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.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |