title: Molar mass fractionation in aqueous two-phase polymer solutions of dextran and poly(ethylene glycol).
abstract: Dextran and poly(ethylene glycol) (PEG) in phase separated aqueous two-phase systems (ATPSs) of these two polymers, with a broad molar mass distribution for dextran and a narrow molar mass distribution for PEG, were separated and quantified by gel permeation chromatography (GPC). Tie lines constructed by GPC method are in excellent agreement with those established by the previously reported approach based on density measurements of the phases. The fractionation of dextran during phase separation of ATPS leads to the redistribution of dextran of different chain lengths between the two phases. The degree of fractionation for dextran decays exponentially as a function of chain length. The average separation parameters, for both dextran and PEG, show a crossover from mean field behavior to Ising model behavior, as the critical point is approached.
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 130022 Changchun, China; University of Chinese Academy of Sciences, 100049 Beijing, China.
authors.forename: Ziliang
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 130022 Changchun, China; School of Chemical Engineering, Changchun University of Technology, 130012 Changchun, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Li
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 130022 Changchun, China.
authors.forename: Xiangling
authors.initials: X
authors.lastname: Ji
authors.affiliation: Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany.
authors.forename: Rumiana
authors.initials: R
authors.lastname: Dimova
authors.affiliation: Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Lipowsky
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 130022 Changchun, China; Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany. Electronic address: yonggang@ciac.ac.cn.
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Liu
mesh_terms: D005591:Chemical Fractionation / Q000379:methods*; D002850:Chromatography, Gel; D003911:Dextrans / Q000737:chemistry* / Q000302:isolation & purification*; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000302:isolation & purification*; D014867:Water / Q000737:chemistry
chemical_list: D003911:Dextrans; D014867:Water; D011092:Polyethylene Glycols
keywords: Aqueous two-phase system; Dextran; Fractionation; GPC; Partition; Poly(ethylene glycol)