title: Microextraction in a tetrabutylammonium bromide/ammonium sulfate aqueous two-phase system and electrohydrodynamic generation of a micro-droplet.
abstract: Microextraction of methyl orange in the aqueous two-phase system (ATPS) formed by dissolving tetrabutylammonium bromide (TBAB) and ammonium sulfate (AS) is reported. Methyl orange was transported from the AS-rich phase to TBAB-rich phase across the interface of the two immiscible phases. The electrohydrodynamic effect on the shape of the interface of two immiscible flows was also observed by applying dc voltage at the T-junction of the microchannel and the generation of a droplet of AS-rich phase was observed when the potential difference between positive and negative electrodes exceeds a threshold voltage. The minimum voltage necessary for the droplet generation depends on pH due to the degree of dissociation and charge accumulation.
authors.affiliation: Department of Chemical and Biomolecular Engineering and Center for Ultramicrochemical Process Systems, Korea Advanced Institute of Science and Technology, Daejeon 305-701, South Korea.
authors.forename: Young Soo
authors.initials: YS
authors.lastname: Song
authors.forename: Young Hoon
authors.initials: YH
authors.lastname: Choi
authors.forename: Do Hyun
authors.initials: DH
authors.lastname: Kim
mesh_terms: D000645:Ammonium Sulfate / Q000737:chemistry*; D001391:Azo Compounds / Q000737:chemistry / Q000302:isolation & purification*; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D011092:Polyethylene Glycols / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D001391:Azo Compounds; D000644:Quaternary Ammonium Compounds; D014867:Water; D011092:Polyethylene Glycols; C100258:methyl orange; C009405:tetrabutylammonium; D000645:Ammonium Sulfate