Application of neutral loss mode in liquid chromatography–mass spectrometry for the determination of corticosteroids in bovine urine Original Research Article

A method for the determination of seven corticosteroids (triamcinolone, prednisolone, prednisone, dexamethasone, betamethasone, flumethasone, triamcinolone acetonide) in the urine of cattle is described. The sample was separated by LC on C18 cartridges and the corticosteroids were determined using tandem mass spectrometric analysis with an atmospheric pressure chemical ionisation (APCI) interface in single reaction monitoring neutral loss mode. For confirmatory use the samples are analysed in multiple reaction ion mode using the typical fragmentation in positive mode for each compound. Data on precision and accuracy for each compound are presented. Neutral loss mode is suitable for the detection of all the corticosteroids that form an adduct with acetonitrile using the APCI interface thus allowing their simultaneous determination with a limit of detection of 1 μg kg−1 and with no need of extensive purification of the sample. The method fully meets the EU legislation requirement for determination of the banned substances.