Determination of drug residues in water by the combination of liquid chromatography or capillary electrophoresis with electrospray mass spectrometry

Methods for the determination of drug residues in water have been developed based on the combination of liquid chromatography (LC) or capillary electrophoresis (CE) with mass spectrometry (MS). For HPLC–MS two types of interfaces (pneumatically assisted electrospray ionization interface or an atmospheric pressure chemical ionization interface, respectively) were employed and compared in terms of detection limits. 2 mM Ammonium acetate at pH 5.5 and a methanol gradient was used for the HPLC–MS allowing the separation of a number of drugs such as paracetamol, clofibric acid, penicillin V, naproxen, bezafibrate, carbamazepine, diclofenac, ibuprofen and mefenamic acid. A 20 mM ammonium acetate solution, pH 5.1 was employed for the separation of clofibric acid, naproxen, bezafibrate, diclofenac, ibuprofen and mefenamic acid by CE–MS. Sample pretreatment was performed by solid-phase extraction (SPE) for HPLC–MS or by a combination of liquid–liquid extraction and SPE for CE–MS. The applicability of both the HPLC–MS and CE–MS method was demonstrated for several river water samples.