Dissociation of neutral intermediates by using charge inversion mass spectrometry

发展了一种碱金属靶电荷反转质谱学，它比碰撞激活解离(CAD)能更清楚地区分烃类异构体。在电荷反转MS中，选择质量的正离子与碱金属靶碰撞，并对两电子转移形成的负离子进行质量分析。电荷反转的内部能量沉积表明，通过近共振中和形成的能量选择的中性分子发生了解离。某些碳氢化合物的电荷反转光谱的相对峰强度强烈地依赖于所用的碱金属靶，这表明内能在激发的中性中间体的解离过程中的重要性。这些结果表明，电荷反转MS作为一种研究能量选择的中性中间体的解离和同分异构体的技术是有用的。

A charge inversion mass spectrometry using alkali metal targets has been developed which produces clearer differentiation of hydrocarbon isomers than collision activated dissociation (CAD). In charge inversion MS, mass-selected positive ions are made to collide with an alkali metal target, and the resulting negative ions formed upon two-electron transfer are mass-analyzed. The internal energy deposition of the charge inversion indicates that dissociation occurs in the energy-selected neutrals formed via near-resonant neutralization. The relative peak intensity in the charge inversion spectra for some hydrocarbons depends strongly on the alkali metal target used, indicating the importance of internal energy in the dissociation of the excited neutral intermediates. These results demonstrate the utility of the charge inversion MS as a technique for the investigation of the dissociation of energy-selected neutral intermediates and for isomeric differentiation.