Fast time response measurements of HNO3in air with a chemical ionization mass spectrometer

Abstract. We report on the development, characterization, and field deployment of a fast time response sensor for measuring ozone (O3) and nitrogen dioxide (NO2) concentrations utilizing chemical ionization time-of-flight mass spectrometry (CI-ToFMS) with oxygen anion (O2−) reagent ion chemistry. We demonstrate that the oxygen anion chemical ionization mass spectrometer (Ox-CIMS) is highly sensitive to both O3 (180 ions s−1 pptv−1 pptv−1) and NO2 (97 ions s−1 pptv−1), corresponding to detection limits (3σ, 1 s averages) of 13 and 9.9 pptv, respectively. In both cases, the detection threshold is limited by the magnitude and variability in the background determination. The short-term precision (1 s averages) is better than 0.3% at 10 ppbv O3 and 4% at 10 pptv NO2. We demonstrate that the sensitivity of the O3 measurement to fluctuations in ambient water vapor and carbon dioxide is negligible for typical conditions encountered in the troposphere. The application of the Ox-CIMS to the measurement of O3 vertical fluxes over the coastal ocean, via eddy covariance (EC), was tested during summer 2018 at Scripps Pier, La Jolla CA. The observed mean ozone deposition velocity (vd(O3)) was 0.011 cm s−1 pptv−1 with a campaign ensemble limit of detection (LOD) of 0.0042 cm s−1 pptv−1 at the 95% confidence level, from each 27-minute sampling period LOD. The campaign mean and one standard deviation range of O3 mixing ratios were 38.9 ± 12.3 ppbv. Several fast ozone titration events from local NO emissions were sampled where unit conversion of O3 to NO2 was observed, highlighting instrument utility as a total odd oxygen (Ox = O3 + NO2) sensor. The demonstrated precision, sensitivity, and time resolution of this instrument highlight its potential for direct measurements of O3 ocean–atmosphere and biosphere–atmosphere exchange from both stationary and mobile sampling platforms.

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Simultaneous detection of ozone and nitrogen dioxide by oxygen anion chemical ionization mass spectrometry: a fast-time-response sensor suitable for eddy covariance measurements

Atmospheric Measurement Techniques ◽

10.5194/amt-13-1887-2020 ◽

2020 ◽

Vol 13 (4) ◽

pp. 1887-1907 ◽

Cited By ~ 3

Author(s):

Gordon A. Novak ◽

Michael P. Vermeuel ◽

Timothy H. Bertram

Keyword(s):

Mass Spectrometry ◽

Nitrogen Dioxide ◽

Eddy Covariance ◽

Chemical Ionization ◽

Limit Of Detection ◽

Deposition Velocity ◽

Time Response ◽

Ionization Mass ◽

Fast Time ◽

Oxygen Anion

Abstract. We report on the development, characterization, and field deployment of a fast-time-response sensor for measuring ozone (O3) and nitrogen dioxide (NO2) concentrations utilizing chemical ionization time-of-flight mass spectrometry (CI-ToFMS) with oxygen anion (O2-) reagent ion chemistry. We demonstrate that the oxygen anion chemical ionization mass spectrometer (Ox-CIMS) is highly sensitive to both O3 (180 counts s−1 pptv−1) and NO2 (97 counts s−1 pptv−1), corresponding to detection limits (3σ, 1 s averages) of 13 and 9.9 pptv, respectively. In both cases, the detection threshold is limited by the magnitude and variability in the background determination. The short-term precision (1 s averages) is better than 0.3 % at 10 ppbv O3 and 4 % at 10 pptv NO2. We demonstrate that the sensitivity of the O3 measurement to fluctuations in ambient water vapor and carbon dioxide is negligible for typical conditions encountered in the troposphere. The application of the Ox-CIMS to the measurement of O3 vertical fluxes over the coastal ocean, via eddy covariance (EC), was tested during the summer of 2018 at Scripps Pier, La Jolla, CA. The observed mean ozone deposition velocity (vd(O3)) was 0.013 cm s−1 with a campaign ensemble limit of detection (LOD) of 0.0027 cm s−1 at the 95 % confidence level, from each 27 min sampling period LOD. The campaign mean and 1 standard deviation range of O3 mixing ratios was 41.2±10.1 ppbv. Several fast ozone titration events from local NO emissions were sampled where unit conversion of O3 to NO2 was observed, highlighting instrument utility as a total odd-oxygen (Ox=O3+NO2) sensor. The demonstrated precision, sensitivity, and time resolution of this instrument highlight its potential for direct measurements of O3 ocean–atmosphere and biosphere–atmosphere exchange from both stationary and mobile sampling platforms.

