Self-assembled Fe3O4-NH2 @g-C3N4 composite for magnetic solid-phase extraction of benzophenones in sea water and lake water coupled with LC-MS/MS determination

Magnetic solid-phase extraction (MSPE) was developed based on a well-designed Fe 3 O 4 -NH 2 @g-C 3 N 4 nanocomposite as sorbent for a mixture of six benzophenones (BPs) in environmental water samples. The composite fabricated via in-situ self-assembled g-C 3 N 4 shell with homogeneous polymerization of cyanuric chloride and cyanuric acid on Fe 3 O 4 -NH 2 core. While high adsorption capacity was derived from g-C 3 N 4 via hydrophobic, π-π and hydrogen bonding interactions to the targets, the fast magnetic separation was realized with Fe 3 O 4 core for less solvent consumption. In combination with LC-MS/MS, the Fe 3 O 4 -NH 2 @g-C 3 N 4 sorbent minimized the interfering components, reduced the matrix effects, and provided the enrichment factors of 121–150 for six BPs with relative standard deviations ≤ 9.7% even after 20 times extraction-desorption cycles. The present method gave the detection limits of 0.3–2.5 ng/L for six BPs with the linear ranges of 1.0–2000 ng/L, and the recoveries of 84.6%−104% in sea water and 86.2%−107% in lake water samples. Thus, the Fe 3 O 4 -NH 2 @g-C 3 N 4 -based MSPE coupled with LC-MS/MS method provided a convenient, efficient, and reliable alternative to monitor trace BPs in environmental water samples.