›› 2018, Vol. 45 ›› Issue (9): 2645-2652.doi: 10.16431/j.cnki.1671-7236.2018.09.038

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Simultaneous Determination of Tilmicosin, Dexamethasone, Florfenicol and Chloramphenicol Residues in Milk by UPLC-MS/MS Method

ZHONG Lingli, GUO Lingan, MAO Jianfei, LI Xi, HU Li, LEI Xinyu, OUYANG Huaxue, LI Huaxian   

  1. Analysis and Testing Center of Sichuan Academy of Agricultural Sciences, Chengdu 610066, China
  • Received:2018-01-09 Online:2018-09-20 Published:2018-09-26

Abstract:

An analytical method was established for the simultaneous determination of tilmicosin,dexamethasone,florfenicol and chloramphenicol in milk by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method.The analytes in milk samples were extracted with acetonitrile,the extract solution was purified by the solid phase extraction cartridge with Oasis PRiME HLB.After concentrated by nitrogen blowing instrument,the analyzed samples were dissolved with sample diluent and excepted fat with n-hexane.The separation was performed on a CAPCELL PAK C18 MG Ⅲ-H column (2 mm×100 mm,3 μm) by gradient elution using methanol(A)-0.1 mmol/L ammonium formate containing 0.01% formic acid (B) as mobile phase:0 to 1.0 min,90% to 60% B;1.0 to 3.0 min,60% to 30% B;3.0 to 4.4 min,30% to 20% B;4.4 to 4.5 min,20% to 90% B;4.5 to 6.0 min,90% B.The analytes were determined by MS/MS under MRM mode,and quantified by matrix-matched external standard method.The results showed that there were good linearities between the peak areas and the concentrations in the range of 1.0 to 100.0 μg/L,with correlation coefficients (r) more than 0.999.The limits of detection (LODs) for the developed method was 0.1 to 0.2 μg/kg,and the limits of quantity (LOQs) was 0.2 to 0.5 μg/kg.Recoveries of 4 compounds ranged from 78.6% to 94.7% when the spiked levels were 0.5,5.0 and 25.0 μg/kg,with the relative standard deviations (RSDs) were 2.4% to 10.1%.Therefore,the developed UPLC-MS/MS method was simple,sensitive and accurate for simultaneous determination of tilmicosin,dexamethasone,florfenicol and chloramphenicol in milk.

Key words: Ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS); milk; tilmicosin; dexamethasone; florfenicol; chloramphenicol

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