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Composition of ultrafine particles in urban Beijing: Measurement using a thermal desorption chemical ionization mass spectrometer

10.5194/egusphere-egu21-11971 ◽

2021 ◽

Author(s):

Xiaoxiao Li ◽

Yuyang Li ◽

Michael Lawler ◽

Jiming Hao ◽

James Smith ◽

...

Keyword(s):

Mass Spectrometer ◽

Thermal Desorption ◽

Ultrafine Particles ◽

Chemical Ionization ◽

Urban Atmosphere ◽

Ionization Mass ◽

Radioactive Materials ◽

Desorption Chemical Ionization ◽

Wide Range ◽

Primary Emissions

Ultrafine particles (UFPs) dominate the particle number population in the urban atmosphere and revealing their chemical composition is important. The thermal desorption chemical ionization mass spectrometer (TDCIMS) can semi-continuously measure UFP composition at the molecular level. We modified a TDCIMS and deployed it in urban Beijing. Radioactive materials in the TDCIMS for aerosol charging and chemical ionization were replaced by soft X-ray ionizers so that it can be operated in countries with tight regulations on radioactive materials. Protonated N-methyl-2-pyrrolidone ions were used as the positive reagent ion, which selectively detects ammonia and low-molecular weight-aliphatic amines and amides vaporized from the particle phase. With superoxide as the negative reagent ion, a wide range of inorganic and organic compounds were observed, including nitrate, sulfate, aliphatic acids with carbon numbers up to 18, and highly oxygenated CHO, CHON, and CHOS compounds. The latter two can be attributed to parent ions or the decomposition products of organonitrates and organosulfates/organosulfonates, respectively. Components from both primary emissions and secondary formation of UFPs were identified. Compared to the UFPs measured at forest and marine sites, those in urban Beijing contain more nitrogen-containing and sulfur-containing compounds. These observations illustrate unique features of the UFPs in this polluted urban environment and provide insights into their origins.

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Using collision-induced dissociation to constrain sensitivity of ammonia chemical ionization mass spectrometry (NH4+ CIMS) to oxygenated volatile organic compounds

Atmospheric Measurement Techniques ◽

10.5194/amt-12-1861-2019 ◽

2019 ◽

Vol 12 (3) ◽

pp. 1861-1870 ◽

Cited By ~ 7

Author(s):

Alexander Zaytsev ◽

Martin Breitenlechner ◽

Abigail R. Koss ◽

Christopher Y. Lim ◽

James C. Rowe ◽

...

Keyword(s):

