Simultaneous determination of nine fluoroquinolones in egg white and egg yolk by liquid chromatography with fluorescence detection

A liquid chromatographic (LC) method with fluorescence detection was developed for determination of nine fluoroquinolones (FQs) in egg white and yolk. Egg white samples were deproteinized with acidified ethanol (egg yolk samples with acetonitrile and acidified ethanol), followed by defatting with hexane once (white) or twice (yolk), and extracting FQs into acetonitrile. After acetonitrile was evaporated, the residue was dissolved in mobile phase, and FQs were detected in LC with a fluorescence detector. Recoveries for nine FQs from white and yolk were 74.7-85.6%, 79.1-91.2%, respectively, with excellent relative standard deviations. The limits of quantification were 5-20 ng g−1.