2,2,6,6-四甲基-4-胺基-哌啶-N-氧基型稳定自由基的质谱研究

Mass Spectrometric Research on Stable Radical of Piperidine N-oxides

摘要: 本文报导了2,2,6,6-四甲基-4-胺基-哌啶-N-氧自由基质谱裂解规律。经高分辨质谱与亚稳测定证实,这些稳定自由基在电子轰击条件下,有以下主要特征碎片离子:(1)(M+H~·-CH_3~·)离子;(2)(M-NO)离子;(3)(M-CH_2O)离子及它们的继发反应产物离子。此外,还能发生哌啶环破裂及取代基消除反应。研究该类化合物,能对被标记生物大分子提供更多结构的信息。

Abstract: In this paper, the fragmentation mechanism of 2, 2, 6, 6-tetramethyl-4-su- bstituted amino piperidine N-oxides are reported. From the data of exactmass measurements and metastable transition, three types of diagnostic ionproduced under EI condition have been proposed: (1) (M+H-CH_3)~+ ion,(2) (M-NO)~+ ion, (3) (M-CH_2O)~+ ion and its sequential fragment ion.In addition, the ions arisen from ring cleavage and elimination reaction arealso observed. On the basis of mass spectrometric behaviour for these com-pounds, some further instructive informations about labeled biological mole-cules can be obtained.