Determination of 18 β-Agonists in Aquatic Products Using High-Performance Liquid Chromatography Tandem Mass Spectrometry

An effective and efficient method for the determination of 18 β-agonists in aquatic products using liquid chromatography tandem mass spectrometry (LC-MS/MS) was successfully established. The method optimization was conducted based on incurred samples to guarantee its practicability. In this method, the sample was hydrolyzed with β-glucuronidase-arylsulfatase in ammonium acetate solution and treated successively with protein precipitation in 5% trichloroacetic acid in water, lipid removal with n-hexane, and further concentration and cleanup by solid-phase extraction (hydrophilic–lipophilic balanced cartridge, primary–secondary amine cartridge). Isotope-labeled internal standards and matrix-matched calibration curves were used for quantification. The limit of quantification (LOQ) was verified at 0.5–1.0 μg/kg (S/N > 10). This method was evaluated with five different matrices, including eel, roasted eel, pufferfish, shrimp, and crab, at 1×, 2×, and 10× LOQs, with good recoveries (>77%) and high replicate repeatability (relative standard deviations (RSDs) <13%, intraday batch repeatability) and further validated by three other accredited laboratories. A total of 3 samples out of 37 tested aquatic products were found positive for unknown incur sources (ractopamine, 0.38–2.1 μg/kg; salbutamol 3.0 μg/kg; tulobuterol 2.9 μg/kg; clenbuterol 1.3 μg/kg; and clenpenterol, 0.3 μg/kg). The method has demonstrated to be reliable, sensitive, and stable for multiresidue screening of β-agonists for food safety monitoring.