Abstract: A method has been developed to determine residual stilbenes such as diethylstilbestrol (DES), dienestrol (DIS) and hexestrol (HS) in animal tissues using solid phase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS). The procedures for extraction, cleanup on an LC-Si solid phase extraction cartridge and derivatization of stilbenes were established and optimized. The analytes were detected by mass spectrometer with electron impact source in selected ion monitoring mode(EI/SIM), and quantified with an external standard calibration curve method. Linear calibration curves were obtained in the concentration ranges from 5 to 500 μg/L for HS and from 10 to 1 000 μg/L for DES and DIS(the correlation coefficients were above 0.99). Recoveries of the stilbenes were 73.0%-86.5%, and the relative standard deviations were between 1.0% and 7.2%. The limits of detection were 0.30 μg/kg for cis-DES, 0.10 μg/kg for trans-DES and HS and 0.15 μg/kg for DIS in pork and swine liver.

Key words: animal tissues , gas chromatography (GC), mass spectrometry (MS), residue, stilbenes, solid phase extraction (SPE)