Chemical Ionization Mass Spectrometer Instrument for the Measurement of Tropospheric HO2and RO2

2003 ◽  
Vol 75 (20) ◽  
pp. 5317-5327 ◽  
Author(s):  
Gavin D. Edwards ◽  
Christopher A. Cantrell ◽  
Sherry Stephens ◽  
Brian Hill ◽  
Olusegun Goyea ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Chemical Ionization ◽  
Ionization Mass

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

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

<p>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.</p>

scholarly journals Using collision-induced dissociation to constrain sensitivity of ammonia chemical ionization mass spectrometry (NH<sub>4</sub><sup>+</sup> CIMS) to oxygenated volatile organic compounds

2019 ◽  
Vol 12 (3) ◽  
pp. 1861-1870 ◽  
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.

Isobutane Chemical Ionization Mass Spectrographic Examination of Explosives

1975 ◽  
Vol 58 (4) ◽  
pp. 734-742 ◽  
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.

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

2006 ◽  
Vol 23 (8) ◽  
pp. 1104-1113 ◽  
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.

scholarly journals Rapid Analysis of PCB in Insulating Oil by Gas Chromatography/Negative Ion Chemical Ionization Mass Spectrometer

2003 ◽  
Vol 13 (4) ◽  
pp. 959-971 ◽  
Author(s):  
Yasuto MACHII ◽  
Osamu KUMAZAKI ◽  
Kenji MIZUNO ◽  
Mitsugu NAGANO ◽  
Yoshio HAYASAKA ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Mass Spectrometer ◽  
Chemical Ionization ◽  
Rapid Analysis ◽  
Negative Ion ◽  
Ionization Mass ◽  
Insulating Oil ◽  
Negative Ion Chemical Ionization

Calibration of a Chemical Ionization Mass Spectrometer for the Measurement of Gaseous Sulfuric Acid

2012 ◽  
Vol 116 (24) ◽  
pp. 6375-6386 ◽  
Author(s):  
Andreas Kürten ◽  
Linda Rondo ◽  
Sebastian Ehrhart ◽  
Joachim Curtius
Keyword(s):  
Sulfuric Acid ◽  
Mass Spectrometer ◽  
Chemical Ionization ◽  
Ionization Mass

scholarly journals Size Resolved Online Chemical Analysis of Nano Aerosol Particles: A Thermal Desorption Differential Mobility Analyzer Coupled to a Chemical Ionization Time Of Flight Mass Spectrometer

2018 ◽  
Author(s):  
Andrea C. Wagner ◽  
Anton Bergen ◽  
Sophia Brilke ◽  
Claudia Fuchs ◽  
Markus Ernst ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Mass Spectrometer ◽  
Thermal Desorption ◽  
Chemical Ionization ◽  
Aerosol Particles ◽  
Transmission Efficiency ◽  
Test Substance ◽  
Ionization Mass ◽  
Differential Mobility Analyzer ◽  
Differential Mobility

Abstract. A new method for size resolved chemical analysis of nucleation mode aerosol particles (size range from ~ 10 to ~ 30 nm) is presented. The Thermal Desorption Differential Mobility Analyzer (TD-DMA) uses an online, discontinuous principle. The particles are charged, a specific size is selected by differential mobility analysis and they are collected on a filament by electrostatic precipitation. Subsequently, the sampled mass is evaporated in a clean carrier gas and analyzed by a chemical ionization mass spectrometer. Gas phase measurements are performed with the same mass spectrometer during the sampling of particles. The characterization shows reproducible results, with a particle size resolution of 1.19 and the transmission efficiency for 15 nm particles being slightly above 50 %. The signal from the evaporation of a test substance can be detected starting from 0.01 ng and shows a linear response in the mass spectrometer. Instrument operation in the range of pg/m3 is demonstrated by an example measurement of 15 nm particles produced by nucleation from dimethylamine, sulfuric acid and water.

scholarly journals Chemical ionization mass spectrometer (CIMS) for ambient measurements of ammonia

2010 ◽  
Vol 3 (2) ◽  
pp. 1133-1162 ◽  
Author(s):  
D. R. Benson ◽  
M. Al-Refai ◽  
S.-H. Lee
Keyword(s):  
Mass Spectrometer ◽  
Chemical Ionization ◽  
Fast Response ◽  
Ionization Mass ◽  
Experimental Conditions ◽  
Molecule Reaction ◽  
Mixing Ratios ◽  
Ambient Nh3 ◽  
Ambient Measurements

Abstract. This study describes a chemical ionization mass spectrometer (CIMS) for fast response, in-situ measurements for gas phase ammonia. Protonated ethanol ions were used as the ion-molecule reaction reagent. The CIMS sensitivity was estimated to be between 4–25 Hz/pptv with 30% uncertainty. The instrument background was below 1 ppbv and at lowest was 300 pptv. The uncertainty associated with the instrumental background was less than 30 pptv under the optimized experimental conditions. The time response was less than 30 s, and the detection limit was approximately 60 pptv. This CIMS was used to measure the ambient NH3 in Kent, Ohio, for several weeks throughout three seasons. The measured ammonia mixing ratios were usually at the sub-ppbv level, and higher during the spring (200±120 pptv) than in the winter (60±75 pptv) and fall (150±80 pptv).

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