title: Effects of comprehensive function of factors on retention behavior of microparticles in gravitational field-flow fractionation.
abstract: Gravitational field-flow fractionation (GrFFF) is a useful technique for separation and characterization for micrometer-sized particles. Elution behavior of micrometer-sized particles in GrFFF was researched in this study. Particles in GrFFF channel are subject to hydrodynamic lift forces (HLF), fluid inertial forces and gravity, which drive them to different velocities by carrier flow, resulting in a size-based separation. Effects of ionic strength, flow rate and viscosity as well as methanol were investigated using polystyrene latex beads as model particles. This study is devoted to experimental verification of the effect of every factor and their comprehensive function. All experiments were performed to show isolated influence of every variable factor. The orthogonal design test was used to evaluate various factors comprehensively. Results suggested that retention ratio of particles increases with increasing flow rate or the viscosity of carrier liquid by adjusting external forces acting on particles. In addition, retention ratio increases as ionic strength decreases because of decreased electrostatic repulsion between particles and channel accumulation wall. As far as methanol, there is no general trend due to the change of both density and viscosity. On the basis of orthogonal design test it was found that viscosity of carrier liquid plays a significant role in determining resolution of micrometer-sized particles in GrFFF.
authors.affiliation: School of Pharmaceutical Sciences, Peking University, Beijing 100191, PR China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Guo
authors.affiliation: School of Pharmaceutical Sciences, Peking University, Beijing 100191, PR China.
authors.forename: Bai-Ling
authors.initials: BL
authors.lastname: Qiu
authors.affiliation: School of Pharmaceutical Sciences, Peking University, Beijing 100191, PR China.
authors.forename: Chen-Qi
authors.initials: CQ
authors.lastname: Zhu
authors.affiliation: School of Pharmaceutical Sciences, Peking University, Beijing 100191, PR China.
authors.forename: Ya-Ya Gao
authors.initials: YG
authors.lastname: Yang
authors.affiliation: School of Pharmaceutical Sciences, Peking University, Beijing 100191, PR China.
authors.forename: Di
authors.initials: D
authors.lastname: Wu
authors.affiliation: School of Pharmaceutical Sciences, Peking University, Beijing 100191, PR China.
authors.forename: Qi-Hui
authors.initials: QH
authors.lastname: Liang
authors.affiliation: School of Pharmaceutical Sciences, Peking University, Beijing 100191, PR China. Electronic address: nanyin.han@pku.edu.cn.
authors.forename: Nan-Yin
authors.initials: NY
authors.lastname: Han
mesh_terms: D031521:Fractionation, Field Flow; D006112:Gravitation; D000432:Methanol / Q000737:chemistry; D008863:Microspheres; D009994:Osmolar Concentration; D055672:Static Electricity; D014783:Viscosity
chemical_list: D000432:Methanol
keywords: Gravitational field-flow fractionation (GrFFF); Ionic strength; Micrometer-sized particles; Orthogonal design test; Viscosity