ESI-Q-TOF-MS/MS研究N-取代邻苯二甲酰亚胺衍生物的裂解途径

Fragmentation Pathways of N-substituted Phthalimide Derivatives Using Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry

为了研究N-取代邻苯二甲酰亚胺类衍生物的质谱裂解行为,应用电喷雾-四极杆-飞行时间串联质谱(ESI-Q-TOF-MS/MS),在正离子模式下研究了5种N-取代邻苯二甲酰亚胺衍生物的质谱裂解行为,并对其质谱裂解途径进行解析,为表征该类化合物提供了依据。实验发现该5种化合物具有相似的裂解途径,即丢失化合物母核N-羟基邻苯二甲酰亚胺,甲醇和CO等中性小分子。化合物1～4的特征离子为丢失N-羟基邻苯二甲酰亚胺和甲醇产生的离子;化合物5的特征离子为丢失N-羟基邻苯二甲酰亚胺产生的类似于卓鎓离子结构的离子,该特征离子继续丢失甲醇和CO,最后卓鎓离子继续开裂丢失一分子C2H2。

N-substituted phthalimide derivatives were studied by electrospray ionization mass spectrometry （ESI-MS） in positive mode in conjunction with high-resolution quadru- pole time-of-flight mass spectrometry （Q-TOF-MS）, in order to study its＇ fragmetation pathways. Based on mass spectrum behaviors of the fragmentation pathways, all the five compounds showed a similar cleavage progress. Classical losses of CO and methanol owing to the presence of ester were observed in all these compounds; in addition, the loss of moth- er nucleus N-hydroxy phthalimide was observed in the five compounds. The characteristic ions of compounds 1--4 were the ions which lost methanol and N-hydroxy phthalimide. However, the characteristic ion of compound 5 was the ion of losing N-hydroxy phthalim- ide, whoses structure was similar to tropylium ion, then continuously lost a molecular C2 H2 after losing methanol and CO in a row.