Polymer-bound flavins: 2. Immobilization of linear flavin-containing polyelectrolytes by adsorption onto silica

Abstract

The adsorption of quaternary ammonium derivatives of linear polystyrene, containing pendant flavin groups, from aqueous solution onto nonporous silica particles was studied. It is shown that interaction takes place between the quaternary ammonium groups in the polymer and ionized silanol groups on the silica surface. Since the maximum specific adsorption was not influenced by the content of quaternary ammonium groups, relatively few quaternary ammonium groups appear to be necessary to bind the copolymers to the silica surface, probably resulting in a large fraction of segments located in loops and tails. The reactivity of the bound flavin, as estimated from kinetics of aerobic oxidation of 1-benzyl-1,4-dihydronicotinamide (BNAH) in aqueous solution, is not influenced by the adsorption process. The immobilized reactive polymer can easily be re-used several times without loss of activity, indicating that desorption of the polymer can be neglected.