권혁주 (중앙대학교)

한상범 (중앙대학교)

권혁주 (중앙대학교)

한상범 (중앙대학교)

Driven by the growing demand for health-functional foods, the domestic soft-shelled turtle aquaculture industry has steadily expanded. Consequently, antimicrobial use is inevitable to prevent mortalities from bacterial and fungal infections. However, due to the absence of officially registered veterinary drugs for soft-shelled turtles, off-label prescriptions are common, posing potential food safety risks. Particularly, under the recently strengthened Positive List System (PLS), establishing a residue monitoring method is necessary. This study developed an LC-MS/MS method for the determination of florfenicol and oxolinic acid. Optimizing the sample preparation involved a QuEChERS extraction coupled with Z-sep+ dispersive solid phase extraction (d-SPE) clean-up to effectively remove lipids from the complex matrix. Separation of the target analytes was performed using a C18 column (150×2.1 mm, 2.6 μm) with a mobile phase of 0.1% formic acid in water and acetonitrile under gradient elution. Validation of the method followed the Codex guidelines (CAC/GL-71-2009) by evaluating selectivity, linearity, recovery, and precision. All coefficients of determination (r²), recoveries, and CVs satisfactorily met the Codex criteria. The limits of quantitation (LOQ) for florfenicol and oxolinic acid were below 0.005 mg/kg. This work was supported by the National Fishery Products Quality Management Service, Ministry of Oceans and Fisheries, Republic of Korea (Project No. 370C-20260074).