title: Comparison of infrared and mass-spectrometric measurements of carbon-13/carbon-12 ratios.
mesh_terms: D002244:Carbon / Q000032:analysis*; D002247:Carbon Isotopes; D007202:Indicators and Reagents; D013058:Mass Spectrometry / Q000379:methods; D013055:Spectrophotometry, Infrared / Q000379:methods
chemical_list: D002247:Carbon Isotopes; D007202:Indicators and Reagents; D002244:Carbon