Determination of widely used non-steroidal anti-inflammatory drugs in water samples by in situ derivatization, continuous hollow fiber liquid-phase microextraction and gas chromatography-flame ionization detector

The aim of this study was to develop an analytical procedure which allows the quantification of pharmaceuticals in water at the ng L−1 level. Hence, it is reported research on the application of a rapid, inexpensive and simple continuous hollow fiber liquid-phase micro extraction (CHF-LPME) for the pre-concentration and determination of non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (IBP), naproxen (NAP), and ketoprofen (KEP), in wastewater. In this method, a 2.50 cm end sealed piece of a polypropylene hollow fiber was immersed into the organic solvent, octanol, for 30 s. After solvent impregnation with the pores of the fiber, the excess amounts of solvent were removed from inside the fiber, and 4.0 μL of octanol, as the acceptor phase, was injected into the fiber carefully. The fiber was settled using a microsyringe into a 10.0 mL glass test tube, and 20.00 mL of the aqueous solution (the donor phase), was circulated by a pump around it. After analyte extraction for an optimized period of time (20 min), 2 μL of the organic solvent was withdrawn into the microsyringe and injected into the GC-FID for further analysis. Finally, based on the optimized analytical conditions, the method was linear in the range of 2.5–500 ng L−1. The limits of detection were 1–2 ng L−1. Repeatability of this method on an intra-day scale was 3.4–10.2% (RSD%). NSAIDs have been detected in several municipal wastewater samples, and the concentration range was 9.0–19.0 ng L−1.