Determination of Benzimidazoles and Its Metabolites Residues in Milk by UPLC-MS/MS

A method based on UPLC-MS/MS has been developed for the determination of benzimidazoles and its metabolites residues in milk.The samples were precipitated by acetonitrile,and the analytes were extracted with ethyl acetate.Then the extract was cleaned by MCX solid phase extraction cartridge.Quantification of all the analytes was achieved by UPLC-MS/MS with multiple reaction monitoring(MRM) using external standard method.Detection limits and quantification limits of this method for the analysis were all 5 and 10 μg/g.The overall recovery varies from 69.9%～113.1% at the spiked level of 10～200 μg/L,and the intra-and inter-batch coefficients was from 1.36%～11.48% and from 1.09%～9.87%,respectively.The method was reliable,sensitive and reproducibility,its performance can meet the requirements of the domestic and international legislation.The method adapts to the determination of benzimidazoles and its metabolites residues in milk.