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Detection of Sulfur Dioxide by Broadband Cavity-Enhanced Absorption Spectroscopy (BBCEAS). SENSORS 2022; 22:s22072626. [PMID: 35408239 PMCID: PMC9002574 DOI: 10.3390/s22072626] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/27/2022] [Accepted: 03/27/2022] [Indexed: 02/04/2023]
Abstract
Sulfur dioxide (SO2) is an important precursor for the formation of atmospheric sulfate aerosol and acid rain. We present an instrument using Broadband Cavity-Enhanced Absorption Spectroscopy (BBCEAS) for the measurement of SO2 with a minimum limit of detection of 0.75 ppbv (3-σ) using the spectral range 305.5–312 nm and an averaging time of 5 min. The instrument consists of high-reflectivity mirrors (0.9985 at 310 nm) and a deep UV light source (Light Emitting Diode). The effective absorption path length of the instrument is 610 m with a 0.966 m base length. Published reference absorption cross sections were used to fit and retrieve the SO2 concentrations and were compared to fluorescence standard measurements for SO2. The comparison was well correlated, R2 = 0.9998 with a correlation slope of 1.04. Interferences for fluorescence measurements were tested and the BBCEAS showed no interference, while ambient measurements responded similarly to standard measurement techniques.
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2
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Keary BP, Ruth AA. Time- and intensity-dependent broadband cavity-enhanced absorption spectroscopy with pulsed intra-cavity laser-induced plasmas. OPTICS EXPRESS 2019; 27:36864-36874. [PMID: 31873458 DOI: 10.1364/oe.27.036864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 11/19/2019] [Indexed: 06/10/2023]
Abstract
A pulsed laser-induced plasma (LIP) was generated in ambient air inside a high-finesse (F≈ 5200) near-concentric optical cavity. The optical plasma emission was successfully trapped and sustained by the cavity, manifested by ring-down times in excess of 4 μs indicating effective mirror reflectivities of ∼0.9994. The light leaking from the cavity was used to measure broadband absorption spectra of gaseous azulene under ambient air conditions between 580 and 645 nm, employing (i) intensity-dependent cavity-enhanced, and (ii) time-dependent cavity-ring down methodologies. Minimum detectable absorption coefficients of 4.7 × 10-8 cm-1 and 7.4 × 10-8 cm-1 were achieved for the respective approaches. The two approaches were compared and implications of pulsed excitation for gated intensity-dependent measurements were discussed.
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3
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Chen J, Fullam DP, Yu S, Böge O, Le PH, Herrmann H, Venables DS. Improving the accuracy and precision of broadband optical cavity measurements. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 218:178-183. [PMID: 30991294 DOI: 10.1016/j.saa.2019.04.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/05/2019] [Accepted: 04/09/2019] [Indexed: 06/09/2023]
Abstract
Most extinction measurements require a stable light source to attain high precision and accuracy. Here, we present a convenient approach to normalize light source intensity in broadband optical cavity measurements. In the absence of sample extinction, we show that the in-band signal - the high finesse spectral region of the optical cavity in which sample extinction is measured with high sensitivity - is strongly correlated with the out-of-band signal. The out-of-band signal is insensitive to sample extinction and can act as a proxy for light source intensity. This normalization approach strongly suppressed in-band intensity changes in two incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) instruments with dissimilar light sources and optical cavity properties. Intensity fluctuations in an arc lamp system were suppressed by a factor of 7 to 16 and in the LED spectrometer by a factor of 10. This approach therefore improves the accuracy and precision of extinction measurements where either property is limited by the light source stability.
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Affiliation(s)
- Jun Chen
- Department of Thermal Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Donovan P Fullam
- School of Chemistry & Environmental Research Institute, University College Cork, Cork, Ireland
| | - Shuaishuai Yu
- Department of Thermal Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Olaf Böge
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), 04318 Leipzig, Germany
| | - Phuoc Hoa Le
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), 04318 Leipzig, Germany
| | - Hartmut Herrmann
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), 04318 Leipzig, Germany
| | - Dean S Venables
- School of Chemistry & Environmental Research Institute, University College Cork, Cork, Ireland; Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), 04318 Leipzig, Germany.
