Hoteling Andrew J, Kawaoka Kenji, Goodberlet Mary C, Yu Wan-Mo, Owens Kevin G
Imaging Materials and Media, R&D, Eastman Kodak Company, Rochester, NY 14650-2132, USA.
Rapid Commun Mass Spectrom. 2003;17(14):1671-6. doi: 10.1002/rcm.1084.
Details of the optimization of the collision-induced dissociation (CID) process, using a collision cell on a matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometer, are described using poly(ethylene glycol) 1000 (PEG 1000) as a model analyte. The effects of collision gas identity (helium, air, and argon), as well as collision gas pressure, on the resulting MS/MS data were investigated. With PEG 1000, helium was found to give the best results with respect to signal-to-noise (S/N) ratio. The optimum pressure for each gas was found to be in the range where the precursor ion signal was attenuated to approximately 30-50% for helium and 40-60% for argon. The effect of cation choice (Li, Na, and K) on the CID of PEG was also studied. CID spectra were produced for each, but PEG cationized with lithium was found to produce the spectra with the highest S/N ratio. The MALDI-TOF CID spectra that were generated for PEG were compared with the high-energy and low-energy MS/MS spectra obtained from a sector mass spectrometer and from a triple quadrupole mass spectrometer, respectively. The results observed for PEG confirm that CID on a MALDI-TOF mass spectrometer is a high-energy MS/MS technique.
以聚乙二醇1000（PEG 1000）作为模型分析物，描述了在基质辅助激光解吸/电离（MALDI）飞行时间（TOF）质谱仪上使用碰撞池对碰撞诱导解离（CID）过程进行优化的细节。研究了碰撞气体种类（氦气、空气和氩气）以及碰撞气体压力对所得串联质谱（MS/MS）数据的影响。对于PEG 1000，发现氦气在信噪比（S/N）方面给出最佳结果。发现每种气体的最佳压力范围是，对于氦气，前体离子信号衰减至约30% - 50%；对于氩气，前体离子信号衰减至约40% - 60%。还研究了阳离子选择（锂、钠和钾）对PEG碰撞诱导解离的影响。分别为每种阳离子生成了CID谱图，但发现用锂阳离子化的PEG产生的谱图具有最高的信噪比。将为PEG生成的MALDI-TOF CID谱图分别与从扇形质谱仪和三重四极杆质谱仪获得的高能和低能MS/MS谱图进行了比较。对PEG观察到的结果证实，MALDI-TOF质谱仪上的CID是一种高能MS/MS技术。
