title: Thermodynamic parameters for the molecular inclusion reaction of dulcin with beta-cyclodextrin. spectrofluorimetric determination of dulcin.
abstract: The inclusion of dulcin in alpha- and beta-cyclodextrin has been studied by fluorescence spectroscopy. To quantitatively describe complex formation between the beta-cyclodextrin and dulcin, an association constant of 290 M(-1) at 21 degrees was obtained. The thermodynamics associated with the complex formation between dulcin and beta-cyclodextrin in aqueous solution has been studied. The obtained value of DeltaG(0) = -13.7 kJ/mole at 21 degrees , together with DeltaH(0) = -33.6 +/- 2.3 kJ/mole and DeltaS(0) = -67.2 +/-8.3 Jmole(-1) K(-1) indicate that dulcin has a very marked tendency to associate with beta-cyclodextrin in water. The inclusion complex of dulcin in beta-cyclodextrin has been used to determine dulein in the range 0.13-5 mug/ml the method has been applied to determine dulcin in soft drinks.
authors.affiliation: Departamento de Química Analítica, Facultad de Ciencias, Universidad de Málaga, 29071-Spain.
authors.forename: A N
authors.initials: AN
authors.lastname: Díaz
authors.forename: L S
authors.initials: LS
authors.lastname: Feria
authors.forename: F G
authors.initials: FG
authors.lastname: Sánchez