Determination of penicillins in milk using LC-UV, LC-MS and LC-MS/MS.

The aim of this work is to establish a method for the simultaneous determination of eight penicillins in milk samples by LC-UV, LC-MS and LC-MS/MS. The procedure involves a step for clean-up and to preconcentrate the analytes by SPE and a subsequent chromatographic analysis. LC-UV, LC-MS and LC-MS/MS have been used for the simultaneous quantification of penicillins in milk. The proposed methods have been validated according to the EU guideline and present LOQ below the maximum limits of residues (MRLs) established by the European Union for penicillins in milk. The developed methods were applied to different milk samples obtained from cows medicated with penicillins.