HPLC-MS/MS Determination of Residual Amounts of 15 Quinolones in Bean Sprouts with Automated Solid Phase Extraction

The bean sprout sample was extracted with EDTA-mcllvaine buffer solution of pH 4.0. MCX solid phase extraction column was used as on-line purification. HPLC-MS/MS was applied to the determination of residual amounts of 15 quinolones in the sample solution. Waters BEH C₁₈ chromatographic column was used as stationary phase, and the mixture of 0.2% (φ, the same below) formic acid solution and 0.2% formic acid acetonitrile solution mixed in different ratios was used as mobile phase in gradient elution. ESI⁺ and multi-reactions monitor mode were adopted in MS/MS. Linear relationships between values of peak area and mass concentration of 15 quinolones were kept in the same range of 5-120 μg·L^-1, with detection limits (3S/N) of 2 μg·kg^-1 and lower limits of determination (10S/N) of 6 μg·kg^-1. On the base of blank sample, test for recovery was made by standard addition method; values of recovery found were in the range of 62.0%-89.3%, with RSDs (n=6) of determined values in the range of 2.4%-11%.