Development and validation of a multi-residue method for determination of antimicrobial sulfonamides, macrolides and quinolones in Iranian feta cheese by SPE clean-up and LC-MS/MS

Abstract

A selective and sensitive multi-residue/multi-class ultra-performance liquid chromatography–tandem mass spectrometry method has been validated for simultaneous analysis of 25 antibiotic residues belong to sulfonamides, macrolides, and quinolones groups, as well as griseofulvin and trimethoprim, in Iranian feta cheese samples. Two specific precursor – product ion transitions were acquired per target compound by a positive electrospray ionisation in multiple reaction monitoring mode. Results were obtained as follows: limit of detection (LOD) and limit of quantification (LOQ) were respectively 3.3 ng g−1 and 10 ng g−1 (except for josamycin, LOD: 8.33 and LOQ: 25 ng g−1). Average recovery ranged between 70% and 120% and relative standard deviation of repeatability was lower than 20%. Finally, the method was applied to determination of target analytes in feta cheese samples obtained from the local hypermarkets and traditional dairy product markets in Tehran, Iran.