A novel and non-destructive approach for ZooMS analysis: ammonium bicarbonate buffer extraction

Bone collagen is found throughout most of the archaeological record. Under experimental conditions, collagen is apparently preserved as an intact molecule, with amino acid compositions and isotopic profiles only changing when almost all of the protein is lost. The ubiquity of collagen in archaeological bone has lead to the development of the use of collagen peptide mass fingerprints for the identification of bone fragments—Zooarchaeology by Mass Spectrometry (ZooMS). We report a novel, but a simple method for the partial extraction of collagen for ZooMS that uses ammonium bicarbonate buffer but avoids demineralisation. We compared conventional acid demineralisation with ammonium bicarbonate buffer extraction to test ZooMS in a range of modern and archaeological bone samples. The sensitivity of the current generation of mass spectrometers is high enough for the non-destructive buffer method to extract sufficient collagen for ZooMS. We envisage that a particular advantage of this method is that it leaves worked bone artefacts effectively undamaged post-treatment, suitable for subsequent analysis or museum storage or display. Furthermore, it may have potential as a screening tool to aid curators in the selection of material for more advanced molecular analysis—such as DNA sequencing.