Simultaneous Determination of Residues of Six Kinds of Zeranols in Pork by High Performance Liquid Chromatography-Tandem Mass Spectrometry and Cleaned up by Immunoaffinity Column
A method was established for the determination of residues of six kinds of zeranols in pork based on immunoaffinity column(IAC) purification by high performance liquid chromatography tandem mass spectrometry(LC-MS/MS).Enzymolyzed samples were extracted with ethyl ether,and the extract was vacuum concentrated to dryness and dissolved in trichloromethane.After re-extracted with sodium hydroxide solution and cleaned up by immunoaffinity column,the analyses were carried out on LC-MS/MS.The chromatographic separation was performed on a Shimadzu Shim-pack VP-ODS C18 column with gradient elution by using acetomitrile and 2 mmol/L ammonium acetate solution as mobile phases.Detection was carried out by electrospray negative ionization mass spectrometry in the multiple reaction monitoring(MRM) mode.The linearities(R0.999) were achieved for the 6 compounds over the range of 0.5-200 μg/L.The quantification limits of the method were 0.05-0.63 μg/kg.The recoveries of the 6 compounds were 71.3%-93.7%,and the relative standard deviations were 3.7%-9.7%.The method is sensitive,reproducible,and applicable to analysis trace residues of zeranols in pork.