Determination of beta-Agonists in Liver and Retina by Liquid Chromatography-Tandem Mass Spectrometry

A liquid chromatography-tandem mass spectrometry (LC/MS/MS) method for the determination of bromobuterol, cimaterol, clenbuterol, clenpenterol, hydroxy-methylclenbuterol, isoxsuprine, mabuterol, ractopamine, ritrodrine, salbutamol, terbutaline, and tulobuterol residues in bovine liver and retina is reported. This procedure uses enzymatic digestion, liquid-liquid extraction, and cleanup on Oasis HLB solid-phase extraction cartridges, followed by determination of the residues by LC-tandem quadrupole MS using atmospheric pressure chemical ionization in the positive ion mode. Overall average recoveries ranged from 23 to 76% for liver and 34 to 77% for retina. The mean values for samples fortified at levels between 0.5-2.0 μg/kg (liver) and 5-20 μg/kg (retina) agreed within 98-118% of the spiked levels, with coefficients of variation ranging from 6 to 20%. The decision limits, CCa, ranged from 0.1 to 0.3 μg/kg for liver, 1-3 μg/kg for retina, and detection capabilities, CCβ, from 0.2-0.5 μg/kg for liver and 2-5 μg/kg for retina.