RESEARCH ARTICLE The occurrence of selected xenobiotics in the Danube river via LC-MS/MS Nataša Milić 1 & Maja Milanović 1 & Jelena Radonić 2 & Maja Turk Sekulić 2 & Anamarija Mandić 3 & Dejan Orčić 4 & Aleksandra Mišan 3 & Ivan Milovanović 3 & Nevena Grujić Letić 1 & Mirjana Vojinović Miloradov 2 Received: 4 September 2017 /Accepted: 25 January 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract 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, carba- mazepine, ibuprofen, and benzotriazole could be proper candidate for hydrophilic anthropogenic markers for quantification of wastewater contamination in surface water in the analyzed Danube section. Keywords The Danube . Pharmaceuticals . Emerging substances . Environmental analysis . Liquid chromatography-mass spectrometry . Water quality Introduction Modern society is faced with the growing demand for fresh water, particularly drinking water. In the last 20 years, due to the rapid development of analytical methods, hundreds of dif- ferent natural and synthetic compounds have been detected in the surface water throughout the world (Kolpin et al. 2002; Caliman and Gavrilescu 2009; Dulio and Slobodnik 2009; Loos et al. 2010; Milić et al. 2014; Petrović et al. 2014; Vojinović Miloradov et al. 2014a). Among them, the emerg- ing substances are recognized as a new class of environmental contaminants which nowadays increasingly attract attention of scientific community and stakeholders. The major source of emerging substances in the aquatic environment is municipal and industrial wastewater (Caliman and Gavrilescu 2009). In developing countries, the emission of untreated or insufficiently treated wastewater pre- sents the main problem. Up to now, there have been no dis- charge protocols for most of the xenobiotics into the water system. The proper indicator of anthropogenic contamination is caffeine (Grujić Letić et al. 2015) largely found in different beverages such as tea, coffee, and energetic drinks as well as in some analgoantipyretic drugs (Norton et al. 2011). The detectible concentration of emerging substances par- ticularly pharmaceuticals in the aquatic environment emerged growing public concerns. In 2015, for the first time, the pre- scription pharmaceuticals (diclofenac, 17-beta-estradiol, 17- alpha-ethinylestradiol, and macrolides such as erythromycin, Responsible editor: Ester Heath * Maja Milanović maja.milanovic@mf.uns.ac.rs 1 Faculty of Medicine, University of Novi Sad, Hajduk Veljkova 3, Novi Sad, Serbia 2 Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovića 6, Novi Sad, Serbia 3 Institute of Food Technology, University of Novi Sad, Bulevar Cara Lazara 1, Novi Sad, Serbia 4 Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 3, Novi Sad, Serbia Environmental Science and Pollution Research https://doi.org/10.1007/s11356-018-1401-z