title: Using differential mobility spectrometry to measure ion solvation: an examination of the roles of solvents and ionic structures in separating quinoline-based drugs.
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.
authors.affiliation: SCIEX, 71 Four Valley Drive, Concord, ON, Canada. larry.campbell@sciex.com.
authors.forename: Chang
authors.initials: C
authors.lastname: Liu
authors.forename: J C Yves
authors.initials: JC
authors.lastname: Le Blanc
authors.forename: Jefry
authors.initials: J
authors.lastname: Shields
authors.forename: John S
authors.initials: JS
authors.lastname: Janiszewski
authors.forename: Christian
authors.initials: C
authors.lastname: Ieritano
authors.forename: Gene F
authors.initials: GF
authors.lastname: Ye
authors.forename: Gillian F
authors.initials: GF
authors.lastname: Hawes
authors.forename: W Scott
authors.initials: WS
authors.lastname: Hopkins
authors.forename: J Larry
authors.initials: JL
authors.lastname: Campbell
mesh_terms: D013058:Mass Spectrometry / Q000379:methods*; D008958:Models, Molecular; D008968:Molecular Conformation; D011804:Quinolines / Q000737:chemistry* / Q000302:isolation & purification*; D012997:Solvents / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D011804:Quinolines; D012997:Solvents; D014867:Water; C037219:quinoline