THERMODYNAMIC PARAMETERS FOR THE MOLECULAR INCLUSION REACTION OF DULCIN WITH BETA-CYCLODEXTRIN - SPECTROFLUOROMETRIC DETERMINATION OF DULCIN

The inclusion of dulcin in alpha- and beta-cyclodextrin has been studi ed by fluorescence spectroscopy. To quantitatively describe complex fo rmation between the beta-cyclodextrin and dulcin, an association const ant of 290 M-1 at 21-degrees was obtained. The thermodynamics associat ed with the complex formation between dulcin and beta-cyclodextrin in aqueous solution has been studied. The obtained value of DELTAG0 = -13 .7 kJ/mole at 21-degrees, together with DELTAH-0 = -33.6+2.3 kJ/mole a nd DELTAS0 = -67.2 +/- 8.3 Jmole-1 K-1 indicate that dulcin has a very marked tendency to associate with beta-cyclodextrin in water. The inc lusion complex of dulcin in beta-cyclodextrin has been used to determi ne dulcin in the range 0.13-5 mug/ml, the method has been applied to d etermine dulcin in soft drinks.