Langejuergen Jens, Allers Maria, Oermann Jens, Kirk Ansgar, Zimmermann Stefan
Leibniz University Hannover , Institute of Electrical Engineering and Measurement Technology, Appelstrasse 9a, 30167 Hannover, Germany.
Anal Chem. 2014 Jul 15;86(14):7023-32. doi: 10.1021/ac5011662. Epub 2014 Jun 27.
We present a high kinetic energy ion mobility spectrometer (HiKE-IMS) for quantitative gas analysis. Drift tube and reaction tube can be operated at reduced fields up to 110 Td. At such conditions the distribution of reactant ion water clusters is shifted toward smaller clusters. Due to the resulting presence of bare reactant ions (e.g., H3O(+)) and the kinetic control of the ionization process with decreasing reaction time, unlike conventional IMS, a quantitative detection with ppbv detection limits of low proton affine analytes even in humid gas mixtures containing high proton affine compounds is possible using a direct sample gas inlet. A significantly improved dynamic range compared to conventional IMS is achieved. An incremental change in reduced fields enables the observation of parameters like field dependent ion mobilites or analyte fragmentation. Also, the characteristic of the analyte signal with respect to the reduced reaction field gives insight into the ionization process of the analyte. Thus, HiKE-IMS enables substance identification by ion mobility and additional analytical information that are not observed with conventional IMS. The instrumental effort is similar to conventional desktop IMS with overall dimensions of the drift and reaction tube of 4 cm × 4 cm × 28.5 cm. However, the mobility resolution is limited and between 30 and 40. Because of the moisture independent ionization and the decrease in competing ion-molecule reactions, no preseparation or membrane inlet is necessary when the compounds of interest are distinguishable either by a significant difference in ion mobility or the additional analytical information.
我们展示了一种用于定量气体分析的高动能离子迁移谱仪（HiKE - IMS）。漂移管和反应管可在高达110 Td的低电场下运行。在这种条件下，反应物离子水簇的分布向较小的簇转移。由于产生了裸反应物离子（例如，H3O(+)）以及随着反应时间减少对电离过程的动力学控制，与传统离子迁移谱不同，即使在含有高质子亲和性化合物的潮湿气体混合物中，使用直接进样气体入口也能够对低质子亲和性分析物进行检测限低至ppbv的定量检测。与传统离子迁移谱相比，实现了显著改善的动态范围。降低电场的增量变化能够观察诸如场依赖离子迁移率或分析物碎片化等参数。此外，分析物信号相对于降低的反应场的特性有助于深入了解分析物的电离过程。因此，HiKE - IMS能够通过离子迁移率进行物质鉴定，并提供传统离子迁移谱未观察到的额外分析信息。仪器的工作量与传统台式离子迁移谱相似，漂移管和反应管的整体尺寸为4 cm×4 cm×28.5 cm。然而，迁移率分辨率有限，在30到40之间。由于与湿度无关的电离以及竞争性离子 - 分子反应的减少，当感兴趣的化合物可以通过离子迁移率的显著差异或额外的分析信息区分时，无需进行预分离或使用膜进样。
