Confirmatory assay for zeranol, taleranol and the Fusarium spp. toxins in bovine urine using liquid chromatography-tandem mass spectrometry

A method is described for the quantitative determination of the veterinary drug zeranol, its epimer taleranol and the mycotoxins zearalenone, alpha-zearalenol and beta-zearalenol in bovine urine. The method is based on liquid chromatography coupled to negative-ion electrospray mass spectrometry-mass spectrometry of urine extracts prepared by solid-phase extraction with C-18 columns. Two transition ions at m/z 277 and 91 are monitored for zeranol and taleranol along with the transition ion at m/z 281 for their respective deuterated (d(4)) internal standards. Similarly, two transitions are monitored for each of the three mycotoxins along with a transition ion for each of their corresponding internal standards. The method has been validated according to the new European Union criteria for analysis of veterinary drug residues, and is suitable for monitoring urine samples taken under National Surveillance Schemes. The method has been validated at 1, 1.5 and 2 ng ml(-1) for zeranol and taleranol and at 5, 10 and 15 ng ml(-1) for each of the three mycotoxins. Correlation between the described method and a routine method, based on gas chromatography-mass spectrometry, was assessed using a range of naturally incurred samples.