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Anttalainen O, Lattouf E, Vanninen P, Hakulinen H, Kotiaho T, Eiceman G. Computational analysis of an electrostatic separator design for removal of volatile organic compounds from indoor air. J Air Waste Manag Assoc 2023; 73:877-889. [PMID: 37795973 DOI: 10.1080/10962247.2023.2265329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 09/18/2023] [Indexed: 10/06/2023]
Abstract
Concentrations of volatile organic compounds (VOCs) in air can be reduced in electrostatic separators where VOCs are ionized using ion-molecule reactions, extracted using electric fields, and eliminated in a waste flow. Embodiments for such separator technology have been explored in only a few studies, despite the possible advantage of purification without adsorbent filters. In one design, based on ionization of VOCs in positive polarity with hydrated protons as reactant ions, efficiencies for removal were measured as 30-40% . The results were fitted to a one-dimensional convective diffusion model requiring an unexpectedly high production rate of reactant ions to match both the model and data. A realistic rate of reactant ion production was used in finite element method simulations (COMSOL) and demonstrated that low removal efficiency could be attributed to non-uniform patterns of sample flow and to incomplete mixing of VOCs with reactant ions. In analysis of complex systems, such as this model, even limited computational modeling can outperform a pure analytical approach and bring insights into limiting factors or system bottlenecks.Implications: In this work, we applied modern computational methods to understand the performance of an air purifier based on electrostatics and ionized volatile organic compounds (VOCs). These were described in the publication early 2000s. The model presented was one-dimensional and did not account for the effects of flow. In our multiphysics finite element models, the efficiency and operation of the filter is better explained by the patterns of flow and flow influences on ion distributions in electric fields. In general, this work helps using and applying computational modelling to understand and improve the performance bottlenecks in air purification system designs.
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Affiliation(s)
- Osmo Anttalainen
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, Helsinki, Finland
| | - Elie Lattouf
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, Helsinki, Finland
| | - Paula Vanninen
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, Helsinki, Finland
| | - Hanna Hakulinen
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, Helsinki, Finland
| | - Tapio Kotiaho
- Drug Research Program and Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
- Department of Chemistry, Faculty of Science, University of Helsinki, Helsinki, Finland
| | - Gary Eiceman
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, Helsinki, Finland
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico, USA
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Lattouf E, Anttalainen O, Hecht O, Ungethüm B, Kotiaho T, Hakulinen H, Vanninen P, Eiceman G. Quantitative Distributions of Product Ions and Reaction Times with a Binary Mixture of VOCs in Ambient Pressure Chemical Ionization. J Am Soc Mass Spectrom 2023. [PMID: 37452772 PMCID: PMC10401699 DOI: 10.1021/jasms.3c00189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
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 cm3·s-1) of kM = 1.11 × 10-9 and kN = 9.17 × 10-10, respectively. The cross reaction of MH+(H2O)x to NH+(H2O)y was measured as kcr = 1.31 × 10-12 at 60 °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 ∼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 ∼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.
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Affiliation(s)
- Elie Lattouf
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
| | - Osmo Anttalainen
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
| | - Oliver Hecht
- AIRSENSE Analytics Gmbh, Hagenower Straße 73, 19061 Schwerin, Germany
| | - Bert Ungethüm
- AIRSENSE Analytics Gmbh, Hagenower Straße 73, 19061 Schwerin, Germany
| | - Tapio Kotiaho
- Drug Research Program and Division of Pharmaceutical Chemistry and Technology and Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
| | - Hanna Hakulinen
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
| | - Paula Vanninen
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
| | - Gary Eiceman
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, 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
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Lattouf E, Anttalainen O, Kotiaho T, Hakulinen H, Vanninen P, Eiceman G. Parametric Sensitivity in a Generalized Model for Atmospheric Pressure Chemical Ionization Reactions. J Am Soc Mass Spectrom 2021; 32:2218-2226. [PMID: 34264074 DOI: 10.1021/jasms.1c00158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Gas phase reactions between hydrated protons H+(H2O)n and a substance M, as seen in atmospheric pressure chemical ionization (APCI) with mass spectrometry (MS) and ion mobility spectrometry (IMS), were modeled computationally using initial amounts of [M] and [H+(H2O)n], rate constants k1 to form protonated monomer (MH+(H2O)x) and k2 to form proton bound dimer (M2H+(H2O)z), and diffusion constants. At 1 × 1010 cm-3 (0.4 ppb) for [H+(H2O)n] and vapor concentrations for M from 10 ppb to 10 ppm, a maximum signal was reached at 4.5 μs to 4.6 ms for MH+(H2O)x and 7.8 μs to 46 ms for M2H+(H2O)z. Maximum yield for protonated monomer for a reaction time of 1 ms was ∼40% for k1 from 10-11 to 10-8 cm3·s-1, for k2/k1 = 0.8, and specific values of [M]. This model demonstrates that ion distributions could be shifted from [M2H+(H2O)z] to [MH+(H2O)x] using excessive levels of [H+(H2O)n], even for [M] > 10 ppb, as commonly found in APCI MS and IMS measurements. Ion losses by collisions on surfaces were insignificant with losses of <0.5% for protonated monomer and <0.1% for proton bound dimer of dimethyl methylphosphonate (DMMP) at 5 ms. In this model, ion production in an APCI environment is treated over ranges of parameters important in mass spectrometric measurements. The models establish a foundation for detailed computations on response with mixtures of neutral substances.
