RESUMO
A sensitive and effective method for determination of 16 kinds of antibiotics, including tetracycline, sulfonamide, fluoroquinolone and macrolide, in livestock and poultry manure using solid phase extraction-ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established.Aiming at the chemical properties and sample impurities of the target, the parameters such as mass spectrum conditions, types of extraction and ultrasonic power were optimized.Finally, the samples were extracted with 50% acetonitrile in phosphate buffer solution (pH =4) for three times, followed by ultrasonic steaming, centrifugal and rotary, dilution, and purified by SAX-HLB.After sample loading, the solid phase was washed with 10 mL of methanol-acetone (80∶20, V/V), evaporated to near dryness at 35℃, and then re-dissolved and vortex mixed in 1 mL of 0.1% formic acid∶methanol (1∶1, V/V).The extracts were analyzed with UPLC-MS/MS and calculated by external standard method based on the monitored product ion.The results indicated that the average spiked recoveries of tetracycline, sulfonamide, fluoroquinolone and macrolide in manure were 56.4%-94.6% with relative standard deviations (RSDs) of 2.6%-19.8%, the LODs (S/N=3) were 0.01-2.50 μg/kg, and the LOQs (S/N=10) were 0.05-7.90 μg/kg.The method was simple with high stability, high sensitivity and good reproducibility, and suitable for the simultaneously determination of many antibiotics in animal and poultry manure.