scholarly journals Validation of a new cavity ring-down spectrometer for measuring tropospheric gaseous hydrogen chloride

2021 ◽  
Author(s):  
Teles C. Furlani ◽  
Patrick R. Veres ◽  
Kathryn E. R. Dawe ◽  
J. Andrew Neuman ◽  
Steven S. Brown ◽  
...  
Keyword(s):  
Response Time ◽  
Hydrogen Chloride ◽  
Limit Of Detection ◽  
Optical Cavity ◽  
Ambient Air ◽  
Detection Methods ◽  
Ambient Atmosphere ◽  
Integration Interval ◽  
Mixing Ratios ◽  
Cavity Ring Down

Abstract. Reliable, sensitive, and widely available hydrogen chloride (HCl) measurements are important for understanding oxidation in many regions of the troposphere. We configured a commercial HCl cavity ring-down spectrometer (CRDS) for sampling HCl in the ambient atmosphere and developed calibration and validation techniques to characterize the measurement uncertainties. The CRDS makes fast, sensitive, and robust measurements of HCl in a high finesse optical cavity coupled to a laser centered at 5739 cm−1. The accuracy was determined to reside between 5–10 %, calculated from laboratory calibrations and an ambient air intercomparison with annular denuders. The precision and limit of detection (3σ) in the 0.5 Hz measurement were below 6 pptv and 18 pptv, respectively for a 30 second integration interval in zero air. The response time of this method is primarily characterized by fitting decay curves to a double exponential equation and is impacted by inlet adsorption/desorption, with these surface effects increasing with RH and decreasing with decreasing HCl mixing ratios. The response time for the tested inlet was 2–6 minutes under the most and least optimal conditions, respectively. An intercomparison with the EPA compendium method for quantification of acidic atmospheric gases showed good agreement, yielding a linear relationship statistically equivalent to unity (slope of 0.97 ± 0.15). The CRDS from this study can detect HCl at atmospherically relevant mixing ratios, often performing comparable or better in sensitivity, selectivity, and response-time from previously reported HCl detection methods.

scholarly journals Validation of a new cavity ring-down spectrometer for measuring tropospheric gaseous hydrogen chloride

2021 ◽  
Vol 14 (8) ◽  
pp. 5859-5871
Author(s):  
Teles C. Furlani ◽  
Patrick R. Veres ◽  
Kathryn E. R. Dawe ◽  
J. Andrew Neuman ◽  
Steven S. Brown ◽  
...  
Keyword(s):  
Response Time ◽  
Hydrogen Chloride ◽  
Limit Of Detection ◽  
Optical Cavity ◽  
Ambient Air ◽  
Detection Methods ◽  
Ambient Atmosphere ◽  
Integration Interval ◽  
Mixing Ratios ◽  
Cavity Ring Down

Abstract. Reliable, sensitive, and widely available hydrogen chloride (HCl) measurements are important for understanding oxidation in many regions of the troposphere. We configured a commercial HCl cavity ring-down spectrometer (CRDS) for sampling HCl in the ambient atmosphere and developed validation techniques to characterize the measurement uncertainties. The CRDS makes fast, sensitive, and robust measurements of HCl in a high-finesse optical cavity coupled to a laser centred at 5739 cm−1. The accuracy was determined to reside between 5 %–10 %, calculated from laboratory and ambient air intercomparisons with annular denuders. The precision and limit of detection (3σ) in the 0.5 Hz measurement were below 6 and 18 pptv, respectively, for a 30 s integration interval in zero air. The response time of this method is primarily characterized by fitting decay curves to a double exponential equation and is impacted by inlet adsorption/desorption, with these surface effects increasing with relative humidity and decreasing with decreasing HCl mixing ratios. The minimum 90 % response time was 10 s and the equilibrated response time for the tested inlet was 2–6 min under the most and least optimal conditions, respectively. An intercomparison with the EPA compendium method for quantification of acidic atmospheric gases showed good agreement, yielding a linear relationship statistically equivalent to unity (slope of 0.97 ± 0.15). The CRDS from this study can detect HCl at atmospherically relevant mixing ratios, often performing comparably or better in sensitivity, selectivity, and response time than previously reported HCl detection methods.

scholarly journals Cavity ring-down spectroscopy sensor for detection of hydrogen chloride

2013 ◽  
Vol 6 (4) ◽  
pp. 7217-7250
Author(s):  
C. L. Hagen ◽  
B. C. Lee ◽  
I. S. Franka ◽  
J. L. Rath ◽  
T. C. VandenBoer ◽  
...  
Keyword(s):  
Hydrogen Chloride ◽  
Near Infrared ◽  
Limit Of Detection ◽  
Optical Cavity ◽  
High Specificity ◽  
Ionization Mass ◽  
Cavity Ring Down Spectroscopy ◽  
Mist Chamber ◽  
Hcl Concentration ◽  
Cavity Ring Down

