Quantification of the gas phase methyl iodide using O2+ as the reagent ion in the PTR-ToF-MS technique.
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| Title: | Quantification of the gas phase methyl iodide using O2+ as the reagent ion in the PTR-ToF-MS technique. |
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| Authors: | R’Mili, Badr1, Temime-Roussel, Brice1, Monod, Anne1, Wortham, Henri1, Strekowski, Rafal S.1 rafal.strekowski@univ-amu.fr |
| Source: | International Journal of Mass Spectrometry. Aug2018, Vol. 431, p43-49. 7p. |
| Subjects: | Gas phase reactions, Methyl iodide, Oxygen, Molecules, Nuclear energy |
| Abstract: | The charge-transfer-reaction between molecular oxygen ions (O 2 + ) and methyl iodide (CH 3 I) is studied to investigate if consistent environmental quantification of the gas phase CH 3 I is possible without prior calibration. The neutral CH 3 I molecule was chosen because this compound is of atmospheric chemistry and environmental importance in the field of nuclear power plant safety and nuclear energy. Molecular oxygen was used as a reagent ion source in a commercial Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (PTR-ToF-MS) to produce molecular oxygen ions (O 2 + ). The use of O 2 + ions allows for fast, sensitive and specific detection of gas phase CH 3 I via an electron exchange reaction O 2 + + CH 3 I → CH 3 I + + O 2 . The instrument response was linear in the 0.23–150 ppbv range and its sensitivity was humidity independent. The detection sensitivity of CH 3 I normalized by the O 2 + count rate of 10 6 cps was found to be S = 22.6 ± 0.3 ncps/ppbv, independent of relative humidity. A typical O 2 + primary ion signal was ( 2.0 ± 0.2 ) × 10 6 cps. The lowest measured CH 3 I concentration was 0.23 ± 0.10 ppb. Error is ±σ. The theoretical collision rate based on the dipole moment and molecular polarizability values is calculated using the Langevin collision rate ( k L ) approximation, the average-dipole-orientation (ADO) theory and the capture rate coefficient ( k CAP ) based on trajectory calculations. The experimental rate constant, k exp , for the electron transfer reaction between O 2 + ions and CH 3 I is calculated to be 1.72 ± 0.22 × 10 - 9 cm 3 s −1 . Listed errors are ±σ and represent precision only. The experimentally determined value agrees very well with the theoretical collision rate values, k L = 1.24 × 10 - 9 cm 3 s -1 , k ADO = 1.73 × 10 - 9 cm 3 s −1 and k CAP = 1.48 × 10 - 9 cm 3 s -1 . The obtained results indicate that the PTR-MS technique is an excellent analytical method to quantify gas phase CH 3 I. [ABSTRACT FROM AUTHOR] |
| Copyright of International Journal of Mass Spectrometry is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 130838516 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Quantification of the gas phase methyl iodide using O2+ as the reagent ion in the PTR-ToF-MS technique. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22R’Mili%2C+Badr%22">R’Mili, Badr</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Temime-Roussel%2C+Brice%22">Temime-Roussel, Brice</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Monod%2C+Anne%22">Monod, Anne</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Wortham%2C+Henri%22">Wortham, Henri</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Strekowski%2C+Rafal+S%2E%22">Strekowski, Rafal S.</searchLink><relatesTo>1</relatesTo><i> rafal.strekowski@univ-amu.fr</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22International+Journal+of+Mass+Spectrometry%22">International Journal of Mass Spectrometry</searchLink>. Aug2018, Vol. 431, p43-49. 7p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Gas+phase+reactions%22">Gas phase reactions</searchLink><br /><searchLink fieldCode="DE" term="%22Methyl+iodide%22">Methyl iodide</searchLink><br /><searchLink fieldCode="DE" term="%22Oxygen%22">Oxygen</searchLink><br /><searchLink fieldCode="DE" term="%22Molecules%22">Molecules</searchLink><br /><searchLink fieldCode="DE" term="%22Nuclear+energy%22">Nuclear energy</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The charge-transfer-reaction between molecular oxygen ions (O 2 + ) and methyl iodide (CH 3 I) is studied to investigate if consistent environmental quantification of the gas phase CH 3 I is possible without prior calibration. The neutral CH 3 I molecule was chosen because this compound is of atmospheric chemistry and environmental importance in the field of nuclear power plant safety and nuclear energy. Molecular oxygen was used as a reagent ion source in a commercial Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (PTR-ToF-MS) to produce molecular oxygen ions (O 2 + ). The use of O 2 + ions allows for fast, sensitive and specific detection of gas phase CH 3 I via an electron exchange reaction O 2 + + CH 3 I → CH 3 I + + O 2 . The instrument response was linear in the 0.23–150 ppbv range and its sensitivity was humidity independent. The detection sensitivity of CH 3 I normalized by the O 2 + count rate of 10 6 cps was found to be S = 22.6 ± 0.3 ncps/ppbv, independent of relative humidity. A typical O 2 + primary ion signal was ( 2.0 ± 0.2 ) × 10 6 cps. The lowest measured CH 3 I concentration was 0.23 ± 0.10 ppb. Error is ±σ. The theoretical collision rate based on the dipole moment and molecular polarizability values is calculated using the Langevin collision rate ( k L ) approximation, the average-dipole-orientation (ADO) theory and the capture rate coefficient ( k CAP ) based on trajectory calculations. The experimental rate constant, k exp , for the electron transfer reaction between O 2 + ions and CH 3 I is calculated to be 1.72 ± 0.22 × 10 - 9 cm 3 s −1 . Listed errors are ±σ and represent precision only. The experimentally determined value agrees very well with the theoretical collision rate values, k L = 1.24 × 10 - 9 cm 3 s -1 , k ADO = 1.73 × 10 - 9 cm 3 s −1 and k CAP = 1.48 × 10 - 9 cm 3 s -1 . The obtained results indicate that the PTR-MS technique is an excellent analytical method to quantify gas phase CH 3 I. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of International Journal of Mass Spectrometry is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.ijms.2018.06.003 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 7 StartPage: 43 Subjects: – SubjectFull: Gas phase reactions Type: general – SubjectFull: Methyl iodide Type: general – SubjectFull: Oxygen Type: general – SubjectFull: Molecules Type: general – SubjectFull: Nuclear energy Type: general Titles: – TitleFull: Quantification of the gas phase methyl iodide using O2+ as the reagent ion in the PTR-ToF-MS technique. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: R’Mili, Badr – PersonEntity: Name: NameFull: Temime-Roussel, Brice – PersonEntity: Name: NameFull: Monod, Anne – PersonEntity: Name: NameFull: Wortham, Henri – PersonEntity: Name: NameFull: Strekowski, Rafal S. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 08 Text: Aug2018 Type: published Y: 2018 Identifiers: – Type: issn-print Value: 13873806 Numbering: – Type: volume Value: 431 Titles: – TitleFull: International Journal of Mass Spectrometry Type: main |
| ResultId | 1 |
