Box 22-3 Isotope Ratio Mass Spectrometry

Natural carbon is composed of 98.9% l2C and 1.1% l3C. The chart shows consistent, small variations in l3C from natural 

SI3C of natural materials provides information about their biological and geographic origins.1314 

Carbon dioxide in human breath Mainland Europe USA 

Variation in, 3C from natural sources. C3. C4. and CAM are types of plants with distinct metabolic pathways leading to different, 3C incorporation. [Adapted from W. Meier-Augenstein. LCGC 1997, IS, 244.] 

If these spectra had been obtained from unknowns, how would we know that the peak 

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