This standard specifies the liquid chromatography-tandem mass spectrometry and liquid chromatography methods for the determination of fumonis n B and fumonis n B content in feed. This standard is applicable to the determination of fumonis n B and fumonis n B content in plant-derived feed ingredients, concentrate supplements and concentrated feeds. The detection limit and quantification limit of this standard method: the detection limit of liquid chromatography tandem mass spectrometry is 0.01mg/kg, and the quantification limit is 0.05mg/kg; the detection limit of liquid chromatography is 0.01mg/kg, and the quantification limit is 0.01mg/kg. is 0.05mg/kg.