| Abstract: | In order to explore the possibility that intramolecular differences in the δ13C value of bone collagen can provide useful infomation for isotopic dietary analysis, a method for reliably measuring the δ13C value of the peptide-bonded carboxyl carbons in collagen was developed and applied to a wide range of modem and ancient species, including humans. Carboxyl carbons were selectively removed as CO2 by decarboxylation of collagen hydrolysates with ninhydrin (2,2-dihydroxy-l,3-indanedione). Carboxyl carbons were usually isotopically heavier than the total carbon in the collagen, with differences ranging from -0.9 to 4.0%c. Animals at higher trophic levels and with more positive δ15N values usually had smaller differences than the lower animals while humans had the largest range, reflecting their larger range of diets. |
