Determination of Non-Steroidal Anti-Inflammatory Drugs in Surface Water and Wastewater by Liquid Chromatography-Tandem Mass Spectrometry

An analytical method based on liquid chromatography–tandem mass spectrometry (LC-MS-MS) has been developed for the determination of pharmaceutical compounds in water samples. The drugs investigated were the analgesics: Ibuprofen, Fenoprofen, Ketoprofen, Naproxen, and Diclofenac and the decomposition product of acetylsalicylic acid: salicylic acid. The selected compounds are acidic, very polar and all are analgesic compounds that can be purchased without medical prescription. Sample enrichment of water samples was achieved by solid-phase extraction procedure (SPE), using Waters Oasis HLB cartridges followed by LC-MS-MS. A narrow-bore 2.1 mm i.d., reversed phase LC C-18 column was used to chromatograph analytes. Average recoveries from 1 L samples varied 75–95% and the detection limits are <1 ng L−1. The method developed was applied to real samples from wastewater and surface waters of Lazio country (Italy).