Understanding and designing field asymmetric waveform ion mobility spectrometry separations in gas mixtures
Understanding and designing field asymmetric waveform ion mobility spectrometry separations in gas mixtures
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DOI：
10.1021/ac049299k
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发表时间：
2004-12-15
影响因子：
7.4
通讯作者：
Smith, RD
中科院分区：
文献类型：
--
作者：
Shvartsburg, AA;Tang, KQ;Smith, RD
场不对称波形离子迁移谱（FAIMS）与质谱分析结合用于电离后分离具有显著的潜力。FAIMS通过利用气体中的离子迁移率以特定于每个离子的方式取决于电场的事实来分级离子混合物。几乎所有以前的工作都使用了纯气体，FAIMS的基本原理已经得到了相当好的理解;然而，在一些气体混合物中观察到了意想不到的现象（例如，N-2/CO2），而不是在其他（N-2/O-2）仍然无法解释。在这里，我们介绍和实验测试的FAIMS分离的混合物中，来自形式主义，确定高场迁移率在异分子气体的通用模型。总体而言，理论研究结果与N-2/CO2的数据一致（尽管存在定量差异），而N-2/O-2的结果符合Blanc定律，与测量结果一致。He/N-2和He/CO2的计算结果也与观测结果一致，并表明为什么向工作气体中加入He通常会增强FAIMS性能。正如所预测的那样，具有极其不同的分子质量和碰撞截面的气体混合物，如He/SF6，表现出壮观的非Blanc效应，这大大提高了技术的分辨率和峰容量。了解FAIMS在气体混合物中的操作，预计将使有针对性的和全球性的分析介质的合理设计。
Field asymmetric waveform ion mobility spectrometry (FAIMS) has significant potential for post-ionization separations in conjunction with MS analyses. FAIMS fractionates ion mixtures by exploiting the fact that ion mobilities in gases depend on the electric field in a manner specific to each ion. Nearly all previous work has used pure gases, for which FAIMS fundamentals are understood reasonably well; however, unexpected phenomena observed in some gas mixtures (e.g., N-2/CO2) but not in others (N-2/O-2) remain unexplained. Here, we introduce and experimentally test a universal model for FAIMS separations in mixtures, derived from formalisms that determine high-field mobilities in heteromolecular gases. Overall, the theoretical findings are consistent with data for N-2/CO2 (although quantitative discrepancies remain), while results for N-2/O-2 fit Blanc's law, in agreement with measurements. Calculations for He/N-2 and He/CO2 are also consistent with observations and suggest why adding He to the working gas generally enhances FAIMS performance. As predicted, mixtures of gases with extremely disparate molecular masses and collision cross sections, such as He/SF6, exhibit spectacular non-Blanc effects, which greatly improve the resolution and peak capacity of technique. Understanding FAIMS operation in gas mixtures is expected to enable the rational design of media for both targeted and global analyses.