title: Towards a less biased dissolution of chitosan.
abstract: The dissolution of polysaccharides is notoriously challenging, especially when one needs a "true" solution. Factors influencing chitosan's solubility include composition, also known as degree of acetylation (DA). The dissolution of chitosan was investigated by visual observation, size-exclusion chromatography (SEC), pressure mobilization (PM), free-solution capillary electrophoresis (CE) and real-time solution-state NMR spectroscopy. Aqueous HCl dissolves around 15% more chitosan than the commonly used aqueous acetic acid (AcOH), however aggregates were detected in SEC suggesting incomplete dissolution. Significant deacetylation of chitosan over the period needed for dissolution at high temperature was observed by NMR spectroscopy in DCl by about 20% of the initial DA value. Accurate DA determination by NMR spectroscopy may thus be possible only in the solid state (with a precision within 1% on the DA % scale above a DA of 10%). Overall a compromise between maximum solubilization and minimum degradation is required in attempting to obtain a "true" solution of chitosan. The completeness of the dissolution may be more influenced by the average DA than by molar mass.
authors.affiliation: Western Sydney University, School of Science and Health, Australian Centre for Research on Separation Sciences (ACROSS), Parramatta, 2150, Australia; Western Sydney University, Molecular Medicine Research Group (MMRG), School of Science and Health, Parramatta, 2150, Australia; Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Joel J
authors.initials: JJ
authors.lastname: Thevarajah
authors.affiliation: Western Sydney University, School of Science and Health, Australian Centre for Research on Separation Sciences (ACROSS), Parramatta, 2150, Australia.
authors.forename: Jerikho C
authors.initials: JC
authors.lastname: Bulanadi
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Wagner
authors.affiliation: Western Sydney University, School of Science and Health, Australian Centre for Research on Separation Sciences (ACROSS), Parramatta, 2150, Australia; Western Sydney University, Molecular Medicine Research Group (MMRG), School of Science and Health, Parramatta, 2150, Australia. Electronic address: m.gaborieau@westernsydney.edu.au.
authors.forename: Marianne
authors.initials: M
authors.lastname: Gaborieau
authors.affiliation: Western Sydney University, School of Science and Health, Australian Centre for Research on Separation Sciences (ACROSS), Parramatta, 2150, Australia.
authors.forename: Patrice
authors.initials: P
authors.lastname: Castignolles
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D019075:Electrophoresis, Capillary; D009682:Magnetic Resonance Spectroscopy; D012995:Solubility
chemical_list: D048271:Chitosan
keywords: Capillary electrophoresis; Chitosan; Dissolution; Size-exclusion chromatography (SEC); Solid-state NMR spectroscopy; Solution-state NMR spectroscopy