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Affiliation(s)
- Elie Lattouf
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
| | - Osmo Anttalainen
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
| | - Tapio Kotiaho
- Drug Research Program and Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, FI-00014 Helsinki, Finland
- Department of Chemistry, Faculty of Science, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland
| | - Hanna Hakulinen
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
| | - Paula Vanninen
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
| | - Gary Eiceman
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
- Department of Chemistry and Biochemistry, New Mexico State University, 1175 N Horseshoe Drive, Las Cruces, New Mexico 88003, United States
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Anttalainen O, Lattouf E, Kotiaho T, Eiceman G. Ion density of positive and negative ions at ambient pressure in air at 12-136 mm from 4.9 kV soft x-ray source. Rev Sci Instrum 2021; 92:054104. [PMID: 34243310 DOI: 10.1063/5.0050669] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The abundance of ions is an essential parameter for ion mobility and mass spectrometry instrument design and for the control or optimization of chemical reactions with reactant ions. This information also advances the study of atmospheric pressure ion kinetics under continuous ionization, which has a role in developing trace level chemical analyzers. In this study, an ionization chamber is described to measure the abundance of ions produced by a 4.9 keV, model L12535, soft x-ray source from Hamamatsu Corporation. Ions of positive and negative polarity were measured independently in an 8 × 30 mm2 cross section at distances of 12-136 mm at ambient air from an uncollimated beam. Ions were collected using electric fields and 16 sets of plates. The ion current decreased exponentially with distance from the source, and the calculated ion concentration varied between 1.0 × 108 and 3.8 × 105 ions cm-3 on plates. A 2D-COMSOL model including losses by recombination and diffusion was favorably matched to changes in ion current intensity in the ionization chamber. Although the ionization chamber was built to characterize a commercial ion source, the design may be considered generally applicable to other x-ray sources.
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Affiliation(s)
- Osmo Anttalainen
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
| | - Elie Lattouf
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
| | - Tapio Kotiaho
- Drug Research Program and Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, FI-00014 Helsinki, Finland
| | - Gary Eiceman
- VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
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McKenzie-Coe A, DeBord JD, Ridgeway M, Park M, Eiceman G, Fernandez-Lima F. Lifetimes and stabilities of familiar explosive molecular adduct complexes during ion mobility measurements. Analyst 2016; 140:5692-9. [PMID: 26153567 DOI: 10.1039/c5an00527b] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Trapped ion mobility spectrometry coupled to mass spectrometry (TIMS-MS) was utilized for the separation and identification of familiar explosives in complex mixtures. For the first time, molecular adduct complex lifetimes, relative stability, binding energies and candidate structures are reported for familiar explosives. Experimental and theoretical results showed that the adduct size and reactivity, complex binding energy and the explosive structure tailor the stability of the molecular adduct complex. The flexibility of TIMS to adapt the mobility separation as a function of the molecular adduct complex stability (i.e., short or long IMS experiments/low or high IMS resolution) permits targeted measurements of explosives in complex mixtures with high confidence levels.
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Affiliation(s)
- Alan McKenzie-Coe
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA.
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Limero T, Nazarov E, Menlyadiev M, Eiceman G. Studies of the ionization chemistry in the re-circulation loop of the differential mobility spectrometer analyzer used to monitor air quality in the international space station. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s12127-014-0164-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Eiceman G. Quantitative calibration of vapor levels of TNT, RDX, and PETN using a diffusion generator with gravimetry and ion mobility spectrometry. Talanta 1997; 45:57-74. [DOI: 10.1016/s0039-9140(97)00107-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/1996] [Revised: 03/31/1997] [Accepted: 03/31/1997] [Indexed: 10/27/2022]
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