title: Sample filtration, concentration, and separation integrated on microfluidic devices.
abstract: Microfabricated devices integrating sample filtration, solid-phase extraction, and chromatographic separation with solvent programming were demonstrated. Filtering of the sample was accomplished at the sample inlet with an array of seven channels each 1 microm deep and 18 microm wide. Sample concentration and separation were performed on channels 5 microm deep and 25 microm wide coated with a C18 phase, and elution was achieved under isocratic, step, or linear gradient conditions. For the solid-phase extraction, signal enhancement factors of 400 over a standard injection of 1.0 s were observed for a 320-s injection. Four polycyclic aromatic compounds were resolved by open channel electrochromatography in under 50 s. Chip operation was unaffected by the presence of the 5-microm silica particles at the filter entrance.
authors.affiliation: Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6142, USA.
authors.forename: B Scott
authors.initials: BS
authors.lastname: Broyles
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Jacobson
authors.forename: J Michael
authors.initials: JM
authors.lastname: Ramsey