Effects of fragile ions on mass resolution and on isolation for tandem mass spectrometry in the quadrupole ion trap mass spectrometer
Effects of fragile ions on mass resolution and on isolation for tandem mass spectrometry in the quadrupole ion trap mass spectrometer
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DOI：
10.1021/ac015610b
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发表时间：
2002-01-15
影响因子：
7.4
通讯作者：
Yost, RA
中科院分区：
文献类型：
--
作者：
McClellan, JE;Murphy, JP;Yost, RA
在四极离子陷阱中，人们已经注意到，除了离子的质量和电荷之外，其他因素可能会影响其测量的m/z，从而导致化合物相关的或“化学”的质量漂移。我们认为离子可以表现出化学质量移动，因为它们是“脆弱的”，并且在应用共振喷射进行质量分析时可能发生碎裂；这些影响是使用包括质子化、去质子化和加合离子的炸药、酰肉碱和大环内酯类抗生素的离子来研究的。脆性离子通过产生比非脆性离子更宽的峰来影响质量分辨率，特别是在较慢的扫描速度下，这是应用共振喷射的结果。在选择串联质谱学实验的母离子时，也可能通过应用隔离波形来碎裂脆弱离子，使得不可能实现对脆弱离子的单位分离。为了获得足够的隔离强度，必须增加隔离波形的陷波宽度，并缩短隔离时间。脆弱离子还需要较低的最佳碰撞能量来实现有效的碰撞诱导解离。我们根据实验结果制定了确定离子脆性程度的标准。
In the quadrupole ion trap, it has been noted that factors other than an ion's mass and charge may affect its measured m/z, resulting in compound-dependent, or "chemical", mass shifts. We propose that ions can exhibit a chemical mass shift because they are "fragile" and may fragment during the application of resonance ejection during mass analysis; these effects were studied using ions that include protonated, deprotonated, and adduct ions of explosives, acylcarnitines, and macrolide antibiotics. Fragile ions affect mass resolution by causing broader peaks than nonfragile ions, especially at slower scan speeds, as the result of the application of resonance ejection. Fragile ions may also be fragmented by the application of the isolation waveform during selection of the parent ion for tandem mass spectrometry experiments, making it impossible to achieve unit isolation of a fragile ion. To obtain adequate isolation intensity, the isolation waveform notch width must be increased and the time period of isolation must be decreased. Fragile ions also require lower optimum collision energy to achieve efficient collision-induced dissociation. We have developed criteria for the determination of the degree of ion fragility based upon experimental results.