Simultaneous determination of polyether ionophores, macrolides and lincosamides in hen eggs by liquid chromatography-electrospray ionization tandem mass spectrometry using a simple solvent extraction.

A liquid chromatography-electrospray ionization tandem mass spectrometric (LC-ESI-MS/MS) method was developed and validated for the determination of residues of 6 polyether ionophores (lasalocid, maduramicin, monensin, narasin, salinomycin, semduramicin), 3 macrolides (erythromycin, tylosin, clarithromycin) and 1 lincosamide (lincomycin) in eggs. Nigericin was used as qualitative internal standard. Samples were deproteinizated/extracted with acetonitrile without pH adjustments.

A liquid chromatography-tandem mass spectrometry confirmatory assay for the simultaneous determination of several tetracyclines in milk considering keto-enol tautomerism and epimerization phenomena.

A liquid chromatography-electrospray ionization tandem mass spectrometric (LC-ESI-MS/MS) method for the analysis of several tetracyclines residues in bovine milk has been developed. Milk deproteinization/extraction of samples was performed with acidified acetonitrile. After diluting and purification by solid-phase extraction (SPE), the extracts were injected into the instrument operated in Multiple Reaction Monitoring (MRM) acquisition mode.