Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/2373
Type: Artigo de periódico
Title: Protomers: formation, separation and characterization via travelling wave ion mobility mass spectrometry
Author: Lalli, Priscila M.
Iglesias, Bernardo A.
Toma, Henrique E.
de Sa, Gilberto F.
Daroda, Romeu J.
Silva Filho, Juvenal C.
Szulejko, Jan E.
Araki, Koiti
Eberlin, Marcos N.
Abstract: Travelling wave ion mobility mass spectrometry (TWIM-MS) with post-TWIM and pre-TWIM collision-induced dissociation (CID) experiments were used to form, separate and characterize protomers sampled directly from solutions or generated in the gas phase via CID. When in solution equilibria, these species were transferred to the gas phase via electrospray ionization, and then separated by TWIM-MS. CID performed after TWIM separation (post-TWIM) allowed the characterization of both protomers via structurally diagnostic fragments. Protonated aniline (1) sampled from solution was found to be constituted of a ca. 5:1 mixture of two gaseous protomers, that is, the N-protonated (1a) and ring protonated (1b) molecules, respectively. When dissociated, 1a nearly exclusively loses NH3, whereas 1b displays a much diverse set of fragments. When formed via CID, varying populations of 1a and 1b were detected. Two co-existing protomers of two isomeric porphyrins were also separated and characterized via post-TWIM CID. A deprotonated porphyrin sampled from a basic methanolic solution was found to be constituted predominantly of the protomer arising from deprotonation at the carboxyl group, which dissociates promptly by CO2 loss, but a CID-resistant protomer arising from deprotonation at a porphyrinic ring NH was also detected and characterized. The doubly deprotonated porphyrin was found to be constituted predominantly of a single protomer arising from deprotonation of two carboxyl groups. Copyright (C) 2012 John Wiley & Sons, Ltd.
Subject: protomers, protonation site
aniline
pyridyl porphyrins
electrospray ionization
travelling wave ion mobility
mass spectrometry, gas phase acidity, gas phase basicity
Editor: Wiley-Blackwell
Citation: Journal of Mass Spectrometry. Wiley-Blackwell, v.47, n.6, p.712-719, 2012
Rights: fechado
Identifier DOI: 10.1002/jms.2999
Date Issue: 2012
Appears in Collections:IQ - Artigos e Outros Documentos

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