Abstract. A laser-based cavity ring-down spectroscopy (CRDS) sensor for measurement of hydrogen chloride (HCl) has been developed and characterized. The instrument uses light from a distributed-feedback diode laser at 1742 nm coupled to a high finesse optical cavity to make sensitive and quantifiable concentration measurements of HCl based on optical absorption. The instrument has a (1σ) limit of detection of < 20 pptv in 1 min and has high specificity to HCl. The measurement response time to changes in input HCl concentration is < 15 s. Validation studies with a previously calibrated permeation tube setup show an accuracy of better than 10%. The CRDS sensor was preliminarily tested in the field with two other HCl instruments (mist chamber and chemical ionization mass spectrometry), all of which were in broad agreement. The mist chamber and CRDS sensors both showed a 400 pptv plume within 50 pptv agreement. The sensor also allows simultaneous sensitive measurements of water and methane, and minimal hardware modification would allow detection of other near-infrared absorbers.

scholarly journals Cavity ring-down spectroscopy sensor for detection of hydrogen chloride

2014 ◽  
Vol 7 (2) ◽  
pp. 345-357 ◽  
Author(s):  
C. L. Hagen ◽  
B. C. Lee ◽  
I. S. Franka ◽  
J. L. Rath ◽  
T. C. VandenBoer ◽  
...  
Keyword(s):  
Hydrogen Chloride ◽  
Near Infrared ◽  
Limit Of Detection ◽  
Optical Cavity ◽  
High Specificity ◽  
Ionization Mass ◽  
Cavity Ring Down Spectroscopy ◽  
Mist Chamber ◽  
Hcl Concentration ◽  
Cavity Ring Down

Abstract. A laser-based cavity ring-down spectroscopy (CRDS) sensor for measurement of hydrogen chloride (HCl) has been developed and characterized. The instrument uses light from a distributed-feedback diode laser at 1742 nm coupled to a high finesse optical cavity to make sensitive and quantifiable concentration measurements of HCl based on optical absorption. The instrument has a (1σ) limit of detection of <20 pptv in 1 min and has high specificity to HCl. The measurement response time to changes in input HCl concentration is <15 s. Validation studies with a previously calibrated permeation tube setup show an accuracy of better than 10%. The CRDS sensor was preliminarily tested in the field with two other HCl instruments (mist chamber and chemical ionization mass spectrometry), all of which were in broad agreement. The mist chamber and CRDS sensors both showed a 400 pptv plume within 50 pptv agreement. The sensor also allows simultaneous sensitive measurements of water and methane, and minimal hardware modification would allow detection of other near-infrared absorbers.

scholarly journals A Dual-Laser Sensor Based on Off-Axis Integrated Cavity Output Spectroscopy and Time-Division Multiplexing Method

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6192
Author(s):  
Kunyang Wang ◽  
Ligang Shao ◽  
Jiajin Chen ◽  
Guishi Wang ◽  
Kun Liu ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Moving Average ◽  
Optical Cavity ◽  
Ambient Air ◽  
Laser Sensor ◽  
Time Division Multiplexing ◽  
Dual Channel ◽  
Cavity Output ◽  
Time Division ◽  
Dual Laser

In this article, a compact dual-laser sensor based on an off-axis integrated-cavity output spectroscopy and time-division multiplexing method is reported. A complete dual-channel optical structure is developed and integrated on an optical cavity, which allows two distributed feedback (DFB) lasers operating at wavelengths of 1603 nm and 1651 nm to measure the concentration of CO2 and CH4, simultaneously. Performances of the dual-laser sensor are experimentally evaluated by using standard air (with a mixture of CO2 and CH4). The limit of detection (LoD) is 0.271 ppm and 1.743 ppb at a 20 s for CO2 and CH4, respectively, and the noise equivalent absorption sensitivities are 2.68 × 10−10 cm−1 Hz−1/2 and 3.88 × 10−10 cm−1 Hz−1/2, respectively. Together with a commercial instrument, the dual-laser sensor is used to measure CO2 and CH4 concentration over 120 h and verify the regular operation of the sensor for the detection of ambient air. Furthermore, a first-order exponential moving average algorithm is implemented as an effective digital filtering method to estimate the gas concentration.

scholarly journals A new laser-based and ultra-portable gas sensor for indoor and outdoor formaldehyde (HCHO) monitoring

