Magnetic dispersive solid phase extraction with graphene/ZnFe2O4 nanocomposite adsorbent for the sensitive determination of mercury in water and fish samples by cold vapor atomic absorption spectrometry

In this study, the magnetic graphene/ZnFe2O4 composite material was synthesized and characterized by X-ray diffraction, scanning electron microscopy equipped with energy dispersive (X-ray spectrometry), Brunauer, Emmett and Teller surface area and zeta potential measurements. This material was investigated for the first time as an adsorbent for the magnetic dispersive solid phase extraction of Hg(II) ions from various samples. Mercury determination in solutions was made by using cold vapor atomic absorption spectrometry. The experimental conditions affecting the preconcentration of mercury were optimized. They were found as follows: sample pH, 6; adsorption and elution contact time, 3 min; elution solvent, 5 mL of 2 mol L−1 HCl. The preconcentration factor, detection limit, and precision (as RSD%) of the method were found to be 30-fold, 10 ng L−1, and 2.7% for mercury, respectively. The developed method was successfully verified by analyzing certified reference materials (DOLT-4 Dogfish Liver and NCS ZC 81002b Human Hair) and by recovery experiments in SPS-WW1 wastewater, tap water, well water, wastewater and fish samples.