Chemical, elemental, and isotopic effects of acid concentration and treatment duration on ancient bone collagen: an exploratory study

Demineralization of bone for collagen extraction is most commonly performed using dilute hydrochloric acid (HCl) despite the fact that little data exists on the effects of differing acid concentration or treatment time on the quantity and quality of collagen extracts and that hydrochloric acid is extremely effective at hydrolyzing peptide bonds. Data on yield, elemental composition, and isotopic signature from bone collagen obtained from multiple extractions performed on two large ancient human bone samples from prehistoric Puerto Rico indicate that there is no meaningful difference between acid treatments ranging from 0.05 to 0.2 M concentration and 24–120 h of treatment. As such, a shorter course of demineralization using more concentrated acid would appear to produce quality results in a shorter time.