Department of Chemical Engineering, Yale University, 06520-2159, New Haven, CT, USA.
J Am Soc Mass Spectrom. 1993 Jul;4(7):524-35. doi: 10.1016/1044-0305(93)85014-O.
The formation of ions from the charged droplets produced in the several spray ionization techniques is viewed as an activated rate process involving field-assisted desorption, in accord with the ideas first set forth by Iribame and Thomson. The novel features of the present treatment are particularly relevant to the unique ability of electrospray ionization to transform large molecules in solution to free ions in the gas phase, with extensive multiple charging. These new features stem mainly from the realization that the spacing of charges on a desorbed ion must relate to the spacing of charges on the surface of the droplet whence it came. The consequences of this "rule" can account for the existence of maxima and minima in the number of charges on the ions of a particular species as well as the nature of the distribution of ions among the intervening charge states. They also explain the dependence of charge state on the configuration in solution of the parent molecule of the desorbed ion. In addition, they provide insight into the sequence in time at which ions in the various charge states leave an evaporating droplet.
从几种喷雾离子化技术中产生的带电液滴形成离子被视为一个涉及场辅助解吸的激活速率过程，这与 Iribame 和 Thomson 首次提出的观点一致。本研究的新颖特点与电喷雾离子化将溶液中的大分子转化为气相中自由离子的独特能力特别相关，同时还伴随着广泛的多重电荷。这些新特点主要源于这样一种认识，即解吸离子上的电荷间距必须与它所来自的液滴表面上的电荷间距相关。这条“规则”的结果可以解释特定物种的离子上电荷数量的最大值和最小值的存在，以及离子在中间电荷状态之间的分布性质。它们还解释了电荷状态对解吸离子母体分子在溶液中的构型的依赖性。此外，它们还深入了解了不同电荷状态的离子在蒸发液滴中离开的时间顺序。
