title: 1H NMR study of rehydration/dehydration and water mobility in β-cyclodextrin.
abstract: The processes of dehydration and rehydration of β-cyclodextrin were studied by analysis of the (1)H NMR (nuclear magnetic resonance) line shape. Dehydration was carried in an open ampoule as a function of temperature and above 400 K total dehydration of β-cyclodextrin was observed. This result was confirmed by the thermogravimetry (TG) measurements. Rehydration was studied as a function of time at room temperature. After 40 days, β-cyclodextrin was found to absorb eight water molecules. The analysis of temperature changes in the shape of the (1)H NMR line of β-cyclodextrin kept in a closed ampoule and its dielectric measurements provided information on the mobility of water molecules. The water molecules were found to perform complex molecular motions, that is, reorientational jumps below 200K and additionally, translational motion (diffusion) above 200K.
authors.affiliation: Faculty of Physics, A. Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Pajzderska
authors.forename: P
authors.initials: P
authors.lastname: Czarnecki
authors.forename: J
authors.initials: J
authors.lastname: Mielcarek
authors.forename: J
authors.initials: J
authors.lastname: Wąsicki
mesh_terms: D003505:Cyclodextrins / Q000737:chemistry*; D003681:Dehydration; D005440:Fluid Therapy; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*
chemical_list: D003505:Cyclodextrins