Optimization of sample preparation for the determination of fluoroquinolone antibiotics residues in aquatic products by UPLC-MS／MS

Abstract:

The preparation was optimized for the quantitative and qualitative determination of six fluoroquinolone antibiotics(FQs) in muscles of aquatic products using ultra-performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry (UPLC-MS／MS). Types of extraction, content of formic acid in extraction solution, styles of the cleanup, and amount of dehydrates were discussed for the purpose of reaching the optimal result of sample preparation. Extraction of the FQs was carried out with acid acetonitrile and defatted with n-hexane, while the water in the muscle was removed by sodium sulfate. Separation of the FQs was achieved by using a BEH C18 column under gradient elution at flow rate of 0.20 mL／min with the mobile phases being composed of 0.1％ formic acid solution and acetonitrile. The mass spectrometer was operated in positive ion mode using electrospray ionization in the multiple reaction monitoring (MRM) mode. The standard curves were linear (R²≥0.998) over the concentration ranging from 1.0 to 1 000 μg／L when the limit of detection (LOD) and limit of quantification (LOQ) were 0.1 and 0.2 μg／kg, respectively. Recoveries of the FQs in spiked samples(fish, shrimp and crab) arranging from 2 to 100 μg／kg were between 76.9% and 95.9％ with the relative standard deviation between 4.8％ and 9.2％.