Skoblin Michael G, Chudinov Alexey V, Sulimenkov Ilia V, Brusov Vladimir S, Makarov Alexander A, Wouters Eloy R, Kozlovskiy Viacheslav I
1 Branch of Talrose Institute for Energy Problems of Chemical Physics, Russian Academy of Science, Chernogolovka, Russia.
2 Thermo Fisher Scientific, Bremen, Germany.
Eur J Mass Spectrom (Chichester). 2017 Aug;23(4):187-191. doi: 10.1177/1469066717719556.
A two-step approach was developed for the study of ion transport in an atmospheric pressure interface. In the first step, the flow in the interface was numerically simulated using the standard gas dynamic package ANSYS CFX 15.0. In the second step, the calculated fields of pressure, temperature, and velocity were imported into a custom-built software application for simulation of ion motion under the influence of both gas dynamic and electrostatic forces. To account for space charge effects in axially symmetric interfaces an analytical expression was used for the Coulomb force. For all other types of interfaces, an iterative approach for the Coulomb force computation was developed. The simulations show that the influence of the space charge is the main contributor to the loss of ion current in the heated capillary. In addition, the maximum ion current which can be transmitted through the heated capillary (0.58 mm inner diameter and 58.5 mm length) is limited to ∼6 nA for ions with m/z = 508 Da and with reduced ion mobility 1.05 cmVs. This limit remains practically constant and independent of the ion current at the entrance of the capillary. For a particular ion type, this limit depends on its m/z ratio and ion mobility.
开发了一种两步法来研究大气压界面中的离子传输。第一步，使用标准气体动力学软件包ANSYS CFX 15.0对界面中的流动进行数值模拟。第二步，将计算得到的压力、温度和速度场导入到一个定制的软件应用程序中，以模拟气体动力学和静电力共同作用下的离子运动。为了考虑轴对称界面中的空间电荷效应，使用了库仑力的解析表达式。对于所有其他类型的界面，开发了一种用于库仑力计算的迭代方法。模拟结果表明，空间电荷的影响是加热毛细管中离子电流损失的主要原因。此外，对于质荷比m/z = 508 Da、折合离子迁移率为1.05 cm²V⁻¹s⁻¹的离子，能够通过加热毛细管（内径0.58 mm，长度58.5 mm）传输 的最大离子电流限制在约6 nA。这个限制实际上保持不变，并且与毛细管入口处的离子电流无关。对于特定的离子类型，这个限制取决于其质荷比和离子迁移率。
