Krylov Evgeny V, Coy Stephen L, Vandermey John, Schneider Bradley B, Covey Thomas R, Nazarov Erkinjon G
Sionex Corporation, 8-A Preston Ct., Bedford, Massachusetts 01730, USA.
Rev Sci Instrum. 2010 Feb;81(2):024101. doi: 10.1063/1.3284507.
Devices based on differential mobility spectrometry (DMS) are used in a number of ways, including applications as ion prefilters for API-MS systems, as detectors or selectors in hybrid instruments (GC-DMS, DMS-IMS), and in standalone systems for chemical detection and identification. DMS ion separation is based on the relative difference between high field and low field ion mobility known as the alpha dependence, and requires the application of an intense asymmetric electric field known as the DMS separation field, typically in the megahertz frequency range. DMS performance depends on the waveform and on the magnitude of this separation field. In this paper, we analyze the relationship between separation waveform and DMS resolution and consider feasible separation field generators. We examine ideal and practical DMS separation field waveforms and discuss separation field generator circuit types and their implementations. To facilitate optimization of the generator designs, we present a set of relations that connect ion alpha dependence to DMS separation fields. Using these relationships we evaluate the DMS separation power of common generator types as a function of their waveform parameters. Optimal waveforms for the major types of DMS separation generators are determined for ions with various alpha dependences. These calculations are validated by comparison with experimental data.
基于差分离子迁移谱（DMS）的设备有多种用途，包括用作大气压电离质谱（API-MS）系统的离子预过滤器、混合仪器（气相色谱-差分离子迁移谱仪，差分离子迁移谱仪-离子迁移谱仪）中的检测器或选择器，以及用于化学检测和识别的独立系统。DMS离子分离基于高场和低场离子迁移率之间的相对差异，即所谓的α依赖性，并且需要施加一种称为DMS分离场的强不对称电场，通常在兆赫兹频率范围内。DMS性能取决于波形和该分离场的大小。在本文中，我们分析了分离波形与DMS分辨率之间的关系，并考虑了可行的分离场发生器。我们研究了理想和实际的DMS分离场波形，并讨论了分离场发生器电路类型及其实现方式。为了便于优化发生器设计，我们提出了一组将离子α依赖性与DMS分离场联系起来的关系式。利用这些关系，我们评估了常见发生器类型的DMS分离能力与其波形参数的函数关系。针对具有不同α依赖性的离子，确定了主要类型的DMS分离发生器的最佳波形。通过与实验数据比较验证了这些计算结果。
