Ultrasound-assisted solid-phase extraction of parabens from environmental and biological samples using magnetic hydroxyapatite nanoparticles as an efficient and regenerable nanosorbent

Magnetic hydroxyapatite nanoparticles (γ-Fe₂O₃@HAP) are shown to be a viable sorbent for the preconcentration and adsorption of parabens (specifically of methyl-, ethyl-, propyl-, butyl-, pentyl-, phenyl- and benzylparaben). The average diameter of the magnetic γ-Fe₂O₃@HAP nanoadsorbents is 25 nm. The effects of amount of nanoadsorbent, pH value and time of adsorption on the adsorption efficiency were studied by chemometry and optimized using a Box–Behnken design, and the respective response surface equations were derived. The loaded magnetic nanoadsorbent can be removed from the aqueous sample by applying an external magnetic field. Following extraction with acetonitrile, the parabens were quantified by gas chromatography with mass spectrometric detection. Under optimum condition, the limit of detection (LOD) and adsorption efficiencies of the method are in the range from 5 to 10 μg L⁻¹ and 95–106%, respectively. The preconcentration factors range from 320 to 350. The results demonstrate that this nanoadsorbent can be applied to the removal of parabens from different water, soil, beverage and urine samples. [Figure not available: see fulltext.].