Simultaneous determination of 11 quinolone residues in freshwater fish samples by magnetic solid-extraction coupled to liquid chromatography-tandem mass spectrometry

In this study, well-defined core-shell ethylenediamine-functional magnetic ferroferric oxide polymers were prepared and were fully characterized by transmission electron microscopy, scanning electron microscopy, FTIR spectroscopy, and vibrating sample magnetometry. Then, it was used as a magnetic solid-phase extraction adsorbent for simultaneous determination of 11 trace quinolone residues in freshwater fish samples coupled to liquid chromatography-tandem mass spectrometry. The obtained results revealed that the adsorbent showed good extraction efficiency and the adsorption mechanisms referred to hydrogen bond and pi-pi stacking interaction. Moreover, the magnetic solid-phase extraction conditions were also carefully optimized. The limits of quantitation of 11 quinolones were in the range of 0.15-0.36 mu g/kg, while spiking recoveries were in the range of 80.2-99.5% for the 11 quinolones in freshwater fish samples at four spiked levels including limits of quantitation, 1.0, 40.0, and 80.0 mu g/kg with the relative standard deviations ranging from 0.8 to 9.1%. The proposed method was applied to analyze 45 freshwater fish samples, and enrofloxacin was detected in 91.1% samples with concentrations ranging from 0.659 to 333 mu g/kg. It could be concluded that the proposed method is fast, simple, sensitive, and accurate for the routine monitor of freshwater fish.

Automated summary

In this study, a well-defined magnetic solid-phase extraction adsorbent with good extraction efficiency was prepared and successfully applied for the simultaneous determination of 11 quinolone residues in freshwater fish samples. The results showed that the proposed method is fast, accurate, and suitable for routine monitoring of freshwater fish.