An adsorbent composed of alginate, polyvinylpyrrolidone and activated carbon (AC@PVP@alginate) for ultrasound-assisted dispersive micro-solid phase extraction of nevirapine and zidovudine in environmental water samples

In this study, AC@PVP@Alginate adsorbent synthesized using a facile cross-linking method was characterized using various techniques. The scanning electron microscopy and N₂-adsorption/desorption analysis results confirmed that the synthesized nanocomposite was porous with a large specific surface area of 372 m² g⁻¹. The porous structure, a large surface area and multiple functional groups make the adsorbent suitable for efficient adsorption of target analytes. The adsorbent was applied in an ultrasonic-assisted dispersive micro-solid phase extraction for determining trace nevirapine and zidovudine in environmental water samples prior to high-performance liquid chromatography equipped with diode array detector analysis. Response surface methodology based on central composite design was applied for experimental parameters optimization. Under optimum experimental conditions, the method exhibited relatively acceptable intra-day precision, expressed as relative standard deviation, of ≤4.8%, low detection limits (LOD) and quantification limits (LOQ) ranging from 0.20 to 0.23 μg L⁻¹ and 0.67–0.75 μg L⁻¹, respectively. A spike recovery approach was used to assess the method applicability to real water samples and satisfactory relative recoveries ranging from 91.6 to 99.1% were obtained. The analysis of real water samples confirmed the presence of both analytes with maximum concentrations of 1.72 μg L⁻¹ in influent wastewater.