Abstract: Certain embodiments described herein are directed to chromatography systems that include a microfluidic device. The microfluidic device can be fluidically coupled to a switching valve to provide for selective control of fluid flow in the chromatography system. In some examples, the microfluidic device may include a charging chamber, a bypass restrictor or other features that can provide for added control of the fluid flow in the system. Methods of using the devices and methods of calculating lengths and diameters to provide a desired flow rate are also described.

Abstract: Certain embodiments described herein are directed to chromatography systems that include a microfluidic device and that implement one or more methods to direct sample to a desired fluid flow path. The methods can be used to backflush a sample to a desired fluid flow path to select certain analytes within a sample.

Abstract: Certain embodiments described herein are directed to devices, systems and methods that are configured to control flow of an explosive carrier gas in a sampling system. In some examples, a flow control device configured to provide release of explosive carrier gas in less than an explosive amount to void space in the sampling system is described. Systems and methods using the flow control device are also disclosed.

Abstract: Certain embodiments described herein are directed to devices that can be used to control fluid flow through one or more detectors. In some configurations, the device can be configured as a manifold that can receive a positive pressure to decouple the flow of fluid through a chromatography column from fluid flow through a detector. In certain configurations, sample flow can be accelerated into a detector cell comprising one or more filaments.

Abstract: Certain embodiments described herein are directed to chromatography systems that include a microfluidic device configured to provide three-way switching or switching between three or more inputs or outputs. The microfluidic device can be fluidically coupled to one or more switching valves to provide for selective control of fluid flow in the chromatography system.

Abstract: Certain embodiments described herein are directed to devices, systems and methods that are configured to control flow of an explosive carrier gas in a sampling system. In some examples, a flow control device configured to provide release of explosive carrier gas in less than an explosive amount to void space in the sampling system is described. Systems and methods using the flow control device are also disclosed.

Abstract: Certain embodiments described herein are directed to chromatography systems that include a microfluidic device. The microfluidic device can be fluidically coupled to a switching valve to provide for selective control of fluid flow in the chromatography system. In some examples, the microfluidic device may include a charging chamber, a bypass restrictor or other features that can provide for added control of the fluid flow in the system. Methods of using the devices and methods of calculating lengths and diameters to provide a desired flow rate are also described.

Abstract: Certain embodiments described herein are directed to chromatography systems that include a microfluidic device configured to provide three-way switching or switching between three or more inputs or outputs. The microfluidic device can be fluidically coupled to one or more switching valves to provide for selective control of fluid flow in the chromatography system.

Abstract: Certain embodiments described herein are directed to chromatography systems that include a microfluidic device. The microfluidic device can be fluidically coupled to a switching valve to provide for selective control of fluid flow in the chromatography system. In some examples, the microfluidic device may include a charging chamber, a bypass restrictor or other features that can provide for added control of the fluid flow in the system. Methods of using the devices and methods of calculating lengths and diameters to provide a desired flow rate are also described.

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: Certain aspects and examples are directed to sorbent devices and methods of using them. In certain embodiments, a sorbent device comprising a body comprising a sampling inlet, a base and a longitudinal diffusion path between the inlet and the base is provided. In some embodiments, the sorbent device can include at least two sorbent materials fluidically coupled to the longitudinal diffusion path, in which the sorbent materials are arranged from a material with a weakest sorbent strength to a material with a strongest sorbent strength with the weakest sorbent strength material adjacent to the sampling inlet.

Abstract: Certain embodiments described herein are directed to chromatography systems that include a microfluidic device and that implement one or more methods to direct sample to a desired fluid flow path. The methods can be used to backflush a sample to a desired fluid flow path to select certain analytes within a sample.

Abstract: Certain embodiments described herein are directed to chromatography systems that include a microfluidic device. The microfluidic device can be fluidically coupled to a switching valve to provide for selective control of fluid flow in the chromatography system. In some examples, the microfluidic device may include a charging chamber, a bypass restrictor or other features that can provide for added control of the fluid flow in the system. Methods of using the devices and methods of calculating lengths and diameters to provide a desired flow rate are also described.

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: A flow control system, method and device for performing thermal desorption is provided. In one embodiment, the system includes a first flow path in which gas flows from a first carrier gas inlet, through a first vessel in a first direction at a first flow rate to adsorb analytes on an adsorbent of said first vessel; a second flow path in which gas flows from a second carrier gas inlet, through said first vessel in the first direction at a second flow rate to further adsorb the analytes on the adsorbent of said first vessel; a third flow path in which a carrier gas flows through said first vessel in a second direction to carry desorbed analytes out of said first vessel; and wherein the second flow rate of carrier gas through said first vessel is greater than the first flow rate of carrier gas through said first vessel.

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: Certain embodiments described herein are directed to chromatography systems that include a microfluidic device. The microfluidic device can be fluidically coupled to a switching valve to provide for selective control of fluid flow in the chromatography system. In some examples, the microfluidic device may include a charging chamber, a bypass restrictor or other features that can provide for added control of the fluid flow in the system. Methods of using the devices and methods of calculating lengths and diameters to provide a desired flow rate are also described.

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: 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: Certain embodiments described herein are directed to devices, systems and methods that are configured to control flow of an explosive carrier gas in a sampling system. In some examples, a flow control device configured to provide release of explosive carrier gas in less than an explosive amount to void space in the sampling system is described. Systems and methods using the flow control device are also disclosed.