| Title: | Quantitative Distributions of Product Ions and Reaction Times with a Binary Mixture of VOCs in Ambient Pressure Chemical Ionization |
| Author(s): | Lattouf E; Anttalainen O; Hecht O; Ungethum B; Kotiaho T; Hakulinen H; Vanninen P; Eiceman G; |
| Address: | "VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland. AIRSENSE Analytics Gmbh, Hagenower Strasse 73, 19061 Schwerin, Germany. Drug Research Program and Division of Pharmaceutical Chemistry and Technology and Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland. New Mexico State University, 1175 N Horseshoe Dr., Las Cruces, New Mexico 88003, United States" |
| ISSN/ISBN: | 1879-1123 (Electronic) 1044-0305 (Print) 1044-0305 (Linking) |
| Abstract: | "A model to quantitatively predict ion abundances from atmospheric pressure chemical ionization (APCI) between hydrated protons and a volatile organic compound (VOC) was extended to binary mixtures of VOCs. The model includes differences in vapor concentrations, rate coefficients, and reaction times and is enhanced with cross reactions between neutral vapors and protonated monomers. In this model, two specific VOCs were considered, a ketone, 6-methyl-5-hepten-2-one (M, and an amine, 2,6-di-tert-butyl-pyridine (N), with measured 'conditional rate coefficients' (in cm(3).s(-1)) of k(M) = 1.11 x 10(-9) and k(N) = 9.17 x 10(-10), respectively. The cross reaction of MH(+)(H(2)O)(x) to NH(+)(H(2)O)(y) was measured as k(cr) = 1.31 x 10(-12) at 60 degrees C. Cross reactions showed an impact on ion abundances at t > 30 ms for equal vapor concentrations of 100 ppb for M and N. In contrast, this impact was negligible for vapor concentrations of 1 ppb and did not exceed 5% change in product ion abundance up to 1000 ms reaction times. The model was validated with laboratory measurements to within approximately 10% using an ion mobility spectrometer and effective reaction time obtained from computational fitting of experimental findings. This was necessitated by complex flow patterns in the ion source volume and was determined as approximately 10.5 ms. The model has interpretative and predictive value for quantitative analysis of responses with ambient pressure ion sources for mass spectrometry and ion mobility spectrometry" |
| Keywords: | atmospheric pressure ionization hydrated proton ionization selectivity rate coefficient vapor concentration volatile organic compound; |
| Notes: | "PubMed-not-MEDLINELattouf, Elie Anttalainen, Osmo Hecht, Oliver Ungethum, Bert Kotiaho, Tapio Hakulinen, Hanna Vanninen, Paula Eiceman, Gary eng 2023/07/15 21:05 J Am Soc Mass Spectrom. 2023 Aug 2; 34(8):1768-1777. doi: 10.1021/jasms.3c00189. Epub 2023 Jul 15" |
