The 13C T1 relaxation times determined for dioxane-D2O solutions by the progressive saturation method have been found to range from 5 sec for 1:1 (v/v) dioxane-D2O to 12 sec for neat dioxane. The concentration dependence roughly parallels the inverse of the viscosity and is likely to be associated with changes in correlation times because of hydrogen bonding. A 2:1 (v/v) dioxane-D2O mixture with a T1 of 6.2 ± 0.6 sec at 30°C has been found to be a useful standard for checking instrument performance in the determination of T1 values. A number of experimental problems associated with measuring T1 are discussed.
Bibliographical noteFunding Information:
* Supported by the Public Health Service, Research Grant No. GM-1 1072, from the Division of General Medical Sciences. t Contribution No. 4840. : Harkness Fellow, 1972-1974.