Response Surface Optimization of the QuEChERS Combined with UHPLC-MS/MS Method for Determination of Tetracyclines in Muscle of Channa argus

A quick, easy, cheap, effective, rugged and safe pre-treatment method (QuEChERS) was established to evaluate the risk of tetracycline residues in the muscle of Channa argus. The Box-Behnken design (BBD) response surface optimization method was used to optimize the extraction and purification conditions. The samples were extracted with 10 mL acetonitrile (containing 1% formic acid) and 2 mL 0.1 mol/L Na₂EDTA-Mcllvaine buffer solution, and the extracts were purified by 150 mg primary secondary amine（PSA）and 200 mg C₁₈, and detected with Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The result showed that the calibration curve was linear in the range of 0.50~100 ng/mL, with high correlation coefficients (r≥0.999). The limits of detection (LOD) and quantification (LOQ) were 0.25～0.75 μg/kg and 0.84～2.00 μg/kg, respectively. The average recoveries of tetracycline, oxytetracycline, chlortetracycline and doxycycline at three different spiked levels in the muscle of Channa argus were 89.5%～118%, with relative standard deviations (RSDs) of 1.11%～8.88%. This method is simple, sensitive and accurate, and can be used for the rapid quantitative determination of tetracyclines in Channa argus.