Mass Spectrometry ◽

Volatile Organic Compounds ◽

Organic Compounds ◽

Mass Spectrometer ◽

Chemical Ionization ◽

Chemical Ionization Mass Spectrometry ◽

Collision Induced Dissociation ◽

Ionization Mass ◽

Oxygenated Volatile Organic Compounds ◽

Volatile Organic

Abstract. Chemical ionization mass spectrometry (CIMS) instruments routinely detect hundreds of oxidized organic compounds in the atmosphere. A major limitation of these instruments is the uncertainty in their sensitivity to many of the detected ions. We describe the development of a new high-resolution time-of-flight chemical ionization mass spectrometer that operates in one of two ionization modes: using either ammonium ion ligand-switching reactions such as for NH4+ CIMS or proton transfer reactions such as for proton-transfer-reaction mass spectrometer (PTR-MS). Switching between the modes can be done within 2 min. The NH4+ CIMS mode of the new instrument has sensitivities of up to 67 000 dcps ppbv−1 (duty-cycle-corrected ion counts per second per part per billion by volume) and detection limits between 1 and 60 pptv at 2σ for a 1 s integration time for numerous oxygenated volatile organic compounds. We present a mass spectrometric voltage scanning procedure based on collision-induced dissociation that allows us to determine the stability of ammonium-organic ions detected by the NH4+ CIMS instrument. Using this procedure, we can effectively constrain the sensitivity of the ammonia chemical ionization mass spectrometer to a wide range of detected oxidized volatile organic compounds for which no calibration standards exist. We demonstrate the application of this procedure by quantifying the composition of secondary organic aerosols in a series of laboratory experiments.

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Isobutane Chemical Ionization Mass Spectrographic Examination of Explosives

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/58.4.734 ◽

1975 ◽

Vol 58 (4) ◽

pp. 734-742 ◽

Cited By ~ 1

Author(s):

Richard Saferstein ◽

Jew-Ming Chao ◽

John J Manura

Keyword(s):

Mass Spectrometer ◽

Mass Spectra ◽

Thermal Instability ◽

Chemical Ionization ◽

High Sensitivity ◽

Gas Pressure ◽

Ionization Mass ◽

Pentaerythritol Tetranitrate ◽

Residue Detection ◽

Acetone Extracts

Abstract The detection of explosive residues in debris is difficult because of the thermal instability of many explosives along with the high sensitivity requirements of the analyses. The isobutane chemical ionization (CI) mass spectra of common civilian and military explosives were obtained under different instrumental parameters. The intent of the study was to determine the feasibility of applying CI to residue detection. The CI spectra of the explosives 1,3,5-trinitro-1,3,5-triazocydohexane, 1,3,5,7-tetraazocyclooctane, and pentaerythritol tetranitrate were shown to be particularly sensitive to the conditions of source temperature and reagent gas pressure. These parameters were adjusted to yield the least complex CI spectra for the explosives studied. The simplicity of the CI spectra obtained makes it a feasible technique for detecting explosive residues in the presence of extraneous materials found in the acetone extracts of debris material. Placement of the extract into the direct probe of the CI mass spectrometer eliminates the need for prior chromatographic treatment of the extract and would optimize the high sensitivity of the CI technique.

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A Chemical Ionization Mass Spectrometer for Ground-Based Measurements of Nitric Acid

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech1900.1 ◽

2006 ◽

Vol 23 (8) ◽

pp. 1104-1113 ◽

Cited By ~ 9

Author(s):

Kazuyuki Kita ◽

Yu Morino ◽

Yutaka Kondo ◽

Yuichi Komazaki ◽

Nobuyuki Takegawa ◽

...

Keyword(s):

Nitric Acid ◽

Mass Spectrometer ◽

Chemical Ionization ◽

Limit Of Detection ◽

Field Tests ◽

Background Level ◽

Ionization Mass ◽

Mixing Ratios ◽

Free Air ◽

Diffusion Scrubber

Abstract A chemical ionization mass spectrometer (CIMS) instrument has been developed for high-precision measurements of gaseous nitric acid (HNO3) specifically under high- and variable-humidity conditions in the boundary layer. The instrument’s background signals (i.e., signals detected when HNO3-free air is measured), which depend on the humidity and HNO3 concentration of the sample air, are the most important factor affecting the limit of detection (LOD). A new system to provide HNO3-free air without changing both the humidity and the pressure of the sampled air was developed to measure the background level accurately. The detection limit was about 23 parts per trillion by volume (pptv) for 50-s averages. Field tests, including an intercomparison with the diffusion scrubber technique, were carried out at a surface site in Tokyo, Japan, in October 2003 and June 2004. A comparison between the measured concentrations of HNO3 and particulate nitrate indicated that the interference from particulate nitrate was not detectable (i.e., less than about 1%). The intercomparison indicated that the two independent measurements of HNO3 agreed to within the combined uncertainties of these measurements. This result demonstrates that the CIMS instrument developed in this study is capable of measuring HNO3 mixing ratios with the precision, accuracy, and time resolution required for atmospheric science.

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