First derivative synchronous fluorescence spectroscopy (FDSFS) was applied to detect and quantify ciprofloxacin (CIP) and levofloxacin (LEV) simultaneously with their photodegradation products, where the photolytic pathway for each analyte was found to be pH dependant. Under the guidance of early published articles, the structure of the produced photolytic products could be concluded, and further related to their resultant fluorescence spectra. The proposed method was subjected to a full validation procedure which enables its application in investigating the photodegradation kinetics for both drugs. The obtained kinetic parameters were in accordance with previous reports and could be linked to predict the antibacterial activity of the resultant photodegradation products. These facts prove the suitability of the suggested FDSFS to serve as a stability-indicating assay method and to trace the photofate of CIP and LEV in the ecosystem as potential contaminants. Furthermore, the greenness of the suggested analytical methodology was evaluated via the ˝ Green Analytical Procedure Index˝ (GAPI), which classifies it as an eco-friendly assay. Eventually, no extraction, treatment, or preparation steps were needed during all analysis steps, which renders the proposed assay an appealing tool in environmental analysis.  

Fluorescence spectra were recorded, the readings were collected and statistically analyzed.