title: Silicon microfabricated column with microfabricated differential mobility spectrometer for GC analysis of volatile organic compounds.
abstract: A 3.0-m-long, 150-microm-wide, 240-microm-deep channel etched in a 3.2-cm-square silicon chip, covered with a Pyrex wafer, and coated with a dimethyl polysiloxane stationary phase is used for the GC separation of volatile organic compounds. The column, which generates approximately 5500 theoretical plates, is temperature-programmed in a conventional convection oven. The column is connected through a heated transfer line to a microfabricated differential mobility spectrometer. The spectrometer incorporates a 63Ni source for atmospheric-pressure chemical ionization of the analytes. Nitrogen or air transport gas (flow 300 cm(3)/min) drives the analyte ions through the cell. The spectrometer operates with an asymmetric radio frequency (RF) electric field between a pair of electrodes in the detector cell. During each radio frequency cycle, the ion mobility alternates between a high-field and a low-field value (differential mobility). Ions oscillate between the electrodes, and only ions with an appropriate differential mobility reach a pair of biased collectors at the downstream end of the cell. A compensation voltage applied to one of the RF electrodes is scanned to allow ions with different differential mobilities to pass through the cell without being annihilated at the RF electrodes. A unique feature of the device is that both positive and negative ions are detected from a single experiment. The combined microfabricated column and detector is evaluated for the analysis of volatile organic compounds with a variety of functionalities.
authors.affiliation: Department of Chemistry, University of Michigan, Ann Arbor, 48109, USA.
authors.forename: Gordon R
authors.initials: GR
authors.lastname: Lambertus
authors.forename: Cory S
authors.initials: CS
authors.lastname: Fix
authors.forename: Shaelah M
authors.initials: SM
authors.lastname: Reidy
authors.forename: Ranaan A
authors.initials: RA
authors.lastname: Miller
authors.forename: David
authors.initials: D
authors.lastname: Wheeler
authors.forename: Erkinjon
authors.initials: E
authors.lastname: Nazarov
authors.forename: Richard
authors.initials: R
authors.lastname: Sacks
mesh_terms: D002849:Chromatography, Gas / Q000295:instrumentation* / Q000379:methods*; D009930:Organic Chemicals / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D013696:Temperature; D014835:Volatilization
chemical_list: D009930:Organic Chemicals; D012825:Silicon