Laserspray ionization, a new atmospheric pressure MALDI method for producing highly charged gas-phase ions of peptides and proteins directly from solid solutions.
Laserspray ionization, a new atmospheric pressure MALDI method for producing highly charged gas-phase ions of peptides and proteins directly from solid solutions.
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DOI：
10.1074/mcp.m900527-mcp200
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发表时间：
2010-02
期刊：
影响因子：
--
通讯作者：
McEwen CN
中科院分区：
文献类型：
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作者：
Trimpin S;Inutan ED;Herath TN;McEwen CN
给出了基质辅助激光解吸/电离(MALDI)过程的第一个例子，该过程产生了与电喷雾电离(ESI)观察到的几乎相同的多电荷质谱图。MALDI以产生单电荷离子的能力而闻名，但在这里描述的实验中，多电荷离子是通过激光烧蚀并入常见MALDI基质2，5-二羟基苯甲酸的分析物，使用标准的溶剂型样品制备方案产生的。已知激光消融在MALDI中产生基质团簇，前提是达到阈值能量。我们认为这些团簇(液滴)是高度带电的，在产生足够的基质蒸发的条件下，离子从液滴中场蒸发类似于ESI。由于多次充电，先进的质荷比范围有限的质谱仪可以用于蛋白质表征。因此，使用Orbitrap质谱计，低飞摩尔量的蛋白质产生质量分辨率为100,000的全范围质谱图，质量精度为<；5-ppm，采集1-S。此外，还给出了第一个利用MALDI进行电子转移解离的蛋白质裂解的例子。
The first example of a matrix-assisted laser desorption/ionization (MALDI) process producing multiply charged mass spectra nearly identical to those observed with electrospray ionization (ESI) is presented. MALDI is noted for its ability to produce singly charged ions, but in the experiments described here multiply charged ions are produced by laser ablation of analyte incorporated into a common MALDI matrix, 2,5-dihydroxybenzoic acid, using standard solvent-based sample preparation protocols. Laser ablation is known to produce matrix clusters in MALDI provided a threshold energy is achieved. We propose that these clusters (liquid droplets) are highly charged, and under conditions that produce sufficient matrix evaporation, ions are field-evaporated from the droplets similarly to ESI. Because of the multiple charging, advanced mass spectrometers with limited mass-to-charge range can be used for protein characterization. Thus, using an Orbitrap mass spectrometer, low femtomole quantities of proteins produce full-range mass spectra at 100,000 mass resolution with <5-ppm mass accuracy and with 1-s acquisition. Furthermore, the first example of protein fragmentation using electron transfer dissociation with MALDI is presented.