Abstract:

To establish a method for the determination of veterinary drug residues in eggs by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), samples were extracted and purified using frozen lipid filtration combined with the QuEChERS method taking advantage of dispersive solid-phase extraction (DSPE). A total of 125 veterinary drug residues in eggs were analyzed, encompassing 11 classes of drugs (nitroimidazoles, benzimidazoles, sulfonamides, quinolones, macrolides, tetracyclines, androgens, progestational hormones, glucocorticoids, estrogens, and chloramphenicols). The drugs were extracted in acetonitrile/water (70:30, v/v) containing 0.1 mol/L EDTA. The precipitation of lipids and proteins was promoted by performing the extractions at very low temperature (-20℃) for 2 h. Further purification was carried out using dispersive solid-phase extraction (DSPE) followed by dilution of the supernatant. Detection and analysis of veterinary drug residues by UHPLC-MS/MS was conducted and quantified by the external standard method. Our results showed that this method gave good linearity within a certain concentration range (relative coefficient, R² ≥ 0.99), and the acceptable limits of quantification were determined to be 2.0-60 μg/kg for the 125 veterinary drugs. Good recovery values (60.4%-119.3%) were achieved for all the 125 veterinary drugs with RSD values ranging from 0.3% to 16.1%. This method proved suitable for the rapid determination of veterinary drug residues in eggs with a simple, accurate, and low-cost procedure.

Key words: egg, QuEChERS, ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), veterinary drugs