Three liquid-phase microextraction of diclofenac and ibuprofen from water samples prior to high performance liquid chromatography

A microextraction method using polypropylene membrane coupled with high performance liquid chromatography (HPLC) was developed for the extraction and determination of non-steroidal analgesic, antiinflammatory drugs (NSAIDs) in water samples. Analytes including diclofenac and ibuprofen were extracted from acidic aqueous sample solution (donor phase) into a thin film of the organic solvent (o-xylene) then back extracted into the basic aqueous solution (acceptor phase). After extraction, 5 μL of the aqueous acceptor phase was withdrawn back into the syringe and injected directly into the HPLC system for further analysis. The parameters influencing the extraction efficiency including kind of the organic solvent and its volume, composition of donor and acceptor phases and the volume ratio between them, extraction time, stirring rate and pH were investigated and optimized. Under the optimal conditions, the obtained enrichment factors were more than 900. Dynamic linear ranges were 0.1-2000 and 0.5-2000 μg L -1 (r > 0.9971) and also the limits of detection (LODs) were 0.05 and 0.1 μg L -1 for diclofenac and ibuprofen, respectively.