Photodissociation spectroscopy of protonated guanosine monophosphate based on IR-laser ablation of droplet beam and quadrupole ion trap mass spectrometry.

Graphical abstract Highlights • UVPD spectrum of GMPH+ ion was measured by IR-laser ablation of droplet beam. • The three types of anti glycosyl-bond conformations with a keto form were observed. • A quadrupole ion trap with 70 ms trap time is essential for conformer separation. Abstract Photodissociation (PD) spectroscopy of protonated guanosine monophosphate (GMPH+) ions was performed using IR-laser ablation of droplet beam and quadruple ion trap techniques. Photofragmentation of GMPH+ gave a protonated guanine ion (GH+) as the main product. A wide-range PD spectrum (3.9–5.4 eV) monitored by the GH+ ion intensity showed four characteristic electronic transitions related to their three different anti glycosyl-bond conformers of GMPH+, which were identified by their π-π* transitions based on time dependent density functional theory calculation. Furthermore, the narrow-bandwidth PD spectrum (4.28–4.33 eV) shows the existence of syn glycosyl-bond conformation with keto form. [ABSTRACT FROM AUTHOR]