Tandem mobility mass spectrometry study of electrosprayed tetraheptyl ammonium bromide clusters
Tandem mobility mass spectrometry study of electrosprayed tetraheptyl ammonium bromide clusters
复制标题
DOI：
10.1016/j.jasms.2005.01.019
复制
发表时间：
2005-05-01
影响因子：
3.2
通讯作者：
Gamero-Castaño, M
中科院分区：
文献类型：
--
作者：
de la Mora, JF;Thomson, BA;Gamero-Castaño, M
从甲酰胺中庚基(4)N(+)Br(-)(以下称为A（+)B(-)）的浓溶液中获得的带电电喷雾离子，在差分迁移率分析仪（DMA）中进行环境空气迁移率选择后，用质谱法（MS）分析。看到的大多数尖锐迁移峰被确定为（AB）(n)A（+）团簇，0 0.495 cm(2)/V/s是亚稳的，蒸发了一个单电荷团簇，可能是（AB）(2)A(+)，在DMA和ms之间，以（Z /Z）（1/2）与m（1/3）的形式绘制团簇的电迁移率Z（都与团簇直径成正比）将所有团簇大小和电荷状态的数据折叠成一条直线Z低于0.495 cm(2)/V/s。这种线性关系揭示了均匀的表观团簇密度为0.935 g/cm(3)，空气分子的有效硬球直径为0.44 nm。在直径小于3nm处观察到异常迁移率增加。(c) 2005年美国质谱学会。
Multiply charged electrospray ions from concentrated solutions of Heptyl(4)N(+)Br(-) (designated A(+)B(-) hereafter) in formamide are analyzed mass spectrometrically (MS) following mobility selection in ambient air in a differential mobility analyzer (DMA). Most of the sharp mobility peaks seen are identified as (AB)(n)A(+) clusters, with 0 0.495 cm(2)/V/s are metastable and evaporate a singly charged cluster, probably (AB)(2)A(+), between the DMA and the MS. Plotting the electrical mobilities Z of the clusters in the form (z/Z)(1/2) versus m(1/3) (both proportional to cluster diameter) collapse the data for all cluster sizes and charge states into one single straight line for Z below 0.495 cm(2)/V/s. This linear relation reveals a uniform apparent cluster density of 0.935 g/cm(3) and an effective hard-sphere diameter of the air molecules of 0.44 nm. An anomalous mobility increase is observed at diameters below 3 nm. (c) 2005 American Society for Mass Spectrometry.