Importance of FTIR Spectra Deconvolution for the Analysis of Amorphous Calcium Phosphates

Abstract

This work will consider Fourier transform infrared spectroscopy – diffuse reflectance infrared reflection (FTIR-DRIFT) for collecting the spectra and deconvolution to identify changes in bonding as a means of more powerful detection. Spectra were recorded from
\namorphous calcium phosphate synthesized by wet precipitation, and from bone. FTIR-DRIFT was used to study the chemical environments of PO4, CO3 and amide. Deconvolution of spectra separated overlapping bands in the ʋ4PO4, ʋ2CO3, ʋ3CO3 and amide region allowing a
\nmore detailed analysis of changes at the atomic level. Amorphous calcium phosphate dried at 80 oC, despite showing an X-ray diffraction amorphous structure, displayed carbonate in positions resembling a carbonated hydroxyapatite. Additional peaks were designated as A1
\ntype, A2 type or B type. Deconvolution allowed the separation of CO3 positions in bone from amide peaks. FTIR-DRIFT spectrometry in combination with deconvolution offers an advanced tool for qualitative and quantitative determination of CO3, PO4 and HPO4 and shows promise to measure the degree of order.