{'fraction_non_alphanumeric': 0.03941908713692946, 'fraction_numerical': 0.00933609958506224, 'mean_word_length': 5.30718954248366, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Letter: Separation of Tautomeric Forms of [2-Nitrophloroglucinol-H]− by an in-Electrospray Ionization Source Hydrogen/Deuterium Exchange Approach

Here we report the observation that, depending on the solvent used for the electrospray, 2-nitrophloroglucinol undergoes a deprotonation from different sites forming two tautomeric gas phase ions. Those ions differ by the collision-induced dissociation (CID) spectra and by the gas phase hydrogen/deuterium (H/D) exchange kinetic. We performed H/D exchange in the electrospray ionization (ESI) source by saturation ESI region with vapors of deuterated solvent (D2O). It was observed that [2-nitrophloroglucinol-H]− exchanges two –OH hydrogens when MeOD is used as the spray solvent but when the spray solvent is 50:50 MeOD/D2O we observed an additional two H/D exchanges at the aromatic ring. We propose that the reaction occurs via a keto–enol tautomerization mechanism which was found to be energetically favorable.