High resolution 31P NMR study of octacalcium phosphate

We have assigned the P-31 high-resolution spectrum of octacalcium phosphate by P-31 double quantum and HETCOR spectroscopy. The P-31 peaks at -0.2, 2.0, 3.3 and 3.7 ppm are assigned to P5/P6, P3, P2/P4 and P I, respectively. Our data reveal that substantial amount of the PO43- groups at the P2 and P4 sites have been transformed to HPO42- in our octacalcium phosphate sample. (C) 2004 Elsevier Inc. All rights reserved.