Capability Title	Isotope ratio mass spectrometry (IRMS)
Laboratory	Pacific Northwest National Laboratory (PNNL)
Capability expert	Jim Moran (PNNL)
Description	IRMS offers precise quantification of the stable isotope content of solid, liquid, and gas samples. Isotopes of hydrogen (δ2H), carbon (δ13C), nitrogen (δ15N), and oxygen (δ18O) are routinely analyzed and can contribute to provenance efforts, fingerprinting fuels, or quantifying species in a mixture. Bulk isotope analysis is performed on liquid and gaseous samples by utilizing an elemental analyzer or thermal conversion elemental analyzer peripheral device coupled to IRMS. Compound specific isotope analysis is provided by coupling the IRMS to a gas chromatograph (δ2H, δ13C, δ15N, δ18O) or high-performance liquid chromatograph (δ13C). Purified, simple gases (e.g., CO2, CO, CH4) can be analyzed using a dual inlet interface to the IRMS
Limitations	The IRMS instrument provides excellent stable isotope measurement precision but no analyte structural identifications which, if needed, would be collected via parallel measurement on a different system.
Unique aspects	Provides high precision of intrinsic (stable isotope) signatures within an analyte.
Availability	Access to the IRMS is based on the availability of staff and instrument resources.
Citations/references	Harvey, S.D., Jarman, K.H., Moran, J.J., Sorensen, C.M., and Wright, B.W. (2012) Characterization of diesel fuel by chemical separation combined with capillary gas chromatography (GC) isotope ratio mass spectrometry (IRMS). Talanta, 99, 262-269.