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4
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Zheng K, Zheng C, Zhang Y, Wang Y, Tittel FK. Review of Incoherent Broadband Cavity-Enhanced Absorption Spectroscopy (IBBCEAS) for Gas Sensing. SENSORS (BASEL, SWITZERLAND) 2018; 18:E3646. [PMID: 30373252 PMCID: PMC6263486 DOI: 10.3390/s18113646] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 10/20/2018] [Accepted: 10/24/2018] [Indexed: 11/30/2022]
Abstract
Incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) is of importance for gas detection in environmental monitoring. This review summarizes the unique properties, development and recent progress of the IBBCEAS technique. Principle of IBBCEAS for gas sensing is described, and the development of IBBCEAS from the perspective of system structure is elaborated, including light source, cavity and detection scheme. Performances of the reported IBBCEAS sensor system in laboratory and field measurements are reported. Potential applications of this technique are discussed.
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Affiliation(s)
- Kaiyuan Zheng
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China.
| | - Chuantao Zheng
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China.
| | - Yu Zhang
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China.
| | - Yiding Wang
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China.
| | - Frank K Tittel
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA.
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5
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Zheng K, Zheng C, Liu Z, He Q, Du Q, Zhang Y, Wang Y, Tittel FK. Near-infrared broadband cavity-enhanced sensor system for methane detection using a wavelet-denoising assisted Fourier-transform spectrometer. Analyst 2018; 143:4699-4706. [PMID: 30183029 DOI: 10.1039/c8an01290c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The majority of broadband cavity-enhanced systems are used to detect trace gas species in the visible spectral range.
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Affiliation(s)
- Kaiyuan Zheng
- State Key Laboratory of Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- China
| | - Chuantao Zheng
- State Key Laboratory of Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- China
| | - Zidi Liu
- State Key Laboratory of Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- China
| | - Qixin He
- State Key Laboratory of Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- China
| | - Qiaoling Du
- State Key Laboratory of Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- China
| | - Yu Zhang
- State Key Laboratory of Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- China
| | - Yiding Wang
- State Key Laboratory of Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- China
| | - Frank K. Tittel
- Department of Electrical and Computer Engineering
- Rice University
- Houston
- USA
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6
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Fang B, Zhao W, Xu X, Zhou J, Ma X, Wang S, Zhang W, Venables DS, Chen W. Portable broadband cavity-enhanced spectrometer utilizing Kalman filtering: application to real-time, in situ monitoring of glyoxal and nitrogen dioxide. OPTICS EXPRESS 2017; 25:26910-26922. [PMID: 29092174 DOI: 10.1364/oe.25.026910] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 10/17/2017] [Indexed: 06/07/2023]
Abstract
This article describes the development and field application of a portable broadband cavity enhanced spectrometer (BBCES) operating in the spectral range of 440-480 nm for sensitive, real-time, in situ measurement of ambient glyoxal (CHOCHO) and nitrogen dioxide (NO2). The instrument utilized a custom cage system in which the same SMA collimators were used in the transmitter and receiver units for coupling the LED light into the cavity and collecting the light transmitted through the cavity. This configuration realised a compact and stable optical system that could be easily aligned. The dimensions and mass of the optical layer were 676 × 74 × 86 mm3 and 4.5 kg, respectively. The cavity base length was about 42 cm. The mirror reflectivity at λ = 460 nm was determined to be 0.9998, giving an effective absorption pathlength of 2.26 km. The demonstrated measurement precisions (1σ) over 60 s were 28 and 50 pptv for CHOCHO and NO2 and the respective accuracies were 5% and 4%. By applying a Kalman adaptive filter to the retrieved concentrations, the measurement precisions of CHOCHO and NO2 were improved to 8 pptv and 40 pptv in 21 s.
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7
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Nakashima Y, Sadanaga Y. Validation of in situ Measurements of Atmospheric Nitrous Acid Using Incoherent Broadband Cavity-enhanced Absorption Spectroscopy. ANAL SCI 2017; 33:519-524. [PMID: 28392531 DOI: 10.2116/analsci.33.519] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) is a useful technique for measuring trace gaseous species in the atmosphere. Recently, IBBCEAS was used to measure concentrations of nitrous acid (HONO) in the troposphere to resolve controversies related to its formation and loss. Here, measurements of HONO and a mixture of HONO and NO2 using IBBCEAS were validated by comparing them with those obtained with a NOx analyzer. Good agreement was found between these methods, given their respective experimental uncertainties. The detection limit of our IBBCEAS instrument was 0.2 ppbv, with a signal-to-noise ratio of 1, and a 5-min integration time.
