Callum E. Flowerday, Ryan Thalman, Matthew C. Asplund, Samuel A. Badstubner, Adam K. Cook, Philip Lundrigan, Jaron C. Hansen
{"title":"开放路径光谱法检测羟基自由基:宽带腔增强吸收光谱(BBCEAS)与BBCEAS耦合法布里-普氏干涉仪(BBCEAS- fp)的比较","authors":"Callum E. Flowerday, Ryan Thalman, Matthew C. Asplund, Samuel A. Badstubner, Adam K. Cook, Philip Lundrigan, Jaron C. Hansen","doi":"10.1021/acs.analchem.5c01515","DOIUrl":null,"url":null,"abstract":"Hydroxyl radical (OH) is the primary atmospheric oxidant, but it is challenging to measure due to its short half-life under atmospheric conditions (approximately 1 s) and low ambient concentrations (approximately 10<sup>6</sup> molecules/cm<sup>3</sup>). While several measurement techniques exist, including laser-induced fluorescence with fluorescence assay by gas expansion (LIF-FAGE), differential optical absorption spectroscopy, and chemical ionization mass spectrometry (CIMS), often only LIF-FAGE and CIMS are considered available for field measurements. This study compares the performance of two instruments: a broadband cavity-enhanced absorption spectroscopy (BBCEAS) coupled with a CCD and a BBCEAS coupled with a Fabry–Pérot interferometer (BBCEAS-FP). The semiportable BBCEAS instrument benefits from spectroscopic specificity, avoiding interference from other species, and features inherent calibration, eliminating calibration errors. The effects of aerosols and turbulence on performance were also evaluated. A low-loss optic was used to measure the optical cavity reflectivity in an open-path configuration, and a butane flame served as the OH source during testing. The BBCEAS instrument achieved an extrapolated 1-h detection limit (1σ) of 1.5 × 10<sup>7</sup> molecules/cm<sup>3</sup> for ambient-temperature OH. Applying a Gauss–Hermite filter reduced noise in the extinction spectrum by 2.66 times, lowering the extrapolated detection limit to 4.6 × 10<sup>6</sup> molecules/cm<sup>3</sup>. The BBCEAS-FP, a more cost-effective and portable instrument, demonstrated a comparable extrapolated 1-h (1σ) detection limit of 1.5 × 10<sup>7</sup> molecules/cm<sup>3</sup>.","PeriodicalId":27,"journal":{"name":"Analytical Chemistry","volume":"134 1","pages":""},"PeriodicalIF":6.7000,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Open Path Spectroscopic Detection of Hydroxyl Radical: A Comparison between Broadband Cavity-Enhanced Absorption Spectroscopy (BBCEAS) and BBCEAS Coupled with a Fabry–Pérot Interferometer (BBCEAS-FP)\",\"authors\":\"Callum E. Flowerday, Ryan Thalman, Matthew C. Asplund, Samuel A. Badstubner, Adam K. Cook, Philip Lundrigan, Jaron C. Hansen\",\"doi\":\"10.1021/acs.analchem.5c01515\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Hydroxyl radical (OH) is the primary atmospheric oxidant, but it is challenging to measure due to its short half-life under atmospheric conditions (approximately 1 s) and low ambient concentrations (approximately 10<sup>6</sup> molecules/cm<sup>3</sup>). While several measurement techniques exist, including laser-induced fluorescence with fluorescence assay by gas expansion (LIF-FAGE), differential optical absorption spectroscopy, and chemical ionization mass spectrometry (CIMS), often only LIF-FAGE and CIMS are considered available for field measurements. This study compares the performance of two instruments: a broadband cavity-enhanced absorption spectroscopy (BBCEAS) coupled with a CCD and a BBCEAS coupled with a Fabry–Pérot interferometer (BBCEAS-FP). The semiportable BBCEAS instrument benefits from spectroscopic specificity, avoiding interference from other species, and features inherent calibration, eliminating calibration errors. The effects of aerosols and turbulence on performance were also evaluated. A low-loss optic was used to measure the optical cavity reflectivity in an open-path configuration, and a butane flame served as the OH source during testing. The BBCEAS instrument achieved an extrapolated 1-h detection limit (1σ) of 1.5 × 10<sup>7</sup> molecules/cm<sup>3</sup> for ambient-temperature OH. Applying a Gauss–Hermite filter reduced noise in the extinction spectrum by 2.66 times, lowering the extrapolated detection limit to 4.6 × 10<sup>6</sup> molecules/cm<sup>3</sup>. The BBCEAS-FP, a more cost-effective and portable instrument, demonstrated a comparable extrapolated 1-h (1σ) detection limit of 1.5 × 10<sup>7</sup> molecules/cm<sup>3</sup>.\",\"PeriodicalId\":27,\"journal\":{\"name\":\"Analytical Chemistry\",\"volume\":\"134 1\",\"pages\":\"\"},\"PeriodicalIF\":6.7000,\"publicationDate\":\"2025-05-28\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Analytical Chemistry\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://doi.org/10.1021/acs.analchem.5c01515\",\"RegionNum\":1,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"CHEMISTRY, ANALYTICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Analytical Chemistry","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acs.analchem.5c01515","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, ANALYTICAL","Score":null,"Total":0}
Open Path Spectroscopic Detection of Hydroxyl Radical: A Comparison between Broadband Cavity-Enhanced Absorption Spectroscopy (BBCEAS) and BBCEAS Coupled with a Fabry–Pérot Interferometer (BBCEAS-FP)
Hydroxyl radical (OH) is the primary atmospheric oxidant, but it is challenging to measure due to its short half-life under atmospheric conditions (approximately 1 s) and low ambient concentrations (approximately 106 molecules/cm3). While several measurement techniques exist, including laser-induced fluorescence with fluorescence assay by gas expansion (LIF-FAGE), differential optical absorption spectroscopy, and chemical ionization mass spectrometry (CIMS), often only LIF-FAGE and CIMS are considered available for field measurements. This study compares the performance of two instruments: a broadband cavity-enhanced absorption spectroscopy (BBCEAS) coupled with a CCD and a BBCEAS coupled with a Fabry–Pérot interferometer (BBCEAS-FP). The semiportable BBCEAS instrument benefits from spectroscopic specificity, avoiding interference from other species, and features inherent calibration, eliminating calibration errors. The effects of aerosols and turbulence on performance were also evaluated. A low-loss optic was used to measure the optical cavity reflectivity in an open-path configuration, and a butane flame served as the OH source during testing. The BBCEAS instrument achieved an extrapolated 1-h detection limit (1σ) of 1.5 × 107 molecules/cm3 for ambient-temperature OH. Applying a Gauss–Hermite filter reduced noise in the extinction spectrum by 2.66 times, lowering the extrapolated detection limit to 4.6 × 106 molecules/cm3. The BBCEAS-FP, a more cost-effective and portable instrument, demonstrated a comparable extrapolated 1-h (1σ) detection limit of 1.5 × 107 molecules/cm3.
期刊介绍:
Analytical Chemistry, a peer-reviewed research journal, focuses on disseminating new and original knowledge across all branches of analytical chemistry. Fundamental articles may explore general principles of chemical measurement science and need not directly address existing or potential analytical methodology. They can be entirely theoretical or report experimental results. Contributions may cover various phases of analytical operations, including sampling, bioanalysis, electrochemistry, mass spectrometry, microscale and nanoscale systems, environmental analysis, separations, spectroscopy, chemical reactions and selectivity, instrumentation, imaging, surface analysis, and data processing. Papers discussing known analytical methods should present a significant, original application of the method, a notable improvement, or results on an important analyte.