determination of δ13c, δ15n, or δ34s by isotope ratio monitoring mass spectrometry using an elemental analyzer /

This report describes procedures used in the Geology,Geophysics, and Geochemistry Science middle of the U.
S. Geological Survey in Denver, and Colorado,to determine the stable-isotope ratios 13C/12C, 15N/14N, and 34S/32S in solid materials. The procedures utilize elemental analyzers connected directly to gas-source isotope-ratio mass spectrometers. A different elemental–analyzer–mass-spectrometer system is used for 13C/12C and 15N/14N than is used for 34S/32S to accommodate differences in reagents,catalysts, and instrument settings.

Source: usgs.gov