2019 ◽  
Vol 12 (11) ◽  
pp. 6079-6089 ◽  
Author(s):  
Joshua D. Shutter ◽  
Norton T. Allen ◽  
Thomas F. Hanisco ◽  
Glenn M. Wolfe ◽  
Jason M. St. Clair ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Limit Of Detection ◽  
Nonlinear Least Squares ◽  
Ambient Air ◽  
Post Processing ◽  
Absorption Data ◽  
Mixing Ratios ◽  
Outdoor Environments ◽  
Indoor And Outdoor Environments ◽  
Indoor And Outdoor

Abstract. In this work, a new commercially available, laser-based, and ultra-portable formaldehyde (HCHO) gas sensor is characterized, and its usefulness for monitoring HCHO mixing ratios in both indoor and outdoor environments is assessed. Stepped calibrations and intercomparison with well-established laser-induced fluorescence (LIF) instrumentation allow a performance evaluation of the absorption-based, mid-infrared HCHO sensor from Aeris Technologies, Inc. The Aeris sensor displays linear behavior (R2 > 0.940) when compared with LIF instruments from Harvard and NASA Goddard. A nonlinear least-squares fitting algorithm developed independently of the sensor's manufacturer to fit the sensor's raw absorption data during post-processing further improves instrument performance. The 3σ limit of detection (LOD) for 2, 15, and 60 min integration times are 2190, 690, and 420 pptv HCHO, respectively, for mixing ratios reported in real time, though the LOD improves to 1800, 570, and 300 pptv HCHO, respectively, during post-processing. Moreover, the accuracy of the sensor was found to be ± (10 % + 0.3) ppbv when compared against LIF instrumentation sampling ambient air. The aforementioned precision and level of accuracy are sufficient for most HCHO levels measured in indoor and outdoor environments. While the compact Aeris sensor is currently not a replacement for the most sensitive research-grade instrumentation available, its usefulness for monitoring HCHO is clearly demonstrated.

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.

scholarly journals Calibration and intercomparison of acetic acid measurements using proton-transfer-reaction mass spectrometry (PTR-MS)

2012 ◽  
Vol 5 (11) ◽  
pp. 2739-2750 ◽  
Author(s):  
K. B. Haase ◽  
W. C. Keene ◽  
A. A. P. Pszenny ◽  
H. R. Mayne ◽  
R. W. Talbot ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Acetic Acid ◽  
Proton Transfer ◽  
Transfer Reaction ◽  
Ambient Air ◽  
Proton Transfer Reaction ◽  
Reaction Mass ◽  
Ambient Atmosphere ◽  
Paired Data ◽  
Mixing Ratios

Abstract. Acetic acid is one of the most abundant organic acids in the ambient atmosphere, with maximum mixing ratios reaching into the tens of parts per billion by volume (ppbv) range. The identities and associated magnitudes of the major sources and sinks for acetic acid are poorly characterized, due in part to the limitations of available measurement techniques. This paper demonstrates that, when properly calibrated, proton-transfer-reaction mass spectrometry (PTR-MS) can be a valuable technique for fast response, accurate quantification of acetic acid in ambient air. Three different PTR-MS configurations were calibrated at low ppbv mixing ratios using permeation tubes, which yielded calibration factors between 7.0 and 10.9 normalized counts per second per ppbv (ncps ppbv−1) at a drift tube field strength of 132 Townsend (Td). Detection limits ranged from 0.06 to 0.32 ppbv with dwell times of 5 s. These calibration factors showed negligible humidity dependence. Acetic acid was measured with PTR-MS on Appledore B Island, ME, during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) campaign and validated based on acetic acid measured in parallel using tandem mist chambers coupled with ion chromatography (MC/IC). Mixing ratios ranged from a minimum of 0.075 ± 0.004 ppbv to 3.555 ± 0.171 ppbv, with a median mixing ratio of 0.530 ± 0.025 ppbv. An orthogonal least squares linear regression of paired data yielded a slope of 1.14 ± 0.06 (2σ), an intercept of 0.049 ± 0.020 (2σ) ppbv, and an R2 of 0.78.

scholarly journals A gas chromatograph for quantification of peroxycarboxylic nitric anhydrides calibrated by thermal dissociation cavity ring-down spectroscopy

2014 ◽  
Vol 7 (6) ◽  
pp. 5953-6019
Author(s):  
T. W. Tokarek ◽  
J. A. Huo ◽  
C. A. Odame-Ankrah ◽  
D. Hammoud ◽  
Y. M. Taha ◽  
...  
Keyword(s):  
Thermal Dissociation ◽  
Ambient Air ◽  
Calibration Method ◽  
Ionization Mass ◽  
Molecular Formula ◽  
Data Set ◽  
Cavity Ring Down Spectroscopy ◽  
Mixing Ratios ◽  
Advantages And Disadvantages ◽  
Cavity Ring Down

