GB/T 22259-2025 Active

This document describes the methods for determining oxytetracycline in feed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and high-performance liquid chromatography (HPLC). This document is applicable to the determination of oxytetracycline in compound feed, concentrated feed, premixes, additive premixes, feed raw materials, and mixed feed additives. For the LC-MS/MS method, the detection limit is 0.02 mg/kg, and the quantification limit is 0.05 mg/kg. For HPLC, the detection limit for compound feed (except aquatic compound feed), concentrated feed, premixes, and feed raw materials is 1.0 mg/kg, and the quantification limit is 2.0 mg/kg. For aquatic compound feed, the detection limit is 5.0 mg/kg, and the quantification limit is 10.0 mg/kg. For additive premixes and mixed feed additives, the detection limit is 2.5 mg/kg, and the quantification limit is 5.0 mg/kg.