Determination of zeranol, taleranol, zearalanone, -zearalenol, -zearalenol and zearalenone in urine by LC-MS/MS

An LC-MS/MS method was developed for the sensitive and selective determination of zeranol, taleranol, zearalanone, -zearalenol, -zearalenol and zearalenone in animal urine. Analysis was performed on the free compounds after enzymatic deconjugation. Sample preparation included liquid-liquid extraction followed by solid-phase extraction (SPE) with C-18 and NH2 columns. For chromatographic separation of hormones an Inertsil((R)) ODS-3 analytical column (150mmx2.1mm, 3 mu m) was used. The analytes were determined and identified by LC-MS/MS on a QTRAP5500 instrument with a TurboIon-Spray source operating in negative electrospray ionisation mode. For confirmatory purposes at least two transitions were obtained for each analyte. According to Commission Decision 2002/657/EC the validation parameters - recovery, repeatability, reproducibility, linearity, specificity, decision limits and detection capabilities - were determined. All parameters were in agreement with 2002/657/EC performance criteria. The apparent recovery ranged from 76.2% to 116.3% for all examined compounds. The repeatability was below 20% and reproducibility did not exceed the limit of 25% for most analytes. Linearity was good for all analytes in the whole range of tested concentrations, as proved by the correlation coefficients greater than 0.99. The decision limits (CC) ranged from 0.04 to 0.18 gl(-1) for all analytes whereas the detection capabilities (CC) ranged from 0.07 to 0.31 gl(-1), respectively. All CC and CC values were below the recommended concentration of 2gl(-1). This analytical method will be used in an integrated system for Polish monitoring programmes for the confirmation of violative screened samples.