September 1, 2009
Journal Article

Improving FAIMS Sensitivity using a Planar Geometry with Slit Interfaces

Abstract

Differential mobility spectrometry or field asymmetric waveform ion mobility spectrometry (FAIMS) is gaining broad acceptance for analyses of gas-phase ions, especially in conjunction with largely orthogonal separation methods such as mass spectrometry (MS) and/or conventional (drift tube) ion mobility spectrometry. In FAIMS, ions are filtered while passing through a gap between two electrodes that may have planar or curved (in particular, cylindrical) geometry. Despite substantial inherent advantages of the planar configuration and its universal acceptance in stand-alone FAIMS devices, commercial FAIMS/MS systems have employed curved FAIMS geometries that could be interfaced to MS more effectively. Here we report a new planar (p-) FAIMS design with slit-shaped entrance and exit apertures that substantially increase ion transmission in and out of the analyzer. The front slit interface effectively couples p-FAIMS to multi-emitter electrospray ionization (ESI) sources, improving greatly the ion current introduced to the device. The back slit interface increases the transmission of ribbon-shaped ion beams output by the p-FAIMS to downstream stages such as a MS. Overall, the ion signal in ESI/FAIMS/MS analyses is raised by over an order of magnitude without affecting the FAIMS resolution.

Revised: June 23, 2010 | Published: September 1, 2009

Citation

Mabrouki R.B., R.T. Kelly, D.C. Prior, A.A. Shvartsburg, K. Tang, and R.D. Smith. 2009. Improving FAIMS Sensitivity using a Planar Geometry with Slit Interfaces. Journal of the American Society for Mass Spectrometry 20, no. 9:1768-1774. PNNL-SA-65387. doi:10.1016/j.jasms.2009.05.019