MS/MS fragmentation patterns of five flavone di-C-glycoside standards from Viola yedoensis were studied by ultrahigh performance liquid chromatography-electrospray ionization-quadrupole time of flight-mass spectrometry (UPLC-ESI-QTOF-MS/MS) in the negative ion mode.The fragmentation pathways of C-6 and C-8 sugars in these flavone di-C-glycosides were consistent with those reported earlier.The results of our study also suggested that the configurations of sugars at C-8 obviously influenced the fragmentation behaviors.The fragmentation behaviors of these flavone diC-glycoside standards were successfully used to characterize flavone C-glycosides in V.yedoensis.Total of 21 flavone di-C-glycosides along with 4 flavonol O-glycosides were identified or tentatively identified on the base of their MS/MS data,accurate molecular weights,or by comparing with reference standards.The UPLC-ESI-QTOF-MS/MS method is rapid,sensitive and accurate,and could be used for the characterization of flavone C-glycosides in traditional Chinese medicines.%采用超高效液相色谱-电喷雾离子源-四极杆飞行时间串联质谱(UPLC-ESI-QTOF-MS/MS)方法,以中药紫花地丁中分离得到的5个黄酮碳苷化合物为对照品,研究了黄酮二糖碳苷类化合物在ESI-QT-OF-MS/MS质谱中的裂解规律.研究进一步证实了文献报道的黄酮二糖碳苷C-6位取代糖基较C-8位糖更易优先发生裂解;但同时发现结构中如果含有不稳定构象的糖基取代时,该规律不再适用.通过对照品的质谱裂解规律,并结合文献和高分辨质谱数据,成功表征和鉴定了紫花地丁中21个黄酮二糖碳苷类以及4个黄酮氧苷类成分.该方法能快速、灵敏、准确地对中药中微量黄酮碳苷类成分的结构进行表征和鉴定.
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