super(1)H MAS and super(1)H arrow right super(31)P CP/MAS NMR Study of Human Bone Mineral

• Published in: Calcified tissue international 2003-10, Vol.73 (5), p.476-486
• Main Authors: Kaflak Hachulska, A, Samoson, A, Kolodziejski, W
• Format: Article
• Language: English
• ISSN: 0171-967X
• DOI: 10.1007/s00223-002-2111-5

Chemical structure of human bone mineral was studied by solid-state nuclear magnetic resonance (NMR) with magic-angle spinning (MAS). Trabecular and cortical bone samples from adult subjects were compared with mineral standards: hydroxyapatite (HA), hydrated and calcined, carbonatoapatite of type B with 9 wt% of CO32- (CHA-B), brushite (BRU) and mixtures of HA with BRU. Proton spectra were acquired with excellent spectral resolution provided by ultra-high speed MAS at 40 kHz. 2D super(1)H- super(31)P NMR heteronuclear correlation was achieved by cross-polarization (CP) under fast MAS at 12 kHz. super(31)P NMR was applied with CP from protons under slow MAS at 1 kHz. Appearance of super(31)P rotational sidebands together with their CP kinetics were analyzed. It was suggested that the sidebands of CP spectra are particularly suitable for monitoring the state of apatite crystal surfaces. The bone samples appeared to be deficient in structural hydroxyl groups analogous to those in HA. We found no direct evidence that the HPO42- brushite-like ions are present in bone mineral. The latter problem is extensively discussed in the literature. The study proves there is a similarity between CHA-B and bone mineral expressed by their similar NMR behavior.