Detection of zilpaterol (Zilmax®) in calf urine and faeces with liquid chromatography–tandem mass spectrometry Original Research Article

Zilpaterol is a new powerful beta-agonist, which is officially registered for fattening purposes in cattle in Mexico and South Africa. Its chemical structure is different from the well-known beta-agonists. Therefore, the routinely used screening methods are not likely to be suited for the analysis of zilpaterol. Also gas chromatography–mass spectrometry and liquid chromatography–mass spectrometry (LC–MS) methods need to be adapted to enable detection of zilpaterol. In this study, a LC–MS3 confirmatory method was developed for the simultaneous detection of zilpaterol and di-aromatic beta-agonists in urine samples. A LC–MS2 method was optimised for the detection of zilpaterol in faeces. To study the excretion profile in urine and faeces, a male veal calf was orally treated with daily doses of Zilmax® during 2 weeks. Zilpaterol was mainly excreted via urine.