Liquid chromatography-thermospray mass spectrometric assay for trenbolone in bovine bile and faeces

A liquid chromatography-thermospray mass spectrometric assay was developed and validated to confirm the presence of illegal residues of the synthetic androgenic growth promoter, trenbolone acetate, in cattle. The assay was specific for 17 alpha-trenbolone, the major bovine metabolite of trenbolone acetate. Methods were developed for the determination of 17 alpha-trenbolone in both bile and faeces, the most appropriate matrices for the control of trenbolone acetate abuse. The clean-up procedure developed relied on enzymatic hydrolysis, followed by sequential liquid-liquid and liquid-solid extraction. The extracts were then subjected to immunoaffinity chromatography. 17 alpha-Trenbolone was detected by selected ion monitoring at m/z 271 using positive ion thermospray ionisation. The limit of detection was approximately 0.5 ng/g in faeces and 0.5 ng/ml in bile.