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Affiliation(s)
- Yoshihiro Nakashima
- Department of Environmental Science on Biosphere, Graduate School of Agriculture, Tokyo University of Agriculture and Technology
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8
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Cossel KC, Waxman EM, Finneran IA, Blake GA, Ye J, Newbury NR. Gas-phase broadband spectroscopy using active sources: progress, status, and applications. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. B, OPTICAL PHYSICS 2017; 34:104-129. [PMID: 28630530 PMCID: PMC5473295 DOI: 10.1364/josab.34.000104] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Broadband spectroscopy is an invaluable tool for measuring multiple gas-phase species simultaneously. In this work we review basic techniques, implementations, and current applications for broadband spectroscopy. We discuss components of broad-band spectroscopy including light sources, absorption cells, and detection methods and then discuss specific combinations of these components in commonly-used techniques. We finish this review by discussing potential future advances in techniques and applications of broad-band spectroscopy.
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Affiliation(s)
- Kevin C. Cossel
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Eleanor M. Waxman
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Ian A. Finneran
- Division of Chemistry & Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Geoffrey A. Blake
- Division of Chemistry & Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Jun Ye
- JILA, National Institute of Standards and Technology and University of Colorado, Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Nathan R. Newbury
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
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9
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Chan K, Jiang S, Ning Z. Speciation of water soluble iron in size segregated airborne particulate matter using LED based liquid waveguide with a novel dispersive absorption spectroscopic measurement technique. Anal Chim Acta 2016; 914:100-9. [DOI: 10.1016/j.aca.2016.01.053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 01/29/2016] [Accepted: 01/31/2016] [Indexed: 12/11/2022]
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10
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Chen Y, Yang C, Zhao W, Fang B, Xu X, Gai Y, Lin X, Chen W, Zhang W. Ultra-sensitive measurement of peroxy radicals by chemical amplification broadband cavity-enhanced spectroscopy. Analyst 2016; 141:5870-5878. [DOI: 10.1039/c6an01038e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The chemical amplification method is combined with the incoherent broadband cavity-enhanced absorption spectroscopy for peroxy radical measurements.
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Affiliation(s)
- Yang Chen
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
| | - Chengqiang Yang
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
| | - Weixiong Zhao
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
| | - Bo Fang
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
| | - Xuezhe Xu
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
| | - Yanbo Gai
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
| | - Xiaoxiao Lin
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
| | - Weidong Chen
- Laboratoire de Physicochimie de l'Atmosphère
- Université du Littoral Côte d'Opale
- 59140 Dunkerque
- France
| | - Weijun Zhang
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
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11
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Peltola J, Hieta T, Vainio M. Parts-per-trillion-level detection of nitrogen dioxide by cantilever-enhanced photo-acoustic spectroscopy. OPTICS LETTERS 2015; 40:2933-2936. [PMID: 26125335 DOI: 10.1364/ol.40.002933] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present a simple and highly sensitive cantilever-enhanced photo-acoustic sensor for detection of nitrogen dioxide. A noise equivalent detection limit of 50 parts-per-trillion in 1 s is demonstrated. The limit was reached with an average optical power of 4.7 W using a continuous-wave laser at 532 nm. The achieved normalized noise equivalent absorption coefficient was 2.6×10(-10) W cm(-1) Hz(-1/2).
