ESI_IT_TOF_MS_n方法对11个异黄酮的裂解规律研究_英文_.docx

Investigations of theESI-IT-TOF-MSnYazhou Zhang1,2, Feng Xu3, Hubiao Chen1*fragmentation behavior of 11 isoflavones withJianye Zhang1, Tao Yi1, Yina Tang1, Jun Xu1, Wanling Peng1,1. School of Chinese Medicine, Hong Kong Baptist University, Hong Kong Special Administrative Region 999077, China2. Guizhou College of Technology, Guiyang 550003, China3. State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health SciencesCenter, Beijing 100191, ChinaAbstract: The fragmentation behavior of isoflavones was studied using electrospray ionization-ion trap-time of flight massspectrometry (ESI-IT-TOF-MSn). It was found that the isoflavone glycoside bond was easily broken. The fragmentation occurred mostly on the C-ring, and the fragment ions of A1,3+ produced by the RDA cracking will predict the hydroxylation replacement on A-ring or B-ring. In addition, four carbonyl groups on the C-ring were fragmented through neutral loss of 28 (-CO). A and B-rings primarily lose substituents which including a neutral losses of 32 (-CH3OH), 16 (-CH4), or 16 (-O), and 18 (-H2O). A-ring in the presence of adjacent hydroxylation, also easily made to be a neutral losses of 28 (-CO) or 18 (-H2O). It is likewise common to see methoxy replaced with a neutral losses of 16 (-CH4) or 32 (-CH3OH) in B-ring, also the hydroxylation on benzene ring can occasionally results with the neutral loss of 28 (-CO).Keywords: Isoflavone, Fragmentation behavior, ESI-IT-TOF-MSnCLC number: R284.1, O657.63Document code: AArticle ID: 1003–1057(2014)9–631–111. Introductionwhich can quickly and at high resolution capture positiveand negative ion pieces from the ion source to ensure that a majority of the ions can reach the detector[2–5]. IT-TOF-MSn greatly improves the sensitivity and resolution of the mass spectrum by taking advantage of the simultaneous multistage mass spectrometry analysis. The Retro Diels-Alder (RDA) cleavage can be used to predict th