Simultaneous determination of chloramphenicol, stilbenes, and resorcylic acid lactones in pork using UPLC–MS/MS with a C₁₈ cartridge and immunoaffinity microextraction in a packed syringe

The aim of this study was to establish an analytical method for the simultaneous detection of chloramphenicol, stilbenes, and resorcylic acid lactones. After enzymatic hydrolysis, pork samples were extracted by ethyl acetate. Two methods were used for purification: a C₁₈ cartridge and immunoaffinity microextraction in a packed syringe. The samples were analyzed by UPLC–MS/MS on an Acquity UPLC^® BEH C₁₈ column with gradient elution. The methods were demonstrated to be suitable for the determination of chloramphenicol, stilbenes, and resorcylic acid lactones in pork. The SPE–UPLC–MS/MS had average recoveries of 42.4–97.1%. The intra-day and inter-day RSDs ranged from 6.1 to 16.9% and 3.7 to 18.4%, respectively. The IA–MPES–UPLC–MS/MS had average recoveries of 14.6–33.3%, and the intra-day and the inter-day RSDs ranged from 4.7 to 19.2% and 1.0 to 16.5%, respectively. Overall, the immunoaffinity microextraction in a packed syringe saves the organic reagent when balancing the C₁₈ cartridge; thus, the dose of the organic reagent is less. However, the recovery of extraction by immunoaffinity microextraction in a packed syringe is less ideal.