Gas phase H+, H3O+ and NH4+ affinities of oxygen-bearing volatile organic compounds. DFT calculations for soft chemical ionisation mass spectrometry

0578226 - ÚFCH JH 2024 RIV GB eng J - Článek v odborném periodiku
Omezzine Gnioua, Maroua - Spesyvyi, Anatolii - Španěl, Patrik
Gas phase H+, H3O+ and NH4+ affinities of oxygen-bearing volatile organic compounds. DFT calculations for soft chemical ionisation mass spectrometry.
Physical Chemistry Chemical Physics. Roč. 25, č. 44 (2023), s. 30343-30348. ISSN 1463-9076. E-ISSN 1463-9084
Grant CEP: GA ČR(CZ) GA21-25486S
Výzkumná infrastruktura: e-INFRA CZ II - 90254
Institucionální podpora: RVO:61388955
Klíčová slova: proton affinities * mass spectrometry * mobility * density
Obor OECD: Physical chemistry
Impakt faktor: 3.3, rok: 2022
Způsob publikování: Open access

Quantum chemistry calculations were performed using the density functional theory, DFT, to understand the structures and energetics of organic ions relevant to gas phase ion chemistry in soft chemical ionisation mass spectrometry analytical methods. Geometries of a range of neutral volatile organic compound molecules and ions resulting from protonation, the addition of H3O+ and the addition of NH4+ were optimised using the B3LYP hybrid DFT method. Then, the total energies and the normal mode vibrational frequencies were determined, and the total enthalpies of the neutral molecules and ions were calculated for the standard temperature and pressure. The calculations were performed for several feasible structures of each of the ions. The proton affinities of several benchmark molecules agree with the accepted values within ±4 kJ mol−1, indicating that B3LYP/6-311++G(d,p) provides chemical accuracy for oxygen-containing volatile organic compounds. It was also found that the binding energies of H3O+ and NH4+ to molecules correlate with their proton affinities. The results contribute to the understanding of ligand switching ion-molecule reactions important for secondary electrospray ionisation, SESI, and selected ion flow tube, SIFT, mass spectrometries.
Trvalý link: https://hdl.handle.net/11104/0347251