Carbonate location in bone tissue mineral by X-ray diffraction and temperature-programmed desorption mass spectrometry

The thermal behavior of bone mineral samples was investigated in the range from 600 to 900oC by X-ray diffraction with line broadening analysis and temperature-programmed desorption mass spectrometry. At least two stages of CO32- release during the thermal evolution were observed, each can be attributed to a different type of carbonate location in the bone mineral. The elimination of CO32- occurring without pronounced variations in the substructural parameters of the biomineral nanocrystals is ascribed to the surface carbonate, while the elimination of CO32- accompanied by the growth of crystals and disappearance of structural distortions is attributed to the lattice carbonate. The sample of affected immature bone with low bioapatite crystallinity was found to have the surface carbonate content greater than the amount of carbonate in the lattice, while for the mature healthy bone the situation is reverse. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)