Improved Thermal Modulator for Gas Chromatography

An improved thermal modulator has been invented for use in a variant of gas chromatography (GC). The variant in question — denoted as two-dimensional gas chromatography (2DGC) or GC-GC — involves the use of three series-connected chromatographic columns, in the form of capillary tubes coated interiorly with suitable stationary phases (compounds for which different analytes exhibit different degrees of affinity). The two end columns are relatively long and are used as standard GC columns. The thermal modulator includes the middle column, which is relatively short and is not used as a standard GC column: instead, its temperature is modulated to affect timed adsorption and desorption of analyte gases between the two end columns in accordance with a 2DGC protocol.