Liquid chromatography tandem mass spectrometry analysis of coccidiostats residues in eggs

The aim of the present work is the development of a rapid and effective analytical procedure for the determination of coccidiostats in eggs. Nicarbazin, robenidine, diclazuril, clazuril, toltrazuril and its metabolite were diluted by distilled water and subjected to clean-up by SPE styrene-divinylbenzene columns. Coccidiostats were eluted with methanol and determined by using HPLC-MS/MS. Separation was carried out on ODS column in gradient mode, with methanol–water mixture acidified with 0.1% formic acid as an eluent. Tandem mass spectrometry analysis was performed with turboion spray ionisation in positive and negative ion mode by using multi reaction monitoring (MRM). The procedure has been successfully applied for eggs during routine and confirmatory analysis. Validation was performed according to Commission Decision 2002/657/EC criteria by determining linearity, precision, recovery, specificity, decision limit (CCα) and detection capability (CCβ). The recovery of coccidiostats ranged from 80% to 94%, with R.S.D. of 15% for all coccidiostats under investigation