First atmospheric observations of three chlorofluorocarbons

Laube, Johannes C.; Engel, Andreas

doi:10.5194/acpd-8-6683-2008

Cited by 4 publications

(4 citation statements)

References 10 publications

(3 reference statements)

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“…2. The GC QP MS system was characterised and used before for studies by Laube and Engel (2008);Brinckmann et al (2012) and showed consistent results in the international comparison IHALACE (International Halocarbons in Air Comparison Experiment) with the NOAA (National Oceanic and Atmospheric Administration) network (Hall et al, 2013). We discuss the use of TOF MS in atmospheric trace gas measurements, in particular for the detection and quantification of halocarbons, focusing on four substances: CFC-11, CFC-12, Halon-1211 and Iodomethane.…”

Section: J Hoker Et Al: Comparison Of Gc/time-of-flight Ms With Gc/mentioning

confidence: 98%

Comparison of GC/time-of-flight MS with GC/quadrupole MS for halocarbon trace gas analysis

et al. 2015

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Abstract. We present the application of time-of-flight mass spectrometry (TOF MS) for the analysis of halocarbons in the atmosphere after cryogenic sample preconcentration and gas chromatographic separation. For the described field of application, the quadrupole mass spectrometer (QP MS) is a state-of-the-art detector. This work aims at comparing two commercially available instruments, a QP MS and a TOF MS, with respect to mass resolution, mass accuracy, stability of the mass axis and instrument sensitivity, detector sensitivity, measurement precision and detector linearity. Both mass spectrometers are operated on the same gas chromatographic system by splitting the column effluent to both detectors. The QP MS had to be operated in optimised single ion monitoring (SIM) mode to achieve a sensitivity which could compete with the TOF MS. The TOF MS provided full mass range information in any acquired mass spectrum without losing sensitivity. Whilst the QP MS showed the performance already achieved in earlier tests, the sensitivity of the TOF MS was on average higher than that of the QP MS in the "operational" SIM mode by a factor of up to 3, reaching detection limits of less than 0.2 pg. Measurement precision determined for the whole analytical system was up to 0.2 % depending on substance and sampled volume. The TOF MS instrument used for this study displayed significant non-linearities of up to 10 % for two-thirds of all analysed substances.

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Section: J Hoker Et Al: Comparison Of Gc/time-of-flight Ms With Gc/mentioning

confidence: 98%

Comparison of GC/time-of-flight MS with GC/quadrupole MS for halocarbon trace gas analysis

et al. 2015

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“…The corrected relative sensitivity is then given by the relative sensitivity divided by the fragmentation factor. The methodology is derived and explained in more detail in [26]. To test the validity of this approach, we tested the predictability of mixing ratios for two other recently-calibrated CFC isomer pairs: CFC-112/CFC-112a and CFC-113/CFC-113a [25].…”

Section: Calibrationmentioning

confidence: 99%

Atmospheric Abundances, Trends and Emissions of CFC-216ba, CFC-216ca and HCFC-225ca

et al. 2014

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Abstract:The first observations of the feedstocks, CFC-216ba (1,2-dichlorohexafluoropropane) and , as well as the CFC substitute HCFC-225ca (3,3-dichloro-1,1,1,2,2-pentafluoropropane), are reported in air samples collected between 1978 and 2012 at Cape Grim, Tasmania. Present day (2012) mixing ratios are 37.8 ± 0.08 ppq (parts per quadrillion; 10 15 ) and 20.2 ± 0.3 ppq for CFC-216ba and CFC-216ca, respectively. The abundance of CFC-216ba has been approximately constant for the past 20 years, whilst that of CFC-216ca is increasing, at a current rate of 0.2 ppq/year. Upper tropospheric air samples collected in 2013 suggest a further continuation of this trend. Inferred annual emissions peaked

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“…For quality assurance of the laboratory instrumentation, five air samples were analysed and compared to our reference GC-QPMS (gas chromatograph coupled to a quadrupole mass spectrometer) which uses a similar preconcentration setup (Hoker et al, 2015). Consistent results with the NOAA network (National Oceanic and Atmospheric Administration) were demonstrated for the GC-QPMS in the past during the IHALACE intercomparison (Hall et al, 2014), however with a different sample preconcentration using liquid nitrogen (Brinckmann et al, 2012;Laube and Engel, 2008;Laube et al, 2010). The current laboratory setup using the Stirling cooler-based preconcentration has been described by Hoker et al (2015) and has shown very consistent results with previous measurements.…”

Section: Laboratory Operation: Flask Sample Measurementsmentioning

confidence: 86%

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

Obersteiner

Bönisch²,

Keber

et al. 2016

Preprint

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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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First atmospheric observations of three chlorofluorocarbons

Cited by 4 publications

References 10 publications

Comparison of GC/time-of-flight MS with GC/quadrupole MS for halocarbon trace gas analysis

Comparison of GC/time-of-flight MS with GC/quadrupole MS for halocarbon trace gas analysis

Atmospheric Abundances, Trends and Emissions of CFC-216ba, CFC-216ca and HCFC-225ca

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

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