Dehalogenation reactions in fast atom bombardment mass spectrometry.
Dehalogenation reactions in fast atom bombardment mass spectrometry.
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快原子轰击质谱中的脱卤反应。
DOI：
10.1021/ac00275a052
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发表时间：
1984
影响因子：
7.4
通讯作者：
McCloskey,JA
中科院分区：
文献类型：
--
作者：
Sethi,SK;Nelson,CC;McCloskey,JA
Sir：快原子轰击（FAB）质谱法对于高极性或不稳定有机化合物的结构分析是一种相当重要的方法（1,2）。该技术通常被认为是一种“软”电离方法，其中低能过程占主导地位，由质子化分子（MH+）和类似物种的单分子解离形成碎片离子。FAB质谱的一般外观通常可以通过类比相应的化学电离或场解吸谱来预测（3,4），FAB与化学电离或场解吸谱有一些共同特点。我们在这里报道了卤化核苷，一类典型的非常适合FAB质谱的化合物，在甘油基质中的FAB过程中经历了广泛的脱卤。在这些过程中，与杂环碱结合的卤素在净反应中被H取代，与其他脱附方法或电子电离产生的离子的主要反应没有相似之处，并且不能代表通常气体离子化学背景下的低能过程。研究了核苷1-8的FAB质谱（图1），以确定化学选择性是否来自卤素（I, Br, Cl， F）的身份或卤素取代的位置，并通过选择性氘化甘油作为基质，确定脱卤后加入的氢的来源是否存在结构选择性。
Sir: Fast atom bombardment (FAB) mass spectrometry is a method of considerable importance for the structural analysis of highly polar or labile organic compounds (1, 2). The technique is generally regarded as a “soft”-ionization method in which low-energy processes predominate, with fragment ions formedby unimolecular dissociation of protonated molecules (MH+) and similar species. The general appearance of FAB mass spectra can often be predicted by analogy to the corresponding chemical ionization or field desorption spectra (3, 4) with which FAB shares some char-acteristics.We report here that halogenated nucleosides, a class of compound typically well suited for FAB mass spectrometry, undergo extensive dehalogenation duringFAB in glycerol matrix. These processes, in whichhalogen bound to the heterocyclic base is replaced by H in the net reaction, have no analogy as major reactions of ions produced by other de-sorption methods or electron ionization and cannot represent low-energy processes in the usual context of gaseous ion chemistry. The FAB mass spectra of nucleosides 1-8 (Chart I) have been studied to determine whether chemical selectivity results from the identity of the halogen (I, Br, Cl, F) or position of halogen substitution and to determine whether structural selectivity exists for the source of hydrogen incorporated after dehalogenation, by using selectively deuterated glycerol as matrix.