Peroxy radical measurements by photoacoustic spectroscopy coupled to chemical amplification

2021 ◽  
Author(s):  
Weidong Chen ◽  
Gaoxuan Wang ◽  
Ahmad Lahib ◽  
Marius Duncianu ◽  
Qian Gou ◽  
...  
Keyword(s):  
Natural Science ◽  
Photoacoustic Spectroscopy ◽  
Limit Of Detection ◽  
Total Concentration ◽  
Peroxy Radical ◽  
Chemical Conversion ◽  
Integration Time ◽  
Peroxy Radicals ◽  
Measurement Sensitivity ◽  
Chemical Amplification

<p>Peroxy radicals (HO<sub>2</sub>+RO<sub>2</sub>) are crucial intermediates in many key atmospheric processes and contribute to the formation of major air pollutants, such as ozone and secondary organic aerosols<sup>1</sup>. Due to their high reactivity and their extremely low concentrations (typically <100 pptv), in-situ real time and interference-free measurements of peroxy radicals remain challenging. In the present work, photoacoustic spectroscopy (PAS)<sup>2</sup> is applied, for the first time to our best knowledge, to the measurements of peroxy radicals with the help of the well established chemical amplification approach. Peroxy radical chemical amplification (PERCA)<sup>3</sup> is based on chemical conversion of peroxy randicals into NO<sub>2</sub> and followed by chemical amplification to achieve the necessary measurement sensitivity for the measurement of atmospheric peroxy radical concentration. The resulting NO<sub>2</sub> concentration is measured by PAS to infer the total concentration of peroxy radicals. The performance of the developed PERCA-PAS approach was demonstrated with a reference ECHAMP chemical amplification system using cavity attenuated phase shift spectroscopy (CAPS) for NO<sub>2</sub> monitoring. The determined amplification gains (referred to as chain length, CL) of the ECHAMP system using PAS are well consistent with the values determined using CAPS. A 1-σ limit of detection of ~12 pptv for peroxy radicals was achieved in an integration time of 90 s at a relative humidity of about 9.8%. The detection limit of the current ECHAMP-PAS system can be further improved by using higher laser power and increasing the number of microphones in the photoacoustic spectrophone, which would allow reaching sub-pptv detection limits for the measurements of peroxy radicals in the atmosphere.</p><p>This work provides a promising technique to develop novel compact and very cost-effective (compared to all methods currently used) sensors, which will allow readily developing network measurements and investigation of the spatial distribution of peroxy radicals in the atmosphere.</p><p><strong>Acknowledgments. </strong>This work is supported by the French national research agency (ANR) under MABCaM and LABEX-CaPPA contracts, the European Funds for Regional Economic Development through the CaPPA project, the CPER-CLIMIBIO program, the LEFE/CHAT INSU program. It is also supported by the National Natural Science Foundation of China (22073013), Natural Science Foundation of Chongqing (cstc2018jcyjAX0050) and Fundamental Research Funds for the Central Universities (2020CDJXZ002).</p><p><strong>Reference</strong></p><p>[1] J. J. Orlando, G. S. Tyndall, Laboratory studies of organic peroxy radical chemistry: an overview with emphasis on recent issues of atmospheric significance, Chem. Soc. Rev. <strong>41</strong>(2012) 6294-6317.</p><p>[2] W. Chen et al., Photonic Sensing of reactive atmospheric species, in Encyclopedia of Analytical Chemistry © 2017 John Wiley & Sons, Ltd. DOI: 10.1002/9780470027318.a9432.</p><p>[3] C. Cantrell, D. Stedman, A possible technique for the measurement of atmospheric peroxy radicals, Geophys. Res. Lett. <strong>9</strong> (1982) 846-849.</p>

Ultra-sensitive measurement of peroxy radicals by chemical amplification broadband cavity-enhanced spectroscopy

The Analyst ◽  
2016 ◽  
Vol 141 (20) ◽  
pp. 5870-5878 ◽  
Author(s):  
Yang Chen ◽  
Chengqiang Yang ◽  
Weixiong Zhao ◽  
Bo Fang ◽  
Xuezhe Xu ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Peroxy Radical ◽  
Peroxy Radicals ◽  
Enhanced Absorption ◽  
Chemical Amplification ◽  
Amplification Method ◽  
Cavity Enhanced Absorption Spectroscopy

