One pot synthesis of magnetic graphene/carbon nanotube composites as magnetic dispersive solid-phase extraction adsorbent for rapid determination of oxytetracycline in sewage water.

A simple and time-saving one pot synthesis of magnetic graphene/carbon nanotube composites (M-G/CNTs) was developed that could avoid the tedious drying process of graphite oxide, and G/CNTs were modified by Fe 3 O 4 nanoparticles in the reduction procedure. It contributed to a shorten duration of the synthesis process of M-G/CNTs. The obtained M-G/CNTs were characterized and the results indicated that CNTs and Fe 3 O 4 nanoparticles were served as spacer distributing to the layers of graphene, which was beneficial for enlarging surface area and improving extraction efficiency. Moreover, M-G/CNTs showed good magnetic property and outstanding thermal stability. Then M-G/CNTs were applied as adsorbent of magnetic dispersive solid-phase extraction for rapid extraction and determination of oxytetracycline in sewage water. Under the optimum conditions, good linearity was obtained in the range of 20–800   ng   mL −1 and the recoveries were ranged from 95.5% to 112.5% with relative standard deviations less than 5.8%.