Qualitative and quantitative determination of tilmicosin in poultry eggs by gas chromatography tandem mass spectrometry after derivatization with acetic anhydride.

A novel GC-MS/MS analytical method was established for the qualitative and quantitative determination of tilmicosin in poultry (Jinghai yellow chicken, Gaoyou duck and Yangzhou goose) eggs. The method was based on LLE and SPE for sample extraction and purification. Pyridine and acetic anhydride were used for the derivatization reaction. When tilmicosin was added to blank poultry egg samples at the LOQ and 75 μg/kg, 150 μg/kg, and 300 μg/kg, the recoveries ranged from 72.80% to 88.75%, the intraday and interday RSDs ranged from 2.31% to 4.56% and 3.29%-5.61%, respectively, and the LODs and LOQs ranged from 3.8 to 5.6 μg/kg and 8.4-10.5 μg/kg, respectively. These results confirmed that the parameters of this novel method meet the requirements of the FAO & WHO (2014) for veterinary drug residue testing. Poultry egg samples purchased from the local market were analysed according to the established method and only one egg sample was found to contain 18.9 μg/kg of tilmicosin.