FT-Raman Spectroscopy: A Tool for Monitoring the Demineralization of Bones

A nondestructive analytical method based on the use of Fourier transform Raman spectroscopy (FT-RS) for identification and quantitative analysis of hydroxyapatite (HAP) and collagen (COL) in bones was developed. A calibration curve based on the Raman spectra of known powder mixtures of HAP–COL was constructed with the use of the Raman bands at 960 cm−1 for HAP and 2937 cm−1 for COL. It was found that I960/I2937 = 0.46/WC — 0.36, where I960 and I2937 are the relative intensities for the 960 and 2937 cm−1 Raman bands, respectively, and Wc represents the weight fraction of collagen. The detection limit for HAP and COL was found to be 2.8 and 0.6 wt %, respectively. The potential of using RS for an in vitro point-by-point analysis (“mapping”) of bones was demonstrated successfully on an artificially demineralized ox femur sample.