To establish a method for the determination of 11 kinds of β-agonists (clenbuterol, ractopamine, salbutamol, terbutaline, cimaterol, clorprenaline, ziprasidone, cimbuterol, bromobutirone, bambuterol, mabutrol) content in pork, beef and pork liver by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS).

After overnight incubation, the samples were extracted with acetonitrile containing 0.5% formic acid, purified by Bond Elut EMR-Lipid dispersive solid-phase extraction (SPE), and then reconstituted with methanol-0.1% formic acid. The sample was separated on a C₁₈ column (2.1 μm×150 mm, 2.7 μm) using methanol-0.1% formic acid as the mobile phase. Gradient elution was performed with electrospray ionization (ESI) positive ion scanning, and quantification was achieved by internal standard method.

The determination coefficient (r²) of the standard curve of 11 kinds of β-agonists in the range of 0.5–25.0 ng/mL was above 0.995. The relative standard deviations (RSDs) of instrument were less than 7.8%. The limit of detection was 0.10 μg/kg. By adding 0.20 μg/kg of the target compounds to the representative matrix, the recovery of the target was 95.0%–110.0% and the precision RSDs were 0.75%–9.53%, so the 0.20 μg/kg was determined as the limit of quantitation. The average recoveries of the target compounds in the representative matrices of pork, beef and pork liver were 78.1%–108.4% at the concentrations of 0.5, 5.0 and 10.0 μg/kg, respectively. The precision RSDs were less than 8.76%. The limit of quantitation and the accuracy of the method were all in line with the requirements of the detection of trace veterinary drug residues.

The method is simple and rapid, with high sensitivity, good recovery and reproducibility, and can be used to determine 11 kinds of β-agonists in animal derived foods.