Simultaneous determination of seven flavonoids in Epimedium by liquid chromatography–tandem mass spectrometry method Cai Sheng Wu a , Bao Lin Guo b , Yu Xin Sheng a , Jin Lan Zhang a, * a Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100050, China b Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100094, China Received 3 December 2007 Abstract In this paper, a sensitive and specific liquid chromatography–electrospray ionisation-mass spectrometry (LC–ESI-MS) method has been developed and validated for the identification and determination of seven flavonoids, namely epimedin A, epimedin B, epimedin C, icariin, sagittatoside B, 2 00 -O-rhamnosyl icariside II, and baohuoside I in Epimedium from different sources. # 2008 Jin Lan Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. Keywords: Flavonoids; Epimedium; Liquid chromatography–electrospray ionization-mass spectrometry; Quantitative determination Epimedium (family Berberidaceae), the dried aerial parts of Epimedium brevicornum Maxim., Epimedium sagittatum Maxim., Epimedium pubescens Maxim., Epimedium wushanense T.S. Ying. and Epimedium koreanum Nakai. is a well-known traditional Chinese medicine [1]. Flavonoids have been proven to be the active components in Epimedium, and more than 60 flavonoids have been isolated from it. Thus, it is important to determine the flavonoids for the evaluation of its quality and the clinical safety. Up to now, quantitative analysis of flavonoid components in Epimedium were mainly based on spectrophotometric method [1,2], capillary electrophoresis [3,4], high performance liquid chromatography [5–7] and ultra-performance liquid chromatography (UPLC) [8]. However, there is no report to determine seven flavonoids in Epimedium by LC–ESI-MS method. In previous work, some flavonoids such as 1 (epimedin A), 2 (epimedin B), 3 (epimedin C), 4 (icariin), 5 (sagittatoside B), 6 (2 00 -O-rhamnosyl icariside II), and 7 (baohuoside I) had been found to be the major active constituents in Epimedium. In this paper, a simple and rapid LC– ESI-MS method was established and validated to determine such flavonoids extracted from Epimedium. The validated method was applied to analyze 35 samples and investigate the difference on the contents of seven flavonoids in Epimedium from different sources. 1. Experimental The assay was performed on a Thermo Finnigan Surveyor MSQ plus system (Thermo Finnigan, Co. Ltd., San Jose, CA USA) consisting of an HPLC connected to a single quadrupole MS analyzer with an electrospray ionization (ESI) www.elsevier.com/locate/cclet Available online at www.sciencedirect.com Chinese Chemical Letters 19 (2008) 329–332 * Corresponding author. E-mail address: zhjl@imm.ac.cn (J.L. Zhang). 1001-8417/$ – see front matter # 2008 Jin Lan Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. doi:10.1016/j.cclet.2008.01.018