Supramolecular clusters clarification in ethanol-water mixture by using fluorescence spectroscopy and 2D correlation analysis

Due to the importance of ethanol-water solutions in many fields the different supramolecular clusters involved in this binary system is studied in detail by using fluorescence spectroscopy , at different concentration and incubation time after mixing. Two-dimensional (2D) correlation analysis is performed on the concentration-dependent mixtures (10–100%) at each incubation time, which find that the correlation intensity of emission peak at 330 nm for (H 2 O) m (EtOH) n not only related to the concentration but also gradually increase with the incubation time. Such results indicate that the cluster of (H 2 O) m (EtOH) n is the most stable one because it tends to be formed with longer incubation time. In addition, the correlation results indicate that at low concentration range of 10–45%, the dominated cluster is (H 2 O) m (EtOH) corresponding to a peak at 373 nm; while at high concentration range of 80–100%, the main cluster is (H 2 O)(EtOH) n corresponding to an emission peak at 308 nm; however, the most stable cluster of (H 2 O) m (EtOH) n , corresponding to the peak at 330 nm, not only predominate at the concentration range of 50–75% but also exist in all mixture at longer incubation time. Therefore, the present study provides a new approach to clarify the different supramolecular clusters in ethanol-water mixtures, which would be applied to other binary solution system.