Characterization of calcium phosphates mixtures

Methodologies based on vibrational spectroscopies (FT-Raman and FT-Infrared) and powder X-ray diffraction (PXRD) were developed for the characterization of mixtures consisting of four calcium phosphate phases that might be found in mineralized tissues or implant materials: hydroxyapatite (HAP), octacalcium phosphate (OCP), dicalcium phosphate dihydrate (DCPD) and dicalcium phosphate anhydrous (DCPA). No single technique was sufficient for the analysis of the quaternary mixture. Characterization of such solids was possible by: (a) combination of Infrared (IR) and Raman spectroscopic analysis, (b) combination of IR and PXRD data, and (c) combination of PXRD patterns recorded before and after heating the mixture of calcium phosphates at 850 °C. Proposed methods were evaluated by establishing the respective detection limits. It was found that the method using the data from the PXRD patterns recorded before and after the heating of the solid mixture has yielded the lower detection limits.