Abstract: A fluid modulator includes a fluid manifold, fluid valve, and pressure/flow controller. The manifold may include a primary tee, exhaust tee, secondary tee, loop conduit, and joining tube. The valve may include a common port, normally-open output port connected to the secondary tee, and normally-closed output port connected to the primary tee. The controller may be configured to provide auxiliary fluid to the common port. In embodiments, the primary tee, exhaust tee, and secondary tee are configured with the primary tee and secondary tee situated at ends of the fluid manifold and the exhaust tee disposed therebetween. In other embodiments, the exhaust tee, the primary tee, and the secondary tee are distributed in a linear fashion with the exhaust tee and secondary tee situated at ends of the fluid manifold and the primary tee disposed therebetween. An embodiment with a single, unitary 5-port fluid manifold is also disclosed.

Abstract: A single stage flow modulator for performing comprehensive chromatography comprises a first chromatographic column, a valve fluidically coupled to at least two fluid conduits, wherein when in a first position, the valve directs a control flow to direct an output of the first chromatographic column to a first detector, and wherein when in a second position, the valve directs a control flow to direct a portion of an output of the first chromatographic column to a second chromatographic column, wherein the portion of the output of the first chromatographic column directed to the second chromatographic column is continuously modulated throughout a sample run.

Abstract: A fluidic switching device is particularly for use in chromatography is described. The device allows a rapid switching between chromatographic columns; particularly, in gas chromatography.

Abstract: A fluidic switching device is particularly for use in chromatography is described. The device allows a rapid switching between chromatographic columns; particularly, in gas chromatography.

Abstract: A two-dimensional gas chromatograph with a primary column (14) and dual secondary columns (26, 28) is described. Flow rates in the primary column are less than those in the secondary columns due to an accumulation valve (16). Typically the ratio of second and third column flow capacities combined to primary column flow capacities between about 10 to 1 and 30 to 1. Volatile organic compounds are detected in environmental samples of air water, soil and in body fluids of animals and humans.

Abstract: A two-dimensional gas chromatograph with a primary column (14) and dual secondary columns (26, 28) is described. Flow rates in the primary column are less than those in the secondary columns due to an accumulation valve (16). Typically the ratio of second and third column flow capacities combined to primary column flow capacities between about 10 to 1 and 30 to 1. Volatile organic compounds are detected in environmental samples of air water, soil and in body fluids of animals and humans.