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12
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13
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Li Z, Ma W, Fu X, Tan W, Zhao G, Dong L, Zhang L, Yin W, Jia S. Continuous-wave cavity ringdown spectroscopy based on the control of cavity reflection. OPTICS EXPRESS 2013; 21:17961-17971. [PMID: 23938668 DOI: 10.1364/oe.21.017961] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A new type of continuous-wave cavity ringdown spectrometer based on the control of cavity reflection for trace gas detection was designed and evaluated. The technique separated the acquisitions of the ringdown event and the trigger signal to optical switch by detecting the cavity reflection and transmission, respectively. A detailed description of the time sequence of the measurement process was presented. In order to avoid the wrong extraction of ringdown time encountered accidentally in fitting procedure, the laser frequency and cavity length were scanned synchronously. Based on the statistical analysis of measured ringdown times, the frequency normalized minimum detectable absorption in the reflection control mode was 1.7 × 10(-9)cm(-1)Hz(-1/2), which was 5.4 times smaller than that in the transmission control mode. However the signal-to-noise ratio of the absorption spectrum was only 3 times improved since the etalon effect existed. Finally, the peak absorption coefficients of the C(2)H(2) transition near 1530.9nm under different pressures showed a good agreement with the theoretical values.
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Affiliation(s)
- Zhixin Li
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Laser Spectroscopy Laboratory, Shanxi University, Taiyuan 030006, China
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14
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Pan H, Cheng CF, Sun YR, Gao B, Liu AW, Hu SM. Laser-locked, continuously tunable high resolution cavity ring-down spectrometer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:103110. [PMID: 22047283 DOI: 10.1063/1.3655445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A continuous-wave cavity ring-down spectrometer with sub-MHz precision has been built using the sideband of a frequency stabilized laser as the tunable light source. The sideband is produced by passing the carrier laser beam through an electro-optic modulator (EOM) and then selected by a short etalon on resonance. The carrier laser frequency is locked to a longitude mode of a thermo-stabilized Fabry-Perot interferometer (FPI) with a long-term absolute frequency stability of 0.2 MHz (5 × 10(-10)). Broad and precise spectral scanning is accomplished, respectively, by selecting a different longitudinal mode of the FPI and by tuning the radio-frequency driving the EOM. The air broadened water absorption line at 12,321 cm(-1) was studied to test the performance of the spectrometer.
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Affiliation(s)
- H Pan
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
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15
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Liao J, Sihler H, Huey LG, Neuman JA, Tanner DJ, Friess U, Platt U, Flocke FM, Orlando JJ, Shepson PB, Beine HJ, Weinheimer AJ, Sjostedt SJ, Nowak JB, Knapp DJ, Staebler RM, Zheng W, Sander R, Hall SR, Ullmann K. A comparison of Arctic BrO measurements by chemical ionization mass spectrometry and long path-differential optical absorption spectroscopy. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jd014788] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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Denzer W, Hancock G, Islam M, Langley CE, Peverall R, Ritchie GAD, Taylor D. Trace species detection in the near infrared using Fourier transform broadband cavity enhanced absorption spectroscopy: initial studies on potential breath analytes. Analyst 2011; 136:801-6. [DOI: 10.1039/c0an00462f] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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17
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Gao B, Jiang W, Liu AW, Lu Y, Cheng CF, Cheng GS, Hu SM. Ultrasensitive near-infrared cavity ring-down spectrometer for precise line profile measurement. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:043105. [PMID: 20441323 DOI: 10.1063/1.3385675] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A cavity ring-down (CRD) spectrometer is built with a continuous-wave Ti:sapphire ring laser. Using a pair of R approximately 0.999 95 high-reflective mirrors, the noise-equivalent minimum detectable absorption loss reaches 7 x 10(-11)/cm over the spectral range of 780-830 nm. A thermal-stabilized Fabry-Perot interferometer is applied to calibrate the CRD spectrum with an accuracy of 1 x 10(-4) cm(-1). The quantitative measurement is carried out for the line profile measurements of some overtone absorption lines of C(2)H(2) near 787 nm. Doppler determined line shape has been observed with milli-Torr acetylene gas in the ring-down cavity. The instrumental line width is estimated from the line profile fitting to be <1 x 10(-4) cm(-1). It demonstrates that the CRD spectrometer with extremely high sensitivity is also very suitable for quantitative measurements including precise line profile studies in the near-infrared.
