Determination of fluoroquinolone drugs in meat by ionic-liquid-based dispersive liquid–liquid microextraction-high performance liquid chromatography
In this study, the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]) was used to develop a dispersive liquid–liquid microextraction method for the extraction of four fluoroquinolone drugs in meat, followed by determination with high performance liquid chromatography. During the experiments, some important parameters (choice of the ionic liquid and its volume, choice of the dispersive solvent and its volume, extraction and centrifugation times, pH and addition of salt) were investigated and optimized. Under the optimal conditions, the method achieved different enrichment factors (11–42 fold) for four fluoroquinolones (norfloxacin, ciprofloxacin, lomefloxacin, enrofloxacin). The results showed that the limits of detection for the four drugs were in the range of 0.5–1.1 ng mL−1 and their recoveries from fortified blank meat standards (chicken, pork and fish) were in the range of 60.4–96.3% with coefficients of variation lower than 11.5%. Among 60 real meat samples, seven samples were determined to contain residues of norfloxacin, ciprofloxacin and enrofloxacin, but the residue levels were lower than their maximum residue levels (100 ng g−1).