Novel magnetic nanoparticles as adsorbent in ultrasound-assisted micro-solid-phase extraction for rapid pre-concentration of some trace heavy metal ions in environmental water samples: desirability function

Abstract

In this research, a simple, rapid, and ecofriendly magnetic nanoparticles (MNPs)-based ultrasound-assisted micro-solid-phase extraction (US-µ-SPE) method has been proposed for simultaneous determination of five heavy metal ions [Cu(Π), Ni(Π), Pb(Π), Co(Π), Cd(Π)] in environmental water samples. Here, CoO–Fe2O3@SiO2@TiO2 NPs were synthesized as an efficient adsorbent with excellent adsorption capacity, high dispersion ability and super-magnetic property for the adsorption of the ions. The parameters influencing the extraction efficiency were evaluated and optimized by statistical experimental design. The pH of sample solution, sonication time, dosages of adsorbent, and the volume, concentration and type of elute are 6.50, 14.2 min, 5.5 mg; 300 µL, 2 mol L−1 of HNO3, respectively. Moreover, the reusability for MNPs was six times. The target ions were successfully quantified using a micro-sampling flame atomic absorption spectrometry (MS-FAAS) technique in five different real water samples: tap water, lake water, river water, well water and distilled water. For all studied metal ions, the proposed method provided high recoveries (94.6–103%), high R2 (0.9993–0.9998), low LODs (0.03–0.18 µg L−1) and repeatability (RSD% = 1.49–3.59).