Abstract: A high performance liquid chromatography-tandem mass spectrometric method is established for detection of residues of 73 veterinary drugs in animal muscle tissues. Animal food is classified based on the food matrix triangle. Samples are prepared for analysis by a quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. After experimental conditions such as extraction solvent and purification agent are optimized, they are finally determined to be acetonitrile containing 5% formic acid and C18. Otherwise, instrumental conditions are optimized for the determination of 73 veterinary drugs. Samples are separated on a HSS T3 column (2.1 mm×100 mm, 1.8 μm) with the mobile phase of aqueous 0.1% formic acid and acetonitrile by gradient elution. Tandem mass spectrometry is operated in the positive ion mode. Multiple reaction monitoring is used for quantification. In pork and beef, the linear relationships are in the range of 0.1~10 ng/mL or 0.5~10 ng/mL with correlation coefficients r＞0.9992 for 73 veterinary drugs. The limits of detection for these veterinary drugs are not more than 5 μg/kg except malathion. The average recoveries at three spiked concentrations vary from 66.1% to 128.5% in pork and from 62.1% to 125.3% in beef. The repeatability is 0.8%~9.6% and 1.5%~11.6% in pork and beef, respectively. This method is simple, sensitive and fast, and could be used in multi-residue analysis of veterinary drugs.

Key words: Veterinary drugs, High performance liquid chromatography, Triple quadrupole mass spectrometry, Determination, Residues