A rule to account for mass shifts of even-electron fragment ions in fast-atom bombardment mass spectrometry
A rule to account for mass shifts of even-electron fragment ions in fast-atom bombardment mass spectrometry
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DOI：
10.1255/ejms.304
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发表时间：
1999-01-01
期刊：
影响因子：
--
通讯作者：
Nakata, H
中科院分区：
文献类型：
--
作者：
Nakata, H
提出了快速原子轰击（FAB）电离质谱法预测碎片离子正确质量数的规则，该规则中的“质量位移”定义为观察到的峰的质量相对于从样品分子的结构式中相应部分计算出的质量的增量或减少。对于带正电的碎片离子，根据断裂键的性质，质量位移为0、+1、+2甚至+3，而带负电的碎片离子的质量位移为0、-1或-2。该规则是基于这样一种认识，即除了少数例外，在FAB电离下形成的碎片离子是偶数电子种，并且应该具有稳定的结构，其中包括(a)通过与双键或含有杂原子的官能团共轭而稳定的带电碳原子，或(b)带正电或带负电的杂原子。该规则也适用于在碰撞诱导解离中观察到的产物离子。
A rule is proposed for prediction of correct mass numbers of fragment ions in fast-atom bombardment (FAB) ionization mass spectrometry, The term "mass shift" in the rule is defined as the increment or diminution for the mass of an observed peak against the mass calculated from the corresponding part of the structural formula of a sample molecule. For positively-charged fragment ions, the mass shift is either 0, +1, +2 or even +3, according to the nature of the cleaved bond, and 0, -1 or -2 for negatively-charged fragment ions. The rule is based on the recognition that, with a few exceptions, fragment ions formed under FAB ionization are even-electron species and should have a stable structure which includes either (a) charged carbon atoms stabilized by conjugation with double bonds or with any heteroatom-containing functional groups, or (b) positively- or negatively-charged heteroatoms, The rule is also applicable to product ions observed in collision-induced dissociation.