Integrated Nanosystems Development Institute(INDI), IUPUI, Department of Mechanical Engineering, Indianapolis, IN, 46106, USA.
Kanomax FMT Inc., St. Paul, MN, 55110, USA.
Sci Rep. 2017 Jul 25;7(1):6456. doi: 10.1038/s41598-017-06448-w.
A new mobility particle analyzer, which has been termed Inverted Drift Tube, has been modeled analytically as well as numerically and proven to be a very capable instrument. The basis for the new design have been the shortcomings of the previous ion mobility spectrometers, in particular (a) diffusional broadening which leads to degradation of instrument resolution and (b) inadequate low and fixed resolution (not mobility dependent) for large sizes. To overcome the diffusional broadening and have a mobility based resolution, the IDT uses two varying controllable opposite forces, a flow of gas with velocity v , and a linearly increasing electric field that opposes the movement. A new parameter, the separation ratio Λ = v /v , is employed to determine the best possible separation for a given set of nanoparticles. Due to the system's need to operate at room pressure, two methods of capturing the ions at the end of the drift tube have been developed, Intermittent Push Flow for a large range of mobilities, and Nearly-Stopping Potential Separation, with very high separation but limited only to a narrow mobility range. A chromatography existing concept of resolving power is used to differentiate between peak resolution in the IDT and acceptable separation between similar mobility sizes.
一种新型的移动颗粒分析仪，称为倒置漂移管，已进行了分析和数值建模，并被证明是一种非常有效的仪器。新设计的基础是以前的离子淌度谱仪的缺点，特别是（a）扩散展宽导致仪器分辨率降低，（b）对于大尺寸，分辨率不足且固定（不依赖于淌度）。为了克服扩散展宽并具有基于淌度的分辨率，IDT 使用两种变化的可控相反力，具有速度 v 的气体流动和与运动相反的线性增加的电场。一个新的参数，分离比Λ=v/v，用于确定给定的纳米颗粒的最佳可能分离。由于系统需要在室温下运行，因此开发了两种在漂移管末端捕获离子的方法，即用于大范围淌度的间歇推流和几乎停止的势分离，具有非常高的分离度，但仅局限于很窄的淌度范围。色谱分辨率的概念用于区分 IDT 中的峰分辨率和类似淌度尺寸之间可接受的分离。
