Patent ID: 7383718

Claim:
A single stage flow modulator for performing comprehensive chromatography, comprising: a first chromatographic column; and 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 valve is isolated from the portion of the output of the first chromatographic column and from an input of the second chromatographic column and uses pressure to direct the control flow, wherein the portion of the output of the first chromatographic column directed to the second chromatographic column is directly transferred from the first chromatographic column to the second chromatographic column and is continuously modulated throughout a sample run to perform continuous heart cutting throughout the sample run resulting in each peak eluting from the first chromatographic column having at least some portion transferred to the second chromatographic column.