title: Size- and shape-dependent separation of TiO2 colloidal sub-populations with gravitational field flow fractionation.
abstract: The simplest field flow fractionation technique, which uses the earth's gravity as the external field is applied to isolate two populations, which differ in both shape and size, from a polydisperse sub-micron TiO2 powder of homogenous density. The fraction eluted first is spherical with an average diameter of 0.31 microm while the second fraction is ellipsoidal and can be associated with a 0.45 microm hydrodynamic diameter. Elution conditions appeared to be very sensitive to electrolyte and surfactant characteristics in the carrier phase as well as on the sample concentration. Using 25 microl (1%, w/w) sample suspension, separations of spherical from ovoid particles was performed in almost 2 h with a mobile phase of 0.001 M KNO3-0.01% (v/v) Fl-70 in water in a 0.025-cm thick channel made of polystyrene walls.
authors.affiliation: Laboratoire de Chimie Analytique et de Bromatologie, Université de Limoges Faculté de Pharmacie, France.
authors.forename: S
authors.initials: S
authors.lastname: Rasouli
authors.forename: P
authors.initials: P
authors.lastname: Blanchart
authors.forename: D
authors.initials: D
authors.lastname: Clédat
authors.forename: P J
authors.initials: PJ
authors.lastname: Cardo
mesh_terms: D005591:Chemical Fractionation / Q000379:methods*; D006112:Gravitation; D010316:Particle Size; D014025:Titanium / Q000302:isolation & purification*
chemical_list: C009495:titanium dioxide; D014025:Titanium