Thermal Proton Transfer Reactions in Ultraviolet Matrix-Assisted Laser Desorption/Ionization
Thermal Proton Transfer Reactions in Ultraviolet Matrix-Assisted Laser Desorption/Ionization
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DOI：
10.1007/s13361-013-0792-9
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发表时间：
2014-03-01
影响因子：
3.2
通讯作者：
Ni, Chi-Kung
中科院分区：
文献类型：
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作者：
Chu, Kuan Yu;Lee, Sheng;Ni, Chi-Kung
热诱导反应不被认为是紫外基质辅助激光解吸电离 (UV-MALDI) 中的关键机制的原因之一是离子与中性比低。大离子与中性比 (10(-4)) 已被用来证明 UV-MALDI 中热诱导反应的不重要性。最近的实验测量表明，在高激光能量密度下，总离子与中性比的上限约为10(-7)，在低激光能量密度下小于10(-7)。因此，重新审视 MALDI 中热诱导反应的可能贡献可能是值得的。在这项研究中，极性流体的概念被用来解释MALDI中初级离子的产生。使用一个简单的模型，即热质子转移，来估计 MALDI 中的离子与中性比。我们证明，与实验测量相比，离子与中性比的理论计算表现出相同的趋势和相似的数量级。尽管热质子转移可能不会产生 MALDI 中观察到的所有离子，但计算表明热诱导反应在 UV-MALDI 中发挥着至关重要的作用。
One of the reasons that thermally induced reactions are not considered a crucial mechanism in ultraviolet matrix-assisted laser desorption ionization (UV-MALDI) is the low ion-to-neutral ratios. Large ion-to-neutral ratios (10(-4)) have been used to justify the unimportance of thermally induced reactions in UV-MALDI. Recent experimental measurements have shown that the upper limit of the total ion-to-neutral ratio is approximately 10(-7) at a high laser fluence and less than 10(-7) at a low laser fluence. Therefore, reexamining the possible contributions of thermally induced reactions in MALDI may be worthwhile. In this study, the concept of polar fluid was employed to explain the generation of primary ions in MALDI. A simple model, namely thermal proton transfer, was used to estimate the ion-to-neutral ratios in MALDI. We demonstrated that the theoretical calculations of ion-to-neutral ratios exhibit the same trend and similar orders of magnitude compared with those of experimental measurements. Although thermal proton transfer may not generate all of the ions observed in MALDI, the calculations demonstrated that thermally induced reactions play a crucial role in UV-MALDI.