A Two-Phase Approach for Time-Domain Ion Mobility Mass Spectrometry

Summary

Drift-tube ion mobility spectrometry (DT-IMS) is largely unmatched in its ability to rapidly screen passengers, cargo, and the surrounding environment for narcotics, explosives, and chemical warfare agents. However, DT-IMS are limited by duty cycle. Most experiments are on the order of < 1%, and this limitation impacts sensitivity. In addition, existing Fourier transform (FT) IMS cannot fully realize multiplexing gains, due to the need for two physical ion gates and most importantly, the need for apodization function to recover IMS spectra from raw frequency-encoded ion signals. Moreover, signal averaging IMS has limited ability to resolve adjacent peaks in a complex spectrum.

Washington State University researchers described a new Fourier transform (FT) IMS design that is directly compatible with standard drift tube ion mobility mass spectrometers (DT-IMMS). This new approach requires only a single gate and does not need signal apodization. An increase in signal-to-noise relative to both previous implementations FT-IMS experiments and signal averaged experiments was observed.

Applications and Advantages

•Three times improvement of signal-to-noise ratio

•Require only a single ion gate, do not require apodization

•Does not require hardware modification

•Highly tractable, can be employed to any standard DT-IMMS