The chemical amplification method is combined with the incoherent broadband cavity-enhanced absorption spectroscopy for peroxy radical measurements.

scholarly journals Quantification of peroxynitric acid and peroxyacyl nitrates using an ethane-based thermal dissociation peroxy radical chemical amplification cavity ring-down spectrometer

2018 ◽  
Vol 11 (7) ◽  
pp. 4109-4127
Author(s):  
Youssef M. Taha ◽  
Matthew T. Saowapon ◽  
Faisal V. Assad ◽  
Connie Z. Ye ◽  
Xining Chen ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Thermal Dissociation ◽  
Peroxy Radical ◽  
Ambient Air ◽  
Oh Radicals ◽  
Ionization Mass ◽  
Chemical Amplification ◽  
Peroxynitric Acid ◽  
Peroxyacyl Nitrates ◽  
Cavity Ring Down

Abstract. Peroxy and peroxyacyl nitrates (PNs and PANs) are important trace gas constituents of the troposphere which are challenging to quantify by differential thermal dissociation with NO2 detection in polluted (i.e., high-NOx) environments. In this paper, a thermal dissociation peroxy radical chemical amplification cavity ring-down spectrometer (TD-PERCA-CRDS) for sensitive and selective quantification of total peroxynitrates (ΣPN  =  ΣRO2NO2) and of total peroxyacyl nitrates (ΣPAN  =  ΣRC(O)O2NO2) is described. The instrument features multiple detection channels to monitor the NO2 background and the ROx ( =  HO2 + RO2 + ΣRO2) radicals generated by TD of ΣPN and/or ΣPAN. Chemical amplification is achieved through the addition of 0.6 ppm NO and 1.6 % C2H6 to the inlet. The instrument's performance was evaluated using peroxynitric acid (PNA) and peroxyacetic or peroxypropionic nitric anhydride (PAN or PPN) as representative examples of ΣPN and ΣPAN, respectively, whose abundances were verified by iodide chemical ionization mass spectrometry (CIMS). The amplification factor or chain length increases with temperature up to 69 ± 5 and decreases with analyte concentration and relative humidity (RH). At inlet temperatures above 120 and 250 °C, respectively, PNA and ΣPAN fully dissociated, though their TD profiles partially overlap. Furthermore, interference from ozone (O3) was observed at temperatures above 150 °C, rationalized by its partial dissociation to O atoms which react with C2H6 to form C2H5 and OH radicals. Quantification of PNA and ΣPAN in laboratory-generated mixtures containing O3 was achieved by simultaneously monitoring the TD-PERCA responses in multiple parallel CRDS channels set to different temperatures in the 60 to 130 °C range. The (1 s, 2σ) limit of detection (LOD) of TD-PERCA-CRDS is 6.8 pptv for PNA and 2.6 pptv for ΣPAN and significantly lower than TD-CRDS without chemical amplification. The feasibility of TD-PERCA-CRDS for ambient air measurements is discussed.

Monitoring of peroxy radicals by chemical amplification enhanced photoacoustic spectroscopy

2021 ◽  
Author(s):  
Gaoxuan Wang ◽  
Ahmad Lahib ◽  
Marius Duncianu ◽  
Qian Gou ◽  
Philip S. Stevens ◽  
...  
Keyword(s):  
Photoacoustic Spectroscopy ◽  
Peroxy Radicals ◽  
Chemical Amplification

scholarly journals Measurements of tropospheric HO<sub>2</sub> and RO<sub>2</sub> by oxygen dilution modulation and chemical ionization mass spectrometry

2011 ◽  
Vol 4 (1) ◽  
pp. 385-442 ◽  
Author(s):  
R. S. Hornbrook ◽  
J. H. Crawford ◽  
G. D. Edwards ◽  
O. Goyea ◽  
R. L. Mauldin III ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Chemical Ionization ◽  
Measurement Techniques ◽  
Peroxy Radical ◽  
Chemical Conversion ◽  
Ionization Mass Spectrometry ◽  
Chemical Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Peroxy Radicals ◽  
Low Efficiency

