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J Am Soc Mass Spectrom. 2017 Oct;28(10):2151-2159. doi: 10.1007/s13361-017-1727-7. Epub 2017 Jun 29.
We provide modeling and experimental data describing the dominant ion-loss mechanisms for differential mobility spectrometry (DMS). Ion motion is considered from the inlet region of the mobility analyzer to the DMS exit, and losses resulting from diffusion to electrode surfaces, insufficient effective gap, ion fragmentation, and fringing field effects are considered for a commercial DMS system with 1-mm gap height. It is shown that losses due to diffusion and radial oscillations can be minimized with careful consideration of residence time, electrode spacing, gas flow rate, and waveform frequency. Fragmentation effects can be minimized by limitation of the separation field. When these parameters were optimized, fringing field effects at the DMS inlet contributed the most to signal reduction. We also describe a new DMS cell configuration that improves the gas dynamics at the mobility cell inlet. The new cell provides a gas jet that decreases the residence time for ions within the fringing field region, resulting in at least twofold increase in ion signal as determined by experimental data and simulations. Graphical Abstract ᅟ.
我们提供了描述差分迁移谱（DMS）中主要离子损失机制的建模和实验数据。从迁移率分析仪的入口区域到 DMS 出口，考虑了离子运动，并且对于具有 1-mm 间隙高度的商业 DMS 系统，考虑了扩散到电极表面、有效间隙不足、离子碎裂和边缘场效应的损失。结果表明，通过仔细考虑停留时间、电极间距、气体流速和波形频率，可以最小化由于扩散和径向振荡引起的损失。通过限制分离场可以最小化碎裂效应。当优化这些参数时，DMS 入口处的边缘场效应对信号降低的影响最大。我们还描述了一种新的 DMS 单元配置，该配置改善了迁移率单元入口处的气体动力学。新单元提供了一个气体射流，减少了离子在边缘场区域内的停留时间，从而根据实验数据和模拟确定离子信号至少增加了两倍。
