一个水合气态的电子捕获:水对碎片化和分子生存的影响
James S Prell1, Jeremy T O'Brien, Anne I S Holm
1Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
Journal of the American Chemical Society
|September 3, 2008
概括
研究人员研究了水如何影响离子碎片化,使用电子捕获解离. 他们确定了重组能 (RE) 和碎片离子出现能,揭示了水.
科学领域:
- 物理化学 物理化学
- 分析化学 分析化学
- 生物化学 生物化学
背景情况:
- 电子捕获解离 (ECD) 是分析的一个关键技术.
- 溶解,特别是用水对ECD过程的影响尚未完全理解.
- 在溶解中量化重组能 (RE) 和碎片外观能量是具有挑战性的.
研究的目的:
- 研究水溶解对莱斯-泰尔-莱斯 (KYK) 离子的电子捕获解离 (ECD) 的影响.
- 通过实验确定碎片离子的重组能 (RE) 和外观能.
- 探索水对离子碎片化途径"化"效应的作用.
主要方法:
- 研究的二质化Lys-Tyr-Lys (KYK) 离子被0-25个水分子溶解.
- 使用电子捕获解离 (ECD) 质谱法.
- 开发了一种离子纳米热量测量技术来测量RE和外观能量.
主要成果:
- 根据水分子蒸发,确定重组能 (RE) 大约为4.3 eV.
- 对特定碎片离子 (b2+, y2+, z2+*, c2+, KYK+H+) 的测量外观能量为9至88kcal/mol.
- 由于水的"化"效应,观察到H原子和氨损失倾向的显著变化.
结论:
- 这项研究提供了通过ECD通过多重电荷的首次实验测量RE和碎片离子外观能量.
- 这些发现表明,水显著影响了ECD中的离子稳定性和碎片化途径.
- 新型离子纳米热量测量技术为研究复杂系统中的外热反应提供了一种新方法.
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