Simultaneous determination of fluoroquinolones residues in sediment by dispersive solid-phase extraction combined with high performance liquid chromatography-tandem mass spectrometry

An efficient method was established for the determination of fluoroquinolones in sediment by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) combined with dispersive solid-phase extraction.The samples were ultrasonically extracted with 20 mL phosphate buffer solution and acetonitrile mixture (1:1,V/V),followed by 0.15 g ethylenediamine tetraacetic acid disodium salt complexation.Then the supernatant extract was cleaned up with a dispersive solid-phase extraction.The analytes were separated on a Ultimate XB-C₁₈ column by gradient elution with 4 mmol/L ammonium acetate-0.1% formic acid -0.1% formic acid methol as mobile phase,detected in multiple reaction monitoring (MRM) with electrospray ionization (ESI) under positive ion mode.And the quantitative results were calculated by the internal standard method.The results showed that the calibration curves were linear (R²>0.99) in the range of 2.5~200 ng/mL for five fluoroquinolones.Limits of quantitation for fluoroquinolones were 2 μg/kg.The average recoveries at spiked levels of 2~50 μg/kg ranged from 79.8% to 112%.Intra-day and inter-day RSDs were 3.2%~9.9% and 5.3%~8.6%,respectively.