Chemical ionization of glyoxal and formaldehyde with H3O+ ions using SIFT-MS under variable system humidity

0531419 - ÚFCH JH 2021 RIV GB eng J - Journal Article
Lacko, Michal - Piel, F. - Mauracher, A. - Španěl, Patrik
Chemical ionization of glyoxal and formaldehyde with H3O+ ions using SIFT-MS under variable system humidity.
Physical Chemistry Chemical Physics. Roč. 22, č. 18 (2020), s. 10170-10178. ISSN 1463-9076. E-ISSN 1463-9084
EU Projects: European Commission(XE) 674911 - IMPACT
Institutional support: RVO:61388955
Keywords : tube mass-spectrometry * flow tube * atmospheric photooxidation * proton affinities * diffusion * kinetics * toluene * no+ * air * molecules
OECD category: Physical chemistry
Impact factor: 3.676, year: 2020
Method of publishing: Open access

Glyoxal (C2H2O2) is a highly reactive molecule present at trace levels in specific gaseous environments. For analyses by chemical ionization mass spectrometry, it is important to understand the gas-phase chemistry initiated by reactions of H3O+ ions with C2H2O2 molecules in the presence of water vapour. This chemistry was studied at variable humidity using a selected ion flow tube, SIFT. The initial step is a proton transfer reaction forming protonated glyoxal C2H3O2+. The second step, in the presence of water vapour, is the association forming C2H3O2+(H2O) and interestingly also protonated formaldehyde CH2OH+. Hydrated protonated formaldehyde CH2OH+(H2O) was also observed. Relative signals of these four ionic products were studied at the end of the flow tube where the reactions took place during 0.3 ms in helium carrier gas (1.5 mbar, 300 K) as the water vapour number density varied up to 10(14) cm(-3). The data were interpreted using numerical kinetics modelling of the reaction sequences and the mechanisms and kinetics of the reaction steps were characterised. The results thus facilitate SIFT-MS analyses of glyoxal in humid air whilst drawing attention to ion overlaps with formaldehyde products.
Permanent Link: http://hdl.handle.net/11104/0310082