Determination of 22 Quinolones Antibiotics Residues in Milk by Ultra Performance Liquid Chromatography with Electrospray Ionization Tandem Mass Spectrometric Detection

The ultra performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS) method has been developed for 22(fluoro)quinolone(QNs) antibiobtics in milk with multiple reaction monitoring(MRM).The analytes were extracted from the sample using Mcllvaine buffer by ultrasonic bath,and purified by solid-phase extraction(SPE) cartridge.The residue was dried under nitrogen and dissolved to UPLC-MS/MS.The interference of matrix was reduced by the matrix-matched calibration standards curve.The linear range was from 3 μg/kg to 300 μg/kg for pipemidic acid,enrofloxacin,cinoxacin,oxolinic acid,from 5 μg/kg to 500 μg/kg for pazufloxacin,from 0.5 μg/kg to 50 μg/kg for ofloxacin,gatifloxacin,sparfloxacin,from 1 μg/kg to 100 μg/kg for other 14 QNs with the good correlation coefficients(r≥0.9851).The lower limit of quantification was 0.008 μg/kg to 0.339 μg/kg.The recoveries were 63.1%-94.6%,0.86%-13.12%,respectively,with relative the standard deviations of 0.86%-13.12%.But the recoveries were lower than 60% for flumequine,nalidixic acid and nadifloxacin.The method is simple,accurate and sensitive for the simultaneous determination of 22 QNs.