Validation of a solid-phase extraction and liquid chromatography–electrospray tandem mass spectrometric method for the determination of nine basic pharmaceuticals in wastewater and surface water samples

This paper reports the development and validation of a quantitative LC–electrospray (ESI)-MS/MS method for the simultaneous analysis of nine basic pharmaceuticals (flubendazole, pipamperone, cinnarizine, ketoconazole, miconazole, rabeprazole, itraconazole, domperidone and propiconazole) in environmental waters. Sample preparation consisted of solid-phase extraction on a Speedisk phenyl and a NH2 solid-phase extraction tube for sample clean-up. Chromatography was performed on a pentafluorophenyl column in a total run time of 24 min. Due to different matrix effects measured in different surface water samples, standard addition was the only method to perform accurate quantification. Limits of detection and quantification were in the range of <0.05–1 ng/l and 0.05–10 ng/l, respectively. The method showed good precision and accuracy. Recoveries were in the range of 60–100%. This method allows to identify and quantify these pharmaceuticals in wastewater and surface water and enables to perform comprehensive studies on the occurrence in and removal of these drugs from influent and effluent wastewaters and surface waters.