Ultrasonic assisted magnetic solid phase extraction based on the use of magnetic waste-tyre derived activated carbon modified with methyltrioctylammonium chloride adsorbent for the preconcentration and analysis of non-steroidal anti-inflammatory drugs in wastewater

In this study, a magnetic waste-tyre derived activated carbon modified with methyltrioctylammonium chloride, was successfully synthesized, characterised, and applied for the extraction and preconcentration of four non-steroidal anti-inflammatory drugs in wastewater. The scanning electron microscopy and N₂-adsorption/desorption analysis results confirmed that the synthesized nanocomposite was porous with a large specific surface area of 570 m² g⁻¹. The significant factors affecting the Ultrasonic assisted magnetic solid phase extraction method were investigated using univariate approach and response surface methodology. The optimum conditions for the extraction and preconcentration of the target analytes were 0%, 15 min, 6.5 and 30 mg, for ionic strength, extraction time, pH and adsorbent mass respectively. The quantification of the target analytes was performed using high performance liquid chromatography equipped with diode array detector. Under optimum conditions, low limits of detection and quantification ranging between 0.054–0.38 μg L⁻¹ and 0.18–1.27 μg L⁻¹, respectively, were obtained. A wide linearity (ranging from limit of detection – 500 μg L⁻¹ with R² ≥ 0.99) and precision lower than 7%, were achieved. The applicability of proposed method was evaluated for the determination of naproxen, ketoprofen and diclofenac in wastewater.