Simple and quick determination of analgesics and other contaminants of emerging concern in environmental waters by on-line solid phase extraction coupled to liquid chromatography–tandem mass spectrometry

A simple and quick analytical method has been developed for the determination of pharmaceutical compounds in water. An on-line solid-phase extraction (SPE) coupled to liquid chromatography–tandem mass spectrometry (LC–MS/MS) method has been optimized to determine 7 contaminants of emerging concern in environmental waters at ng L−1 levels. This procedure requires minimal sample handling and small sample volume (900 μL) with a total running time of 18 min. Several SPE parameters were evaluated and optimized in order to achieve a high sample throughput. Therefore sample volume, carryover and reusability of the cartridges were evaluated. Performance characteristics were evaluated and good linearity was obtained (R2 > 0.98). Recoveries were evaluated in spiked samples at three concentrations and the values ranged from 71 to 104%. Intra and inter-day precision was lower than 10 and 13% respectively. Limits of quantification were equal to or lower than 10 ng L−1, except for 1,7-dimethylxanthine (20 ng L−1) and ibuprofen (50 ng L−1). The method was applied to 20 environmental water samples, and ibuprofen was the compound most widely detected at concentrations up to 42.06 μg L−1, whereas the other compounds were detected in fewer samples at lower concentrations (up to 15.99 μg L−1).