Abstract. An improved method for the measurement of hydroperoxy radicals (HO2) and organic peroxy radicals (RO2, where R is any organic group) has been developed that combines two previous chemical conversion/chemical ionization mass spectrometry (CIMS) peroxy radical measurement techniques. Applicable to both ground-based and aircraft platforms, the method provides good separation between HO2 and RO2 and frequent measurement capability with observations of both HO2 and HO2+RO2 amounts each minute. This allows for analyses of measured [HO2]/[HO2+RO2] ratios on timescales relevant to tropospheric photochemistry. By varying both [NO] and [O2] simultaneously in the chemical conversion region of the PeRCIMS (Peroxy Radical CIMS) inlet, the method exploits the changing conversion efficiency of RO2 to HO2 under different inlet [NO]/[O2] to selectively observe either primarily HO2 or the sum of HO2 and RO2. Two modes of operation have been established for ambient measurements: in the first half of the minute, RO2 radicals are measured at close to 100% efficiency along with HO2 radicals (low [NO]/[O2] = 2.53×10−5) and in the second half of the minute, HO2 is detected while the majority of ambient RO2 radicals are measured with low efficiency, approximately 15% (high [NO]/[O2] = 6.80×10−4). The method has been tested extensively in the laboratory under various conditions and for a variety of organic peroxy radicals relevant to the atmosphere and the results of these tests are presented. The modified PeRCIMS instrument has been deployed successfully using the new measurement technique on a number of aircraft campaigns, including on the NSF/NCAR C-130 during the MIRAGE-Mex and NASA INTEX-B field campaigns in the spring of 2006. A brief comparison of the peroxy radical measurements during these campaigns to a photochemical box model indicates good agreement under tropospheric conditions where NOx (NO+NO2) concentrations are lower than 0.5 ppbV (parts per billion by volume).

Chemical amplification enhanced measurements of peroxy radicals by photoacoustic spectroscopy

2021 ◽  
Author(s):  
Gaoxuan Wang ◽  
Ahmad Lahib ◽  
Marius Duncianu ◽  
Qian Gou ◽  
Philip S. Stevens ◽  
...  
Keyword(s):  
Photoacoustic Spectroscopy ◽  
Peroxy Radicals ◽  
Chemical Amplification

scholarly journals Quantification of peroxynitric acid and peroxyacyl nitrates using an ethane-based thermal dissociation peroxy radical chemical amplification cavity ring-down spectrometer

2018 ◽  
Author(s):  
Youssef M. Taha ◽  
Matthew T. Saowapon ◽  
Faisal V. Assad ◽  
Connie Z. Ye ◽  
Xining Chen ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Thermal Dissociation ◽  
Peroxy Radical ◽  
Ambient Air ◽  
Oh Radicals ◽  
Ionization Mass ◽  
Chemical Amplification ◽  
Peroxynitric Acid ◽  
Peroxyacyl Nitrates ◽  
Cavity Ring Down

Abstract. Peroxy and peroxyacyl nitrates (PNs and PANs) are important trace gas constituents of the troposphere which are challenging to quantify by differential thermal dissociation with NO2 detection in polluted (i.e., high-NOx) environments. In this paper, a thermal dissociation peroxy radical chemical amplification cavity ring-down spectrometer (TD-PERCA-CRDS) for sensitive and selective quantification of total peroxynitrates (ΣPN = ΣRO2NO2) and of total peroxyacyl nitrates (ΣPAN = ΣRC(O)O2NO2) is described. The instrument features multiple detection channels to monitor the NO2 background and the ROx (= HO2 + RO2 + ΣRO2) radicals generated by TD of ΣPN and/or ΣPAN. Chemical amplification is achieved through addition of 0.6 ppm NO and 1.6 % C2H6 to the inlet. The instrument's performance was evaluated using peroxynitric acid (PNA) and peroxyacetic or peroxypropionic nitric anhydride (PAN or PPN) as representative examples of ΣPN and ΣPAN, respectively, whose abundances were verified by iodide chemical ionization mass spectrometry (CIMS). The amplification factor or chain length increases with temperature up to 69 ± 5 and decreases with analyte concentration and relative humidity (RH). At inlet temperatures above 120 °C and 250 °C, respectively, PNA and ΣPAN fully dissociated, though their TD profiles partially overlap. Furthermore, interference from ozone (O3) was observed at temperatures above 150 °C, rationalized by its partial dissociation to O atoms which react with C2H6 to form C2H5 and OH radicals. Quantification of PNA and ΣPAN in laboratory-generated mixtures containing O3 was achieved by simultaneously monitoring the TD-PERCA responses in multiple parallel CRDS channels set to different temperatures in the 60 °C to 130 °C range. The (1 s, 1σ) limit of detection (LOD) of TD-PERCA-CRDS is 3.4 pptv for PNA and 1.3 pptv for ΣPAN and significantly lower than TD-CRDS without chemical amplification. The feasibility of TD-PERCA-CRDS for ambient air measurements is discussed.

