Experimental and theoretical investigation into the correlation between mass and ion mobility for choline and other ammonium cations in N2
Experimental and theoretical investigation into the correlation between mass and ion mobility for choline and other ammonium cations in N2
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DOI：
10.1021/ac701888e
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发表时间：
2008-03-15
影响因子：
7.4
通讯作者：
Kanik, Isik
中科院分区：
文献类型：
--
作者：
Kim, Hyungjun;Kim, Hugh I.;Kanik, Isik
使用电喷雾电离离子迁移谱法研究了质量范围为60-146 amu的许多叔胺和季铵阳离子（三甲基胺、四甲基铵、三甲基乙基铵、N，N-二甲基氨基乙醇、胆碱、N，N-二甲基甘氨酸、甜菜碱、乙酰胆碱、（3-羧基丙基）三甲基铵）。测得的离子迁移率表明，在N-2的质量和迁移率之间的高度相关性。此外，相同的实验不确定性内的迁移率观察到类似的离子质量的结构不同的离子。例如，二甲基乙基铵（88 amu）阳离子和质子化的N，N-二甲基氨基乙醇阳离子（90 amu）显示出相同的迁移率（1.93 cm（2）V-1 s（-1）），尽管N，N-二甲基氨基乙醇含有羟基官能团，而二甲基乙基铵仅含有烷基。采用修正轨道法（TJ），以非球形N-2分子为漂移气体进行了计算分析。铵阳离子碰撞截面的离子-中性相互作用的细节的灵敏度进行了研究，并与其他类别的有机分子（羧酸和非生物氨基酸）。在研究的质量范围内的分子离子的特定电荷分布的碰撞截面上有一个微不足道的影响。
A number of tertiary amine and quaternary ammonium cations spanning a mass range of 60-146 amu (trimethylamine, tetramethylammonium, trimethylethylammonium, N,N-dimethylaminoethanol, choline, N,N-dimethylglycine, betaine, acetylcholine, (3-carboxypropyl)trimethylammonium) were investigated using electrospray ionization ion mobility spectrometry. Measured ion mobilities demonstrate a high correlation between mass and mobility in N-2. In addition, identical mobilities within experimental uncertainties are observed for structurally dissimilar ions with similar ion masses. For example, dimethylethylammonium (88 amu) cations and protonated N,N-dimethylaminoethanol cations (90 amu) show identical mobilities (1.93 cm(2) V-1 s(-1)) though N,N-dimethylaminoethanol contains a hydroxyl functional group while dimethylethylammonium only contains alkyl groups. Computational analysis was performed using the modified trajectory (TJ) method with nonspherical N-2 molecules as the drift gas. The sensitivity of the ammonium cation collision cross sections to the details of the ion-neutral interactions was investigated and compared to other classes of organic molecules (carboxylic acids and abiotic amino acids). The specific charge distribution of the molecular ions in the investigated mass range has an insignificant affect on the collision cross section.