In Situ Monitoring of the Unsaturated Phospholipid Monolayer Oxidation in Ambient Air by HD-SFG Spectroscopy

2020 ◽  
Vol 124 (25) ◽  
pp. 5246-5250
Author(s):  
Ken-ichi Inoue ◽  
Chunji Takada ◽  
Lin Wang ◽  
Akihiro Morita ◽  
Shen Ye
Keyword(s):  
Ambient Air ◽  
In Situ Monitoring ◽  
Phospholipid Monolayer

scholarly journals A versatile, refrigerant- and cryogen-free cryofocusing–thermodesorption unit for preconcentration of traces gases in air

2016 ◽  
Vol 9 (11) ◽  
pp. 5265-5279 ◽  
Author(s):  
Florian Obersteiner ◽  
Harald Bönisch ◽  
Timo Keber ◽  
Simon O'Doherty ◽  
Andreas Engel
Keyword(s):  
Rapid Heating ◽  
Ambient Air ◽  
In Situ Monitoring ◽  
Gas Chromatography Mass Spectrometry ◽  
Research Station ◽  
Vacuum Insulation ◽  
Laboratory Operation ◽  
And Performance ◽  
Set Up

Abstract. We present a compact and versatile cryofocusing–thermodesorption unit, which we developed for quantitative analysis of halogenated trace gases in ambient air. Possible applications include aircraft-based in situ measurements, in situ monitoring and laboratory operation for the analysis of flask samples. Analytes are trapped on adsorptive material cooled by a Stirling cooler to low temperatures (e.g. −80 °C) and subsequently desorbed by rapid heating of the adsorptive material (e.g. +200 °C). The set-up involves neither the exchange of adsorption tubes nor any further condensation or refocusing steps. No moving parts are used that would require vacuum insulation. This allows for a simple and robust design. Reliable operation is ensured by the Stirling cooler, which neither contains a liquid refrigerant nor requires refilling a cryogen. At the same time, it allows for significantly lower adsorption temperatures compared to commonly used Peltier elements. We use gas chromatography – mass spectrometry (GC–MS) for separation and detection of the preconcentrated analytes after splitless injection. A substance boiling point range of approximately −80 to +150 °C and a substance mixing ratio range of less than 1 ppt (pmol mol−1) to more than 500 ppt in preconcentrated sample volumes of 0.1 to 10 L of ambient air is covered, depending on the application and its analytical demands. We present the instrumental design of the preconcentration unit and demonstrate capabilities and performance through the examination of analyte breakthrough during adsorption, repeatability of desorption and analyte residues in blank tests. Examples of application are taken from the analysis of flask samples collected at Mace Head Atmospheric Research Station in Ireland using our laboratory GC–MS instruments and by data obtained during a research flight with our in situ aircraft instrument GhOST-MS (Gas chromatograph for the Observation of Tracers – coupled with a Mass Spectrometer).

scholarly journals Evaluation of a cavity ring-down spectrometer for in situ observations of <sup>13</sup>CO<sub>2</sub>

2013 ◽  
Vol 6 (2) ◽  
pp. 301-308 ◽  
Author(s):  
F. R. Vogel ◽  
L. Huang ◽  
D. Ernst ◽  
L. Giroux ◽  
S. Racki ◽  
...  
Keyword(s):  
Co2 Concentration ◽  
Ambient Air ◽  
In Situ Monitoring ◽  
Wide Spread ◽  
Isotope Ratio Mass Spectrometer ◽  
In Situ Observations ◽  
One Year ◽  
Cavity Ring Down

Abstract. With the emergence of wide-spread application of new optical techniques to monitor δ13C in atmospheric CO2 there is a growing need to ensure well-calibrated measurements. We characterized one commonly available instrument, a cavity ring-down spectrometer (CRDS) system used for continuous in situ monitoring of atmospheric 13CO2. We found no dependency of δ13C on the CO2 concentration in the range of 303–437 ppm. We designed a calibration scheme according to the diagnosed instrumental drifts and established a quality assurance protocol. We find that the repeatability (1-σ) of measurements is 0.25‰ for 10 min and 0.15‰ for 20 min integrated averages, respectively. Due to a spectral overlap, our instrument displays a cross-sensitivity to CH4 of 0.42 ± 0.024‰ ppm−1. Our ongoing target measurements yield standard deviations of δ13C from 0.22‰ to 0.28‰ for 10 min averages. We furthermore estimate the reproducibility of our system for ambient air samples from weekly measurements of a long-term target gas to be 0.18‰. We find only a minuscule offset of 0.002 ± 0.025‰ between the CRDS and Environment Canada's isotope ratio mass spectrometer (IRMS) results for four target gases used over the course of one year.

