The effects of salts on the nmr spectra of D2O in collagen fibers

The effects of two salts, MgCl2 and MgSO4 on the wide‐line nmr spectrum of D2O in oriented, undernatured collagen fibers have been examined at four different D2O contents. MgCl2 was found to decrease the nmr doublet splitting, as compared with equal quantities of pure D2O while the major effect of MgSO4 was to inhibit the adsorption of D2O without significantly affecting its nmr spectrum. The results, together with a few observations of KCl and LiCl solutions, indicate that even fairly high concentrations of salt have only small effects on the nmr spectrum of D2O in fibrous collagen. It is considered unlikely that either “two‐state” or “structured‐water” models can satisfactorily account for the D2O‐nmr doublet spectrum or the effects of salts on it, over the entire range of observed D2O content.