NEGATIVE ION CHEMICAL IONIZATION MASS SPECTROMETRY OF PERFLUOROACYL DERIVATIVES

的负离子化学电离(NCI)质谱图 五氟丁酰基(PFP)和七氟丁酰基(HFB)衍生物 含有碱离子的2-氨基苯酚是由一种机制产生的 涉及44amu的损失，而反映这种损失的离子也 在其他化合物的PFP或HFB衍生物的NCI光谱中观察到 邻羟基苯胺，包括3-羟基联胺和正丙基 2-羟基苯胺和2-氨基酪氨酸酯。一个相应的 在三氟乙酰(TFA)的NCI谱中没有观察到离子 2-氨基苯酚的衍生物或在PFP或HFB的光谱中 羟基苯胺的间异构体或对位异构体的衍生物 2-乙氨基苯酚。对这一损失的机制进行了研究 串联质谱仪、联动扫描和高分辨质谱仪 光谱分析显示，它反映了二氧化碳的消除，并表明 碎裂途径涉及HF的初始损失，在 氢原子就是从它衍生出来的 衍生的酰胺氮，然后形成一个环 一种中间体，随后从该中间体中除去二氧化碳以生产 另一种环形结构。由44Amu的损失产生的离子也是 在儿茶酚的HFB或PFP衍生物的NCI光谱中观察到， 包括L-多巴和儿茶酚本身，以及这种损失的机制 也可以涉及形成环中间体，从该环中间体产生二氧化碳 随后被淘汰。这种二氧化碳损失的发生可能是 用于区分羟基苯胺和羟基苯胺的区域异构体 以区分邻苯二酚和间苯二酚或对苯二酚核。

The negative ion chemical ionization (NCI) mass spectra of the pentafluoroproprionyl (PFP) and heptafluorobutyryl (HFB) derivatives of 2-aminophenol contain a base ion which is generated by a mechanism involving the a loss of 44 amu, and ions reflecting this loss are also observed in the NCI spectra of the PFP or HFB derivatives of other ortho hydroxyanilines, including 3-hydroxybenzidine and the n-propyl esters of 2-hydroxyanilinic acid and 2-aminotyrosine. A corresponding ion is not observed in the NCI spectra of the trifluoroacetyl (TFA) derivative of 2-aminophenol or in the spectra of the PFP or HFB derivatives of meta or para isomers of hydroxyaniline or of 2-ethylaminophenol. Examination of the mechanism of this loss by tandem mass spectrometry, linked scanning, and high resolution mass spectrometry revealed that it reflects elimination of CO2 and indicate that the fragmentation pathway involves an initial loss of HF, in which the hydrogen atom is derived from the deriv atized amide nitrogen, followed by formation of a ring intermediate from which CO2 is subsequently eliminated to yield another ring structure. An ion generated by loss of 44 amu is also observed in the NCI spectra of HFB or PFP derivatives of catechols, including L-dopa and catechol itself, and the mechanism of this loss may also involve formation of a ring intermediate from which CO2 is subsequently eliminated. The occurrence of this loss of CO2 can be used to achieve distinction among regio-isomers of hydoxyanilines and to distinguish a catechol from a resorcinol or hydroquinone nucleus.