title: Axial thermal gradients in microchip gas chromatography.
abstract: Fabrication technologies for microelectromechanical systems (MEMS) allow miniaturization of conventional benchtop gas chromatography (GC) to portable, palm-sized microfabricated GC (μGC) devices, which are suitable for on-site chemical analysis and remote sensing. The separation performance of μGC systems, however, has not been on par with conventional GC. Column efficiency, peak symmetry and resolution are often compromised by column defects and non-ideal injections. The relatively low performance of μGC devices has impeded their further commercialization and broader application. In this work, the separation performance of μGC columns was improved by incorporating thermal gradient gas chromatography (TGGC). The analysis time was ∼20% shorter for TGGC separations compared to conventional temperature-programmed GC (TPGC) when a wide sample band was introduced into the column. Up to 50% reduction in peak tailing was observed for polar analytes, which improved their resolution. The signal-to-noise ratios (S/N) of late-eluting peaks were increased by 3-4 fold. The unique focusing effect of TGGC overcomes many of the previous shortcomings inherent in μGC analyses.
authors.affiliation: Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, United States.
authors.forename: Anzi
authors.initials: A
authors.lastname: Wang
authors.affiliation: Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT 84602, United States.
authors.forename: Sampo
authors.initials: S
authors.lastname: Hynynen
authors.affiliation: Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT 84602, United States.
authors.forename: Aaron R
authors.initials: AR
authors.lastname: Hawkins
authors.affiliation: Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, United States; Department of Statistics, Brigham Young University, Provo, UT 84602, United States.
authors.forename: Samuel E
authors.initials: SE
authors.lastname: Tolley
authors.affiliation: Department of Statistics, Brigham Young University, Provo, UT 84602, United States.
authors.forename: H Dennis
authors.initials: HD
authors.lastname: Tolley
authors.affiliation: Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, United States. Electronic address: milton_lee@byu.edu.
authors.forename: Milton L
authors.initials: ML
authors.lastname: Lee
mesh_terms: D002849:Chromatography, Gas / Q000295:instrumentation* / Q000379:methods*; D055617:Micro-Electrical-Mechanical Systems; D055616:Microtechnology; D059629:Signal-To-Noise Ratio; D013696:Temperature
keywords: Gas chromatography; Microfabrication; Peak focusing; Resolution; Thermal gradient