Thermal desorption effects on fragment ion production from multi-photon ionized uridine and selected analogues - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue RSC Advances Année : 2021

Thermal desorption effects on fragment ion production from multi-photon ionized uridine and selected analogues

Résumé

Experiments on neutral gas-phase nucleosides are often complicated by thermal lability. Previous mass spectrometry studies of nucleosides have identified enhanced relative production of nucleobase ions (e.g. uracil + from uridine) as a function of desorption temperature to be the critical indicator of thermal decomposition. On this basis, the present multi-photon ionization (MPI) experiments demonstrate that laser-based thermal desorption is effective for producing uridine, 5-methyluridine, and 2 0-deoxyuridine targets without thermal decomposition. Our experiments also revealed one notable thermal dependence: the relative production of the sugar ion C 5 H 9 O 4 + from intact uridine increased substantially with the desorption laser power and this only occurred at MPI wavelengths below 250 nm (full range studied 222-265 nm). We argue that this effect can only be rationalized plausibly in terms of changing populations of different isomers, tautomers, or conformers in the target as a function of the thermal desorption conditions. Furthermore, the wavelength threshold behavior of this thermally-sensitive MPI channel indicates a critical dependence on neutral excited state dynamics between the absorption of the first and second photons. The experimental results are complemented by density functional theory (DFT) optimizations of the lowest-energy structure of uridine and two further conformers distinguished by different orientations of the hydroxymethyl group on the sugar part of the molecule. The energies of the transitions states between these three conformers are low compared with the energy required for decomposition.
Fichier principal
Vignette du fichier
published.pdf (876.4 Ko) Télécharger le fichier
Origine : Publication financée par une institution

Dates et versions

hal-03350973 , version 1 (21-09-2021)

Identifiants

Citer

J. Bocková, A. Rebelo, M. Ryszka, R. Pandey, D. Mészáros, et al.. Thermal desorption effects on fragment ion production from multi-photon ionized uridine and selected analogues. RSC Advances, 2021, 11 (34), pp.20612 - 20621. ⟨10.1039/d1ra01873f⟩. ⟨hal-03350973⟩
30 Consultations
24 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More