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Affiliation(s)
- Bo Gao
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
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Paul D, Furgeson A, Osthoff HD. Measurements of total peroxy and alkyl nitrate abundances in laboratory-generated gas samples by thermal dissociation cavity ring-down spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2009; 80:114101. [PMID: 19947740 DOI: 10.1063/1.3258204] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A novel measurement technique, thermal dissociation cavity ring-down spectroscopy (TD-CRDS), for rapid (1 s time resolution) and sensitive (precision approximately 100 parts per trillion by volume (10(-12); pptv)) quantification of total peroxy nitrate (SigmaPN) and total alkyl nitrate (SigmaAN) abundances in laboratory-generated gas mixtures is described. The organic nitrates are dissociated in a heated inlet to produce NO(2), whose concentration is monitored by pulsed-laser CRDS at 532 nm. Mixing ratios are determined by difference relative to a cold inlet reference channel. Conversion of laboratory-generated mixtures of AN in zero air (at an inlet temperature of 450 degrees C) is quantitative over a wide range of mixing ratios (0-100 parts per billion by volume (10(-9), ppbv)), as judged from simultaneous measurements of NO(y) using a commercial NO-O(3) chemiluminescence monitor. Conversion of PN is quantitative up to about 4 ppbv (at an inlet temperature of 250 degrees C); at higher concentrations, the measurements are affected by recombination reactions of the dissociation products. The results imply that TD-CRDS can be used as a generic detector of dilute mixtures of organic nitrates in air at near-ambient concentration levels in laboratory experiments. Potential applications of the TD-CRDS technique in the laboratory are discussed.
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Affiliation(s)
- Dipayan Paul
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
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Liu Y, Morales-Cueto R, Hargrove J, Medina D, Zhang J. Measurements of peroxy radicals using chemical amplification-cavity ringdown spectroscopy. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:7791-7796. [PMID: 19921895 DOI: 10.1021/es901146t] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The peroxy radical chemical amplification (PERCA) method is combined with cavity ringdown spectroscopy(CRDS) to detect peroxy radicals (HO2 and RO2). In PERCA, HO2 and RO2 are first converted to NO2 via reactions with NO, and the OH and RO coproducts are recycled back to HO2 in subsequent reactions with CO and O2; the chain reactions of HO2 are repeated and amplify the level of NO2. The amplified NO2 is then monitored by CRDS, a sensitive absorption technique. The PERCA-CRDS method is calibrated using a HO2 radical source (0.5-3 ppbv), which is generated by thermal decomposition of H2O2 vapor (permeated from 2% H2O2 solution through a porous Teflon tubing) up to 600 degrees C. Using a 2-m long 6.35-mm o.d. Teflon tubing as the flow reactor and 2.5 ppmv NO and 2.5-10% vol/vol CO, the PERCA amplification factor or chain length, Delta[NO2]/([HO2]+[RO2]), is determined to be 150 +/- 50 (90% confidence limit) in this study. The peroxy radical detection sensitivity by PERCA-CRDS is estimated to be approximately 10 pptv/60 s (3sigma). Ambient measurements of the peroxy radicals are carried out at Riverside, California in 2007 to demonstrate the PERCA-CRDS technique.
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Affiliation(s)
- Yingdi Liu
- Department of Chemistry, University of California, Riverside, California 92521, USA
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Denzer W, Hamilton ML, Hancock G, Islam M, Langley CE, Peverall R, Ritchie GAD. Near-infrared broad-band cavity enhanced absorption spectroscopy using a superluminescent light emitting diode. Analyst 2009; 134:2220-3. [DOI: 10.1039/b916807a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Langridge JM, Ball SM, Shillings AJL, Jones RL. A broadband absorption spectrometer using light emitting diodes for ultrasensitive, in situ trace gas detection. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:123110. [PMID: 19123548 DOI: 10.1063/1.3046282] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A broadband absorption spectrometer has been developed for highly sensitive and target-selective in situ trace gas measurements. The instrument employs two distinct modes of operation: (i) broadband cavity enhanced absorption spectroscopy (BBCEAS) is used to quantify the concentration of gases in sample mixtures from their characteristic absorption features, and (ii) periodic measurements of the cavity mirrors' reflectivity are made using step-scan phase shift cavity ringdown spectroscopy (PSCRDS). The latter PSCRDS method provides a stand-alone alternative to the more usual method of determining mirror reflectivities by measuring BBCEAS absorption spectra for calibration samples of known composition. Moreover, the instrument's two modes of operation use light from the same light emitting diode transmitted through the cavity in the same optical alignment, hence minimizing the potential for systematic errors between mirror reflectivity determinations and concentration measurements. The ability of the instrument to quantify absorber concentrations is tested in instrument intercomparison exercises for NO(2) (versus a laser broadband cavity ringdown spectrometer) and for H(2)O (versus a commercial hygrometer). A method is also proposed for calculating effective absorption cross sections for fitting the differential structure in BBCEAS spectra due to strong, narrow absorption lines that are under-resolved and hence