Abstract: The effects of four pretreatment methods (acetonitrile extraction-evaporation concentration, acetonitrile extraction-solid phase extraction (SPE), matrix solid-phase dispersion (MSPD) extraction and MSPD-SPE) for the simultaneous analysis of diclazuril and toltrazuril residues in chicken tissues were compared. The average recovery of 70% for the former three methods as achieved. In comparison with other methods, the MSPD method saved more than 60% in time and solvent. So, MSPD as the sample pretreatment method, an MSPD-high performance liquid chromatography with ultraviolet detection (MSPD-HPLC/UV) method was established for the analysis. Under the optimal chromatographic conditions, the linear range was between 50 and 1000 μg/kg. At the added levels of 50, 500, 1000 ng/g, the recoveries of diclazuril and toltrazuril in chicken tissues ranged from 71.13%~84.02% with the relative standard deviations (RSD) in the range of 3.76%~12.11%, and the RSDs of intra- and inter-day analyses ranged from 3.70%~6.77%. The detection limits of diclazuril and toltrazuril were less than 10 μg/kg. The quantitative limits of diclazuril and toltrazuril were less than 20 μg/kg. The method meet the requirements of the residue analysis on accuracy and precision.

Key words: chicken tissues , diclazuril, high performance liquid chromatography (HPLC), residues, sample pretreatment, toltrazuril, matrix solid-phase dispersion extraction