▎ 摘　　要

Silica-coated magnetic graphene nanocomposite (designated Fe3O4@SiO2/graphene) was synthesized and applied for preconcentration of Cd in different water samples. The extraction process was achieved in a single step by mixing the chelating agent, adsorbents and water samples via ultrasound-assisted action. The magnetic adsorbents were isolated from sample solution with an adscititious magnet. The eluted metal ions from the adsorbents was analysed by flame atomic absorption spectrometry. The advantages of the new method include short analysis time and simple extraction procedure. Under optimum conditions, the relative standard deviation of 300.0 mu g L-1 Cd was 4.54%. A concentration factor of 25.0 and the detection limit of 0.54 mu g L-1 for Cd was obtained. Satisfactory recoveries (90.5-98.5%) were achieved in four real environmental water samples.