scholarly journals Airborne observations of formic acid using a chemical ionisation mass spectrometer

2011 ◽  
Vol 4 (5) ◽  
pp. 5807-5835 ◽  
Author(s):  
M. Le Breton ◽  
M. R. McGillen ◽  
J. B. A. Muller ◽  
A. Bacak ◽  
D. E. Shallcross ◽  
...  
Keyword(s):  
Formic Acid ◽  
Mass Spectrometer ◽  
Limit Of Detection ◽  
Lower Boundary ◽  
Standard Addition ◽  
Airborne Measurements ◽  
Mixing Ratios ◽  
Chemical Ionisation ◽  
Ionisation Mass ◽  
Ionisation Mass Spectrometer

Abstract. The first airborne measurements of formic acid mixing ratios over the United Kingdom were measured on the FAAM BAe-146 research aircraft on the 16 March 2010 with a chemical ionisation mass spectrometer using I− reagent ions. The I− ionisation scheme was able to measure formic acid mixing ratios at 1 Hz in the lower boundary layer. In-flight standard addition calibrations from a formic acid source were used to determine the instrument sensitivity of 35±6 ion counts pptv−1 s−1 and a limit of detection of 25 pptv. Routine measurements were made through a scrubbed inlet to determine the instrumental background. Three plumes of formic acid were observed over the UK, originating from London, Humberside and Tyneside. The London plume had the highest formic acid mixing ratio throughout the flight, peaking at 358 pptv. No significant correlations of formic acid with NOx and Ozone were found. A trajectory model was employed to determine the sources of the plumes and compare modelled mixing ratios with measured values. The model underestimated formic acid concentrations by up to a factor of 2. This is explained by missing sources in the model, considered to be primary emissions of formic acid of mainly anthropogenic origin and lack of precursor emissions, such as isoprene, from biogenic sources.

scholarly journals Airborne observations of formic acid using a chemical ionization mass spectrometer

2012 ◽  
Vol 5 (12) ◽  
pp. 3029-3039 ◽  
Author(s):  
M. Le Breton ◽  
M. R. McGillen ◽  
J. B. A. Muller ◽  
A. Bacak ◽  
D. E. Shallcross ◽  
...  
Keyword(s):  
Formic Acid ◽  
Mass Spectrometer ◽  
Chemical Ionization ◽  
Limit Of Detection ◽  
Standard Addition ◽  
Ionization Mass ◽  
Airborne Measurements ◽  
Mixing Ratios ◽  
Primary Emissions ◽  
The Uk

Abstract. The first airborne measurements of formic acid mixing ratios over the United Kingdom were measured on the FAAM BAe-146 research aircraft on 16 March 2010 with a chemical ionization mass spectrometer using I− reagent ions. The I− ionization scheme was able to measure formic acid mixing ratios at 1 Hz in the boundary layer. In-flight standard addition calibrations from a formic acid source were used to determine the instrument sensitivity of 35 ± 6 ion counts pptv−1 s−1 and a limit of detection of 25 pptv. Routine measurements were made through a scrubbed inlet to determine the instrumental background. Three plumes of formic acid were observed over the UK, originating from London, Humberside and Tyneside. The London plume had the highest formic acid mixing ratio throughout the flight, peaking at 358 pptv. No significant correlations of formic acid with NOx and ozone were found, but a positive correlation was observed between CO and HCOOH within the two plumes where coincident data were recorded. A trajectory model was employed to determine the sources of the plumes and compare modelled mixing ratios with measured values. The model underestimated formic acid concentrations by up to a factor of 2. This is explained by missing sources in the model, which were considered to be both primary emissions of formic acid of mainly anthropogenic origin and a lack of precursor emissions, such as isoprene, from biogenic sources, whose oxidation in situ would lead to formic acid formation.

scholarly journals Airborne hydrogen cyanide measurements using a chemical ionisation mass spectrometer for the plume identification of biomass burning forest fires

2013 ◽  
Vol 13 (2) ◽  
pp. 5649-5685 ◽  
Author(s):  
M. Le Breton ◽  
A. Bacak ◽  
J. B. A. Muller ◽  
S. J. O'Shea ◽  
P. Xiao ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Biomass Burning ◽  
Forest Fires ◽  
Hydrogen Cyanide ◽  
Global Emission ◽  
Highly Sensitive ◽  
Research Aircraft ◽  
Chemical Ionisation ◽  
Ionisation Mass ◽  
Ionisation Mass Spectrometer

Abstract. A Chemical Ionisation Mass Spectrometer (CIMS) was developed for measuring hydrogen cyanide (HCN) from biomass burning events in Canada using I− reagent ions on board the FAAM BAe-146 research aircraft during the BORTAS campaign in 2011. The ionisation scheme enabled highly sensitive measurements at 1 Hz frequency through biomass burning plumes in the troposphere. A strong correlation between the HCN, carbon monoxide (CO) and acetonitrile (CH3CN) was observed, indicating the potential of HCN as a biomass burning (BB) marker. A plume was defined as being 6 standard deviations above background for the flights. This method was compared with a number of alternative plume defining techniques employing CO and CH3CN measurements. The 6 sigma technique produced the highest R2 values for correlations with CO. A Normalised Excess Mixing Ratio (NEMR) of 3.76 ± 0.022 pptv ppbv−1 was calculated which is within the range quoted in previous research (Hornbrook et al., 2011). The global tropospheric model STOCHEM-CRI incorporated both the observed ratio and extreme ratios derived from other studies to generate global emission totals of HCN via biomass burning. Using the ratio derived from this work the emission total for HCN from BB was 0.92 Tg (N) yr−1.

