Abstract
A multiresidue method was developed and validated to screen bovine urine samples for 10 β-2-adrenergic agonistic drugs—brombuterol, cimaterol, clenbuterol, clenpenterol, isoxsuprine, mabuterol, ractopamine, ritodrine, salbutamol, and tulobuterol—at the 2 μg/L level. The method is also quantitative in the range of 1 to 4 μg/L for all analytes except salbutamol. The procedure uses enzymatic digestion, liquid–liquid extraction, and cleanup on solid-phase extraction columns, followed by detection using a liquid chromatograph-tandem quadrupole mass spectrometer operated in the positive-ion atmospheric pressure chemical ionization multiple-reaction monitoring mode. Method validation included assessment of recoveries, repeatabilities, linearity of responses, decision limits, and detection capabilities. Overall average recoveries ranged from 70–91%; recoveries were generally lower for salbutamol. The decision limits ranged from 0.4–1.0 μg/L, and detection capabilities from 0.6–1.7 μg/L.