title: Electrically heated, air-cooled thermal modulator and at-column heating for comprehensive two-dimensional gas chromatography.
abstract: An instrument for comprehensive two-dimensional gas chromatography (GCxGC) is described using an electrically heated and air-cooled thermal modulator requiring no cryogenic materials or compressed gas for modulator operation. In addition, at-column heating is used to eliminate the need for a convection oven and to greatly reduce the power requirements for column heating. The single-stage modulator is heated by current pulses from a dc power supply and cooled by a conventional two-stage refrigeration unit. The refrigeration unit, together with a heat exchanger and a recirculating pump, cools the modulator to about -30 degrees C. The modulator tube is silica-lined stainless steel with an internal film of dimethylpolysiloxane. The modulator tube is 0.18 mm i.d. x 8 cm in length. The modulator produces an injection plug width as small as 15 ms.
authors.affiliation: Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Libardoni
authors.forename: J Hunter
authors.initials: JH
authors.lastname: Waite
authors.forename: Richard
authors.initials: R
authors.lastname: Sacks