Removal, preconcentration and determination of Ni(II) from different environmental samples using modified magnetite nanoparticles prior to flame atomic absorption spectrometry

In this paper, a simple, fast and reliable solid phase extraction (SPE) method to determine Ni(II) using dimethylglyoxim/sodium dodecyl sulfate-immobilized on alumina-coated magnetite nanoparticles (DMG/SDS-ACMNPs) as a new adsorbent prior to its determination by flame atomic absorption spectrometry (FAAS) is described. Under the optimal experimental conditions, the preconcentration factor, detection limit, linear range and relative standard deviation (RSD) of nickel(II) ions were 320 (for 800 mL of sample solution), 4.6 ng mL−1, 10.0–100.0 ng mL−1 and 1.9% (for 50.0 ng mL−1, n = 7), respectively. This method avoided the time-consuming column-passing process of loading large volume samples in traditional SPE through the rapid isolation of DMG/SDS-ACMNPs with an adscititious magnet. The proposed method was successfully applied to determine the content of Ni(II) in soil, spinach, tomato, black tea, tobacco and different water samples and suitable recoveries were obtained.