Micro FT-IR and EXAFS Studies on Periodic and Chaotic Precipitation in Bile Salt Systems

Micro FT-IR and EXAFS spectroscopy methods were utilized to characterize the periodic and chaotic precipitation occuring in some metal bile salt systems in sol-gel medium. The results indicate that the precipitates were just the corresponding metal bile salt complexes, and the agar gel medium has very weak interaction with the dispersed ions. In addition, comparison between the EXAFS spectra of the precipitate formed in the CoCl2-NaDC gel system and of the complexes Co(DC)2 synthesized in water-ethanol solvent suggested that the two complexes were of similar composition but the precipitate in the gel had a more ordered coordination structure.