scholarly journals Quantification of Non-refractory Aerosol Nitrate in Ambient Air by Thermal Dissociation Cavity Ring-Down Spectroscopy

2020 ◽  
Vol 54 (16) ◽  
pp. 9854-9861
Author(s):  
Natasha M. Garner ◽  
Laura C. Matchett ◽  
Hans D. Osthoff
Keyword(s):  
Thermal Dissociation ◽  
Ambient Air ◽  
Cavity Ring Down Spectroscopy ◽  
Cavity Ring Down

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 A compact, high-purity source of HONO validated by Fourier transform infrared and thermal-dissociation cavity ring-down spectroscopy

2020 ◽  
Vol 13 (8) ◽  
pp. 4159-4167 ◽  
Author(s):  
Nicholas J. Gingerysty ◽  
Hans D. Osthoff
Keyword(s):  
Fourier Transform ◽  
Thermal Dissociation ◽  
Fourier Transform Infrared ◽  
Ambient Air ◽  
Cavity Ring Down Spectroscopy ◽  
Mixing Ratios ◽  
Gas Streams ◽  
Ambient Air Measurements ◽  
By Products ◽  
Cavity Ring Down

Abstract. A well-characterized source of nitrous acid vapour (HONO) is essential for accurate ambient air measurements by instruments requiring external calibration. In this work, a compact HONO source is described in which gas streams containing dilute concentrations of HONO are generated by flowing hydrochloric acid (HCl) vapour emanating from a permeation tube over continuously agitated dry sodium nitrite (NaNO2) heated to 50 ∘C. Mixing ratios of HONO and potential by-products including NO, NO2, and nitrosyl chloride (ClNO) were quantified by Fourier transform infrared (FTIR) and thermal-dissociation cavity ring-down spectroscopy (TD-CRDS). A key parameter is the concentration of HCl, which needs to be kept small (<4 ppmv) to avoid ClNO formation. The source produces gas streams containing HONO in air in >95 % purity relative to other nitrogen oxides. The source output is rapidly tuneable and stabilizes within 90 min. Combined with its small size and portability, this source is highly suitable for calibration of HONO instruments in the field.

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

2014 ◽  
Vol 7 (10) ◽  
pp. 3263-3283 ◽  
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 ◽  
Molecular Formula ◽  
Response Factors ◽  
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 (PAN-GC) coupled to electron capture detection. Calibration of a PAN-GC remains a challenge, because the response factors 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 response factors 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. The PAN-GC limits of detection for PAN, PPN, and MPAN during FOSSILS were 1, 2, and 3 pptv, respectively. 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 A compact, high-purity source of HONO validated by Fourier Transform Infrared and Thermal Dissociation Cavity Ring-down Spectroscopy

2020 ◽  
Author(s):  
Nicholas J. Gingerysty ◽  
Hans D. Osthoff
Keyword(s):  
Fourier Transform ◽  
Thermal Dissociation ◽  
Fourier Transform Infrared ◽  
Ambient Air ◽  
Cavity Ring Down Spectroscopy ◽  
Mixing Ratios ◽  
Gas Streams ◽  
Ambient Air Measurements ◽  
By Products ◽  
Cavity Ring Down

Abstract. A well-characterized source of nitrous acid vapour (HONO) is essential for accurate ambient air measurements by instruments requiring external calibration. In this work, a compact HONO source is described in which gas streams containing dilute concentrations of HONO are generated by flowing hydrochloric acid (HCl) vapour emanating from a permeation tube over continuously agitated dry sodium nitrite (NaNO2) heated to 50 ºC. Mixing ratios of HONO and potential by-products including NO, NO2 and nitrosyl chloride (ClNO) were quantified by Fourier Transform Infrared (FTIR) and thermal dissociation cavity ring-down spectroscopy (TD-CRDS). A key parameter is the concentration of HCl, which needs to be kept small ( 97 % purity relative to other nitrogen oxides. The source output is rapidly tuneable and stabilizes within 90 min. Combined with its small size and portability this source is highly suitable for calibration of HONO instruments in the field.

scholarly journals Impact of ozone and inlet design on the detection of isoprene-derived organic nitrates by thermal dissociation cavity ring-down spectroscopy (TD-CRDS)

