Determination of residues of anabolic drugs in meat by gas chromatography-mass spectrometry.

The residues in meat of seven estrogenic drugs used in anabolic preparations for animal production were analysed as trimethylsilyl ethers by electron-impact gas chromatography-mass spectrometry following a simple clean-up procedure. The compounds under investigation were: 17 beta-estradiol,l diethylstilbestrol,l hexestrol, dienestrol, stilbestrol, ethynylestradiol and zeranol. The method includes extractive homogenization of 10 g of meat in tetrahydrofuran, followed by liquid-liquid partition between acetonitrile and hexane and finally a chromatographic purification step on a small silica gel column. Gas chromatography was carried out on a 10-m glass capillary column coated with SE-54 using a temperature program from 100 to 250 degrees C. The capillary column was connected to the ion source by an all-glass open-split interface with a scavenger gas-line. Detection of anabolic residues was performed with selected ion monitoring on intensive ions in the mass region above m/e 400, resulting in a detection limit of 1-5 ppb (10(9)). Quantitative determinations were performed using dodecyl gallate as an internal standard applying the signal ratio of the drug and the standard.