Using differential mobility spectrometry to measure ion solvation: An examination of the roles of solvents and ionic structures in separating quinoline-based drugs
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Date
2015
Authors
Liu, Chang
Le Blanc, J. C. Yves
Shields, Jefry
Janiszewski, John S.
Ieritano, Christian
Ye, Gene F.
Hawes, Gillian F.
Hopkins, W. Scott
Campbell, J. Larry
Journal Title
Journal ISSN
Volume Title
Publisher
Royal Society of Chemistry
Abstract
Understanding the mechanisms and energetics of ion solvation is critical in many scientific areas. Here, we present a methodlogy for studying ion solvation using differential mobility spectrometry (DMS) coupled to mass spectrometry. While in the DMS cell, ions experience electric fields established by a high frequency asymmetric waveform in the presence of a desired pressure of water vapor. By observing how a specific ion's behavior changes between the high- and low-field parts of the waveform, we gain knowledge about the aqueous microsolvation of that ion. In this study, we applied DMS to investigate the aqueous microsolvation of protonated quinoline-based drug candidates. Owing to their low binding energies with water, the clustering propensity of 8-substituted quinolinium ions was less than that of the 6- or 7-substituted analogues. We attribute these differences to the steric hinderance presented by subtituents in the 8-position. In addition, these experimental DMS results were complemented by extensive computational studies that determined cluster structures and relative thermodynamic stabilities.
Description
Keywords
differential mobility spectrometry