Concentration dependence of F-19 nuclear magnetic resonance decay shapes and second moments in bone mineral

F-19 nuclear magnetic resonance (NMR) spin-echoes and free induction decays (FIDs) have been observed from samples of fluoridated trabecular canine bo ne powder, with fluoride concentrations ([F]) ranging from approximately 10 to 33 mg F/g Ca. Curve fitting of echo envelopes and FIDs was performed us ing a two-component model function, where one of the components incorporate s the effects of one-dimensional dipolar coupling. This function provides a good match for both echo envelopes and FIDs. Estimates of the total second moment and its homonuclear (F-F coupling) component were obtained from the fitting procedure. Based on the second moment measurements, it is argued t hat F-19 spins in bone mineral typically experience weaker heteronuclear di polar coupling than those in the mineral hydroxyapatite (HAP), which is oft en considered to be a prototype for bone mineral. (C) 1999 Elsevier Science B.V. All rights reserved.