Magnetic hierarchical nickel/nickel oxide/carbon nanorods (Ni/NiO@C) were prepared via the pyrolysis of a metal-organic
framework containing nickel(II) nickel (Ni-MOF; Ni3(BTC)2) under argon atmosphere. In this material, magnetic Ni/NiO@C
nanoparticles are embedded in porous carbon nanorods, and the morphology is similar to that of the original Ni-MOF precursor.
The synthesized nanorods were applied as magnetic sorbents in the solid-phase extraction of five benzoylurea insecticides
(flufenoxuron, chlorbenzuron, teflubenzuron, diflubenzuron and triflumuron), and their performance was evaluated under opti-
mized conditions. The results show that the material exhibits high extraction recoveries from spiked samples (82.9%–107.6%)
and linear response in the range of 0.2–450μg·L−1. It is also characterized by relatively low limits of detection (50–100 ng·mL−1)
at a signal-to-noise ratio of 3. The sorbent is chemically stable and can be repeatedly recycled, with little decline in extraction
capacity after 20 cycles of reuse. The method was successfully applied to the quantification of benzoylureas in tea, wolfberry,
millet, and oat samples, and it showed high extraction efficiency.