Application of a novel solid-phase-extraction sampler and ultra-performance liquid chromatography quadrupole-time-of-flight mass spectrometry for determination of pharmaceutical residues in surface sea water

In the present study, a multi-residue method based on a bag-solid phase extraction (bag-SPE) technique was evaluated for determination of 10 pharmaceuticals in surface water close to the effluent of a sewage treatment plant (STP) and along a coastal gradient from a STP effluent.The 10 compounds selected were caffeine, atenolol, metoprolol, oxazepam, carbamazepine, ketoprofen, naproxen, ibuprofen, diclofenac and gemfibrozil. All analyses were performed using ultra-performance liquid chromatography (UPLC) combined with quadrupole time-of-flight (QTOF) mass spectrometry. The detection limits (LOD) ranged from 1.0 to 13 ng L−1. The method showed linear concentration ranges from 25 to 800 ng L−1 with regression coefficients (R2) better than 0.9801. The recoveries of the selected analytes ranged from 11 to 65% with relative standard deviations (RSD) of <16% and inter-day variations of less than 18%. Isotopically labeled surrogate standards were used to compensate for sampling losses and matrix effects.Four of the selected 10 pharmaceuticals (caffeine, metoprolol, oxazepam and carbamazepine) were quantified, at concentrations ranging from 4 to 210 ng L−1.