Objective: To use liquid chromatography-mass spectrometry techniques for qualitative analysis of alkaloids of Morus alba L. leaves and determine the content of total alkaloids in alkaloids in Morus alba L. leaves by HPLC-UV with pre-column derivatization. Method: The chromatographic separation was performed on a HiQSiL C18 column(250 mm×4.6 mm

5 μm) using acetonitrile and 0.1% acetic acid aqueous solution under isocratic elution(50:50

V/V) at a flow rate of 0.8 mL.min-1. Morus alba L. leaves alkaloids was analyzed with 9-fluorenylmethyl chlorformate(FMOC-Cl) as the pre-column derivative agent. Detection wavelength was set at 254 nm with electrospray ionization source(ESI) and positive ion mode. And 1-deoxynojirimycin as the external standard to calculate mulberry leaf total alkaloid content. Result: Six alkaloid compounds were identified as DNJ

fagomine

3-epi-fagomine

DAB

Calystegine B2 and 2-O-β-Glc-DAB.The content of 3 batches test samples were more than 75% by external standard method. Conclusion: The method is sensitive

accurate

simple

and reliable. It can be used for quantitative analysis of Morus alba L. leaves alkaloids and preparation.