Uni-Bayreuth grafik-uni-bayreuth



PreCon-GC-C-IRMS coupling


Pre-concentration: PreCon (Finnigan MAT, Bremen, Germany)

Gas chromatograph: 5890 Series II (Hewlett-Packard, Wilmington, USA)

Interface: Combustion Interface II (Finnigan MAT, Bremen, Germany)

Isotope ratio mass spectrometer: delta V plus (Thermo Fisher Scientific, Bremen, Germany), or facultatively delta S




This instrument coupling is being used for the substance specific determination of N, O and C isotope abundances (δ15N, δ18O, δ13C) of atmospheric trace gases (specifically N2O and CH4) in the natural abundance range. Air samples collected in glass vessels (100 ml volume) are transferred in a helium stream through a chemical trap for water vapour and CO2. Subsequently the trace gases are concentrated in freezing traps. Methane is combusted to CO2 in an oxidation oven. Before gas chromatographic separation the trace gases are cryo-focussed in another freezing trap. In an interface N2O or CO2 standard gas with known isotope abundance is introduced into the gas stream. The relative abundances of the isotopes 13C and 12C (CO2) or 15N and 14N and simultaneously 18O and 16O (N2O) are subsequently being analysed by isotope ratio mass spectrometry.

last modified 2018-12-20