SEARCH Articles Figures Tables Chromatography isotope ratio mass spectrometry Gas chromatography isotope ratio mass Gas chromatography, isotope Gas chromatography-isotope ratio Gas chromatography-isotope ratio mass spectrometry GC-IRMS) Gas chromatography/mass spectrometry Gas mass spectrometry Isotope ratio mass spectrometry Isotope ratios Isotope spectrometry Isotopes masses Isotopic mass spectrometry Isotopic masses MASS RATIO Mass spectrometry isotopes