Characteristics of positive and negative secondary ions emitted from [Formula: see text] and [Formula: see text] impacts.
Characteristics of positive and negative secondary ions emitted from [Formula: see text] and [Formula: see text] impacts.
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DOI：
10.1002/sia.5009
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发表时间：
2013-01
影响因子：
1.7
通讯作者：
Della-Negra, S.
中科院分区：
文献类型：
--
作者：
DeBord, J. D.;Fernandez-Lima, F. A.;Verkhoturov, S. V.;Schweikert, E. A.;Della-Negra, S.
SIMS 分析目前的局限性是二次离子产率不足，部分原因是传统一次离子的效率低下。与其他常用射弹相比，大量金簇被证明是显着提高二次离子产率的途径。在 520 keV 的撞击能量下，每个射弹能够平均产生超过 10 个二次离子，某些撞击事件会产生 >100 个二次离子。通过对模型五肽亮氨酸脑啡肽的单一目标的单次撞击观察到多达七个去质子化分子离子，进一步显示了该射弹增强信号的能力。亮氨酸脑啡肽的正光谱和负光谱揭示了两种不同的发射机制，负责发射具有低内能的完整分子离子或小碎片物质。使用一系列苄基吡啶鎓盐测量该弹丸的内部能量分布，并与 110 keV 的小型多原子弹丸以及之前报道的电喷雾电离和快原子轰击的分布进行比较。这些结果表明，不仅对于小碎片离子（例如， CN–，通常在 SIMS 分析中观察到，但也可用于特征分子离子。对于亮氨酸脑啡肽的例子，这些物种中每一个的产量都大于统一。
The current limitation for SIMS analyses is insufficient secondary ion yields, due in part to the inefficiency of traditional primary ions. Massive gold clusters are shown to be a route to significant gains in secondary ion yields relative to other commonly used projectiles. At an impact energy of 520 keV, is capable of generating an average of greater than ten secondary ions per projectile, with some impact events generating >100 secondary ions. The capability of this projectile for signal enhancement is further displayed through the observation of up to seven deprotonated molecular ions from a single impact on a neat target of the model pentapeptide leu-enkephalin. Positive and negative spectra of leu-enkephalin reveal two distinct emission regimes responsible for the emission of either intact molecular ions with low internal energies or small fragment species. The internal energy distribution for this projectile is measured using a series of benzylpyridinium salts and compared with the small polyatomic projectile at 110 keV as well as distributions previously reported for electrospray ionization and fast atom bombardment. These results show that offers high secondary ion yields not only for small fragment ions, e.g. CN–, typically observed in SIMS analyses, but also for characteristic molecular ions. For the leu-enkephalin example, the yields for each of these species are greater than unity.
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影响因子：
7.4
作者：
Delcorte, A.;Garrison, B. J.;Hamraoui, K.
通讯作者：
Hamraoui, K.
影响因子：
1.7
作者：
Li, Guangtao;Cyriac, Jobin;Cooks, R. Graham
通讯作者：
Cooks, R. Graham
影响因子：
6.7
作者：
Wirtz, T;Migeon, HN
通讯作者：
Migeon, HN
DOI：
10.1016/j.jasms.2007.11.019
发表时间：
2008-03-01
影响因子：
3.2
作者：
Nefliu, Marcela;Smith, Jonell N.;Cooks, R. Graham
通讯作者：
Cooks, R. Graham
DOI：
10.1021/jz200708j
发表时间：
2011-07-22
期刊：
The journal of physical chemistry letters
影响因子：
--
作者：
Brenes DA;Postawa Z;Wucher A;Blenkinsopp P;Garrison BJ;Winograd N
通讯作者：
Winograd N