title: Semi-preparative asymmetrical flow field-flow fractionation: A closer look at channel dimensions and separation performance.
abstract: The design and performance of a semi-preparative asymmetrical flow field-flow fractionation (SP-AF4) channel are investigated with the objective of better understanding and exploiting the relationship between channel dimensions, sample loading, and resolution. Most size-based separations of nanometer and submicrometer particles are currently limited to analytical scale quantities (<100μg). However, there is a strong need to fractionate and collect larger quantities so that fundamental properties of the more narrowly dispersed fractions can be studied using additional characterization methods and for subsequent applications. In this work, dimensions of the spacer that defines the form of SP-AF4 channels are varied and their performances are assessed with respect to sample focusing position and loading. Separations are performed in aqueous and organic carrier fluids. A critical evaluation of channel dimensions showed that increasing the channel breadth is a practical and effective route to maintaining separation resolution while increasing sample loads to milligram quantities. Good size resolution (∼1.0) is achieved for separations of 10mg of 50 and 100nm silica nanoparticles suspended in water and up to 0.6mg of ∼10 to 35nm inorganic hybrid nanoparticles suspended in tetrahydrofuran. This work represents important advances in the understanding of SP-AF4 separations and extends sample loading capacities in both aqueous and organic solvents.
authors.affiliation: Department of Chemistry, Colorado School of Mines, Golden, CO 80401, USA.
authors.forename: Carmen R M
authors.initials: CRM
authors.lastname: Bria
authors.affiliation: Department of Chemistry, Colorado School of Mines, Golden, CO 80401, USA.
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Skelly
authors.affiliation: Department of Chemistry and Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: James R
authors.initials: JR
authors.lastname: Morse
authors.affiliation: Department of Chemistry and Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Raymond E
authors.initials: RE
authors.lastname: Schaak
authors.affiliation: Department of Chemistry, Colorado School of Mines, Golden, CO 80401, USA. Electronic address: krwillia@mines.edu.
authors.forename: S Kim Ratanathanawongs
authors.initials: SKR
authors.lastname: Williams
mesh_terms: D031521:Fractionation, Field Flow / Q000295:instrumentation* / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D012822:Silicon Dioxide
keywords: Field-flow fractionation; Focusing; Nanoparticles; Semi-preparative