Stable Isotope Facility

University of Wyoming

Combustion (GC-C-IRMS) Pyrolysis (GC-TC-IRMS)

Compound Specific Isotope Analysis

Compound specific isotope analysis (CSIA) analyzes specific compounds for δ¹³C, δ¹⁵N, δ¹⁸O, and δ²H ratios through the use of gas chromatograph separation coupled to either combustion or pyrolysis interfaces.  δ¹⁸O and δ²H ratios of a sample are determined by the analysis of the CO and H₂ generated when the sample flows through the pyrolysis reactor.  For δ¹³C and δ¹⁵N analysis, the CO₂ and N₂ are generated by the combustion of the sample. At SIF, the compound specific analysis technique used to generate CO and H₂ for δ¹⁸O and δ²H ratios is as follows: after a sample mixture is injected into a gas chromatograph, the mixture is separated through the gas chromatograph column, the individual compounds pass through a pyrolysis reactor before being sent to the IRMS for analysis.  For compound specific analysis of samples for δ¹³C or δ¹⁵N, the same steps apply except the samples are combusted after gas chromatograph separation (GC-C-IRMS).

Typical sample size:    varies

The GC-C-IRMS used for compound specific analysis is available to qualified University of Wyoming researchers.  UWSIF DOES NOT perform these analyses.