Determination of selected human pharmaceutical compounds in effluent and surface water samples by high-performance liquid chromatography–electrospray tandem mass spectrometry

A simple method is presented for the analysis of 13 pharmaceutical and pharmaceutical metabolite compounds in sewage effluents and surface waters. The pharmaceutical compounds were extracted using a generic solid-phase extraction (SPE) procedure using Phenomenex Strata X as a stationary phase. Extracts were quantitatively analysed by four separate reversed-phase high-performance liquid chromatography–electrospray tandem mass spectrometry (HPLC–ESI-MS/MS) techniques and quantified by comparison with an internal standard ([13C]-phenacetin). Recoveries and limits of detection (LOD) for sulfamethoxazole (120%, 50 ng l−1), acetyl-sulfamethoxazole (56%, 50 ng l−1), trimethoprim (123%, 10 ng l−1), erythromycin (73%, 10 ng l−1), paracetamol (75%, 50 ng l−1), ibuprofen (117%, 20 ng l−1), clofibric acid (83%, 50 ng l−1), mefenamic acid (24%, 50 ng l−1), diclofenac (62%, 20 ng l−1), propranolol (45%, 10 ng l−1), dextropropoxyphene (63%, 20 ng l−1) and tamoxifen (42%, 10 ng l−1) were all acceptable. The recovery of lofepramine (4%) was too low to be of use in a monitoring programme. Application of the method to samples collected from UK sewage effluents and surface waters showed detectable concentrations of mefenamic acid, diclofenac, propranolol, erythromycin, trimethoprim and acetyl-sulfamethoxazole in both matrices. Ibuprofen and dextropropoxyphene were detected in sewage effluents alone. All other pharmaceutical compounds were below the methods limits of detection.