ALIGNED FIBER COLUMNS FOR SIZE-EXCLUSION CHROMATOGRAPHY

Chromatographic columns are being developed that contain, instead of porous particles as in classical packed columns, bundles of aligned porous silica fibers of claimed diameter 18 μm and average pore size 270 Å. From these properties, the material is comparable to conventional silica particles as a stationary phase for high-performance liquid chromatography. However, as fibers can be packed much more densely than spherical particles, the interstitial volume of the packing is significantly lower, while the pore volume can be higher. This combination of geometrical properties is important for size-exclusion chromatography. The performance of a prototype Aligned Fiber Column was tested by measuring the elution times and band broadening of polystyrene molecular weight standards with methylene chloride as the eluent. The results were compared to those found for columns packed with 10- or 3-μm silica particles. In view of possible applications for the separation of biopolymers, the surface of the column was modified by grafting alkyl diol groups in an in situ silanization process. The results obtained with several different proteins show a very low residual activity of the surface (only strongly basic proteins are retained), a slight decrease in the pore volume and pore diameters, with little change in the posority ratio. As this was the first attempt at in situ diol bonding of any silica material, some polymerization of the silane occurred, seriously decreasing the efficiency of the column. © 1990.