Preconcentration of trace cadmium ion using magnetic graphene nanoparticles as an efficient adsorbent

Graphene-based magnetic nanoparticles (G-Fe3O4) were prepared and used as an effective adsorbent for the solid-phase extraction of trace quantities of cadmium from water and vegetable samples. The method avoids some of the time-consuming steps associated with traditional solid phase extraction. The excellent sorption property of the G-Fe3O4 system is attributed to pi - pi stacking interaction and hydrophobic interactions between graphene and the Cd-PAN complex. The effects of pH, the amount of G-Fe3O4, extraction time, type and volume of eluent, desorption time and interfering ions on the extraction efficiency were optimized. The preconcentration factor is 200. Cd(II) was then quantified by flame atomic absorption spectrometry with a detection limit of 0.32 ng mL(-1). The relative standard deviation (at 50 ng mL(-1); for n = 10) is 2.45 %. The method has a linear analytical range from 1.1 to 150 ng mL(-1), and the recoveries in case of real samples are in the range between 93.1 % and 102.3 %.