Development and Application of a Chemical Ionization Focusing Integrated Ionization Source TOFMS for Online Detection of OVOCs in the Atmosphere
Single photon ionization (SPI) based on vacuum ultraviolet (VUV) lamps has been extensively investigated and applied due to its clean mass spectra as a soft ionization method. However, the photon energy of 10.6 eV and photon flux of 10<sup>11</sup> photons s<sup>−1</sup> of a...
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| Format: | Article |
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MDPI AG
2023-09-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/28/18/6600 |
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| author | Ruidong Liu Yingzhe Guo Mei Li Jing Li Dong Yang Keyong Hou |
| author_facet | Ruidong Liu Yingzhe Guo Mei Li Jing Li Dong Yang Keyong Hou |
| author_sort | Ruidong Liu |
| collection | DOAJ |
| description | Single photon ionization (SPI) based on vacuum ultraviolet (VUV) lamps has been extensively investigated and applied due to its clean mass spectra as a soft ionization method. However, the photon energy of 10.6 eV and photon flux of 10<sup>11</sup> photons s<sup>−1</sup> of a commercial VUV lamp limits its range of ionizable analytes as well as its sensitivity. This work designs a chemical ionization focusing integrated (CIFI) ionization source time-of-flight mass spectrometry (TOFMS) based on a VUV lamp for the detection of volatile organic compounds (VOCs) and oxygenated volatile organic compounds (OVOCs). The photoelectrons obtained from the VUV lamp via the photoelectric effect ionized the oxygen and water in the air to obtain the reagent ions. The ion–molecule-reaction region (IMR) is constituted by a segmented quadrupole that radially focuses the ions using a radio-frequency electric field. This significantly enhances the yield and transport efficiency of the product ions leading to a great improvement in sensitivity. As a result, a 44-fold and 1154-fold increase in the signal response for benzene and pentanal were achieved, respectively. To verify the reliability of the ionization source, the linear correspondence and repeatability of benzene and pentanal were investigated. Satisfactory dynamic linearity was obtained in the mixing ratio range of 5–50 ppbv, and the relative standard deviation (RSD) of inter-day reached 3.91% and 6.26%, respectively. Finally, the CIFI−TOFMS was applied to the determination of OVOCs, and the LOD of 12 types of OVOCs reached the pptv level, indicating that the ionization source has the potential for accurate and sensitive online monitoring of atmospheric OVOCs. |
| first_indexed | 2024-03-10T22:24:30Z |
| format | Article |
| id | doaj.art-c1ca6a4669af48e3a5cd41425b4debb6 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T22:24:30Z |
| publishDate | 2023-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-c1ca6a4669af48e3a5cd41425b4debb62023-11-19T12:09:47ZengMDPI AGMolecules1420-30492023-09-012818660010.3390/molecules28186600Development and Application of a Chemical Ionization Focusing Integrated Ionization Source TOFMS for Online Detection of OVOCs in the AtmosphereRuidong Liu0Yingzhe Guo1Mei Li2Jing Li3Dong Yang4Keyong Hou5Environment Research Institute, Shandong University, Qingdao 266237, ChinaEnvironment Research Institute, Shandong University, Qingdao 266237, ChinaEnvironment Research Institute, Shandong University, Qingdao 266237, ChinaEnvironment Research Institute, Shandong University, Qingdao 266237, ChinaEnvironment Research Institute, Shandong University, Qingdao 266237, ChinaEnvironment Research Institute, Shandong University, Qingdao 266237, ChinaSingle photon ionization (SPI) based on vacuum ultraviolet (VUV) lamps has been extensively investigated and applied due to its clean mass spectra as a soft ionization method. However, the photon energy of 10.6 eV and photon flux of 10<sup>11</sup> photons s<sup>−1</sup> of a commercial VUV lamp limits its range of ionizable analytes as well as its sensitivity. This work designs a chemical ionization focusing integrated (CIFI) ionization source time-of-flight mass spectrometry (TOFMS) based on a VUV lamp for the detection of volatile organic compounds (VOCs) and oxygenated volatile organic compounds (OVOCs). The photoelectrons obtained from the VUV lamp via the photoelectric effect ionized the oxygen and water in the air to obtain the reagent ions. The ion–molecule-reaction region (IMR) is constituted by a segmented quadrupole that radially focuses the ions using a radio-frequency electric field. This significantly enhances the yield and transport efficiency of the product ions leading to a great improvement in sensitivity. As a result, a 44-fold and 1154-fold increase in the signal response for benzene and pentanal were achieved, respectively. To verify the reliability of the ionization source, the linear correspondence and repeatability of benzene and pentanal were investigated. Satisfactory dynamic linearity was obtained in the mixing ratio range of 5–50 ppbv, and the relative standard deviation (RSD) of inter-day reached 3.91% and 6.26%, respectively. Finally, the CIFI−TOFMS was applied to the determination of OVOCs, and the LOD of 12 types of OVOCs reached the pptv level, indicating that the ionization source has the potential for accurate and sensitive online monitoring of atmospheric OVOCs.https://www.mdpi.com/1420-3049/28/18/6600chemical ionization sourcesegmented quadrupoleoxygenated volatile organic compoundschemical ionizationphotoionization |
| spellingShingle | Ruidong Liu Yingzhe Guo Mei Li Jing Li Dong Yang Keyong Hou Development and Application of a Chemical Ionization Focusing Integrated Ionization Source TOFMS for Online Detection of OVOCs in the Atmosphere Molecules chemical ionization source segmented quadrupole oxygenated volatile organic compounds chemical ionization photoionization |
| title | Development and Application of a Chemical Ionization Focusing Integrated Ionization Source TOFMS for Online Detection of OVOCs in the Atmosphere |
| title_full | Development and Application of a Chemical Ionization Focusing Integrated Ionization Source TOFMS for Online Detection of OVOCs in the Atmosphere |
| title_fullStr | Development and Application of a Chemical Ionization Focusing Integrated Ionization Source TOFMS for Online Detection of OVOCs in the Atmosphere |
| title_full_unstemmed | Development and Application of a Chemical Ionization Focusing Integrated Ionization Source TOFMS for Online Detection of OVOCs in the Atmosphere |
| title_short | Development and Application of a Chemical Ionization Focusing Integrated Ionization Source TOFMS for Online Detection of OVOCs in the Atmosphere |
| title_sort | development and application of a chemical ionization focusing integrated ionization source tofms for online detection of ovocs in the atmosphere |
| topic | chemical ionization source segmented quadrupole oxygenated volatile organic compounds chemical ionization photoionization |
| url | https://www.mdpi.com/1420-3049/28/18/6600 |
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