TIME-RESOLVED FLUORESCENCE AND ANISOTROPY OF 1-PYRENE BUTYRIC-ACID AND PYRANINE AS PROBES OF SOLVENT ORGANIZATION IN SUCROSE SOLUTIONS

The microenvironment of solute-solvent interactions in aqueous sucrose solutions, ranging from 0 to 80 wt% in concentration, was investigate d using time resolved fluorescence techniques. The fluorescence lifeti mes and rotational correlation times of the trace fluorescent probes, PBA (1-pyrene butyric acid) and pyranine (trisodium 8-hydroxy-1,3,6-py renetrisulfonate), were measured in sucrose solutions. The behavior of the fluorescence lifetimes and the increase in the rotational correla tion times with increasing sucrose concentration provided no evidence for the formation of water exclusive solute clusters in the metastable solutions. Instead, the results indicated the formation of a network of hydrogen bonding interactions between dispersed sucrose molecules.