Determination of 25 quinolones in water and milk by a magnetic sorbent Fe3O4@SiO2-HBTA-TTA-COF combining with UPLC-MS/MS

In this study, a novel magnetic covalent organic framework (Fe 3 O 4 @SiO 2 -HBTA-TTA-COF) was synthesized, which was fully characterized by scanning electron microscopy, transmission electron microscopy, etc. Furthermore, a new method was developed for the determination of 25 quinolones (QNs) in water and milk using the Fe 3 O 4 @SiO 2 -HBTA-TTA-COF as magnetic solid-phase extraction adsorbent coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Meanwhile, various experimental parameters were optimized including sample solution pH, adsorbent dosage and extraction time, etc. Under the optimal conditions, good linearity in the range of 0.1–200 μg·L −1 (R 2  ≥ 0.999) were obtained, the recoveries of 25 QNs were 70.04 %–104.4 % with the relative standard deviations lower than 9.87 % (n = 5), the limits of detection were 0.003–0.010 μg·L −1 for water and 0.018–0.722 μg·kg −1 for milk. This established method was high-sensitive and high-throughput, which can be used as a good alternative method for the selective determination of 25 QNs in water and milk.