ELECTRON COLLISION-INDUCED DISSOCIATION FOR MASS SPECTRO

我们的项目是开发、测试和评估电子束技术 用于质谱学鉴定的碰撞诱导解离 化合物的结构解析。目前，解离是 主要是由质量选择的束流离子与气体碰撞引起的 目标。我们建议改用电子束来诱导 解离。高效率所需的强电子电流 将从Spindt型场发射阴极获得解离， 最近在SRI国际开发的。电子的重要优势 使用气体靶时的碰撞诱导解离(El CID) 是：1)所产生的解离模式类似于 由电子电离产生，形成了巨大的EI谱库 可用于识别目的；2)所有质谱仪将 当使用相同的电子时产生相似的离解图案 碰撞能；3)电子束可快速切换， 允许使用锁定放大器技术；4)信号损耗和 散射和电荷交换引起的分辨率下降 碰撞池中的中和将被消除；5)解离 效率应随质量近似线性增加；以及6) 电子枪将不会给质谱仪真空带来气体负载， 尺寸要小，价格也相对便宜。这些改进应该 使电子CID技术更加实用和普遍适用 用于复杂生物的分析和结构阐明 化合物。

Our project is to develop, test and evaluate an electron beam technique for collision-induced dissociation for mass spectrometric identification and structure elucidation of compounds. At present, dissociation is primarily induced by collision of the mass selected beam ions with a gas target. We propose instead to use an electron beam to induce dissociation. The intense electron current required for efficient dissociation will be obtained from Spindt-type field emission cathodes, recently developed at SRI International. Important advantages of electron collision-induced dissociation (El CID) over the use of the gas target are: 1) The resultant dissociation pattern would be similar to that produced by electron ionization making the vast library of EI spectra available for identification purposes; 2) All mass spectrometers will produce similar dissociation patterns when using the same electron collision energy; 3) The electron beam could be switched rapidly, permitting the use of lock-in amplifier techniques; 4) Signal losses and resolution degradation caused by scattering and charge-exchange neutralization in the collision cell would be eliminated; 5) Dissociation efficiency should increase approximately linearly with mass; and 6) The electron gun would introduce no gas load to the mass spectrometer vacuum, be small in size and relatively inexpensive. These improvements should make the electron CID technique more practical and universally applicable for the analysis and structural elucidation of complex biological compounds.