Premium
Baseline resolution of isomers by traveling wave ion mobility mass spectrometry: investigating the effects of polarizable drift gases and ionic charge distribution
Author(s) -
Lalli Priscila M.,
Corilo Yuri E.,
Fasciotti Maíra,
Riccio Maria Francesca,
Sa Gilberto F.,
Daroda Romeu J.,
Souza Gustavo H. M. F.,
McCullagh Michael,
Bartberger Michael D.,
Eberlin Marcos N.,
Campuzano Iain D. G.
Publication year - 2013
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.3245
Subject(s) - chemistry , ion mobility spectrometry , ion , mass spectrometry , ionic bonding , polarizability , analytical chemistry (journal) , baseline (sea) , traveling wave , charge (physics) , resolution (logic) , chemical physics , chromatography , organic chemistry , molecule , physics , mathematical analysis , oceanography , mathematics , quantum mechanics , artificial intelligence , computer science , geology
We have studied the behavior of isomers and analogues by traveling wave ion mobility mass spectrometry (TWIM‐MS) using drift‐gases with varying masses and polarizabilities. Despite the reduced length of the cell (18 cm), a pair of constitutional isomers, N ‐butylaniline and para ‐butylaniline, with theoretical collision cross‐section values in helium (Ω He ) differing by as little as 1.2 Å 2 (1.5%) but possessing contrasting charge distribution, showed baseline peak‐to‐peak resolution ( R p‐p ) for their protonated molecules, using carbon dioxide (CO 2 ), nitrous oxide (N 2 O) and ethene (C 2 H 4 ) as the TWIM drift‐gas. Near baseline R p‐p was also obtained in CO 2 for a group of protonated haloanilines ( para ‐chloroaniline, para ‐bromoaniline and para ‐iodoaniline) which display contrasting masses and theoretical Ω He , which differ by as much as 15.7 Å 2 (19.5%) but similar charge distributions. The deprotonated isomeric pair of trans ‐oleic acid and cis ‐oleic acid possessing nearly identical theoretical Ω He and Ω N2 as well as similar charge distributions, remained unresolved. Interestingly, an inversion of drift‐times were observed for the 1,3‐dialkylimidazolium ions when comparing He, N 2 and N 2 O. Using density functional theory as a means of examining the ions electronic structure, and He and N 2 ‐based trajectory method algorithm, we discuss the effect of the long‐range charge induced dipole attractive and short‐range Van der Waals forces involved in the TWIM separation in drift‐gases of differing polarizabilities. We therefore propose that examining the electronic structure of the ions under investigation may potentially indicate whether the use of more polarizable drift‐gases could improve separation and the overall success of TWIM‐MS analysis. Copyright © 2013 John Wiley & Sons, Ltd.