Abstract Fragmentation of protonated and/or deprotonated small-molecule compounds in tandem mass spectrometry after electrospray ionization involves complex processes and competitive pathways. In order to increase the understanding, the fragmentation observed for large collections of organic molecules, mainly drugs and pesticides, has been studied and reviewed. In the current study, attention is focused at nitro-group related and halogen-related fragmentation of organic compounds with nitro and halogen groups. Fragmentation of 140 nitro-group and 300 halogen-containing compounds has been studied. Both nitro and halogen moieties can show losses of a radical (•OH, •NO, •NO2, •Cl, •Br, or •I), which may or may not be in competition with losses of the corresponding molecules (HNO, HNO2, HCl, HBr, or HI). For compounds with a nitro group, the chemical surroundings may influence the fragmentation, as illustrated by the ortho-effect, but also by examples of concerted losses. The competitive nature of the various fragmentation pathways is important in understanding the fragmentation, but the complexity of the processes hinders the ability to predict whether or not a particular fragmentation route is taken. While nitro-group and/or halogen-related fragmentation is observed for many compounds, there are also many compounds with nitro-group or halogen-substituents that follow different fragmentation pathways.

中文翻译：

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有机硝基和卤素化合物的串联质谱：分子损失和自由基损失之间的竞争

摘要 电喷雾电离后的串联质谱中质子化和/或去质子化小分子化合物的碎裂涉及复杂的过程和竞争途径。为了加深理解，对大量有机分子（主要是药物和杀虫剂）所观察到的碎片进行了研究和审查。在目前的研究中，注意力集中在具有硝基和卤素基团的有机化合物的硝基相关和卤素相关的碎裂。已经研究了 140 个硝基和 300 个含卤素化合物的断裂。硝基和卤素部分都可以显示出自由基（•OH、•NO、•NO2、•Cl、•Br 或•I）的损失，这可能会或可能不会与相应分子（HNO、HNO2 、HCl、HBr 或 HI)。对于带有硝基的化合物，化学环境可能会影响碎片，如正交效应所示，但也有协同损失的例子。各种碎片化途径的竞争性质对于理解碎片化很重要，但过程的复杂性阻碍了预测是否采用特定碎片化路线的能力。虽然在许多化合物中观察到硝基和/或卤素相关的碎裂，但也有许多化合物具有遵循不同碎裂途径的硝基或卤素取代基。但过程的复杂性阻碍了预测是否采用特定碎片化路线的能力。虽然在许多化合物中观察到硝基和/或卤素相关的碎裂，但也有许多化合物具有遵循不同碎裂途径的硝基或卤素取代基。但过程的复杂性阻碍了预测是否采用特定碎片化路线的能力。虽然在许多化合物中观察到硝基和/或卤素相关的碎裂，但也有许多化合物具有遵循不同碎裂途径的硝基或卤素取代基。