title: Challenges in analysis of high-molar mass dextrans: comparison of HPSEC, AsFlFFF and DOSY NMR spectroscopy.
abstract: Dilute solutions of various dextran standards, a high-molar mass (HMM) commercial dextran from Leuconostoc spp., and HMM dextrans isolated from Weissella confusa and Leuconostoc citreum were analyzed with high-performance size-exclusion chromatography (HPSEC), asymmetric flow field-flow fractionation (AsFlFFF), and diffusion-ordered NMR spectroscopy (DOSY). HPSEC analyses were performed in aqueous and dimethyl sulfoxide (DMSO) solutions, while only aqueous solutions were utilized in AsFlFFF and DOSY. The study showed that all methods were applicable to dextran analysis, but differences between the aqueous and DMSO-based solutions were obtained for HMM samples. These differences were attributed to the presence of aggregates in aqueous solution that were less prevalent in DMSO. The study showed that DOSY provides an estimate of the size of HMM dextrans, though calibration standards may be required for each experimental set-up. To our knowledge, this is the first study utilizing these three methods in analyzing HMM dextrans.
authors.affiliation: Department of Food and Environmental Sciences, P.O. Box 27, FIN-00014 University of Helsinki, Finland. Electronic address: henry.maina@helsinki.fi.
authors.forename: Ndegwa Henry
authors.initials: NH
authors.lastname: Maina
authors.forename: Leena
authors.initials: L
authors.lastname: Pitkänen
authors.forename: Sami
authors.initials: S
authors.lastname: Heikkinen
authors.forename: Päivi
authors.initials: P
authors.lastname: Tuomainen
authors.forename: Liisa
authors.initials: L
authors.lastname: Virkki
authors.forename: Maija
authors.initials: M
authors.lastname: Tenkanen
mesh_terms: D002138:Calibration; D005591:Chemical Fractionation; D002850:Chromatography, Gel; D003911:Dextrans / Q000737:chemistry / Q000302:isolation & purification; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D007934:Leuconostoc / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008970:Molecular Weight; D012015:Reference Standards; D012996:Solutions; D012997:Solvents / Q000737:chemistry; D014867:Water / Q000737:chemistry; D058836:Weissella / Q000737:chemistry*
chemical_list: D003911:Dextrans; D012996:Solutions; D012997:Solvents; D014867:Water; D004121:Dimethyl Sulfoxide
keywords: AsFlFFF; DOSY; Dextran; HPSEC; Leuconostoc citreum; Polysaccharides; Weissella confusa