exhibit non-Beer-Lambert law behavior at the resolution of the BBCEAS measurements. This approach is tested on BBCEAS spectra of water vapor's 4v+delta absorption bands around 650 nm. The most immediate analytical application of the present instrument is in quantifying the concentration of reactive trace gases in the ambient atmosphere. The instrument's detection limits for NO(3) as a function of integration time are considered in detail using an Allan variance analysis. Experiments under laboratory conditions produce a 1sigma detection limit of 0.25 pptv for a 10 s acquisition time, which improves with further signal averaging to 0.09 pptv in 400 s. Finally, an example of the instrument's performance under field work conditions is presented, in this case of measurements of the sum of NO(3)+N(2)O(5) concentrations in the marine boundary layer acquired during the Reactive Halogens in the Marine Boundary Layer field campaign.
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Affiliation(s)
- Justin M Langridge
- Department of Chemistry, University Chemical Laboratory, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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Orphal J, Ruth AA. High-resolution Fourier-transform cavity-enhanced absorption spectroscopy in the near-infrared using an incoherent broad-band light source. OPTICS EXPRESS 2008; 16:19232-19243. [PMID: 19582015 DOI: 10.1364/oe.16.019232] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
An incoherent broad-band cavity-enhanced absorption (IBB-CEA) set-up was used in combination with a Fourier-transform (FT) spectrometer in order to explore the potential of this technique for high-resolution molecular spectroscopy in the near-infrared region. Absorption spectra of overtone bands of CO2, OCS, and HD18O were measured between 5800 and 7000 cm(-1) using a small sampling volume (1100 cm3, based on a 90 cm cavity length). The quality of the spectra in this study is comparable to that obtained with Fourier transform spectrometers employing standard multi-pass reflection cells, which require substantially larger sampling volumes. High-resolution methods such as FT-IBB-CEAS also provide an elegant way to determine effective mirror reflectivities (R(eff), i.e. a measure of the inherent overall cavity loss) by using a calibration gas with well-known line strengths. For narrow absorption features and non-congested spectra this approach does not even require a zero-absorption measurement with the empty cavity. Absolute cross-sections or line strengths of a target species can also be determined in one single measurement, if gas mixtures with known partial pressures are used. This feature of FT-IBB-CEAS reduces systematic errors significantly; it is illustrated based on CO2 as calibration gas.
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Affiliation(s)
- Johannes Orphal
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), Université de Paris-Est, CNRS UMR 7583, Créteil, France
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Kebabian PL, Wood EC, Herndon SC, Freedman A. A practical alternative to chemiluminescence-based detection of nitrogen dioxide: cavity attenuated phase shift spectroscopy. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:6040-5. [PMID: 18767663 DOI: 10.1021/es703204j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We present results obtained from a greatly improved version of a previously reported nitrogen dioxide monitor (Anal Chem. 2005, 77, 724-728) that utilizes cavity attenuated phase shift spectroscopy (CAPS). The sensor, which detects the optical absorption of nitrogen dioxide within a 20 nm bandpass centered at 440 nm, comprises a blue light emitting diode, an enclosed stainless steel measurement cell (26 cm length) incorporating a resonant optical cavity of near-confocal design and a vacuum photodiode detector. An analog heterodyne detection scheme is used to measure the phase shift in the waveform of the modulated light transmitted through the cell induced by the presence of nitrogen dioxide within the cell. The sensor, which operates at atmospheric pressure, fits into a 19 in.-rack-mounted instrumentation box, weighs 10 kg, and utilizes 70 W of electrical power with pump included. The sensor response to nitrogen dioxide (calculated as the cotangent of the phase shift) is demonstrated to be linear (r2 > 0.9999) within +/- 1 ppb over a range of 0-320 ppb (by volume). The device exhibits a detection limit (3sigma precision) of less than 60 parts per trillion (0.060 ppb) with 10 s integration, a value derived from measurements at NO2 concentration levels of both 0 and 20 ppb; the detection limit improves as the integration time is increased to several hundred seconds. The observed baseline drift is less than +/- 0.5 ppb overthe course of a month. An intercomparison of measurements of ambient NO2 concentrations over several days using this sensor with a quantum cascade laser-based infrared absorption spectrometer and a standard chemiluminescence-based NOx analyzer is presented. The data from the CAPS sensor are highly correlated (r2 > 0.99) with the other two instruments. The absolute agreement between the CAPS and each of the two other instruments is within the expected statistical noise associated with the infrared laser-based absorption spectrometer (+/- 0.3 ppb with 10 s sampling) and chemiluminescence analyzer (+/- 0.4 ppb with 60 s averaging). The major limitation concerning accuracy is a direct spectral interference with phototchemically produced 1,2-dicarbonyl species (e.g., glyoxal, methylglyoxal). However, this interference can be readily removed by shifting the detection band to a slightly longer wavelength and ensuring that the lower edge of the detection band is greater than 455 nm.
