title: Correlation of SEC/MALLS with ultracentrifuge and viscometric data for chitosans.
abstract: Attempts have been made to correlate estimates of molecular weight for a group of cationic polysaccharides known as chitosans between the highly popular technique of size-exclusion chromatography coupled to multi-angle laser light scattering, "SEC-MALLS", and the less convenient but more established technique of sedimentation equilibrium in the analytical ultracentrifuge. Four pharmaceutical grade chitosans of various molecular weights and degrees of acetylation (4-30%) were chosen. Better correlation than previous was achieved, although some batch variability was observed. Despite the broad spectrum in degree of acetylation, a log s degrees(20,w) versus log Mw scaling plot appeared to fit a straight line with power-law exponent b=0.25 +/- 0.04, i.e. between the limits of rod (0.15) and coil (0.4-0.5), although this may be the average of a lower b value at low Mw and higher b at high Mw. With regard to viscosity, a logeta versus logMw scaling plot appeared to also fit a straight line with power-law exponent a=0.96 +/- 0.10, again between the coil (0.5-0.7) and rod (1.8) limits.
authors.affiliation: NCMH Physical Biochemistry Laboratory, School of Biosciences, University of Nottingham, Sutton Bonington, LE12 5RD, UK.
authors.forename: Monica
authors.initials: M
authors.lastname: Fee
authors.forename: Neil
authors.initials: N
authors.lastname: Errington
authors.forename: Kornelia
authors.initials: K
authors.lastname: Jumel
authors.forename: Lisbeth
authors.initials: L
authors.lastname: Illum
authors.forename: Alan
authors.initials: A
authors.lastname: Smith
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Harding
mesh_terms: D002499:Centrifugation, Density Gradient / Q000379:methods*; D002686:Chitin / Q000031:analogs & derivatives* / Q000032:analysis* / Q000737:chemistry* / Q000145:classification; D048271:Chitosan; D002850:Chromatography, Gel / Q000379:methods*; D007834:Lasers; D008970:Molecular Weight; D009391:Nephelometry and Turbidimetry / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D014461:Ultracentrifugation / Q000379:methods; D014783:Viscosity
chemical_list: D002686:Chitin; D048271:Chitosan