Simultaneous Determination of Four Nonsteroidal Anti-Inflammatory Drugs and Three Estrogen Steroid Hormones in Wastewater Samples by Dispersive Liquid–Liquid Microextraction Based on Solidification of Floating Organic Droplet and HPLC

Abstract Background: Nonsteroidal anti-inflammatory drugs (NSAIDs) and estrogen steroid hormones (estrogens) are pharmaceuticals intensively studied in environmental analysis due to their toxic effect on animal and human beings. Objective: Development of a simple, fast, and sensitive extraction method for the simultaneously analysis of four NSAIDs (ketoprofen, naproxen, ibuprofen, and diclofenac) and three estrogens (17ß-estradiol, 17α-ethynylestradiol, and estriol) from wastewater samples. Method: Dispersive liquid–liquid microextraction based on solidification of floating organic droplet followed by HPLC analysis with UV detection was developed. The influence of the main extraction parameters, e.g., the volume of extraction solvent and of disperser, the pH, and the ionic strength of sample were evaluated. Results: Good resolutions between the selected drugs were obtained using a reverse-phase column and a mobile phase of acetonitrile and water. This method provides good linearity (r > 0.999) in a concentration range of 1–100 µg/mL, good intra- and inter-day precision (RSD <7%) and low LOQs. The obtained enrichment factors were ranged between 162 and 180 for NSAIDs and between 118 and 185 for estrogens. The relative recoveries were situated >80% for all analysed drugs, except estriol (59%) both in synthetic and real wastewater samples. Conclusions: The developed method has been successfully applied for the analysis of the selected drugs in wastewater samples collected from the influent of a wastewater treatment plant. Highlights: Four NSAIDs and three estrogens from wastewater samples were simultaneously extracted and analysed using only 10 mL of sample and 50 μL of extraction solvent.