Abstract: Study on MS Fragmentation Pattern of Quinolones DerivativesYu Zhenpei;Zhao Yajun;He Xiaoran;He Meiyu;Lin Xiaoyuan;Yuan Jinfang(Department of Chemistry,Peking University,Beijing 100871,China)Abstract:Mass spectra of three kinds of quinolones derivatives, totally 17 compounds, were investigated.Experiment data shows that each type of compounds has its characteristic fragmentation psttern.In this paper the influence of double bond on fragmentation was discussed and the similarity of the quinolones with flavones was compared.Keywords:quinolones,electron impact,MIKES