Abstract. The peroxycarboxylic nitric anhydrides (PANs, molecular formula RC(O)O2NO2) can readily be observed by gas chromatography coupled to electron capture detection (PAN-GC). Calibration of a PAN-GC remains a challenge because the response factors (RF's) differ for each of the PANs and because their synthesis in sufficiently high purity is non-trivial, in particular for PANs containing unsaturated side chains. In this manuscript, a PAN-GC and its calibration using diffusion standards, whose output was quantified by blue diode laser thermal dissociation cavity ring-down spectroscopy (TD-CRDS), are described. The PAN-GC peak areas correlated linearly with total peroxy nitrate (ΣPN) mixing ratios measured by TD-CRDS (r > 0.96). Accurate determination of RF's required the concentrations of PAN impurities in the synthetic standards to be subtracted from ΣPN. The PAN-GC and its TD-CRDS calibration method were deployed during ambient air measurement campaigns in Abbotsford, BC, from 20 July to 5 August, 2012, and during the Fort McMurray Oil Sands Strategic Investigation of Local Sources (FOSSILS) campaign at the AMS13 ground site in Fort McKay, AB, from 10 August to 5 September 2013. For the Abbotsford data set, the PAN-GC mixing ratios were compared and agreed with those determined in parallel by thermal dissociation chemical ionization mass spectrometry (TD-CIMS). Advantages and disadvantages of the PAN measurement techniques used in this work and the utility of TD-CRDS as a PAN-GC calibration method are discussed.

scholarly journals Comparison of formaldehyde measurements by Hantzsch, CRDS and DOAS in the SAPHIR chamber

2021 ◽  
Vol 14 (6) ◽  
pp. 4239-4253
Author(s):  
Marvin Glowania ◽  
Franz Rohrer ◽  
Hans-Peter Dorn ◽  
Andreas Hofzumahaus ◽  
Frank Holland ◽  
...  
Keyword(s):  
Water Vapour ◽  
Organic Compounds ◽  
Limit Of Detection ◽  
Linear Regression Analysis ◽  
Ambient Air ◽  
Optical Absorption Spectroscopy ◽  
Fluorescence Measurement ◽  
Good Precision ◽  
Mixing Ratio ◽  
Mixing Ratios

Abstract. Three instruments that use different techniques to measure gaseous formaldehyde (HCHO) concentrations were compared in experiments in the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich. One instrument (AL4021, Aero-Laser GmbH) detects HCHO using the wet-chemical Hantzsch reaction (for efficient gas-phase stripping), chemical conversion and fluorescence measurement. An internal HCHO permeation source allows for daily calibrations. This instrument was characterized by sulfuric acid titration (overall accuracy 8.6 %) and yields measurements with a time resolution of 90 s and a limit of detection (3σ) of 0.3 ppbv. In addition, a new commercial instrument that makes use of cavity ring-down spectroscopy (CRDS) determined the concentrations of HCHO, water vapour, and methane (G2307, Picarro, Inc.). Its limit of detection (3σ) is specified as 0.3 ppbv for an integration time of 300 s, and its accuracy is limited by the drift of the zero signal (manufacturer specification 1.5 ppbv). A custom-built high-resolution laser differential optical absorption spectroscopy (DOAS) instrument provided HCHO measurements with a limit of detection (3σ) of 0.9 ppbv and an accuracy of 7 %​​​​​​​ using an optical multiple reflection cell. The measurements were conducted from June to December 2019 in experiments in which either ambient air flowed through the chamber or the photochemical degradation of organic compounds in synthetic air was investigated. Measured HCHO concentrations were up to 8 ppbv. Various mixtures of organic compounds, water vapour, nitrogen oxides and ozone were present in these experiments. Results demonstrate the need to correct the baseline in measurements performed by the Hantzsch instrument to compensate for drifting background signals. Corrections were equivalent to HCHO mixing ratios in the range of 0.5–1.5 ppbv. The baseline of the CRDS instrument showed a linear dependence on the water vapour mixing ratio with a slope of (-11.20±1.60) ppbv %−1 below and (-0.72±0.08) ppbv %−1 above a water vapour mixing ratio of 0.2 %. In addition, the intercepts of these linear relationships drifted within the specification of the instrument (1.5 ppbv) over time but appeared to be equal for all water mixing ratios. Regular zero measurements are needed to account for the changes in the instrument zero. After correcting for the baselines of measurements by the Hantzsch and the CRDS instruments, linear regression analysis of measurements from all three instruments in experiments with ambient air indicated good agreement, with slopes of between 0.98 and 1.08 and negligible intercepts (linear correlation coefficients R2>0.96). The new small CRDS instrument measures HCHO with good precision and is accurate if the instrument zero is taken into account. Therefore, it can provide measurements with similar accuracy to the DOAS instrument but with slightly reduced precision compared to the Hantzsch instrument.

Sign in / Sign up

Export Citation Format

Share Document