A high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) was developed for the simultaneous determination of seven macrolide antibiotics

ie.tilmicosin

roxithromycin

spiramycin

tylosin

erythromycin

clarithromycin and azithromycin in additive premix

concentrate supplement

complete feed and concentrated feed.The samples were extracted with 1% ammoniated acetonitrile solution

followed by Oasis PRiME HLB solid phase extraction for further purification.The analytes were separated on an ACQUITY UPLC BEH C18 column(2.1 mm×100 mm

1.7 μm) by gradient elution using 0.1% formic acid solution and acetonitrile as mobile phases

then analyzd by MS/MS with electrospray ionization in positive mode

and quantified by external standard method.Results showed that there were good linear relationships for 3 target analytes

ie.tilmicosin

spiramycin and erythromycin in the concentration range of 0.5-50 μg/L(r2>0.99) and for the other 4 target analytes in the range of 0.25-50 μg/L(r2>0.99).The limits of detection and the limits of quantitation were in the ranges of 1.25-2.5 μg/kg and 2.5-5.0 μg/kg

respectively.At three spiked levels of 5

10 and 50 μg/kg

the average recoveries for target compounds ranged from 61.4% to 103% with relative standard deviations of 0.43%-15%.The developed method is simple

rapid

sensitive and low matrix interference

and it is suitable for the routine supervision and quantitative detection of macrolide antibiotics in different feeds.