The effect of 1H NMR spectroscopic characteristics of OH- on F- ions in the apatite structure was investigated. The samples include hydrothermal synthesized hydroxyapatite (HAP, sample code F0) and fluoridated hydroxyapatite (F-HAP) with F/F+OH mole ratio from 5% to 95%. The following figures are found: (1) There is difference in the 1H NMR chemical shift for hydroxyl in apatite structure (δ = -0.04 x 10-6 – 1.61 x 10-6) and absorbed water (δ = - 0.04 x 10-6 – 1.61 x 10-6). (2) The chemical shift of 1H due to H-O bond (δA) shifts to lower field region as F content increase in apatite. (3) As F enter the structure, a new NMR resonance occurs near 0.90 x 10-6 – 1.61 x 10-6, whose intensity increases with F, This phenomena indicates that a F-H bond is formed in apatite structural channel. As the position and intensity of these NMR peaks correlated positively with the F content, it is possible to use the chemical shift of 1H and the relative intensity of the spectral peaks to distinguish the crystalline HAP and non-crystalline phosphate, and to estimate the F and/or OH content in binary fluor-hydrohyapatite.
Study on 1H NMR Spectroscopy of Fluor-hydroxylapatite
STOPPA, Francesco;TONUCCI, Lucia;
2002-01-01
Abstract
The effect of 1H NMR spectroscopic characteristics of OH- on F- ions in the apatite structure was investigated. The samples include hydrothermal synthesized hydroxyapatite (HAP, sample code F0) and fluoridated hydroxyapatite (F-HAP) with F/F+OH mole ratio from 5% to 95%. The following figures are found: (1) There is difference in the 1H NMR chemical shift for hydroxyl in apatite structure (δ = -0.04 x 10-6 – 1.61 x 10-6) and absorbed water (δ = - 0.04 x 10-6 – 1.61 x 10-6). (2) The chemical shift of 1H due to H-O bond (δA) shifts to lower field region as F content increase in apatite. (3) As F enter the structure, a new NMR resonance occurs near 0.90 x 10-6 – 1.61 x 10-6, whose intensity increases with F, This phenomena indicates that a F-H bond is formed in apatite structural channel. As the position and intensity of these NMR peaks correlated positively with the F content, it is possible to use the chemical shift of 1H and the relative intensity of the spectral peaks to distinguish the crystalline HAP and non-crystalline phosphate, and to estimate the F and/or OH content in binary fluor-hydrohyapatite.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
