This standard specifies dihydroergotine, ergoconine, ergois conine, ergocorine, ergois carine, ergocriptine, ergois carine, ergocine, atropine, ergois carine, A liquid chromatography-tandem mass spectrometry method for the determination of the contents of 15 alkaloids: Senecioreniform, Seneciofeline, Monocrotaline, Senecione and Scopolamine. This standard is applicable to the determination of single or multiple components of the above 15 alkaloids in pasture. The detection limit and quantitation limit of this standard method: the detection limit of the above 15 alkaloids is 0.005 mg/kg, and the quantitation limit is 0.01 mg/kg.