Identification of main corticosteroids as illegal feed additives in milk replacers by liquid chromatography–atmospheric pressure chemical ionisation mass spectrometry

Corticosteroids were proposed as growth promoting agents to improve commercial quality of meat. We developed a liquid chromatography–atmospheric pressure chemical ionisation mass spectrometry (LC–APCI-MS) method able to identify the presence in milk replacers, when given by mouth, of dexamethasone, betamethasone, flumethasone, triamcinolone, prednisone, prednisolone, methylprednisolone, fludrocortisone and beclomethasone, at levels in the range of 20–100 ppb. C 18 solid-phase extraction, LC-RP C 8 column separation, data acquisition (positive ions) in the scan range m/ z 200–550 allowed us to differentiate and identify compounds by protonated molecules, their methanolic adducts and fragmentation patterns.