Preparation of ionic liquid-modified SiO₂@Fe₃O₄ nanocomposite as a magnetic sorbent for use in solid-phase extraction of zinc(II) ions from milk and water samples

摘要

In this study, silica-coated magnetite nanoparticles modified with triethoxysilylpropylpyridinium hexafluorophosphate ionic liquid were synthesized and used as a sorbent for the solid-phase extraction and preconcentration of zinc ions from aqueous solutions. The structure and morphology of the synthesized nanosorbent were characterized by X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. After desorption with acidic ethanol, zinc was quantified by flame atomic absorption spectrometry. The experimental factors affecting the extraction/preconcentration of the analyte were investigated and optimized. Under the optimized experimental conditions, the calibration graph was linear in the concentration range of 0.5–15 ng mL?1 (with an R2 value of 0.998). The limit of detection and the preconcentration factor were 0.17 ng mL?1 and 100, respectively. The relative standard deviation for six replicate determinations of 10 ng mL?1 Zn was 2.3%. The method was validated by the successful analysis of a standard reference material (NIST SRM 1549; non-fat milk powder) and employed for the determination of zinc in several samples of water and milk, with recoveries in the range of 97.0–102.5% for the spiked samples.