| 1. |
- Chakraborty, Reena, et al.
(författare)
-
Steady state fluorescence spectroscopy of pyranine as a trace extrinsic probe to study structure in aqueous sugar solutions
- 1992
-
Ingår i: Journal of Crystal Growth. - 0022-0248 .- 1873-5002. ; 125:1-2, s. 81-96
-
Tidskriftsartikel (refereegranskat)abstract
- The steady state fluorescence behavior of pyranine has been monitored in aqueous solutions of sucrose, glucose, fructose, and lactose. In each case it is possible to use the ratio of peak intensities at 440 and 511 nm (the PIR) as an indicator of the degree of supersaturation of the sugar solutions. We observed both bulk water and water of solvation in all solutions examined, regardless of degree of sapersaturation. In each case the amounts of bulk water and water of solvation per molecule of sugar appear to be nearly equal at saturation. We did not observe any evidence of solvent exclusive clusters in any of the systems we studied
|
|
| 2. |
- Chakraborty, Reena, et al.
(författare)
-
Use of pyranine as a trace fluorescent probe to study structure in aqueous sucrose solutions
- 1991
-
Ingår i: Particle design via crystallization. - Washington, DC : American Institute of Chemical Engineers. - 0816905533 ; , s. 114-123
-
Konferensbidrag (refereegranskat)abstract
- Emission spectroscopy using pyranine as a trace fluorescent probe was evaluated as a means of studying solution structure in aqueous sucrose solutions. Spectra of pyranine doped sucrose solutions of 0-70 wt% were obtained, indicating two microenvironments. The peak intensity ratio (defined as the ratio of peak intensities at 440 nm and 511 nm) was observed to be a very sensitive function of the water content in supersaturated solutions. The two microenvironments were designated as bulk water and that near the solvated sucrose molecules. Calculations yielded six water molecules of solvation per molecule of sucrose. This is in agreement with values in literature. The number of molecules of water per molecule of sucrose in the bulk water environment varies exponentially from 165 in a 10% solution to three for a 70% solution at 20 degrees C. These results indicate that this technique can be used successfully to measure water content in supersaturated solutions.
|
|
| 3. |
- Pan, Borlan, et al.
(författare)
-
Time resolved fluorescence and anisotropy of 1-pyrene butyric acid and pyranine as probes of solvent organization in sucrose solutions
- 1993
-
Ingår i: Journal of Crystal Growth. - 0022-0248 .- 1873-5002. ; 130:3-4, s. 587-599
-
Tidskriftsartikel (refereegranskat)abstract
- The microenvironment of solute-solvent interactions in aqueous sucrose solutions, ranging from 0 to 80 wt% in concentration, was investigated using time resolved fluorescence techniques. The fluorescence lifetimes and rotational correlation times of the trace fluorescent probes, PBA (1-pyrene butyric acid) and pyranine (trisodium 8-hydroxy-1,3,6-pyrenetrisulfonate), were measured in sucrose solutions. The behavior of the fluorescence lifetimes and the increase in the rotational correlation 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.
|
|
