The occurrence of selected xenobiotics in the Danube river via LC-MS/MS.

Having in mind that there is a general lack of monitoring plans and precaution measures in the developing countries and that the Danube is the second longest river in Europe, the estimation of the relevant concentration levels of unregulated xenobiotics is a topic of interest both on local and international level. The selected pharmaceuticals, caffeine, and benzotriazole presented in the collected water samples from seven representative locations around the territory of Novi Sad, Serbia, during 1-year period, were analyzed with the use of solid-phase extraction followed by the liquid chromatography coupled with triple quad tandem mass spectrometry. The most frequently detected compounds were caffeine and carbamazepine in the concentrations up to 621 and 22.2 ng/L, respectively, while the maximum concentration of the analyzed pharmaceuticals was obtained for ibuprofen (60.1 ng/L). The presence of benzotriazole along the analyzed section of the river was confirmed in the concentration levels up to 26.7 ng/L. Although sulfamethoxazole and desmethyldiazepam were detected at trace levels (0.22 and 3.41 ng/L, respectively); the presence of these pharmaceuticals in complex mixtures should not be neglected. Due to the frequent detection caffeine, carbamazepine, ibuprofen, and benzotriazole could be proper candidate for hydrophilic anthropogenic markers for quantification of wastewater contamination in surface water in the analyzed Danube section.