Loboda AV, Krutchinsky AN, Bromirski M, Ens W, Standing KG
Department of Physics and Astronomy, University of Manitoba, Winnipeg MB R3T2N2, Canada.
Rapid Commun Mass Spectrom. 2000;14(12):1047-57. doi: 10.1002/1097-0231(20000630)14:12<1047::AID-RCM990>3.0.CO;2-E.
A matrix-assisted laser desorption/ionization (MALDI) source has been coupled to a tandem quadrupole/time-of-flight (QqTOF) mass spectrometer by means of a collisional damping interface. Mass resolving power of about 10,000 (FWHM) and accuracy in the range of 10 ppm are observed in both single-MS mode and MS/MS mode. Sub-femtomole sensitivity is obtained in single-MS mode, and a few femtomoles in MS/MS mode. Both peptide mass mapping and collision-induced dissociation (CID) analysis of tryptic peptides can be performed from the same MALDI target. Rapid spectral acquisition (a few seconds per spectrum) can be achieved in both modes, so high throughput protein identification is possible. Some information about fragmentation patterns was obtained from a study of the CID spectra of singly charged peptides from a tryptic digest of E. coli citrate synthase. Reasonably successful automatic sequence prediction (>90%) is possible from the CID spectra of singly charged peptides using the SCIEX Predict Sequence routine. Ion production at pressures near 1 Torr (rather than in vacuum) is found to give reduced metastable fragmentation, particularly for higher mass molecular ions. Copyright 2000 John Wiley & Sons, Ltd.
通过碰撞阻尼接口，将基质辅助激光解吸/电离（MALDI）源与串联四极杆/飞行时间（QqTOF）质谱仪相连。在单重质谱模式和串联质谱模式下，均观察到约10,000（半高宽）的质量分辨率和10 ppm范围内的精度。单重质谱模式下可获得亚飞摩尔灵敏度，串联质谱模式下为几飞摩尔。胰蛋白酶肽段的肽质量图谱分析和碰撞诱导解离（CID）分析均可在同一MALDI靶板上进行。两种模式下均可实现快速光谱采集（每个光谱只需几秒），因此高通量蛋白质鉴定成为可能。通过对大肠杆菌柠檬酸合酶胰蛋白酶消化产物中单价肽段的CID光谱研究，获得了一些关于裂解模式的信息。使用SCIEX Predict Sequence程序，从单价肽段的CID光谱中可以实现相当成功的自动序列预测（>90%）。发现在接近1托的压力下（而非在真空中）产生离子可减少亚稳裂解，尤其是对于较高质量的分子离子。版权所有2000约翰威立父子有限公司。
