Journal of Food Safety and Quality

Objective To establish a method for rapid detection of toltrazuril and other veterinary drug residues in milk using ultra performance liquid chromatography-tandem mass spectrometry based on solid-phase extraction purification technology. Methods The samples were ultrasonically extracted with a 0.1% acetic acid-acetonitrile solution and purified using an solid phase extraction column (HMR-Lipid). Separation was achieved on a BEH C18 chromatographic column with 0.1? acetic acid in water-acetonitrile as the mobile phase. The target compounds were ionized in the negative ion mode of electrospray ionization and detected in multiple reaction monitoring mode, with quantification performed using the internal standard method. Factors such as extraction, purification and chromatographic conditions of the target compounds in the samples were optimized. Results The target compounds had good linearity in the mass concentration range of 0.5–50.0 ng/mL, with correlation coefficients all greater than 0.999. The limits of detection were 0.23–0.52 μg/kg, and the limits of quantitation were 0.23–1.45 μg/kg. The spiked recoveries ranged from 92.4% to 105.2%, and the precisions were between 0.32% and 7.00%. Conclusion The sample pretreatment could be completed within 15 minutes. This method is simple, rapid, highly sensitive and accurate for both qualitative and quantitative analysis, and is suitable for the detection of toltrazuril and other veterinary drug residues in milk.

milk; coccidiostat; solid-phase extraction; ultra performance liquid chromatography-tandem mass spectrometry; rapid determination