Instrumentation

Isotopic analysis of H and O in water samples:

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. 

Isotopic analysis of C and N in soils, plants and animal tissues:

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). 

Isotopic analysis of H and O in solid materials:

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).

Isotopic analysis of C in gas samples:

Gas samples are collected in exetainers and analyzed using a gas bench coupled with a continuous flow isotope ratioing mass spectrometer (Delta plusXP, ThermoFinnigan).