Abstract: The present study aimed to compare the alkaloids of Radix Sophorae Tonkinensis and Radix Sophorae Flavescens using UPLC/Q-TOF MS^E.The analysis procedure was carried on an Acquity UPLC BEH C₁₈ column by employing Acetonitrile-5 mmol/L ammonium formate aqueous solution at a flow rate of 0.5 mL/min,and quadrupole tandem time-of-flight mass spectrometry (Q-TOF) in positive ion mode was used as detector.Chemical structures of alkaloids were tentatively identified by the molecular weight of ion chromatographic peak and its characteristic fragmentations combined with related references.In addition,principal component analysis and orthogonal partial least-squares analysis were employed for cluster analysis.The results showed that 12 and 11 alkaloids were identified from Radix SophoraeTonkinensis and Radix Sophorae Flavescens, respectively;10 of which were identical,but the contents of these 10 identical compounds differed greatly between Radix sophorae Tonkinensis and Radix Sophorae Flavescens,and cluster analysis also revealed that Radix Sophorae Tonkinensis was significant different from Radix Sophorae Flavescens.The present study indicated that the category of alkaloids in Radix Sophorae Tonkinensis and Radix Sophorae Flavescens were similar but their contents were of great difference.The different clinic curative effects between Radix Sophorae Tonkinensis and Radix Sophorae Flavescens may be due to the content differences among alkaloid,or other components besides alkaloids.

Key words: Radix Sophorae Tonkinensis, Radix Sophorae Flavescens, alkaloid, UPLC/Q-TOF MS^E