Rapid determination of pharmaceuticals from multiple therapeutic classes in wastewater by solid-phase extraction and ultra-performance liquid chromatography tandem mass spectrometry

A new analytical method utilizing ultra-performance liquid chromatography (UPLC) tandem mass spectrometry (MS/MS) has been developed to determine 16 pharmaceuticals from 8 therapeutic classes in wastewater: bezafibrate, clofibric acid, carbamazepine, caffeine, chloramphenicol, diclofenac, gemfibrozil, indomethacin, ketoprofen, mefenamic acid, metoprolol, nalidixic acid, N,N-diethyl-metatoluamide, propranolol, sulpiride and trimethoprim. Key parameters of MS/MS, UPLC and solid phase extraction (SPE) were optimized. In general, recovery of target pharmaceuticals was over 70% for the wastewater effluent samples and 50% for the influent samples. The effects of matrix suppression, loss during the pretreatment as well as instrument variability were successfully pcorrected by two internal standards, and acceptable relative recovery was obtained. Target compounds were quantitatively analyzed using multiple reaction monitoring (MRM) mode, and the detection limits ranged from 0.3 to 20 ng/L. A detailed study, matrix effect in effluent wastewater was also present. The method was applied to detecting pharmaceuticals in the wastewater from three wastewater treatment plants (WWTPs) in Beijing, China and the results demonstrated that most target compounds were detectable in both the influent and effluent, with the mean concentrations ranging from 20.5 to 5775.6 ng/L and 4.6 to 418.6 ng/L, respectively.