title: Electrokinetic trapping using titania nanoporous membranes fabricated using sol-gel chemistry on microfluidic devices.
abstract: We have developed a new method for analyte preconcentration on a microfluidic device using a porous membrane fabricated via sol-gel chemistry. These porous membranes were fabricated within the channels of glass microfluidic devices exploiting laminar flow to bring an alcoholic sol-gel precursor (titanium isopropoxide in 2-propanol) into contact with an alcohol-water solution at a channel cross intersection. These two streams reacted at the fluidic interface to form a porous titania membrane. The thickness of the membrane could be altered by changing the [H2O]. Analyte concentration was accomplished by applying a voltage across the titania membrane. The level of analyte enrichment was monitored, and enrichment factors of above 4000 in 400 s were obtained for 2,7-dichlorofluorescein.
authors.affiliation: Department of Chemistry, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Kurt W
authors.initials: KW
authors.lastname: Hoeman
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Lange
authors.forename: Gregory T
authors.initials: GT
authors.lastname: Roman
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Higgins
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Culbertson
mesh_terms: D004586:Electrophoresis / Q000295:instrumentation* / Q000379:methods*; D005452:Fluoresceins / Q000302:isolation & purification; D007477:Ions / Q000737:chemistry; D008567:Membranes, Artificial; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods*; D008856:Microscopy, Fluorescence; D044367:Phase Transition; D010710:Phosphates / Q000737:chemistry; D016062:Porosity; D015203:Reproducibility of Results; D014025:Titanium / Q000737:chemistry*
chemical_list: D005452:Fluoresceins; D007477:Ions; D008567:Membranes, Artificial; D010710:Phosphates; C009495:titanium dioxide; C037631:2',7'-dichlorofluorescein; D014025:Titanium; C018279:sodium phosphate