Magnetic hydrophobic deep eutectic solvents for orbital shaker-assisted dispersive liquid-liquid microextraction (MAGDES-OS-DLLME)- Determination of nickel and copper in food and water samples by FAAS

In this work, a cheap and widely applicable dispersive liquid-liquid microextraction (DLLME) method was developed for the extraction of Ni(II) and Cu(II) from water and food samples and analysis using flame atomic absorption spectrometry. DLLME was assisted by orbital shaker, while ferrofluid as an extractant was based on deep eutectic solvent (DES). This ferrofluid was made of hydrophobic DES (hDES), composed of lauric acid and menthol (molar ratio 1:2), and toner powder@aliquat 336 magnetic particles. The extraction procedure does not require any heating or centrifugation. The method limits of detection value were 0.15 mu g L-1 and 0.03 mu g L-1 for Ni(II) and Cu(II) respectively along with wide linearity range (0.4-250 mu g L-1). The validation of the method was performed using certified reference materials (CRMs). The studies revealed excellent accuracy between results obtained by the developed method and expected values for all CRMs. The relative recoveries of Ni(II) and Cu(II) ions ranged from 92.8% to 98.6%. The developed method was further used for the determination of Ni(II) and Cu (II) in real water and food samples and provided quantitative recoveries.