Fourier transform infrared study on sol-gel derived manganese-doped hydroxyapatite

Manganese is one of metallic elements which appear in biological apatite like bone and teeth. Its important effect on the growth and development of bone has been well known. Here, we have synthesized manganese-doped hydroxyapatite (HA) via sol-gel method. White ammoniacal solution of monomers were refluxed until white gel formed, followed by drying and calcination at 500-900 degrees C. Four different concentration of manganese (2, 5, 10 and 15 mol%) were successfully incorporated into HA crystals. XRD analysis showed that the crystallinity increased with the increased amount of manganese. SEM measurement also showed that individual particles become bigger with the increasing content of Mn. Tricalcium phosphate appeared as an additional phase when calcined at 800 degrees C. It was also proven that the incorporation of manganese reduced the peak intensity of tricalcium phosphate. FTIR analysis is in good agreement with the results from XRD measurement where the peaks of OH (630 cm(-1)) and PO(4)(3-) (565 cm(-1), 601 cm(-1), 960 cm(-1), 1020 cm(-1) and 1100 cm(-1)) bands of HA phase show higher intensity with the increasing concentration of manganese. FTIR measurement also showed that the presence of HPO(4)(2-) (880cm(-1)) decreased in intensity with the increased Mn content, showing that the anion exist in less crystalline phase of HA.