scholarly journals Airborne hydrogen cyanide measurements using a chemical ionisation mass spectrometer for the plume identification of biomass burning forest fires

2013 ◽  
Vol 13 (18) ◽  
pp. 9217-9232 ◽  
Author(s):  
M. Le Breton ◽  
A. Bacak ◽  
J. B. A. Muller ◽  
S. J. O'Shea ◽  
P. Xiao ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Biomass Burning ◽  
Forest Fires ◽  
Hydrogen Cyanide ◽  
Global Emission ◽  
Highly Sensitive ◽  
Research Aircraft ◽  
Chemical Ionisation ◽  
Ionisation Mass ◽  
Ionisation Mass Spectrometer

Abstract. A chemical ionisation mass spectrometer (CIMS) was developed for measuring hydrogen cyanide (HCN) from biomass burning events in Canada using I− reagent ions on board the FAAM BAe-146 research aircraft during the BORTAS campaign in 2011. The ionisation scheme enabled highly sensitive measurements at 1 Hz frequency through biomass burning plumes in the troposphere. A strong correlation between the HCN, carbon monoxide (CO) and acetonitrile (CH3CN) was observed, indicating the potential of HCN as a biomass burning (BB) marker. A plume was defined as being 6 standard deviations above background for the flights. This method was compared with a number of alternative plume-defining techniques employing CO and CH3CN measurements. The 6-sigma technique produced the highest R2 values for correlations with CO. A normalised excess mixing ratio (NEMR) of 3.68 ± 0.149 pptv ppbv−1 was calculated, which is within the range quoted in previous research (Hornbrook et al., 2011). The global tropospheric model STOCHEM-CRI incorporated both the observed ratio and extreme ratios derived from other studies to generate global emission totals of HCN via biomass burning. Using the ratio derived from this work, the emission total for HCN from BB was 0.92 Tg (N) yr−1.

Improved detection sensitivity for heavy trace elements using a miniature laser ablation ionisation mass spectrometer

2017 ◽  
Vol 32 (11) ◽  
pp. 2182-2188 ◽  
Author(s):  
R. Wiesendanger ◽  
M. Tulej ◽  
A. Riedo ◽  
S. Frey ◽  
H. Shea ◽  
...  
Keyword(s):  
Trace Elements ◽  
Laser Ablation ◽  
Mass Spectrometer ◽  
Detection Sensitivity ◽  
Laser Spectrometer ◽  
Lunar Meteorite ◽  
Ionisation Mass ◽  
Ionisation Mass Spectrometer

Detecting heavy trace elements with a miniature laser spectrometer on a lunar meteorite.

scholarly journals Measurements of hydroperoxy radicals (HO<sub>2</sub>) at atmospheric concentrations using bromide chemical ionisation mass spectrometry

2019 ◽  
Vol 12 (2) ◽  
pp. 891-902 ◽  
Author(s):  
Sascha R. Albrecht ◽  
Anna Novelli ◽  
Andreas Hofzumahaus ◽  
Sungah Kang ◽  
Yare Baker ◽  
...  
Keyword(s):  
Water Vapour ◽  
Mass Spectrometer ◽  
Ion Source ◽  
Detection Sensitivity ◽  
Detection Methods ◽  
Integration Time ◽  
Key Species ◽  
Atmospheric Concentrations ◽  
Chemical Ionisation ◽  
Ionisation Mass

Abstract. Hydroxyl and hydroperoxy radicals are key species for the understanding of atmospheric oxidation processes. Their measurement is challenging due to their high reactivity; therefore, very sensitive detection methods are needed. Within this study, the measurement of hydroperoxy radicals (HO2) using chemical ionisation combined with a high-resolution time-of-flight mass spectrometer (Aerodyne Research Inc.) employing bromide as the primary ion is presented. The sensitivity reached is equal to 0.005×108 HO2 cm−3 for 106 cps of bromide and 60 s of integration time, which is below typical HO2 concentrations found in the atmosphere. The detection sensitivity of the instrument is affected by the presence of water vapour. Therefore, a water-vapour-dependent calibration factor that decreases approximately by a factor of 2 if the water vapour mixing ratio increases from 0.1 % to 1.0 % needs to be applied. An instrumental background, most likely generated by the ion source that is equivalent to a HO2 concentration of (1.5±0.2)×108 molecules cm−3, is subtracted to derive atmospheric HO2 concentrations. This background can be determined by overflowing the inlet with zero air. Several experiments were performed in the atmospheric simulation chamber SAPHIR at the Forschungszentrum Jülich to test the instrument performance in comparison to the well-established laser-induced fluorescence (LIF) technique for measurements of HO2. A highly linear correlation coefficient of R2=0.87 is achieved. The slope of the linear regression of 1.07 demonstrates the good absolute agreement of both measurements. Chemical conditions during experiments allowed for testing the instrument's behaviour in the presence of atmospheric concentrations of H2O, NOx, and O3. No significant interferences from these species were observed. All of these facts demonstrate a reliable measurement of HO2 by the chemical ionisation mass spectrometer presented.

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.

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