scholarly journals Evaluation of a cavity ring-down spectrometer for in-situ observations of <sup>13</sup>CO<sub>2</sub>

2012 ◽  
Vol 5 (4) ◽  
pp. 6037-6058 ◽  
Author(s):  
F. R. Vogel ◽  
L. Huang ◽  
D. Ernst ◽  
L. Giroux ◽  
S. Racki ◽  
...  
Keyword(s):  
Ambient Air ◽  
In Situ Monitoring ◽  
Concentration Dependency ◽  
Isotope Ratio Mass Spectrometer ◽  
In Situ Observations ◽  
One Year ◽  
Spectrometer System ◽  
Cavity Ring Down

Abstract. With the emergence of wide-spread application of cavity ring-down spectrometers (CRDS) to monitor δ13C in atmospheric CO2 there is a growing need to ensure well calibrated measurements. We characterized a cavity ring-down spectrometer system used for continuous in-situ monitoring of atmospheric 13CO2. We found no concentration dependency of the δ13C ratio within the range of 303–437 ppm. We designed a calibration scheme according to the diagnosed instrumental drifts and established a quality assurance protocol. We find that the repeatability of 10 min measurements is 0.25‰ and 0.15‰ for 20 min integrated averages. We found the cross-sensitivity to C4 in the samples to be 0.42 ± 0.02‰ ppm−1. Our ongoing target measurements yield standard deviations of 0.26–0.28‰ for 10 min averages. We furthermore estimate the reproducibility of the system for ambient air samples from weekly measurements of a long-term target gas to be 0.18‰. We find only a miniscule offset of 0.002 ± 0.025‰ of the CRDS and Environment Canada's isotope ratio mass spectrometer (IRMS) results for four target gases used over the course of one year.

scholarly journals A versatile, refrigerant-free cryofocusing-thermodesorption unit for preconcentration of traces gases in air

2016 ◽  
Author(s):  
F. Obersteiner ◽  
H. Bönisch ◽  
T. Keber ◽  
S. O'Doherty ◽  
A. Engel
Keyword(s):  
Rapid Heating ◽  
Ambient Air ◽  
In Situ Monitoring ◽  
Gas Chromatography Mass Spectrometry ◽  
Research Station ◽  
Stage Design ◽  
Vacuum Insulation ◽  
Laboratory Operation ◽  
And Performance

Abstract. We present a compact and versatile cryofocusing thermodesorption unit, which we developed for quantitative analysis of halogenated trace gases in ambient air. Possible applications include aircraft-based in-situ measurements, in situ monitoring and laboratory operation for the preconcentration of analytes from flask samples. Analytes are trapped on adsorptive material cooled by a Stirling cooler to low temperatures (e.g. −80 °C) and desorbed subsequently by rapid heating of the adsorptive material (e.g. +200 °C). The setup neither involves exchange of adsorption tubes nor any further condensation or refocusation steps. No moving parts are used that would require vacuum insulation. This allows a simple and robust single stage design. Reliable operation is ensured by the Stirling cooler, which does not require refilling of a liquid refrigerant while allowing significantly lower adsorption temperatures compared to commonly used Peltier elements. We use gas chromatography mass spectrometry for separation and detection of the preconcentrated analytes after splitless injection. A substance boiling point range of approximately −80 °C to +150 °C and a substance mixing ratio range of less than 1 ppt (pmol mol−1) to more than 500 ppt in preconcentrated sample volumes of 0.1 to 10 L of ambient air is covered, depending on the application and its analytical demands. We present the instrumental design of the preconcentration unit and demonstrate capabilities and performance through the examination of injection quality, analyte breakthrough and analyte residues in blank tests. Application examples are given by the analysis of flask samples collected at Mace Head Atmospheric Research Station in Ireland using our laboratory GC TOFMS instrument and by data obtained during a research flight with our in-situ aircraft instrument GhOST MS.

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