts does not exceed the flow rate of the fluid supplied to the column. In certain embodiments, the rate of change of the volume of the fluid in the column as the column temperature decreases is modeled, and the rate of contraction of the gas in the column is estimated therefrom. In some embodiments, the column temperature and/or inlet pressure are controlled by a programmable chromatographic oven.

Abstract: A method for introducing standard gas into a sample vessel is generally disclosed comprising providing a vessel containing a sample gas and a receptacle with a vessel port, such as sampling needle, pressurizing the vessel with a carrier gas, and introducing a volume of standard gas into the flow path of the carrier gas being used to pressurize the vessel when the vessel port of the receptacle is located within the vessel. In some embodiments, a rotary valve is loaded with the standard gas, and the valve is brought into fluid communication with the flow path of the carrier gas when the vessel port is within the vessel.

Abstract: A system for controlling the flow rate into a chromatographic column is disclosed generally comprising communicating a fluid to the column through a transfer line, measuring the transfer line inlet pressure, determining the transfer line outlet pressure, and adjusting the applied pressure until the inlet and outlet pressures produce a desired flow rate for the transfer line outlet. In certain embodiments, the applied pressure is adjusted by controlling a proportional valve. In some embodiments, the outlet pressure is determined by measuring the pressure difference across the transfer line and calculating the transfer line outlet pressure from the measured inlet pressure and the pressure difference.

Abstract: A system for pre-concentrating analytes in a sample prior to introduction into a chromatographic column is generally disclosed comprising a housing, an adsorbent disposed in the housing, and first and second conduits having an inlet and an outlet, respectively, for transferring fluid out of and into the housing during adsorption/dry purge and desorption stages, respectively. In some embodiments, the inlet of the first conduit and the outlet of the second conduit are both disposed in one end of the housing and are offset from each other with respect to the adsorbent.

Abstract: Disclosed are systems and methods that include providing a vessel having an adsorbent disposed therein, the vessel having an inlet and an outlet for communicating a carrier gas through the vessel; determining a differential pressure between the inlet and the outlet for a known flow rate at the outlet; and, determining a geometric measure for the vessel based on a ratio of the known flow rate and the differential pressure. In some embodiments, the methods and systems can include a viscosity in the ratio, determining a flow rate at ambient pressure using a factor based on a ratio of a gas pressure at the output and ambient pressure, and/or, determining a flow rate at ambient temperature using a factor based on a ratio of a temperature at the output and ambient temperature.

Abstract: A system for interfacing a sampling device and a chromatograph and for pre-concentrating analytes in a sample prior to introducing the sample into the chromatographic column is generally disclosed comprising an interface housing with a first channel and an adsorbent housing with a second channel, which contains at least one adsorbent. Valveless conduits permit fluid to be communicated between the sampling device and the first channel, between the first channel and the second channel, and the first channel and the column. In some embodiments, fluid flows in one direction when the analytes are adsorbed and in the opposite direction when analytes are desorbed. In certain embodiments, two different adsorbents are disposed in the second channel to adsorb different types of analytes.