title: Rapid determination of complex mixtures by dual-column gas chromatography with a novel stationary phase combination and spectrometric detection.
abstract: Fast GC separations of a broad range of analytes are demonstrated using a capillary column coated with a novel immobilized ionic liquid (IIL) stationary phase. Both completely cross-linked and partially cross-linked columns were evaluated, yielding approximately 1600 and approximately 2000 theoretical plates per meter, respectively. Enhanced separation is demonstrated using a dual-column ensemble comprised of an IIL column, a commercially coated Rtx-1 column, and a pneumatic valve connecting the inlet to the junction point between the two columns. Enhanced separation of 20 components, with two sets of co-eluting peaks is shown in approximately 150 s, while sacrificing only a length of time equivalent to the sum of the stop flow pulses, or about 15.5 s. A novel application of a band trajectory model that shows band position as a function of analysis time as analytes move through the column ensemble is employed to determine pulse application times. The model predicts component retention times within a few seconds. Another method of selectivity enhancement of the IIL stationary phase-coated columns is demonstrated using a differential mobility spectrometer (DMS) that provides a second dimension separation based on ion mobility in a high-frequency electrical field. The DMS is able to separate all but one set of co-eluting components from the IIL column. The separation of 13 components found in the headspace above U.S. currency is demonstrated using the IIL column in a dual-column ensemble as well as with the DMS.
authors.affiliation: Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA. glambert@umich.edu
authors.forename: Gordon R
authors.initials: GR
authors.lastname: Lambertus
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Crank
authors.forename: Megan E
authors.initials: ME
authors.lastname: McGuigan
authors.forename: Shai
authors.initials: S
authors.lastname: Kendler
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Armstrong
authors.forename: Richard D
authors.initials: RD
authors.lastname: Sacks
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D008962:Models, Theoretical; D013057:Spectrum Analysis / Q000379:methods*