High pressure effects in high-field asymmetric waveform ion mobility spectrometry

Rationale High‐Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) is an analytical technique based on the principle of non‐linear electric field dependence of coefficient of mobility of ions for separation that was originally conceived in the Soviet Union in the early 1980s. Being well deve...

Full description

Saved in:
Bibliographic Details
Published in:Rapid communications in mass spectrometry 2016-08, Vol.30 (16), p.1914-1922
Main Authors: Wang, Yonghuan, Wang, Xiaozhi, Li, Lingfen, Chen, Chilai, Xu, Tianbai, Wang, Tao, Luo, Jikui
Format: Article
Language:English
Subjects:
Compensation
Dispersion
Electric fields
Electric potential
Ionic mobility
Resolution
Separation
Waveforms
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Rationale High‐Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) is an analytical technique based on the principle of non‐linear electric field dependence of coefficient of mobility of ions for separation that was originally conceived in the Soviet Union in the early 1980s. Being well developed over the past decades, FAIMS has become an efficient method for the separation and characterization of gas‐phase ions at ambient pressure, often in air, to detect trace amounts of chemical species including explosives, toxic chemicals, chemical warfare agents and other compounds. However the resolution of FAIMS and ion separation capability need to be improved for more applications of the technique. Methods The effects of above‐ambient pressure varying from 1 to 3 atm on peak position, resolving power, peak width, and peak intensity are investigated theoretically and experimentally using micro‐fabricated planar FAIMS in purified air. Results Peak positions, varying with pressure in a way as a function of dispersion voltage, could be simplified by expressing both compensation and dispersion fields in Townsend units for E/N, the ratio of electric field intensity (E) to the gas number density (N). Conclusions It is demonstrated that ion Townsend‐scale peak positions remain unchanged for a range of pressures investigated, implying that the higher the pressure is, stronger compensation and separation fields are needed within limits of air breakdown field. Increase in pressure is found to separate ions that could not be distinguished in ambient pressure, which could be interpreted as the differentials of ions' peak compensation voltage expanded wider than the dilation of peak widths leading to resolving power enhancement with pressure. Increase in pressure can also result in an increase in peak intensity.
ISSN:0951-4198
1097-0231
DOI:10.1002/rcm.7663