scholarly journals Measurements of tropospheric HO<sub>2</sub> and RO<sub>2</sub> by oxygen dilution modulation and chemical ionization mass spectrometry

2011 ◽  
Vol 4 (4) ◽  
pp. 735-756 ◽  
Author(s):  
R. S. Hornbrook ◽  
J. H. Crawford ◽  
G. D. Edwards ◽  
O. Goyea ◽  
R. L. Mauldin III ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Chemical Ionization ◽  
Measurement Techniques ◽  
Peroxy Radical ◽  
Chemical Conversion ◽  
Ionization Mass Spectrometry ◽  
Chemical Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Peroxy Radicals ◽  
Low Efficiency

Abstract. An improved method for the measurement of hydroperoxy radicals (HO2) and organic peroxy radicals (RO2, where R is any organic group) has been developed that combines two previous chemical conversion/chemical ionization mass spectrometry (CIMS) peroxy radical measurement techniques. Applicable to both ground-based and aircraft platforms, the method provides good separation between HO2 and RO2, and frequent measurement capability with observations of both HO2 and HO2 + RO2 amounts each minute. These improvements allow for analyses of measured [HO2]/[HO2 + RO2] ratios on timescales relevant to tropospheric photochemistry. By varying both [NO] and [O2] simultaneously in the chemical conversion region of the PeRCIMS (Peroxy Radical CIMS) inlet, the method exploits the changing conversion efficiency of RO2 to HO2 under different inlet [NO]/[O2] to selectively observe either primarily HO2 or the sum of HO2 and RO2. Two modes of operation have been established for ambient measurements: in the first half of the minute, RO2 radicals are measured at close to 100% efficiency along with HO2 radicals (low [NO]/[O2] = 2.53 × 10−5) and in the second half of the minute, HO2 is detected while the majority of ambient RO2 radicals are measured with low efficiency, approximately 15% (high [NO]/[O2] = 6.80 × 10−4). The method has been tested extensively in the laboratory under various conditions and for a variety of organic peroxy radicals relevant to the atmosphere and the results of these tests are presented. The modified PeRCIMS instrument has been deployed successfully using the new measurement technique on a number of aircraft campaigns, including on the NSF/NCAR C-130 during the MIRAGE-Mex and NASA INTEX-B field campaigns in the spring of 2006. A brief comparison of the peroxy radical measurements during these campaigns to a photochemical box model indicates good agreement under tropospheric conditions where NOx (NO + NO2) concentrations are lower than 0.5 ppbV (parts per billion by volume).

scholarly journals Peroxy Radical Measurements by Ethane – Nitric Oxide Chemical Amplification and Laser-Induced Fluorescence/Fluorescence Assay by Gas Expansion during the IRRONIC field campaign in a Forest in Indiana

2019 ◽  
Author(s):  
Shuvashish Kundu ◽  
Benjamin L. Deming ◽  
Michelle M. Lew ◽  
Brandon P. Bottorff ◽  
Pamela Rickly ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Deciduous Forest ◽  
Peroxy Radical ◽  
Ozone Production ◽  
Peroxy Radicals ◽  
Radical Reactivity ◽  
Chemical Amplification ◽  
Mixed Deciduous Forest ◽  
Gas Expansion ◽  
No2 Detection

Abstract. Peroxy radicals were measured in a mixed deciduous forest atmosphere in Bloomington, Indiana, USA, during the Indiana Radical, Reactivity and Ozone Production Intercomparison (IRRONIC) during the summer of 2015. Total peroxy radicals ([XO2] ≡ [HO2] + Ʃ[RO2]) were measured by a newly developed technique involving nitric oxide (NO) – ethane (C2H6) chemical amplification followed by NO2 detection by cavity attenuated phase shift spectroscopy (hereinafter referred to as ECHAMP). The sum of hydroperoxy radicals (HO2) and a portion of organic peroxy radicals ([HO2*] = [HO2] + Ʃαi[RiO2], 0 

scholarly journals Measurements of tropospheric HO<sub>2</sub> and RO<sub>2</sub> by oxygen dilution modulation and chemical ionization mass spectrometry

