Analytical Sciences


Abstract − Analytical Sciences, 19(8), 1199 (2003).

In situ UV-VIS Detection of the Association of Water-Soluble Anionic Porphyrin and Aromatic Bases in Aqueous Solution at High Tempeatures Using a Capillary Flow Hydrothermal Reactor System
Kunio KAWAMURA
Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Gakuen-cho 1-1, Sakai, Osaka 599-8531, Japan
The association between anionic water-soluble porphyrin and aromatic heterocyclic bases has been investigated to demonstrate the usefulness of a new in situ UV-VIS monitoring method of hydrothermal reactions. Spectral and absorbance changes in the presence of bases were possible to be detected by the new method at temperatures up to 150°C. The association constants (Kass,1) were determined from the absorbance-base concentration curves. The logarithmic values of Kass,1 were proportional to the number of rings of the bases, but this relationship became ambiguous beyond 100°C. This fact indicates that stacking between porphyrin and bases does indeed become weak at high temperatures.