PHOTOLYTIC DEGRADATION OF FLUOROQUINOLONE CARBOXYLIC-ACIDS IN AQUEOUS-SOLUTION .2. ISOLATION AND STRUCTURAL ELUCIDATION OF POLAR PHOTOMETABOLITES

Subsequent to irradiation with a xenon lamp simulating sunlight, fluor oquinolone carboxylic acids in aqueous solution form polar pyridone di carboxylic and tricarboxylic acids. After liquid/liquid partition with chloroform/water these substances can be isolated by ion exchange chr omatography of the aqueous phase. They can be regarded as intermediate compounds on the route to a complete photomineralization. The structu ral elucidation is performed by such mass spectroscopic methods as MS, GC/MS and HPLC/MS, whereby HPLC/MS shows the highest reliability. Add itionally H-1- and C-13-NMR measurements confirm the structure of the main polar degradation product.