New Device Improves Resolving Power and Ion Transmission in Differential Ion Mobility Spectrometry

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A research team led by Simin Zhang and T.-W. Dominic Chan has developed a new CaptiveSpray differential ion mobility spectrometry device that enhances ion transmission and improves resolving power. This team of scientists, from the Department of Chemistry at The Chinese University of Hong Kong, incorporated a circular channel and a gas flow homogenizing channel (GFHC) between the CaptiveSpray ion source and planar differential ion mobility spectrometry (DMS) to create the new device.

The GFHC reduced gas flow heterogeneity prior to the DMS device entering. The optimal flared entrance greatly reduces gas flow velocity at the inlet region, which helps reduce disparities between the minimum and maximum gas velocity along the x-axis. The circular electrode was machined with channels along the x- and y-axis for the passage of auxiliary gas and was applied with a potential to focus the incoming ions from the CaptiveSpray source into the DMS channel.

Using reserpine as a reference standard, the researchers were able to achieve substantial signal enhancement with a concomitant reduction of the peak width in the ionogram.

This research has been published in the Journal of the American Society of Mass Spectrometry on April 10, 2023, and the study can be referenced under the title "CaptiveSpray Differential Ion Mobility Spectrometry Device with Enhanced Ion Transmission and Improved Resolving Power." The authors of the study include Simin Zhang, Xiangfeng Chen, H.-T. Kitty Wong, T.-Y Lui, Danna Hu, and T.-W. Dominic Chan.


The new device addresses the limitations of previous differential ion mobility spectrometry devices, which had lower ion transmission and resolving power. The GFHC, circular channel, and optimized flared entrance help to increase ion transmission, reduce gas flow heterogeneity, and improve resolving power. The device’s performance was validated with reserpine, and the results were highly promising.

The development of this new device will greatly benefit researchers in the fields of environmental analysis, forensics, and clinical diagnostics, where highly sensitive and accurate detection is critical. The new CaptiveSpray differential ion mobility spectrometry device has the potential to advance the detection and analysis of a wide range of chemicals and substances.


Zhang, S.; Chen, X.; Wong, H-T. K.; Lui, T. -Y.; Hu, D.; Chan, T.-W. D. Captive Spray Differential Ion Mobility Spectrometry Device with Enhanced Ion Transmission and Improved Resolving Power. J. Am. Soc. Mass Spectrom. 2023 DOI: