Chemical ionisation mass spectrometer for measurements of OH and Peroxy radical concentrations in moderately polluted atmospheres

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.

Download Full-text

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

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-5649-2013 ◽

2013 ◽

Vol 13 (2) ◽

pp. 5649-5685 ◽

Cited By ~ 2

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.

Download Full-text

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-13-9217-2013 ◽

2013 ◽

Vol 13 (18) ◽

pp. 9217-9232 ◽

Cited By ~ 40

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.

Download Full-text

Importance of direct anthropogenic emissions of formic acid measured by a chemical ionisation mass spectrometer (CIMS) during the Winter ClearfLo Campaign in London, January 2012

Atmospheric Environment ◽

10.1016/j.atmosenv.2013.10.029 ◽

2014 ◽

Vol 83 ◽

pp. 301-310 ◽

Cited By ~ 29

Author(s):

Thomas J. Bannan ◽

Asan Bacak ◽

Jennifer B.A. Muller ◽

A. Murray Booth ◽

Benjamin Jones ◽

...

Keyword(s):

Formic Acid ◽

Mass Spectrometer ◽

Anthropogenic Emissions ◽

Chemical Ionisation ◽

Ionisation Mass ◽

Ionisation Mass Spectrometer

Download Full-text

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

Journal of Analytical Atomic Spectrometry ◽

10.1039/c7ja00193b ◽

2017 ◽

Vol 32 (11) ◽

pp. 2182-2188 ◽

Cited By ~ 9

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.

Download Full-text

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

Atmospheric Measurement Techniques ◽

10.5194/amt-12-891-2019 ◽

2019 ◽

Vol 12 (2) ◽

pp. 891-902 ◽

Cited By ~ 4

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.

Download Full-text