2010 ◽  
Vol 10 (9) ◽  
pp. 22219-22277
Author(s):  
R. S. Hornbrook ◽  
J. H. Crawford ◽  
G. D. Edwards ◽  
O. Goyea ◽  
R. L. Mauldin III ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Chemical Ionization ◽  
Measurement Techniques ◽  
Peroxy Radical ◽  
Chemical Conversion ◽  
Ionization Mass Spectrometry ◽  
Chemical Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Peroxy Radicals ◽  
Measurement Capability

Abstract. An improved method for the measurement of hydroperoxy radicals (HO2) and organic peroxy radicals (RO2, where R is any organic group) has been developed that combines two previous chemical conversion/chemical ionization mass spectrometry (CIMS) peroxy radical measurement techniques. Applicable to both ground-based and aircraft platforms, the method provides good separation between HO2 and RO2 and frequent measurement capability with observations of both HO2 and HO2 + RO2 amounts each minute. This allows for analyses of measured [HO2]/[HO2 + RO2] ratios on timescales relevant to tropospheric photochemistry. By varying both [NO] and [O2] simultaneously in the chemical conversion region of the PeRCIMS (Peroxy Radical CIMS) inlet, the method exploits the changing conversion efficiency of RO2 to HO2 under different inlet [NO]/[O2] to selectively observe either primarily HO2 or the sum of HO2 and RO2. Two modes of operation have been established for ambient measurements: in the first half of the minute, RO2 radicals are measured at close to 100% efficiency along with HO2 radicals (low [NO]/[O2] = 2.53 × 10−5) and in the second half of the minute, HO2 is detected while the majority of ambient RO2 radicals are measured with approximately 15% efficiency (high [NO]/[O2] = 6.80 × 10−4). The method has been tested extensively in the laboratory under various conditions and for a variety of organic peroxy radicals relevant to the atmosphere and the results of these tests are presented. The modified PeRCIMS instrument has been deployed successfully using the current measurement technique on a number of aircraft campaigns, including on the NSF/NCAR C-130 during the MIRAGE-Mex and NASA INTEX-B field campaigns in the spring of 2006. A brief comparison of the peroxy radical measurements during these campaigns to a photochemical box model confirms that the PeRCIMS is able to successfully separate and measure HO2 and RO2 under the majority of tropospheric conditions.

The Influence of Irradiation Temperature on U.V. Induced Defect Creation in Dry Silica

1985 ◽  
Vol 61 ◽  
Author(s):  
R. A. B. Devine ◽  
C. Fiori ◽  
J. Robertson
Keyword(s):  
Oxygen Vacancy ◽  
Peroxy Radical ◽  
Irradiation Temperature ◽  
Threshold Temperature ◽  
Peroxy Radicals ◽  
Oxygen Hole ◽  
Spin Resonance ◽  
Dependent Growth ◽  
Dose Dependent ◽  
Annealing Curve

ABSTRACTElectron spin resonance measurements have been carried out on samples of Suprasil Wl (dry silica) subjected to ultraviolet laser radiation (λ = 248 nm, E = 5 eV/photon). Studies have been made for fixed irradiation temperature (room) variable accumulated ultraviolet dose and fixed accumulated dose (3000 J/cm2) at various irradiation temperatures in the range 110 K to 335 K. Three principal defect centers are observed. Non-bridging oxygen hole centers are created at all temperatures in the range studied with slightly higher efficiency at room temperature (ration 300 K/150 K ∼ 2.5). Comparison of the dose dependent growth curve of the 4.8 eV absorption and its isochronal annealing curve with those for the oxygen hole center clearly identify the origin of the absorption band with this defect. A threshold temperature ∼ 200 K is found for oxygen vacancy creation consistent with results on single crystalline quartz. Post irradiation annealing at 593 K eliminates the vacancy centers and the peroxy radical resonance appears. Its growth as a function of accumulated ultraviolet dose and irradiation temperature supports the hypothesis that peroxy radicals form by the trapping of diffusing, molecular oxygen at the oxygen vacancy center.

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