Protomer Formation Can Aid the Structural Identification of Caffeine Metabolites.
Anal Chem
; 94(30): 10601-10609, 2022 08 02.
Article
en En
| MEDLINE
| ID: mdl-35861491
ABSTRACT
The structural annotation of isomeric metabolites remains a key challenge in untargeted electrospray ionization/high-resolution mass spectrometry (ESI/HRMS) metabolomic analysis. Many metabolites are polyfunctional compounds that may form protomers in electrospray ionization sources and therefore yield multiple peaks in ion mobility spectra. Protomer formation is strongly structure-specific. Here, we explore the possibility of using protomer formation for structural elucidation in metabolomics on the example of caffeine, its eight metabolites, and structurally related compounds. It is observed that two-thirds of the studied compounds formed high- and low-mobility species in high-resolution ion mobility. Structures in which proton hopping was hindered by a methyl group at the purine ring nitrogen (position 3) yielded structure-indicative fragments with collision-induced dissociation (CID) for high- and low-mobility ions. For compounds where such a methyl group was not present, a gas-phase equilibrium could be observed for tautomeric species with two-dimensional ion mobility. We show that the protomer formation and the gas-phase properties of the protomers can be related to the structure of caffeine metabolites and facilitate the identification of the structural isomers.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Cafeína
/
Espectrometría de Masa por Ionización de Electrospray
Tipo de estudio:
Diagnostic_studies
Idioma:
En
Revista:
Anal Chem
Año:
2022
Tipo del documento:
Article
País de afiliación:
Suecia