ION FRAGMENTATION ACTIVATED BY MATRIX-ASSISTED LASER-DESORPTION IONIZATION IN AN ION-TRAP REFLECTRON TIME-OF-FLIGHT DEVICE
ION FRAGMENTATION ACTIVATED BY MATRIX-ASSISTED LASER-DESORPTION IONIZATION IN AN ION-TRAP REFLECTRON TIME-OF-FLIGHT DEVICE
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DOI：
10.1002/rcm.1290080514
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发表时间：
1994-05-01
影响因子：
2
通讯作者：
LUBMAN, DM
中科院分区：
文献类型：
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作者：
FOUNTAIN, ST;LEE, H;LUBMAN, DM
离子阱存储/反射式飞行时间质谱仪已被用于研究基质辅助激光解吸/电离（MALDI）激活后大离子的衰变。研究表明，大离子可能在很长一段时间内发生裂解，在某些情况下甚至可延长至毫秒。这些碎片被存储在离子阱中，并在反射式装置中作为稳定离子被检测到，而不是作为在飞向探测器的飞行时间内因衰变而产生的亚稳离子。发现离子衰变强烈依赖于激光强度，而较小的影响可能归因于MALDI过程中使用的基质。观察到的裂解还强烈依赖于施加在环形电极上的射频电压；较高的射频电压会增强裂解。门控射频实验进一步证明了在初始激活过程中射频电压水平在产生裂解方面的重要性。对缓冲气体成分和压力影响的研究表明，压力增加可能会因离子阱中的碰撞冷却而导致裂解减少。然而，在离子阱中增加压力使用氩气或氮气缓冲气体可能会导致从离子阱中提取时发生裂解，在飞行管中产生亚稳离子。讨论了利用时间变量在离子阱中获得裂解以进行快速测序的意义。
An ion-trap storage/reflectron time-of-flight mass spectrometer has been used to study the decay of large ions following activation by matrix-assisted laser desorption/ionization (MALDI). It is shown that large ions may undergo fragmentation over long periods of time, extending even to milliseconds in some cases. These fragments are stored in the trap and detected as stable ions in the reflectron device, rather than as metastable ions due to decay during the flight time to the detector. The ion decay is found to depend strongly on the laser intensity, while a smaller effect may be due to the matrix used in the MALDI process. The fragmentation observed was found to also depend strongly on the RF voltage applied to the ring electrode; higher RF voltage produced enhanced fragmentation. A gated RF experiment further demonstrated the importance of the level of the RF voltage, during the initial activation event, in producing fragmentation. A study of the effects of buffer gas composition and pressure showed that increased pressure may result in reduced fragmentation due to collisional cooling in the trap. However, the use of argon or nitrogen buffer gas at increased pressure in the trap may result in fragmentation upon extraction from the trap, producing metastable ions in the flight tube. The implications of the use of the time variable for obtaining fragmentation in the trap for rapid sequencing are discussed.