Determination of Bisphenol A in Water Samples by HPLC–UV After Magnetic Solid-Phase Extraction Using Nanoparticles Derived from Iron Mining Tailings

A magnetic nanosorbent was synthesized from a ferric precursor recovered from iron mining tailings and applied in magnetic solid-phase extraction (MSPE) for the determination of bisphenol A (BPA) in aqueous matrices. An analytical method based on high-performance liquid chromatography with UV detection (HPLC–UV) was developed for the extraction and determination of BPA in water samples. BPA is classified as an emerging contaminant and an endocrine-disrupting compound due to its potential to interfere with the endocrine system. The Fe 3 O 4 @SiO 2 –NH 2 nanosorbent was prepared using ferric ions obtained via acid leaching of mining tailings, an abundant industrial waste. The material was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), scanning electron microscopy (SEM), transmission electron microscopy (TEM), pH at the point of zero charge (pHPZC), and wettability measurements. The MSPE procedure was optimized by evaluating the elution solvent, sample pH, eluent volume, sample volume, sorbent amount, and stirring time. The method exhibited good linearity (R 2 > 0.99), with limits of detection and quantification of 30 and 80 ng mL −1 , respectively. Intra- and interday precision and accuracy showed relative standard deviation (RSD) and relative error (RE) values below 15%. The proposed method was successfully applied to real water samples, and its greenness was evaluated using AGREEprep and AGREE metrics. The use of iron mining tailings as a secondary source of ferric precursor represents a sustainable and cost-effective strategy for the preparation of functional magnetic nanomaterials.