Dielectric Determination of Bound Water of Bone

Abstract
The dielectric constant [epsilon]'' and dielectric loss [epsilon]" of human cortical bone have been measured for frequencies of 1, 10, 50 and 100 kc and for hydration (h) from 0 to 65 mg-H2O/g bone. The absorption isotherm has also been determined. Curves of [epsilon]'' and [epsilon]" vs h are found to alter sharply at a particular value of the hydration, hc, defining the critical hydration1 of bone. The quantity hc, ranges from a37to 48 mg-H2O/ g-bone, depending on the density of the sample. It is interpreted as the amount of water necessary to occupy the primary absorption sites in bone, i.e., as the bound water of the system. The relationship of hc with previously reported values of the bound water in hide collagen and synthetic hydroxyapatite is discussed.