Ice Shell Purification of Ice-Active Compounds

Ice fractionation allows for the selective purification of ice-active compounds from aqueous solutions. A variety of approaches have been developed to allow the interaction of ice with solutions of interest. We describe here a version where a thin layer of ice is formed on the inside of a suitable flask, which is then exposed to solutions containing ice-binding molecules under conditions where the ice shell is allowed to grow slowly. Under these conditions, ice-binding compounds are incorporated into the newly formed ice, and other solutes are accumulated in the remaining liquid fraction.