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Affiliation(s)
- Paul L Kebabian
- Center for Sensor Systems and Technology, Aerodyne Research, Inc., 45 Manning Road, Billerica, Massachusetts 01821-3976, USA
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Langridge JM, Laurila T, Watt RS, Jones RL, Kaminski CF, Hult J. Cavity enhanced absorption spectroscopy of multiple trace gas species using a supercontinuum radiation source. OPTICS EXPRESS 2008; 16:10178-10188. [PMID: 18607425 DOI: 10.1364/oe.16.010178] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Supercontinuum radiation sources are attractive for spectroscopic applications owing to their broad wavelength coverage, which enables spectral signatures of multiple species to be detected simultaneously. Here we report the first use of a supercontinuum radiation source for broadband trace gas detection using a cavity enhanced absorption technique. Spectra were recorded at bandwidths of up to 100 nm, encompassing multiple absorption bands of H(2)O, O(2) and O(2)-O(2). The same instrument was also used to make quantitative measurements of NO(2) and NO(3). For NO(3) a detection limit of 3 parts-per-trillion in 2 s was achieved, which corresponds to an effective 3sigma sensitivity of 2.4 x 10(-9) cm(-1)Hz(-1/2). Our results demonstrate that a conceptually simple and robust instrument is capable of highly sensitive broadband absorption measurements.
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Affiliation(s)
- J M Langridge
- Department of Chemistry, University of Cambridge, Lensfield Road,Cambridge CB2 1EW, UK
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Gherman T, Venables DS, Vaughan S, Orphal J, Ruth AA. Incoherent broadband cavity-enhanced absorption spectroscopy in the near-ultraviolet: application to HONO and NO2. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:890-895. [PMID: 18323118 DOI: 10.1021/es0716913] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The first application of incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) in the near-ultraviolet for the simultaneous detection of two key atmospheric trace species, HONO and NO2, is reported. For both compounds the absorption is measured between 360 and 380 nm with a compact cavity-enhanced spectrometer employing a high power light-emitting diode. Detection limits of approximately 4 ppbv for HONO and approximately 14 ppbv for NO2 are reported for a static gas cell setup using a 20 s acquisition time. Based on an acquisition time of 10 min and an optical cavity length of 4.5 m detection limits of approximately 0.13 ppbv and approximately 0.38 ppbv were found for HONO and NO2 in a 4 m3 atmospheric simulation chamber, demonstrating the usefulness of this approach for in situ monitoring of these important species in laboratory studies or field campaigns.
