VUV Photoionization and Dissociation of Tyramine and Dopamine： the Joint Experimental and Theoretical Studies  

酪胺和多巴胺VUV光电离／解离的实验和理论研究

作　　者：郭会军[1] 叶莉莉[1] 贾良元[1] 张李东[1] 齐飞[1] 

机构地区：[1]中国科学技术大学国家同步辐射实验室,合肥230029

出　　处：《Chinese Journal of Chemical Physics》2012年第1期11-18,I0003,共9页化学物理学报（英文）

基　　金：Authors thank Dr. Yang Pan for useful discussions This work was supported by the National Natural Science Foundation of China （No.10805047）.

摘　　要：Photon induced dissociation investigations of neutral tyramine and dopamine are carried out with synchrotron vacuum uRraviolet photoionization mass spectrometry and theoretical calculations. At low photon energy, only molecular ions are measured by virtue of nearthreshold photoionization. While increasing photon energy to 11.7 eV or more, four distinct fragment ions are obtained for tyramine and dopamine, respectively. Besides, the ionization energies of tyramine and dopamine are determined to be 7.984-0.05 and 7.674-0.05 eV by measuring the photoionization efficiency curves of corresponding molecular ions. With help of density function theory calculations, the detailed fragmentation pathways are established as well. These two molecular cations have similar aminoethyl group elimination pathways, CTHsO2＋ （m/z=124） and C7H8O＋ （m/z=108） are supposed to be generated by the McLafferty rearrangement via γ-hydrogen （7-H） shift inducing β-fission. And CH2NH2＋ is proposed to derive from the direct fission of C7-C8 bond. Besides, the McLafferty rearrangement and the C7-C8 bond fission are validated to be dominant dissociation pathways for tyramine and dopamine cations.

关 键 词：TYRAMINE DOPAMINE VUV photoionization Mass spectrometry Ionization energy Dissociation pathway 

分 类 号：O[理学]