ArticleAnalytical chemistry2022
Protomer Formation Can Aid the Structural Identification of Caffeine Metabolites.
Article in Analytical chemistry, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 10 papers.
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Who cites it
10 citing papers in PubMed, 15 citations in OpenAlex.
- ToxBase: A Multidimensional ToxCast Reference Database for High-Throughput Human Exposome Analysis.Environmental science & technology · 2026Article
- Steroid Fingerprinting with Cryogenic Gas-Phase Infrared Spectroscopy.ACS measurement science au · 2026Article
- Infrared Ion Spectroscopy Combined with Ion Mobility Spectrometry for Identification of Caffeine Metabolite Isomers and Protomers.Journal of the American Society for Mass Spectrometry · 2026Article
- Distinguishing Isomeric Caffeine Metabolites through Protomers and Tautomers Using Cryogenic Gas-Phase Infrared Spectroscopy.Analytical chemistry · 2025Article
- Critical review on in silico methods for structural annotation of chemicals detected with LC/HRMS non-targeted screening.Analytical and bioanalytical chemistry · 2025Review
- Characterization of Anticancer Drug Protomers Using Electrospray Ionization and Ion Mobility Spectrometry-Mass Spectrometry.Journal of the American Society for Mass Spectrometry · 2024Article
- Impact of Protonation Sites on Collision-Induced Dissociation-MS/MS Using CIDMD Quantum Chemistry Modeling.Journal of chemical information and modeling · 2024Article
- Understanding of protomers/deprotomers by combining mass spectrometry and computation.Analytical and bioanalytical chemistry · 2023Review
- Traveling Wave Ion Mobility-Derived Collision Cross Section Database for Plant Specialized Metabolites: An Application toJournal of proteome research · 2022Article
- Recent advances in high-resolution traveling wave-based ion mobility separations coupled to mass spectrometry.Mass spectrometry reviewsReview
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Authors and funding
4 authors at 3 institutions in 3 countries.
Funding
No grant is acknowledged in the PubMed record.
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.
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