Preliminary characterization of calcium chemical environment in apatitic and non-apatitic calcium phosphates of biological interest by X-ray absorption spectroscopy

Diane Eichert (1) , Murielle Salomé (1) , Mihai Banu (2) , Jean Susini (1) , Christian Rey (2)

1 ESRF - European Synchrotron Radiation Facility
2 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux

Several reports have mentioned the existence of non-apatitic environments of phosphate and carbonate ions in synthetic and biological poorly crystalline apatites. However there were no direct spectroscopic evidences for the existence of non-apatitic environment of calcium ions. Xray Absorption Spectroscopy, at the K-edge of calcium, allows the discrimination between different calcium phosphates of biological interest despite great spectral similarities. A primary analysis of the spectra reveals the existence, in synthetic poorly crystalline apatites, of variable features related to the maturation stage of the sample and corresponding to the existence of nonapatitic environments of calcium ions. Although these features can also be found in several other calcium phosphate salts, and do not allow a clear identification of the ionic environments of calcium ions, they give a possibility to directly determine the maturity of poorly crystalline apatite from calcium X-ray Absorption Near Edge Structure spectra.

Mots clés: Calcium phosphate; XAS; Microspectroscopy; Maturation; Synchrotron

Domaines: Matériaux

Diane Eichert, Murielle Salomé, Mihai Banu, Jean Susini, Christian Rey. Preliminary characterization of calcium chemical environment in apatitic and non-apatitic calcium phosphates of biological interest by X-ray absorption spectroscopy. Spectrochimica Acta Part B: Atomic Spectroscopy, 2005, 60 (6), pp.850-858. ⟨10.1016/j.sab.2005.05.012⟩. ⟨hal-03601376⟩