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The analysis and presence of clotrimazole, an antifungal agent with logK(OW) > 4, was thoroughly studied in the aquatic environment. For that reason analytical methods based on gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry were developed and validated to quantify clotrimazole with limits of quantification down to 5 and 1 ng/L, respectively. Both methods were compared in an intercalibration exercise. The complete mass-spectrometric fragmentation pattern could be elucidated with the aid of quadrupole time of flight mass spectrometry. Since clotrimazole tends to adsorb to laboratory glassware, studies on its adsorption behaviour were made to ensure the appropriate handling of water samples, e.g. pH, storage time, pretreatment of sampling vessels or material of the vials used for final extracts. The phenomena of adsorption to suspended matter were investigated while analysing different waste-water samples. Application of the methods in various investigated wastewater and surface water samples demonstrated that clotrimazole could only be detected in the low nanogram per litre range of anthropogenic influenced unfiltered water samples after acidification to pH 2.

Barbiturates have been widely used as sedative hypnotics in the mid-1960s and since then mainly as veterinary drugs. To monitor their presence and fate in the aquatic environment, a method based on gas chromatography-mass spectrometry (GC-MS) has been developed to quantify butalbital, secobarbital, hexobarbital, aprobarbital, phenobarbital, and pentobarbital, all with a limit of detection (LOD) down to 1 ng/L. From the various investigated waste and surface water samples, barbiturates were only, but regularly detected in the Mulde, a tributary of the river Elbe in Germany at relevant concentrations up to several microg/L. Investigations of groundwater being affected with wastewater infiltration several decades ago also revealed a barbiturate pattern, indicating a strong recalcitrance of these drugs. To confirm this hypothesis, studies were carried out on biotic and abiotic degradation. Both, the biodegradability under aerobic conditions and hydrolysis did not show any degradation, implementing, that the investigated barbiturates, once released into the aquatic environment, show high stability over a long period of time.

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The transformation products 2-(isopropylcarbamoyl)phenylsulfamic acid and 2-(1-hydroxypropane-2-yl)-1,2-dihydroindazol-3-one could be determined during the photolysis of the herbicide bentazone. Degradation experiments were carried out with different types of water in a natural sunlight simulating system. Besides the anticipated hydroxylated bentazone, the second transformation product was identified by means of exact mass measurement using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/QqToF MS). Both phototransformation products occurred in all water types tested. The required irradiation time was matrix dependent. 2-(Isopropylcarbamoyl)phenylsulfamic acid was detected in a drainage channel in the Ebro river delta (Catalonia, Spain).