A preliminary investigation of the application of differential scanning calorimetry to the study of collagen degradation in archaeological bone

The study investigated the potential application of differential scanning calorimetry (DSC) to archaeological bone collagen deterioration. The thermal transition of collagen was compared with the preservation state of the bones. Methods of sample preparation were shown to have a significant effect upon the ability to extract reproducible, reliable thermal data from the collagen. Three main protocols were examined, but the optimal method of collagen extraction (10%, w/v ethyldiamine tetraacetic acid demineralisation of bone shards) was slow, reducing the overall utility of DSC for archaeology. Comparison of the Tmax (the maximum temperature of thermal transition) with the diagenetic state of the bone revealed no correlation with histological deterioration or alterations to the bone mineral or organic components. A correlation was observed, however, in young bone samples between Tmax and age. This correlation was improved when thermal age, a parameter that integrates thermal history with the temperature dependence of collagen gelatinisation, was used. In thermally older bones Tmax displayed little variation.