RADIOCARBON DATING OF PEPTIDES ISOLATED FROM CONTAMINATED FOSSIL BONE-COLLAGEN BY COLLAGENASE DIGESTION AND REVERSED-PHASE CHROMATOGRAPHY

The peptide mixture, resulting from collagenase (enzymatic) cleavage of fossil bone collagen, is separated into a fraction containing the very bone-specific tripeptides glycine-proline-hydroxyproline (GlyProHyp) and glycine-proline-alanine (GlyProAla), and more hydrophobic fractions, using reversed-phase chromatography. The suitability of these fractions for C-14 bone dating and stable isotope analysis is discussed, firstly by assessing the theoretical benefits of their use as compared to other bone-specific extracts, and secondly by examining C-14 ages of the fractions in a selection of bones that had previously been giving dubious results using the Oxford routine bone pretreatment. In most cases, the age obtained on the tripeptides GlyProHyp and GlyProAla was in better agreement with the expected age than the original C-14 measurement. In some cases the ages of the fractions were similar, indicating more of an archaeological than a radiocarbon dating problem. We conclude that the use of GlyProHyp/GlyProAla is the best solution to date for C-14 dating of contaminated bone samples.