ABSTRACT
A high performance liquid chromatography-tandem mass spectrometric( HPLC-MS/MS) method was developed for the simultaneous determination of four phenolic and salicylanilide anthelmintics including nitroxinil, oxyclozanide, closantel and rafoxanide in cattle and ovine tissues. Muscle, liverand kidney were extracted with acetonitrile-acetone(60:40, V/V)and fat with 1% triethylamine in acetonitrile, then the extract was purified with MAX solid-phase extraction column. Qualitative and quantitative analysiswas achieved by HPLC-MS/MS undernegative multiple reaction monitoring ( MRM) mode. Good correlation coefficients were obtained (R>0. 99) in the concentration range of 1-100 μg/L. The limits of detection (LOD) and limits of qualification (LOQ) for the four compounds were 1 and 2. 5 μg/kg, respectively. The mean recoveries at the four levels of LOQ, 0. 5 maximum residue limit (MRL), MRL, 2MRL were between 71% and 112%,with the intra-day relative standard deviation(RSD)in the range of 1. 1%-14. 0%and inter-day RSD in the range of 6. 4%-14. 7%. Forty samples from the market were analyzed with the method, only two samples were found to show phenolic and salicylanilide anthelmintics residues.