Samples in 2 mL vials are loaded into a GC-PAL autosampler connected to a Picarro Model L1102-i Cavity Ringdown Spectrometer. Each sample is analyzed six times to minimize memory effects. The value of the sixth analysis is reported.
Samples are packed into tin capsules and combusted in an elemental analyzer (NC 2500 Elemental Analyzer, CE instruments). The combustion gases are entrained in a helium flow. The sample is diluted in a Finnigan MAT Conflo II and analyzed in a continuous flow isotope ratioing mass spectrometer (Delta plusXL, Finnigan MAT GmbH, 28197 Bremen, Germany).
Samples are packed into silver capsules and combusted in a TC/EA (High Temperature Conversion Elemental Analyzer, ThermoFinnigan). The combustion gases are entrained in a helium flow. The sample is diluted in a ThermoFinnigan Conflo III and analyzed in a continuous flow isotope ratioing mass spectrometer (Delta plusXP, ThermoFinnigan).
Gas samples are collected in exetainers and analyzed using a gas bench coupled with a continuous flow isotope ratioing mass spectrometer (Delta plusXP, ThermoFinnigan).