First atmospheric observations of three chlorofluorocarbons

Laube, Johannes C.; Engel, Andreas

doi:10.5194/acp-8-5143-2008

Cited by 8 publications

(4 citation statements)

References 11 publications

(6 reference statements)

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“…To ensure internal consistency of our laboratory instrumentation, five air samples were analysed with the GC-TOFMS instrument (Obersteiner et al, 2016) and compared to our reference GC-QPMS (gas chromatograph coupled to a quadrupole mass spectrometer) which uses a similar preconcentration set-up (Hoker et al, 2015). Consistent results with the NOAA network (National Oceanic and Atmospheric Administration) have been demonstrated for the GC-QPMS in the past during the international halocarbons in air comparison experiment (IHALACE; Hall et al, 2014) intercomparison (Hall et al, 2014), but with a different sample preconcentration using liquid nitrogen (Brinckmann et al, 2012;Laube and Engel, 2008;Laube et al, 2010). The current laboratory set-up 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: 77%

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

Obersteiner

Bönisch²,

Keber

et al. 2016

Atmos. Meas. Tech.

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We present a compact and versatile cryofocusingthermodesorption 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 Tracerscoupled with a Mass Spectrometer).

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Section: Laboratory Operation: Flask Sample Measurementsmentioning

confidence: 77%

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

Obersteiner

Bönisch²,

Keber

et al. 2016

Atmos. Meas. Tech.

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“…An indoor sample taken at our institute contained no C 2 F 3 Cl and no CF 2 CFCF 2 Cl but a very small amount of CF 2 CFCF 2 CFCl 2 .The estimated mixing ratios for the six outdoor samples were in the lower and sub-ppt range and can be found in Table 1. The corresponding MS signals were reintegrated compared to Laube and Engel, 2008 by using an improved version of the integration software.…”

Section: Resultsmentioning

confidence: 99%

First atmospheric observations of three chlorofluorocarbons

Laube¹,

Engel²

2008

Preprint

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Abstract. We report the first atmospheric observations of the Chlorofluorocarbons (CFCs) trifluorochloroethene, 3-chloropentafluoropropene and 4,4-dichlorohexafluoro-1-butene by means of Gas Chromatography with Electron Capture and Mass Spectrometric detection (GC-ECD-MS) in air samples taken at the Taunus Observatory operated by the University of Frankfurt (Main) and the Jungfraujoch High Altitude Research Station in Switzerland. These substances belong to a class of CFCs containing a double bond and are suspected to originate from the production and thermal degradation of widely used fluoropolymers like polychlorotrifluoroethene (PCTFE). Their atmospheric lifetimes are expected to be rather short. As a quantitative calibration is not available for these species by now we use a relative sensitivity method to estimate the observed atmospheric abundances. Identification was possible because of an air plume containing high concentrations of these substances. We suggest that the abundances found on this occasion originated from a local source. However, we have also observed the novel CFCs in air masses representative of background conditions, though with much lower concentrations. These species and some of their degradation products are toxic and could also be relevant for stratospheric and tropospheric ozone depletion.

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“…2. The GC QP terised 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.…”

mentioning

confidence: 78%

Application of GC/Time-of-Flight-MS for halocarbon trace gas analysis and comparison with GC/Quadrupole-MS

Hoker¹,

Obersteiner²,

Bönisch³

et al. 2014

Preprint

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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 the 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, 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 third of all analysed substances.

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First atmospheric observations of three chlorofluorocarbons

Cited by 8 publications

References 11 publications

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

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

First atmospheric observations of three chlorofluorocarbons

Application of GC/Time-of-Flight-MS for halocarbon trace gas analysis and comparison with GC/Quadrupole-MS

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