MEMBRANE-SURFACE FOR CARBOHYDRATE ANALYSIS

A poly(methyldiallylamine-chlorohydrin) polymer was used to surface modify microporous PVDF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), and UPE (ultra high molecular weight polyethylene) membranes. These membranes were used to covalently bond hydrophilic charged carbohydrate molecules. The surfaces were characterized in terms of the structural variations of the monomer units. Immobilization occurs by a two-step process whereby strong imagewise electrostatic forces bring nucleophile (charged carbohydrate conjugate) and electrophile (membrane surface desorptive media groups) into close proximity for a pH triggered reaction to covalently bond the carbohydrate. The immobilization potential of the surfaces is described by the chlorohydrin and epoxy groups available for reaction, and is inversely proportional to the amount of alkali employed during membrane surface modification. Conjugation of complex carbohydrate mixtures to a charged fluorophore, followed by electrophoresis, transfer to the membrane surface, and immobilization produced covalently bonded bands, enabling carbohydrate structural analysis in highly desorptive media.