title: Programmed cross flow asymmetrical flow field-flow fractionation for the size separation of pullulans and hydroxypropyl cellulose.
abstract: Different functions for the programming of the cross flow in asymmetrical flow field-flow fractionation were studied with the aim to find the flow conditions most suitable for the molar mass distribution analysis of high molecular weight polysaccharides. A mixture of four differently sized pullulans covering the molar mass range 5.8 x 10(3)-1.6 x 10(6) g mol(-1) were used as a model sample. Two types of programs were studied, linear and exponential decays, both with and without initial periods of a constant cross flow. For comparison, nonprogrammed runs, i.e. using constant cross flow, were studied. It was found that exponentially decaying cross flow gave the most uniform molar mass selectivity across the fractogram. The programmed cross flow was applied to the molar mass distribution analysis of a technical quality of hydroxypropyl cellulose.
authors.affiliation: Department of Technical Analytical Chemistry, Center for Chemistry and Chemical Engineering, Lund University, SE-221 00 Lund, Sweden. Mats.Andersson6@comhem.se
authors.forename: Mats
authors.initials: M
authors.lastname: Leeman
authors.forename: Karl-Gustav
authors.initials: KG
authors.lastname: Wahlund
authors.forename: Bengt
authors.initials: B
authors.lastname: Wittgren
mesh_terms: D002482:Cellulose / Q000031:analogs & derivatives* / Q000302:isolation & purification; D031521:Fractionation, Field Flow / Q000379:methods*; D005936:Glucans / Q000302:isolation & purification*; D008970:Molecular Weight
chemical_list: D005936:Glucans; C009109:pullulan; D002482:Cellulose; C008079:hydroxypropylcellulose