Labowsky M
Department of Chemical Engineering, Yale University, New Haven, Connecticut, 06520
J Colloid Interface Sci. 1998 Oct 1;206(1):19-28. doi: 10.1006/jcis.1998.5599.
The electrospray ion source has recently revolutionized mass spectrometry by allowing researchers to produce gaseous ions of very large molecular weights such as proteins and polymers. The process by which these high-molecular-weight ions are produced, however, is not very well understood. The purpose of the present work is to study the fields in the vicinity of each charge in order to shed some light on the ion formation process for charged dielectric droplets. An important feature of this work, therefore, is the treatment of the charge as discrete rather than continuous. The picture that emerges is of discrete charges in a dielectric droplet thermally oscillating around a potential well, located slightly below the droplet surface. The charges produce localized electrostatic pressures on the droplet surface that are higher (15.5 and 70% for dielectric constants of 80 and 20, respectively) than expected if the charge distribution were continuous. These high localized pressures could locally stretch the surface and result in the emission of ions or small charged droplets. The magnitude of these localized pressures is a function of the number of charges and the dielectric constant of the droplet. Copyright 1998 Academic Press.
电喷雾离子源最近给质谱分析带来了变革，它使研究人员能够产生诸如蛋白质和聚合物等非常大分子量的气态离子。然而，产生这些高分子量离子的过程尚未得到很好的理解。本工作的目的是研究每个电荷附近的场，以便对带电介电液滴的离子形成过程有所了解。因此，这项工作的一个重要特点是将电荷视为离散的而非连续的。所呈现的图景是，介电液滴中的离散电荷围绕着一个位于液滴表面稍下方的势阱进行热振荡。这些电荷在液滴表面产生局部静电压力，该压力比电荷分布为连续时预期的要高（介电常数为80和20时，分别高出15.5%和70%）。这些高局部压力可能会局部拉伸表面并导致离子或小带电液滴的发射。这些局部压力的大小是电荷数量和液滴介电常数的函数。版权所有1998年学术出版社。
