▎ 摘　　要

Graphene oxide nanosheets were modified with magnetite nanoparticles, and a hyperbranched polyamidoamine dendrimer was then covalently attached to their surface. The resulting material is shown to be an efficient sorbent for preconcentration of the synthetic dyes tartrazine, quinoline yellow, sunset yellow and carmoisine via ultrasound-assisted magnetic solid phase extraction. The electrostatic interaction and hydrogen bonding were considered to be the main mechanism for the dyes adsorption. The sorbent was characterized by transmission electron microscopy, field emission scanning electron microscopy, FT-IR, X-ray diffraction and vibrating sample magnetometry. The effects of pH value, sorbent dosage, eluent volume, and sonication time were optimized by central composite design and desirability function. The dyes were quantified by HPLC with detection at 450 nm. Under optimized conditions, the method has a linear response in the 2-3000, 5-2000, 1-5000 and 22500 ng.mL(-1) concentration range for tartrazine, quinoline yellow, sunset yellow and carmoisine, respectively. The limits of detection are as low as 0.6, 1.5, 0.3 and 0.6 for tartrazine, quinoline yellow, sunset yellow and carmoisine, respectively.