Utilizing nanoflower-like NiFe2O4 for dispersive micro solid phase extraction of copper at ultratrace level in food and water samples.

Nanoflower-like NiFe2O4 (NFO-NF) was synthesized and employed to develop a dispersive micro solid phase extraction procedure for copper. NFO-NF was characterized by Fourier-transform infrared spectroscopy (FT-IR), scanning transmission electron microscopy (STEM), scanning electron microscopy-dispersive X-ray spectroscopy (SEM-EDX), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD). The optimal conditions for experimental parameters were pH: 8.0, adsorbent dose: 2 mg, both adsorption and desorption times: 60 s, sample volume: 30 mL, and eluent: 1.0 mL of 1.0 mol L-1 HNO₃. An effective enrichment factor (30-fold) for copper was obtained. The limit of detection and limit of quantitation of Cu (II) were 2.1 μg L-1, 8.5 μg kg-1, and 7.0 μg L-1, 25.4 μg kg-1 for water and food samples, respectively. The suggested method's accuracy was verified by certified reference materials with recoveries of higher than 90 %. The copper content of food and water samples was successfully determined by using presented method.