Interpretation of mass spectra by a Vocus proton-transfer-reaction mass spectrometer (PTR-MS) at an urban site: insights from gas chromatographic pre-separation
<p>Volatile organic compounds (VOCs) are important atmospheric components that contribute to air pollution, but their accurate quantification by proton-transfer-reaction mass spectrometry (PTR-MS) remains challenging. In this work, we coupled a gas chromatograph (GC) prior to PTR-MS and analyz...
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Copernicus Publications
2025-07-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://amt.copernicus.org/articles/18/3547/2025/amt-18-3547-2025.pdf |
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| author | Y. Zhang Y. Wang Y. Wang C. Li Y. Li S. Yin M. S. Claflin B. M. Lerner D. Worsnop L. Wang L. Wang L. Wang L. Wang L. Wang |
| author_facet | Y. Zhang Y. Wang Y. Wang C. Li Y. Li S. Yin M. S. Claflin B. M. Lerner D. Worsnop L. Wang L. Wang L. Wang L. Wang L. Wang |
| author_sort | Y. Zhang |
| collection | DOAJ |
| description | <p>Volatile organic compounds (VOCs) are important atmospheric components that contribute to air pollution, but their accurate quantification by proton-transfer-reaction mass spectrometry (PTR-MS) remains challenging. In this work, we coupled a gas chromatograph (GC) prior to PTR-MS and analyzed complex ambient air in urban Shanghai to speciate the PTR signal to identify the VOC species that were responsible for the generation of the ions detected by PTR. We classified 176 individual PTR signals with associated compounds resolved by the GC based on whether they could be used to quantify a VOC species without pre-separation. In this classification, Category I includes 45 decent signal ions that were produced from a single VOC species and thus can be used for reliable quantification, although some of the Category I ions are not the conventionally used protonated quasi-molecular ions (MH<span class="inline-formula"><sup>+</sup></span>). Category II includes 39 signal ions that were produced from a group of isomers and can be used to quantify the isomeric sum, but with an increased uncertainty if a single calibration factor for one specific isomer is used to represent all structures. Category III includes 92 signal ions that were generated from more than one non-isomeric species (e.g., through protonation, fragmentation, cluster formation) and thus merely gave an upper limit of VOC concentrations. In addition, we propose taking aromatic compounds, for instance, the quantification of selected VOCs, utilizing either non-MH<span class="inline-formula"><sup>+</sup></span> or non-Category I ions. Our results help to achieve more comprehensive species identification and reliable VOC quantification in PTR measurements.</p> |
| format | Article |
| id | doaj-art-398c602a0bf7416dacd72365cc803bfe |
| institution | DOAJ |
| issn | 1867-1381 1867-8548 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj-art-398c602a0bf7416dacd72365cc803bfe2025-08-20T02:47:58ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482025-07-01183547356810.5194/amt-18-3547-2025Interpretation of mass spectra by a Vocus proton-transfer-reaction mass spectrometer (PTR-MS) at an urban site: insights from gas chromatographic pre-separationY. Zhang0Y. Wang1Y. Wang2C. Li3Y. Li4S. Yin5M. S. Claflin6B. M. Lerner7D. Worsnop8L. Wang9L. Wang10L. Wang11L. Wang12L. Wang13Department of Environmental Science and Engineering, Jiangwan Campus, Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP), Fudan University, Shanghai 200438, ChinaDepartment of Environmental Science and Engineering, Jiangwan Campus, Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP), Fudan University, Shanghai 200438, Chinanow at: Department of Earth and Environmental Sciences, University of Manchester, Manchester M13 9PL, UKDepartment of Environmental Science and Engineering, Jiangwan Campus, Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP), Fudan University, Shanghai 200438, ChinaDepartment of Environmental Science and Engineering, Jiangwan Campus, Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP), Fudan University, Shanghai 200438, ChinaDepartment of Environmental Science and Engineering, Jiangwan Campus, Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP), Fudan University, Shanghai 200438, ChinaAerodyne Research, Inc., Billerica, Massachusetts 01821, USAAerodyne Research, Inc., Billerica, Massachusetts 01821, USAAerodyne Research, Inc., Billerica, Massachusetts 01821, USADepartment of Environmental Science and Engineering, Jiangwan Campus, Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP), Fudan University, Shanghai 200438, ChinaShanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, ChinaIRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather/Climate Extremes Impact and Public Health, Fudan University, Shanghai, ChinaNational Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Shanghai, ChinaCollaborative Innovation Center of Climate Change, Nanjing, 210023, China<p>Volatile organic compounds (VOCs) are important atmospheric components that contribute to air pollution, but their accurate quantification by proton-transfer-reaction mass spectrometry (PTR-MS) remains challenging. In this work, we coupled a gas chromatograph (GC) prior to PTR-MS and analyzed complex ambient air in urban Shanghai to speciate the PTR signal to identify the VOC species that were responsible for the generation of the ions detected by PTR. We classified 176 individual PTR signals with associated compounds resolved by the GC based on whether they could be used to quantify a VOC species without pre-separation. In this classification, Category I includes 45 decent signal ions that were produced from a single VOC species and thus can be used for reliable quantification, although some of the Category I ions are not the conventionally used protonated quasi-molecular ions (MH<span class="inline-formula"><sup>+</sup></span>). Category II includes 39 signal ions that were produced from a group of isomers and can be used to quantify the isomeric sum, but with an increased uncertainty if a single calibration factor for one specific isomer is used to represent all structures. Category III includes 92 signal ions that were generated from more than one non-isomeric species (e.g., through protonation, fragmentation, cluster formation) and thus merely gave an upper limit of VOC concentrations. In addition, we propose taking aromatic compounds, for instance, the quantification of selected VOCs, utilizing either non-MH<span class="inline-formula"><sup>+</sup></span> or non-Category I ions. Our results help to achieve more comprehensive species identification and reliable VOC quantification in PTR measurements.</p>https://amt.copernicus.org/articles/18/3547/2025/amt-18-3547-2025.pdf |
| spellingShingle | Y. Zhang Y. Wang Y. Wang C. Li Y. Li S. Yin M. S. Claflin B. M. Lerner D. Worsnop L. Wang L. Wang L. Wang L. Wang L. Wang Interpretation of mass spectra by a Vocus proton-transfer-reaction mass spectrometer (PTR-MS) at an urban site: insights from gas chromatographic pre-separation Atmospheric Measurement Techniques |
| title | Interpretation of mass spectra by a Vocus proton-transfer-reaction mass spectrometer (PTR-MS) at an urban site: insights from gas chromatographic pre-separation |
| title_full | Interpretation of mass spectra by a Vocus proton-transfer-reaction mass spectrometer (PTR-MS) at an urban site: insights from gas chromatographic pre-separation |
| title_fullStr | Interpretation of mass spectra by a Vocus proton-transfer-reaction mass spectrometer (PTR-MS) at an urban site: insights from gas chromatographic pre-separation |
| title_full_unstemmed | Interpretation of mass spectra by a Vocus proton-transfer-reaction mass spectrometer (PTR-MS) at an urban site: insights from gas chromatographic pre-separation |
| title_short | Interpretation of mass spectra by a Vocus proton-transfer-reaction mass spectrometer (PTR-MS) at an urban site: insights from gas chromatographic pre-separation |
| title_sort | interpretation of mass spectra by a vocus proton transfer reaction mass spectrometer ptr ms at an urban site insights from gas chromatographic pre separation |
| url | https://amt.copernicus.org/articles/18/3547/2025/amt-18-3547-2025.pdf |
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