Electrospray droplet impact/secondary ion mass spectrometry: cluster ion formation
Electrospray droplet impact/secondary ion mass spectrometry: cluster ion formation
复制标题
DOI：
10.1002/rcm.2633
复制
发表时间：
2006-01-01
影响因子：
2
通讯作者：
Hiraoka, Kenzo
中科院分区：
文献类型：
--
作者：
Mori, Kunihiko;Asakawa, Dalki;Hiraoka, Kenzo
通过孔口采样到真空室中的电喷雾液滴被10 kV加速并撞击在不锈钢基底上。电喷雾液滴的质量和动能粗略估计分别为几个10（6）u和类似于10（6）eV。观察到分子离子M+和质子化分子[M+H]（+）作为沉积在金属基底（未使用基质）上的金和晕苯的二次离子。电离可能发生在液滴抛射体与固体样品的高动量相干碰撞产生的冲击波中。在10（-2）M三氟乙酸（TFA）水溶液的电喷雾液滴碰撞电离（EDI）中，观察到H+（H2O）（n）和CF 3COO-（H2O）（n）（n = 150）团簇离子作为二次离子。这表明，以类似于10（6）eV的动能与金属基板碰撞的带电液滴没有完全蒸发，而是分解成许多微小的微滴。在10（-2）M TFA水溶液中，观察到H_3O ~+（H_2O）（n）和CF_3COO ~-（H_2O）（n）团簇离子以及Cs ~+（H_2O）（n）、I ~-（H_2O）（n）、Cs ~+（CsI）（n）和I ~-（CsI）（n）团簇离子的离子信号强度异常（幻数）。版权所有（c）2006约翰威利父子有限公司。
The electrospray droplets that are sampled through an orifice into the vacuum chamber are accelerated by 10kV and impact on the stainless steel substrate. The mass and the kinetic energy of electrospray droplets are roughly estimated to be a few 10(6) u and similar to 10(6) eV, respectively. The molecular ion M+, and the protonated molecule [M+H](+) are observed as secondary ions for chrysene and coronene deposited on the metal substrate (no matrix used). The ionization may take place in the shock wave generated by the high-momentum coherent collision between the droplet projectile and the solid sample. Cluster ions of H+(H2O)(n) and CF3COO-(H2O)(n), with n up to similar to 150, were observed as secondary ions formed by the electrospray droplet impact ionization (EDI) for 10(-2) M trifluoroacetic acid (TFA) aqueous solution. This indicates that the charged droplets that collide with the metal substrate with the kinetic energy of similar to 10(6) eV do not vaporize completely but are disintegrated into many tiny microdroplets. The ion signal intensity anomalies (i.e. magic numbers) were observed for the cluster ions of H3O+(H2O)(n) and CF3COO-(H2O)(n) for 10(-2) M TFA aqueous solution and of Cs+(H2O)(n), I-(H2O)(n), Cs+(CsI)(n), and I-(CsI)(n) for 10(-2) M CsI aqueous solution. Copyright (c) 2006 John Wiley & Sons, Ltd.