Simultaneous Detrmination of Salbutamol，Ractopamine，and Clenbuterol in Animal Feeds by SPE and LC-MS

摘要

A liquid chromatography–mass spectrometry (LC–MS) method for the simultaneous determination of salbutamol, ractopamine, and clenbuterol in commercial feeds was developed. Samples were extracted with phosphoric acid-methanol solution, and further clean-up was achieved with a Cl 8 cation exchange mixed mode cartridge. Separation of analytes was developed on a Cl 8 column with O.OlM aqueous ammonium formate solution (_pH 3.8)–acetonitrile by gradient program, and characterized by LC–MS on a quadrupole detector, in electrospray positive ion mode. This method provides average recoveries for salbutamol, ractopamine, and clenbuterol of 83-110% and coefficients of variation of 1.5-11 % in feeds spiked in the range of 0.5-500 mg/kg. The limits of detection and quantification in feeds were 0.01 mg/kg and 0.05 mg/kg, respectively. Such limits are well below the dose of 2-25 mg/kg feed proposed as effective.