Multinuclear n.m.r. studies of group I cations in furcellaran gels

Multinuclear n.m.r. experiments were carried out in order to study the possible selective interaction between group I cations and furcellaran. It has been shown that the intensity of the 39K, 87Rb and 133Cs spectra show a change in the vicinity of the sol-gel transition. However, the intensity of the 23Na spectrum showed no singularity at the sol-gel transition. These studies suggest that the selective interactions of the group I cations upon gelation of furcellaran resemble those observed for the structurally related kappa-carrageenan.