DEXTRAN-COATED SILICA AND ITS BEHAVIOR IN HIGH-PERFORMANCE SIZE-EXCLUSION CHROMATOGRAPHY

Aminopropyltriethoxysilane-treated silica was coated with p-nitropheny l chloroformate-activated dextran. The remaining active carbonates on the dextran layer were hydrolysed in aqueous environment. Hence, the s ilica surface is covered with a hydrophilic dextran layer free of resi dual active groups. The performance of this covalent dextran-coated si lica was evaluated for its use in size-exclusion chromatography of bio polymers, From the obtained data, one can conclude that the dextrans f orm a good neutralizing barrier between acidic silanols and proteins. The protein adsorption was dependent on the ionic strengh of the eluen t and the thickness of the dextran layer, which was controlled by the molecular mass of the applied dextran.