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Affiliation(s)
- Titus Gherman
- Department of Physics and Department of Chemistry, University College Cork, Cork, Ireland
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Fiedler SE, Hese A, Heitmann U. Influence of the cavity parameters on the output intensity in incoherent broadband cavity-enhanced absorption spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2007; 78:073104. [PMID: 17672752 DOI: 10.1063/1.2752608] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The incoherent broadband cavity-enhanced absorption spectroscopy is a technique in measuring small absorptions over a broad wavelength range. The setup consists of a conventional absorption spectrometer using an incoherent lamp and a charge coupled device detector, as well as a linear optical cavity placed around the absorbing sample, which enhances the effective path length through the sample. In this work the consequences of cavity length, mirror curvature, reflectivity, different light injection geometries, and spot size of the light source on the output intensity are studied and the implications to the signal-to-noise ratio of the absorption measurement are discussed. The symmetric confocal resonator configuration is identified as a special case with optimum imaging characteristics but with higher requirements for mechanical stability. Larger spot sizes of the light source were found to be favorable in order to reduce the negative effects of aberrations on the intensity.
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Affiliation(s)
- Sven E Fiedler
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany.
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28
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Islam M, Seetohul LN, Ali Z. Liquid-phase broadband cavity-enhanced absorption spectroscopy measurements in a 2 mm cuvette. APPLIED SPECTROSCOPY 2007; 61:649-58. [PMID: 17650378 DOI: 10.1366/000370207781269846] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A novel implementation of broadband cavity enhanced absorption spectroscopy (BBCEAS) has been used to perform sensitive visible wavelength measurements on liquid-phase solutions in a 2 mm cuvette placed at normal incidence to the cavity mirrors. The overall experimental methodology was simple, low cost, and similar to conventional ultraviolet-visible absorption spectroscopy. The cavity was formed by two concave high reflectivity mirrors. Three mirror sets with nominal reflectivities (R) of R = 0.99, 0.9945, and 0.999 were used. The light source consisted of a high intensity red, green, blue, or white LED. The detector was a compact charge-coupled device (CCD) spectrograph. Measurements were made on the representative analytes, Ho(3+), and the dyes brilliant blue-R, sudan black, and coumarin 334 in appropriate solvents. Cavity enhancement factors (CEF) of up to 104 passes for the high reflectivity mirrors were obtained. The number of passes was limited by relatively high scattering and absorption losses in the cavity, of approximately 1 x 10(-2) per pass. Measurements over a wide wavelength range (420-670 nm) were also obtained in a single experiment with the white LED and the R = 0.99 mirror set for Ho(3+) and sudan black. The sensitivity of the experimental setup could be determined by calculating the minimum detectable change in the absorption coefficient alpha(min). The values ranged from 5.1 x 10(-5) to 1.2 x 10(-3) cm(-1). The limit of detection (LOD) for the strong absorber brilliant blue-R was 620 pM. A linear dynamic range of measurements of concentration over about two orders of magnitude was demonstrated. The overall sensitivity of the experimental setup compared very favorably with previous generally more experimentally complex and expensive liquid-phase cavity studies. Possible improvements to the technique and its applicability as an analytical tool are discussed.
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Affiliation(s)
- Meez Islam
- School of Science and Technology, University of Teesside, Borough Road, Middlesbrough TS1 3BA.
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Taketani F, Kawai M, Takahashi K, Matsumi Y. Trace detection of atmospheric NO2 by laser-induced fluorescence using a GaN diode laser and a diode-pumped YAG laser. APPLIED OPTICS 2007; 46:907-15. [PMID: 17279136 DOI: 10.1364/ao.46.000907] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We report on the development of a highly sensitive detection system for measuring atmospheric NO(2) by means of a laser-induced fluorescence (LIF) technique at 473 nm using a diode-pumped Nd:YAG laser. A GaN-based laser diode emitting at 410 nm is also used as an alternative fluorescence-excitation source. For laboratory calibrations, standard NO(2) gas is diluted with synthetic air and is introduced into a fluorescence-detection cell. The NO(2) LIF signal is detected by a photomultiplier tube and processed by a photon-counting method. The minimum detectable limits of the NO(2) instrument developed have been estimated to be 0.14 ppbv and 0.39 ppbv (parts per billion, 10(-9), by volume) in 60 s integration time (signal-to-noise ratio of 2) for 473 and 410 nm excitation systems, respectively. Practical performance of the instrument has been demonstrated by the 24 hour continuous measurements of ambient NO(2) in a suburban area.
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Affiliation(s)
- Fumikazu Taketani
- Solar-Terrestrial Environment Laboratory, Graduate School of Science, Nagoya University, Honohara, Toyokawa, Aichi, Japan
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