The Approach for Determination of Concentration and Location of Major Impurities (Mg, Na, K) in Biological Apatite of Mineralized Tissues.

Biological apatite is the main mineral phase of bone tissue and of numerous calcified pathological deposits. Mg, Na, and K are usually absent in the structure of pure apatite and are present in such biominerals in significant concentrations. In present work the approach was tested for the determination of predominant location of these elements through separation of apatite and non-apatitic components of bone tissue mineral. The preparation procedures include the annealing and subsequent ultrasonication of powdered material in aqueous medium; concentrations of elements were determined by atomic spectrum analysis. The results suggest that Mg and Na in bone apatite can be both in the structurally bounded (substituting calcium in lattice) and in the labile state (being localized on the crystal surface), while K is not able to join the apatite structure in significant amount or be chemically bounded to it. [ABSTRACT FROM AUTHOR]