The presence of emerging substances in surface water is of a great concern knowing they are the main source for community water supply needs. This study describes the development, optimization and application of an analytical method for the determination of ibuprofen in the Danube samples. Caffeine concentrations, as an indicator of human waste, were determined and maximum risk indexes for aquatic organisms were calculated. The Danube samples were collected from ten representative locations. A Solid-phase extraction was used for ibuprofen and caffeine separation and the analysis was performed by High-performance liquid chromatography method. Ibuprofen concentrations ranged (30.62-111.40) ng/L and caffeine (305.94-375.97) ng/L. Low risk on aquatic organisms was determined for ibuprofen and potential sublethal effect for caffeine was obtained. The results indicated that ibuprofen was effectively separated from other substances in the samples under defined chromatographic conditions for short period of time (4 minutes). Applied HPLC method showed good repeatability, accuracy, selectivity and robustness. Further studies including continuous monitoring of caffeine in the Danube are necessary in order to assess the real risks and possible prevention.
Keywords: Danube; HPLC; ibuprofen; maximum risk index.