2021 ◽  
Author(s):  
Patrick Dewald ◽  
Raphael Dörich ◽  
Jan Schuladen ◽  
Jos Lelieveld ◽  
John N. Crowley
Keyword(s):  
Thermal Dissociation ◽  
Volume Ratio ◽  
Reaction Chamber ◽  
Organic Nitrates ◽  
Temperature Dependent ◽  
Alkyl Nitrates ◽  
Cavity Ring Down Spectroscopy ◽  
Viable Solution ◽  
Peroxy Nitrates ◽  
Cavity Ring Down

Abstract. We present measurements of isoprene-derived organic nitrates (ISOP-NITs) generated in the reaction of isoprene with the nitrate radical (NO3) in a 1 m3 Teflon reaction chamber. Detection of ISOP-NITs is achieved via their thermal dissociation to nitrogen dioxide (NO2), which is monitored by cavity ring-down spectroscopy (TD-CRDS). Using thermal dissociation inlets (TDIs) made of quartz, the temperature-dependent dissociation profiles (thermograms) of ISOP-NITs measured in the presence of ozone (O3) are broad (350 to 700 K), which contrasts the narrower profiles previously observed for e.g. isopropyl nitrate (iPN) or peroxy acetyl nitrate (PAN) under the same conditions. The shape of the thermograms varied with the TDI’s surface to volume ratio and with material of the inlet walls, providing clear evidence that ozone and quartz surfaces catalyse the dissociation of unsaturated organic nitrates leading to formation of NO2 at temperatures well below 475 K, impeding the separate detection of alkyl nitrates (ANs) and peroxy nitrates (PNs). We present a simple, viable solution to this problem and discuss the potential for interference by the thermolysis of nitric acid (HNO3), nitrous acid (HONO) and O3.

Trace detection of C2H2 in ambient air using continuous wave cavity ring-down spectroscopy combined with sample pre-concentration

2007 ◽  
Vol 90 (1) ◽  
pp. 1-9 ◽  
Author(s):  
M. Pradhan ◽  
R.E. Lindley ◽  
R. Grilli ◽  
I.R. White ◽  
D. Martin ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Ambient Air ◽  
Trace Detection ◽  
Cavity Ring Down Spectroscopy ◽  
Cavity Ring Down

scholarly journals A cavity ring-down spectroscopy sensor for measurements of gaseous elemental mercury – Part 1: Development for high time resolution measurements in ambient air

2012 ◽  
Vol 5 (6) ◽  
pp. 8995-9020
Author(s):  
A. Pierce ◽  
D. Obrist ◽  
H. Moosmüller ◽  
X. Faïn ◽  
C. Moore
Keyword(s):  
Time Resolution ◽  
Frequency Conversion ◽  
Elemental Mercury ◽  
Ambient Air ◽  
High Time ◽  
High Time Resolution ◽  
Concentration Data ◽  
Cavity Ring Down Spectroscopy ◽  
Gaseous Elemental Mercury ◽  
Cavity Ring Down

Abstract. The ability to make high time resolution measurements of gaseous elemental mercury (GEM) concentrations in air is imperative for the understanding of mercury cycling. Here we describe further development and field implementation of a laboratory prototype pulsed cavity ring-down spectroscopy (CRDS) system for high time resolution, continuous and automated measurement of GEM concentrations in ambient air. In particular, we present use of an external, isotopically enriched Hg cell for automated wavelength locking and wavelength stabilization to maintain laser wavelength on the peak of GEM absorption line in ambient air. We further describe implementation of differential absorption measurements using a piezoelectric tuning element that allows for continuous accounting of system baseline extinction losses needed to calculate GEM absorption coefficients. Data acquisition systems and software programs were modified to acquire high-speed ring-down data at 50 Hz repetition rate as well as process and analyze data in real time. The system was installed in a mobile trailer, and inlet systems and temperature controls were designed to minimize effects of changes in ambient air temperature and ozone (O3) concentration. Data that identify technical challenges and interferences that occurred during measurements, including temperature fluctuations, interferences by ambient O3 and drifts in frequency conversion efficiencies are discussed. Successful development of a CRDS system capable of measuring ambient air GEM concentrations with high time resolution is based on minimizing these interferences.

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