【作者】 马风伟； 季宝成； 夏兵； 周燕；

【Author】 Fengwei Ma;BaochengJi;Bing Xia;Yan Zhou;Chengdu Institute of Biology,Chinese Academy of Sciences;

【机构】 中国科学院成都生物研究所；

【摘要】 本文采用探针电喷雾电离方式,采用离子加合技术对米团花(Leucosceptrum canum)中两对差向异构体(leucosceptroidsA1和A2,B1和B2)进行快速的区分,通过串联质谱对锂离子加合物[M+Li]~+进行碰撞诱导裂解,产生碎片离子;发现leucosceptroidA2的稳定性较A1强,在碰撞能量为小于25e V,其准分子离子峰为基峰,碎片离子m/z229在碰撞能量大于30 eV时才变为基峰;而对于leucosceptroid B1和B2来说,其稳定性均较差,容易碎裂,但B1裂解生成m/z 175离子的丰度呈现先增高后降低的趋势,而B2中m/z175的丰度呈现增高后一直处于基峰,因此通过比较碎片离子强度随碰撞能量的变化,绘制裂解曲线,简便快速的实现差向异构体的区分。更多还原

【Abstract】 Probe electrospray ionization-mass spectrometry was used to analysis the lithiatedleucosceptroids.Two pairs of diastereomeric isomers(A1 and A2,B1 and B2) were successfullydifferentiated by comparing their relative abundances.The relative abundances of the product ions of [A1+Li]+ were different from that of [A2+Li]~+.The precursor ion of leucosceptroid A2 was almost intact under collision energy at eV and the relative abundance was higher than its product ions under 25 eV.Similar breakdown curves were obtained for leucosceptroid B1 and B2 at low collision energy.However the product ion at m/z 175 of leucosceptroid B2 was the always base peak when the collision energy higher than 25 eV.Both the two pairs of diastereomeric isomers could be differentiated by breakdown curve.更多还原