Generation of highly charged peptide and protein ions by atmospheric pressure matrix-assisted infrared laser desorption/ionization ion trap mass spectrometry
Generation of highly charged peptide and protein ions by atmospheric pressure matrix-assisted infrared laser desorption/ionization ion trap mass spectrometry
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DOI：
10.1021/ac070628t
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发表时间：
2007-07-15
影响因子：
7.4
通讯作者：
Dreisewerd, Klaus
中科院分区：
文献类型：
--
作者：
Koenig, Simone;Kollas, Oliver;Dreisewerd, Klaus
我们发现，如果脉冲红外激光和甘油基质用于四极离子陷阱的大气压基质辅助激光解吸/电离质谱仪，可以产生高电荷态离子。对于像缓激肽这样的小肽，双质子化离子已经形成了质谱图中最丰富的分析物信号。电荷态分布的中心随着分析物尺寸的增大而增大。例如，检测到的胰岛素具有与电荷状态4对应的最丰富的离子信号，而对于细胞色素c，10倍质子化的离子物种产生最强烈的信号。观察到肌红蛋白最多有13个电荷。高的m/z比允许我们使用Paul陷阱来检测MALDI产生的蛋白质离子，由于它们的高分子量，在它们的单质子化电荷状态下是不服从的。多重电荷的形成关键取决于向分析物基质溶液中加入稀酸。文中还给出了双电荷肽碰撞诱导解离产生的串联质谱图。这一发现允许推测电喷雾电离过程参与了这些MALDI实验。
We show that highly charged ions can be generated if a pulsed infrared laser and a glycerol matrix are employed for atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry with a quadrupole ion trap. Already for small peptides like bradykinin, doubly protonated ions form the most abundant analyte signal in the mass spectra. The center of the charge-state distribution increases with the size of the analyte. For example, insulin is detected with a most abundant ion signal corresponding to a charge state of four, whereas for cytochrome c, the 10 times protonated ion species produces the most intense signal. Myoglobin is observed with up to 13 charges. The high m/z ratios allow us to use the Paul trap for the detection of MALDI-generated protein ions that are, owing to their high molecular weight, not amenable in their singly protonated charge state. Formation of multiple charges critically depends on the addition of diluted acid to the analyte-matrix solution. Tandem mass spectra generated by collision-induced dissociation of doubly charged peptides are also presented. The findings allow speculations about the involvement of electrospray ionization processes in these MALDI experiments.