Deuterium–Hydrogen Exchange between Water and Macromolecules: Accessibility of Cellulose

Abstract

ALTHOUGH many workers have observed the exchange reaction of heavy water with macromolecules indirectly by the change in composition of the water^1,2, and by infra-red measurements^3–5, only one group has reported the measurement of the exchange directly by the change in weight of the macromolecules. Burley, Nicholls and Speakman⁶ measured the increase in weight when wool keratin reacted with the vapour of heavy water. They used a quartz spring balance with a small sample (about 0.1 gm.). In the present work, in which the gravimetric method was also employed, a much larger sample (about 6 gm.) was used. The sample was placed in a glass cell similar to one used in the measurement of adsorption isotherms of water on fibrous macromolecules⁷.