SIMULTANEOUS DETERMINATION OF 14 QUINOLONES IN ROYAL JELLY BY LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY USING ANION-EXCHANGE SOLID-PHASE EXTRACTION

A new method based on liquid chromatography-tandem mass spectrometry has been developed for simultaneous determination of 14 quinolones (QNs) residues, including ciprofloxacin, danofloxacin, difloxacin, enoxacin, enrofloxacin, flumequine, lomefloxacin, marbofloxacin, norfloxacin, orbifloxacin, ofloxacin, pipemidic acid, pefloxacin, and sarafloxacin in royal jelly. The proposed analytical procedure involves extraction of the QNs from samples by 0.1 M sodium hydroxide aqueous solution, a step for clean-up and preconcentration of the analytes by anion-exchange solid-phase extraction (SPE) and liquid chromatographic separation with mass spectrometric detection. Internal standard calibration was applied with norfloxacin-D-5 as internal standard (I.S.). Satisfactory recovery (from 64% to 113%), excellent repeatability precision (relative standard deviations, RSDs below 6%), reproducibility precision (RSDs below 10%), and low limits of quantifications (LOQs from 0.3 to 2.5 mu g kg(-1)) were evaluated from spiked royal jelly samples at 2.5, 5.0, and 10.0 mu g kg(-1) three concentration levels. This protocol has been validated by five authoritative laboratories and successfully used for analysis of a large number of import-export samples (n > 2000). Norfloxacin and ciprofloxacin were found to be the most common contamination in royal jelly in the ranges of 3.5-30 mu g kg(-1) and 4.5-20 mu g kg(-1), respectively.