Electrostatic spray of liquid : Study on the charged particles in the condensed phase

由于缺乏合适的方法，离子溶剂化的研究是一项相当困难的任务。本文研究了在强电场作用下，溶解在液体中的离子被萃取到气相中，并详细研究了离子在凝聚相中的物理化学行为。这将有助于阐明溶剂效应、离子在缩合相中的化学反应性、溶剂化电子等。为了探讨离子溶剂化的机理，利用高压质谱仪对其热化学稳定性、结构和稳定性进行了研究。结果表明，F^-离子对溶剂分子具有很强的反应性，常与溶剂分子形成共价体。相反，其他卤化物离子（Cl^-, Br^-, I^-）只能被溶剂分子静电溶解。水是多种离子的优良溶剂。我们指出这是由于不同溶剂化壳层的水配体的相互极化，这加强了它们之间的相互作用（增强效应）。第一层的醇分子与离子的相互作用比水分子强。然而，醇对离子的增强作用弱于水，因此醇一般是比水更差的溶剂。在B =烷基取代的H_2O和NH_3中，共轭碱B's的气相质子亲和与共轭离子BH^+'s的水化自由能之间存在近似的线性关系。这意味着如果共轭碱B具有较高的质子亲和力，则其共轭酸离子BH更容易从缩合相被萃取到气相。因此，电喷雾可以成为医学、制药和农业领域分析溶剂化离子的有用工具。对溶液中的离子进行了电喷涂和质谱分析。所有检测到的主离子都是伪分子离子。这表明离子萃取过程非常温和。少

The study on the ion solvation is a rather difficult task because of the lack of suitable methodology. In this work, the extraction of ions dissolved in the liquid into the gas phase by applying a strong electric field to the liquid are studied, and an information on the physicochemical behavior of ions in the condensed phase is investigated in detail. This will lead to the elucidation of the solvent effect, chemical reactivity of ions in the condensed phase, solvated electron, etc.In order to investigate the mechanism of ion solvation, the thermochemical stabilities, structures, and stabilities were studied using the high-pressure mass spectrometer. It was found that the F^- ion is highly reactive toward the solvent molecules and often forms the covalent bodn with them. In contrast, other halide ions (Cl^-, Br^-, I^-) are solvated only electrostatically by solvent molecules. Water is a superior solvent toward a variety of ions. We pointed out that this is due to the mutual polarizatio … More n of water ligands belonging to the different solvation shells which strengthens the interaction between them (enhancement effect). The alcohol molecules in the first shell experience stronger interaction with ions than watermolecules. However, the enhancement effect for alcohols is weaker than that for water, and thus alcohols are generally poorer solvents than water toward ions.An approximate linear relationship was found between gas-phase proton affinities of conjugate bases B's and free energies of hydration of conjugate ions BH^+'s for B = alkyl-substituted H_2O and NH_3. This means that if the conjugate base B has a higher proton affinity, its conjugate acid ion BH is easier to be extracted from the condensed phase to the gas phase. Thus the electrospray could be a useful tool for the analysis of solvated ions in the fields of medicine, pharmacy, and agriculture.The ions in solution were electrosprayed and mass-analysed. All of the detected major ions are found to be pseudo-molecular ions. This indicates that the ion extraction process is very mild. Less